Geological Report envisaged by the Project on “Development of climate resilient flood and flash flood and geological disaster management practices for river basin”.

prohibitio1 garemos erovnuli saagento

Content

1. Topicality of the problem (E.M. Tsereteli, M. Gaprindashvili) 3

2. Overview of state of affairs in from the standpoint of geological disasters (E.M. Tsereteli, M. Gaprindashvili) 5

3. Key factors causing development of natural disasters and assessment methodology (E.M. Tsereteli, M. Gaprindashvili) 18

3.1 Impact of geological composition and properties of stratum on development-reactivation of geological processes (E.M. Tsereteli, M. Gaprindashvili) 20

3.2 The role of geomorphological factors in development of exogenic and geological processes and preparation of forecasts (E.M. Tsereteli, M. Gaprindashvili) 28

3.3 The role of climatic-meteorological factors in development of landslide-gravitational and mudslide processes (E.M. Tsereteli, M. Gaprindashvili) 32

4. Principles of development of mudslide and landslide risk assessment map for Rioni river basin (E.M. Tsereteli, M. Gaprindashvili) 44

5. Mudslide and landslide prevention measures (I. Chkeidze) 49

6. The risk of development of landslides and mudslides by municipalities 55

6.1 (O. Abutidze, O. Kurtsikidze) 55

6.2 Municipality (O. Abutidze, O. Kurtsikidze) 84

6.3 Forecasts on development of disastrous geological processes on the territories of Oni and Ambrolauri Municipalities (O. Abutidze, O. Kurtsikidze) 121

6.4 Municipality (Z. Dolidze, Z. Maisuradze) 122

6.5 Municipality (Z. Dolidze, Z. Maisuradze) 147

6.6Forecasts on development of disastrous geological processes on the territories of Lentekhi and Tsageri Municipalities (Z. Dolidze, Z. Maisuradze) 171

prohibitio2 garemos erovnuli saagento

6.7 Tskaltubo Municipality (O. Gogrichiani, G. Kunchulia) 173

6.8 Municipality(O. Gogrichiani, G. Kunchulia) 186

6.9 Forecasts on development of disastrous geological processes on the territories of Tskaltubo and Samtredia Municipalities (O. Gogrichiani, G. Kunchulia) 200

7. Bibliography 201

Geological Report envisaged by the Project on “Development of climate resilient flood and flash flood and geological disaster management practices for Rioni river basin”.

1. Topicality of the problem

In last decades of 20th century protection of population from natural disasters, maintenance of lands and in general sustainable eco system, as well as safe operation of engineering sites became the most important social economic, demographic, ecologic and political problem of the most of countries in the world. In World Bank report on natural disasters of 2005, it is stated that more than half of the population of planet lives in high risk areas. Economic losses caused by natural disasters have reached almost tens billion dollars. Just in 1999-2003 economic losses caused by disasters compiled 212692 billion USD. According to the report prepared by the Centre for Research on the Epidemiology of Disasters in 2007, the losses caused by disasters compiled 34 billion USD just in 2006. Natural disaster processes develop in two absolutely different manner and have different consequences: these are dangerous meteorological events formed in the atmosphere and natural geological processes developed on earth‟s surface and in its crust. However, often despite the conditions causing formation of these two diametrically different occurrences, connection between them is synergetic and determines the level of development and re-activation of particular event. Natural disasters became even more topical in the beginning of 20th century; when the scale of disasters increased enormously on the background of human pressure on the environment and global climate changes, as a result of which the risks, related to such disasters become unmanageable. Due to the above mentioned the decisions reached onJohannesburg (South Africa) Summit, held under the auspices of the United Nations in 2002 and international conference of Hyogo (Japan) of 2005 dedicated to disaster risk reduction and mitigation of results were accepted as guiding principles by many countries. Consequently, national programmes for risk management were elaborated in many developed countries. The year 2002 was announced as the international year of mountains, many countries elaborated national programmes for development of mountains

prohibitio3 garemos erovnuli saagento and disaster risk prevention, and certain European countries became parties to the “Alpine Convention”.

Due to the fact that South Caucasus region, and most especially Georgia, belongs to the most complex regions of the world highland areas by the scale of development, recurrence, frequency and negative impact of geological disasters on the population, engineering and industrial sites, the government of Georgia initiated regulation of these events in 1995 (decree # 36) and established national committee for mitigation of disaster risks. Earlier (1993) special decree was adopted (#967) on Development of unified system for environmental monitoring in Georgia. The Ministry of Environment and Natural resources was assigned with the authority of coordination of the abovementioned system. In 1997 was issued a special order (# 66) of the President of Georgia on Development of disastrous geological processes in Georgia and measures for protecting lands and underground hydrospherefrom thenegative impact of disastrousprocesses. In 1999 the government of Georgia adopted the law on “Socio-economic and cultural development of high-mountainous regions of Georgia” and the laws on “Environmental Protection” and “Soil Protection”, which among other issues dwelt on negative impact of natural disasters. In 2007 the President of Georgia issued special order (#542) on “Protection of population and territory form natural and technogenic threats in Georgia”. Laterthe Security Council revised the law and elaborated new version of natural and technogenic disaster risks. In 2012 natural disasters management problems were included among priorities of the second action programme (NEAP-2) of the Ministry of Environment and Natural resources. Thus, normative base adopted in Georgia in the sphere of disaster management, which is based on the UN framework programmes on disaster management and mitigation, in general responds to the problems in given sphere and requirements of the legislative framework are implemented within the scope of financial and technical resources of the country.

2. Overview of State of Affairs in Georgia from the Standpoint of Geological Disasters

In Georgia landslide and mudslide processes and water erosion are at the top of problems due to related exogeological disaster risks and negative impact. By the scale of development of these events and their negative impact onthe population and economy of the country, Georgia occupies leading position among high land countries of the world. Besides, almost whole territory of the country is under the risk of earthquakes, the magnitude of which is 7-9. Impact of such earthquakes is directly stimulating and provoking gravitational landslideand mudslide processes.

Earthquakes occurred in Rioni river basins of the magnitude over 4.0 Table 1 # Year Geographical location (settlements)

prohibitio4 garemos erovnuli saagento X Coordinate Y Coordinate magnitude

Oni municipality, 700 meters away to the 1 453 376750 4706383 4.7 south from village Bajikhevi , upper reach of 2 1350 344380 4729251 7 river Ritseuli Oni municipality, 700 meters away to the 3 1902 368742 4717638 4.5 north-east of village Chalebi , territory 4 1915 285004 4664151 4.3 adjoining to village Dabla Gomi , territory adjoining 5 1923 311315 4718961 4 to village Tsiperchi 6 1931 Oni municipality, village Usholta 368533 4706533 4.1 Tsageri municipality, 500 meters to the 7 1953 319519 4718743 4 north of village Ustkheri Ambrolauri municipality, 5,5 km to the 8 1953 360762 4728902 4,7 north of village 9 1971 Oni municipality, village Tskhmori 374933 4710525 4 Oni municipality, 600 meters to the west 10 1971 373075 4712225 4 from village Zhashkva Oni municipality, 1,2 km to the south- 11 1972 368575 4708754 4 east of village Bokva Oni municipality, 900 meters to north- 12 1987 365742 4711030 4.2 west of village Zvareti Oni municipality, 800 meters to south- 13 1991 369253 4705520 4 west of village Shkmeri Oni municipality, river Jejora gorge, 4,8 14 1991 399148 4703691 4.1 km to south-east of village Shuachala Oni municipality, 5,0 km to south-east of 15 1991 375129 4703080 4.1 village Kharistvali Oni municipality, upper reach of river 16 1991 403432 4710294 4 Jejora Oni municipality, 2,0 km south-east of 17 1991 371187 4703374 4 village Kharistvali Oni municipality, 7,5 km south-east of 18 1991 village Mtsikalta (near mountain 367205 4701560 4 Khikhata) Oni municipality, 1,0 km to south-west 19 1991 391494 4708470 5.5 of village Nadarbazevi 20 1991 Oni municipality, village Gadamshi 363698 4719846 4.5 Oni municipality, 2,5 km south-west of 21 1991 378333 4702912 6 village Lesora (near Phkoni mountain) Oni municipality, 750 meters to south of 22 1991 356513 4709659 5.3 village Samtisi Oni municipality, 500 meters to south of 23 1994 381029 4716306 4.3 village Kcazhe Tskaltubo municipality, 2,0 km to south 24 2004 304573 4665471 4 of village Tkachiri prohibitio5 garemos erovnuli saagento Oni municipality, 1,5 km to south-east of 25 2006 373118 4714557 4.1 town of Oni Oni municipality, 900 meters to north of 26 2006 380495 4709095 5.2 village Iri Oni municipality, 500 meters to west of 27 2009 374247 4713426 6 village Pipileti Oni municipality, 1,3 to north of village 28 2009 379700 4705887 4.2 Lesora Oni municipality, 2,3 km to east of village 29 2009 373033 4709893 4 Tskhmori 30 2009 Oni municipality, village Lachta 372006 4716577 4.1 Oni municipality, 1,7 km to south-east of 31 2009 382141 4709289 4.6 village Tsedisi Oni municipality, 1,3 km to north of 32 2009 368558 4707866 4.6 village Usholta Oni municipality, 1,4 km to south-west 33 2009 379186 4709451 4.5 of village Tsedisi Oni municipality, territory adjacent to 34 2009 372034 4713688 4.5 village Samitso

In Georgia major part of population, agricultural lands, roads, oil and gas pipelines, hydrotechnical – amelioration facilities, power transmission lines and mountain tourism zones periodically are subjected to disastrousprocesses and the areas under the risk are expanding substantially. This is confirmed by the inventory of areas, damaged by disastrous geological processes or located within the risk zone, developed by the Ministry of Environment and Natural Resources (diagram 1).

Territories of Georgia, damaged by disastrous geological processes in different years, including territories within the risk zone

Chart 1

prohibitio6 garemos erovnuli saagento ml n. ha/ mln.ha 5

4.5

4

3.5

3

2.5

2

1.5

1

0.5

0 1970 1977 1981 1987-88 1991-92 1997 2005

wel i /Year

As of today in Georgia have been identified: about 53 thousand landslide gravitational bodies and areas with high probability of their formation; about 3000 mudslide transforming waterways; about 5000 locations of formation of avalanches; washout ofriver-banks and sea shores occurs on more than 1500 locations, with total length of more than 2000 kilometres (diagram 1).

Mudslides – Water born 29% erosion and floods – 25%

Mudslide- gravitational occurrences 21.52%

Around 70% of the territory of the country, about 3000 settlements (62%) and 400000 households are under the risk of geological disasters; 14,2% of agricultural lands were seriously

prohibitio7 garemos erovnuli saagento damaged by geological processes and require conducting of cardinal protective measures; and 13,1% of agricultural lands are located within the high risk area. Geological disasters occur on all landscape-geographical zones –starting from the seaside and ending with highlands and they have impacted all spheres of economy. Geo-ecological disasters conditioned by natural processes are most frequent in the mountain zone, which is occupying 70% of the territory of the country. Potential negative impact of these geological disasters on geopolitical and economic development of the country is enormous. 2/3 of landslides that occurred in the country have taken place in the mountain zones; such disastrous processes mudflows, avalanches, rockslides and glacial flows are typical for mountain zones. Consequently more than 80% of economic damage was caused to mountainous regions and majority of ecomigrants are from highland areas. This causes vacation of villages.

The incomplete picture of damage caused by geological disasters to economy of Georgia and human casualties is as following: In conditions of activation of disasters, damage caused to the economy of the county is around 100 million dollars. In case of extreme activation of disasters the damage exceeds billion. During 1967 – 2009 more than 300 settlements were under the risk of disaster (63%). - 60000 households were resettled to different locations with the status of eco migrants; - Human casualties caused by disaster exceeded 1000, including 600 after 1987; - More than 400000 residential houses and engineering facilities were damaged and under risk; - 1.5 million haters of agricultural land was damaged and was written off from the useful land fund; - About 560 kilometres of roads were damaged and require rehabilitation; - During 1967 – 68 in the West Georgia 30000 hectares of agricultural lands were damaged and written off from the useful land fund; 20000 residential houses were damaged and destroyed; 5000 households were resettled to other locations. The damage reached 500 million dollars; - In 1979 – 1975 the damage caused by disaster reached 650 million USD; - In 1987 – 1988 the disaster which covered the whole Georgia caused damage, exceeding 1 billion USD; - In 1991 – 92 the damage caused by earthquakes, landslides and mudslides reached compiled 10 billion USD; - In 2004 – 2005 in Georgia 1552 rockslides were activated and mudslide transformation took place in 413 waterways. Under the risk of disaster were 1228 settlements and 9724 households; 10 persons died; damage amounted to 523 million GEL;

prohibitio8 garemos erovnuli saagento - In total the damage caused by disasters during 1995 – 2012 amounted to 770 million USD and 104 persons died (table 1). Landslide gravitational and mudslides, as well as river bank and sea shore washouts represents the highest risk.

prohibitio9 garemos erovnuli saagento

Specialized surveys confirm that landslide-gravitational processes, mudslides and washouts of river banks and sea shores increase with geometrical progression year by year. This is proved by landslide gravitational events mapped in different years in Georgia (chart 2) and mudslide transforming rivers (chart 3).

Map of Landslide-gravitational processes occurring in Georgia in different years

Chart 2

number 60000

50000

40000

30000

20000

10000

0 1942 1960 1963 1968 1972 1981 1987-89 1991-92 2000 2012 year

prohibitio10 garemos erovnuli saagento Chart 3

3000

2500

2000

1500

1000

500

0 1960 1970 1981 1994 2000 2012 weli

Besides, if before last decades of XX century activation of landslide-gravitational and mudslide processes and erosive washouts were basically occurring in certain cyclical nature and their recurrence depended on geological-climatic conditions of relevant location and in average were repeated with intervals of 3-5 years, after the 90s activation of disastrous processes is above the average background indicator. This is proved by incomplete data on the damage incurred by landslide – mudslide processes in 1995 – 2012, reflected in table 1.

Incomplete data on damage incurred by landslide – mudslide processes in 1995 – 2012 in Georgia Table 2

Losses incurred by Landslide Mudslide landslides and Sites under risk

mudslides

years GEL)

dynamic

lands (ha.

mudslides

(million USD) (million USD) (million USD)

Approximately)

Human Human casualties Human casualties

Residential houses Residential

Approximate direct Approximate direct

losses (million GEL)losses (million GEL)losses (million

Total losses (million

Damaged agricultural

Number of settlements Number of settlements

Number of transformed Number of landslides in Number in of landslides

1 2 3 4 5 6 7 8 9 10 11 1995 670 132/80 6 250 96/58 12 228/1.38 179 274 195 1996 610 80.3/48.5 4 165 27/16.3 5 107.3/64.8 232.3 403 626 1997 871 102/61.8 3 335 44/26.5 7 146/88.3 336.5 458 227 1998 543 67/40.5 5 173 20/12 6 87/52.5 229.6 370 159 1999 56 12/7.2 1 27 4.5/2.7 _ 16.5/9.9 137.8 157 314 2000 65 1.3/0.7 1 23 3.0/1.8 _ 16/9.6 162.2 240 207 2001 75 15/1.0 1 26 4.0/2.4 _ 19/11.5 127.5 191 127 2002 69 13.8/8.3 1 23 2.5/1.5 2 16.3/9.8 147.9 203 193 2003 71 14.5/8.7 3 28 4.0/2.4 _ 18.5/11.1 106.5 90 207 2004 949 147/89 4 258 28/17 2 175/106 16289.2 755 6042 2005 603 96/58 2 155 9.0/5.45 4 105/63.5 7589.6 473 3682 prohibitio11 garemos erovnuli saagento 2006 356 70.5/42.7 1 63 9.0/5.45 _ 79.5/48.1 3172.5 531 2066 2007 136 20.5/12.17 - 104 11.5/7 _ 32/19.5 1389.1 269 707 2008 311 48/47.2 10 126 15/9.1 8 63/38.2 1387.7 392 1198 2009 323 63.5/38.14 1 193 16.5/10 3 80/48 8232.3 521 2696 2010 250 20/12.1 3 81 5.0/3 2 25/15.1 1155 366 822 2011 91 unknown 3 37 9.0/5.45 8 20/5.45 652 181 463 2012 325 unknown 1 88 50.0/30.3 5 50/30.3 1255 239 845 total

Recent activation of natural disasters and complication of geodynamic situation on the background of sensitive geological environment is preconditioned the following: 1. Abnormal increase of negative meteorological events provoking geological processes on the background of global climate changes; 2. Large scale technogenic impact on the environment and severe disturbance of balance; 3. Low awareness of society on danger of geological disasters, insufficiently informed population and decision makers, lack of information on trends of activation of geological disasters, insufficient forecasts and assessment on possible development of these processes, unavailability of comprehensive disaster risk mitigation strategy and management tools. In Georgia by the scale of development andreactivation of geological disasters and its negative impact Rioni river basinis the most noteworthy. In the upper part of this area occur all disastrous geological processes characteristic to highland areas– landslides, rockslides, mudslides, erosive processes, avalanches, karst processes and glacier mudflows. In the lower part of the river Rioni occur floods and flash floods, erosive washing out of the river banks and landslides. Besides, the whole territory of the region is within the area of 8-9 magnitude earthquake risk, effect of the impact of which is enormous and it provokes landslide-gravitation processes and mudflows. In total, the area of Rioni river basin belongs to the most complicated regions of Georgia by the scope of damage by geological disasters, intensity of recurrence and level of risk. Large scale development of geological disasters and their periodical reactivationprevents sustainable development of the region and utilization of such potential, as its diverse and unique climate and landscapes. As a result of the above mentioned, in the highland area of this region (especially in Lechkumi Municipalities) is observed the trend of depopulationand socio-economic potential of the region degraded. Massive migration of population started since second half of XX century, when the lack of the lands suitable for cultivation was followed by activation of disastrous processes. For example, in 1926 population of Racha Lechkumi was 1013 thousands, this figure decreased up to 75.5 thousands by 1975 and in 2000 thepopulation reduced to 41.2 thousands.More than 60% of 60000 household, resettled with the status of eco migrants during last 45 years are from the river Rioni basin. Geological disasters were followed by empting tens of mountain villages and degradation of the lands. Ecomigration of population became more active since the beginning of XX century, especially in Tsageri and Lentekhi municipalities, where hundreds of houses were distorted, agricultural lands and roads were damaged and tens of villages were isolated from local centres and psychological stress of population reached its climax. prohibitio12 garemos erovnuli saagento Losses caused by geological disasters in the region even in conditions of background development amount to tens of million dollars, while in case of extreme activation – hundreds of millions and sometimes exceed billion. According to unspecified data only mudflows in the river basins of Rioni and Tskhenistskali caused more than 220 deaths since the beginning of 1977. The losses caused by extreme activation of mudflows in mentioned regions amounted to 100 million USD in 1977 (2). Special engineering – geological – amelioration large scale (1:10000) surveys, conducted in Tsageri, Ambrolauri and Oni municipalities by “Sakgeologia” in 70-80s of XX century demonstrate thelevel of damage of mountainous territory of the region and the risk, that the population is subjected to; the territory of 77,5 thousand hectares was assessed taking into consideration the categories of the level of damage and risks and it was zoned by the above mentioned parameters with indication of preventive measures. 553 land slide districts in dynamic state and 90 mudflow transforming rivers were mapped on the survey area. 33.4% of the territory was in area of high risk, and areas, which were intensively damaged and required cardinal protective measures amounted to 24%. At the same time, according to the data of erosion prevention master plan (5) , developed in 80s 80% - 100%, of soils of mountainous territory of Rioni river basin (Lentekhi, Oni, Ambrolauri) are eroded, while the area of eroded soils of Tskaltubo and Samtredia municipalities does not exceed 13 – 15%. In the lowlands of river Rioni most frequent disastrous processes are floods and flash flood and consequent erosive washing out of fertile lands and development of coastal landslides. Such negative impact caused complications historically and nowadays as well. However, in the past population had fewer problems caused by disasters due to lower density and the distance from the river banks. Currently, significant part of population as well as roads and oil/gas pipelinesare in the zone of floods flash floods and intensive erosive washing out. Washing out causes loss of productive lands. This process is mainly preconditioned by the river regime and morphodynamic conditions of the river banks, as well as extension of the horizon, sensitive to erosion washouts on the large territories. That is why intensive deformation of the river beds takes place not just in period of floods, but in usual conditions of the rivers and consequently the volumes of washing out of the banks during the year fluctuates from 0.5 -1m to 3-5 m and more. This is clearly confirmed by the fall of first terraces on some sections of the river Rioni. In general it must be mentioned, that in Georgia and especially in Rioni river basin special activation of geological disasters started in the last decades of XX century. Among the factors provoking activation of the process, first of all should be mentioned human impact on the environment, excessive precipitation, misbalance and active earthquakes. In particular, the epicentre of 9 magnitude earthquake of 1991, which is located in the upper part of river Rioni is still “alive”. Hundreds of landslide-gravitational bodies were developed and activated and about 12000 buildings were destroyed by the earthquakes of Racha- of 1991, great part of which were related to landslide events provoked by earthquakes. Due to mentioned more than 40% of prohibitio13 garemos erovnuli saagento houses were not subject to restoration. 70 households of village Chorda were within the zone of 152 million m3; Jashkvi and Barjiskhevi villages were within the zone of 170 – 200 million m3 landslide (Oni municipality). Multiple seismic dislocations, terminations and tranches appeared on the surface. Rockslides developed on the territories of Utsera, Gomi, Shkmeri, Tbeti, Kedisubani, Znakvi, Chorjo, Kldisubani, Chvishi villages. After the high magnitude earthquake of 1991 on the territory of Racha were registered earthquakes of 5-7 magnitude. Such earthquakes occurred in 2005 in Ghendushi, in 2011 in Chrebalo (Ambrolauri) and in 2009 in Gomi (Oni), which was followed by activation of hundreds of landslide bodies. Currently within the area of Rioni river basin, which covers 6 administrative districts (Oni, Ambrolauri, Lentekhi, Tsageri, Tskaltubo, Samtredia) with total area of 5950km2 and 356 settlements the trends of activation of above background level disasters are observed almost every year and their extreme activation on average occurs once in 3-5 years. In 2013 were registered around 655 landslide bodies and 210 mudflow transforming waterways, within the area of which are 197 settlements. More than 60% of settlements are within the zone of landslide and mudslide disaster risk. Table 3 reflects the data on these risks.

prohibitio14 garemos erovnuli saagento Geological processes identified within the territory of Rioni rive-basin by different administrative units (municipalities) and facilities, under the risk of their impact Table 3

Geological processes Facilities within the geological disaster risk zone Municipalities Mudslide Lands/including Landslides transformed Settled areas agricultural Motorways and other engineering facilities water course lands (ha) Oni-Shovi and Oni-Iri central highway and rural roads- 18 km; bridges – 8; water supply Oni 109 52 42 2649 facilities and headworks – 3; medium-voltage transmission line towers- 4

Ambrolauri- central highway and rural roads – 22km; bridges – 5; water supply Ambrolauri 121 29 39 3559,6 facilities and headworks – 2; medium-voltage transmission line towers – 2

Letekhi-Koruldashi central highway and rural roads – 19,5 km; bridges – 5; power transmission line – 3;pipe bridges – 5; power Lentechi 79 86 43 2118 transmission lines; bank protection embankments – 12; water supply facility headworks – 1 Tsageri-Orbeli central highway and rural roads Tsageri 187 36 43 3944,8 – 11,6 km; school – 1; damaged bank protection embankments – 11 Kutaisi-Oni central highway – 1,5 km; pipe Tskaltubo 79 6 14 524,7 bridges – 2

Samtredia 80 1 16 366 Rural roads – 0,5 km; bridge – 1

Total 655 210 197 13162

prohibitio15 garemos erovnuli saagento Lately on the territory under examination, as well as on the whole territory of the country natural geological disasters have become more activated and consequently, there is the need of development of effective organizational, legal and political management framework and elaboration of a long-term strategy. For the purpose of elaboration of a long-term strategy for management of natural disasters and successfully launch and operate early notification system we need to identify types of natural disasters, occurring on regional and national levels and develop and maintain inventory of natural disasters. We need to obtain exhaustive information on spatial and temporal characteristics of occurrence of natural disasters, as well as collect information on trends and factors, which directly or indirectly impact development and reactivation of such processes and determine their scale. We also need to identify those technogenic loads, which undermine environmental haemostatics and cause destabilization.

The practice has confirmed, that even the most developed countries cannot ensure implementation of full-fledged measures targeted at protection from different types of geological disasters, or evacuate the population in advance from the disaster-prone territories. It should also be noted, that quite often quite costly capital measures, implemented for the purpose of controlling of far-reaching geological processes, do not ensure attaining of desirable effects. That is why it is important to establish what kind of geological processes are occurring on the territory under consideration, what is the category of its vulnerability, trends of activation of processes and the related risks; the settled areas should be ranked by the level of risks, that they are subjected to and the inventory should be maintained. Geologically most sensitive and vulnerable areas need to be delimitated; resilience of geological environment towards technogenic load should be determined and optimal preventive measures need to be identified for the purpose of aversion of emergency situations. This is the baseline information, which shall be used for the purposes of permanent geological monitoring and early notification system for ensuring protection of population and management of strategic facilities in emergency situations. Present project is targeted towards seeking effective solutions to the above mentioned problems, as it shall assist municipalities of rural areas in elaboration of sustainable socio-economic development plans and long-term strategy focused on ensuring soundness of the environment. As we did not possess complete baseline information on the status of affairs from the standpoint of natural disasters in the region under consideration, as well as specifics of determinant elements, provoking such natural disasters, we had to systematize and analyze available archived materials and conduct field surveys of certain scope and character.

3. Key Factors, Provoking Geological Disasters and Assessment Methodology

Analysis of patterns of relationship of development and reactivation of modern exodynamic processes is impossible without proper understanding of those key provoking factors, which impact prohibitio16 garemos erovnuli saagento and trigger such processes. International practice has revealed, that wherever territories are developed without due assessment of geodynamic conditions, or obtained information is not sufficient for establishment of interaction between engineering facilities and natural-geological environment, it is almost impossible to avert negative geo-ecological occurrences. This problem is especially clearly pronounced in mountainous conditions. This is true in case of such diverse and complicated region, as Georgia and especially Rioni river basin.

Modern research of given problem is possible only trough indepth study of elements components) of geographical environment and their perceiving as a unified functional category. Unity of different factors influences formation and activation of exodynamic processes, which transform in time and space. Among them are key provoking factors, triggering disruption of the haemostatic balance and causing impact through stress of the physical field. Consequently, we cannot establish cause-and-effect relationships related to each specific geological process (especially if there are several interrelated processes), unless we establish determinant components (elements) of geological environment, which permanently exist in stationary conditions, as well as background conditions and provoking factors, existing in stochastic nonstationary regime and separate agents, triggering them.

In the 80s of the XX century with support of UNESCO and UNEP leading researchers of scientific-research institutes of different countries have examined and identified factors, predetermining common patterns of development of landslide and mudslide processes in stationary conditions and factors, causing activation of these processes and modification of regimes in nonstationary conditions (7). Although the methodology was developed for landslides and mudslides, it is fully applicable to other exogenic geological processes. It is noteworthy, that developed methodological guidelines contain results of examination of landslides and mudslides on the territory of Georgia. (8)

Professor A. Sheko and his co-authors (7) classify factors, causing development of exogenic geological processes into 3 groups: 1. Permanently ongoing – geological structure (tectonics, stratigraphy, lithology) and geomorphologic specificity; 2. Undergoing slow transformation: a) independent (key) – tectonic movements, climate changes; b) derived – geo-ecological, hydro-geological and soil and vegetation cover related processes, linked to eustatic variations of ocean and sea levels; 3. Undergoing quick transformation: a) independent (key) – meteorological, hydrological, seismic, economic activities; b) derived – surface water run-off, humidity and ice content in the stratum, rock hardness and deformability properties.

prohibitio17 garemos erovnuli saagento We consider, that out of diversity of factors, that precondition development of geological processes and occurrences, for the purpose of establishing patterns of formation and activation of exogeological processes in time and space we should rely on those regional and zonal regularities within the system of geological environment, which serve as precondition for certain processes, while factors and agents occurring in stochastic nonstationary regime promote to disruption of homeostatic equilibrium and provoke and reactivate processes.

To such key determining factors, causing disruption of geological environment and impact regional and zonal development of exogeological natural disasters belong: geological structure, relief, modern tectonic movements and climatic conditions; out of nonstationary factors ongoing in stochastic regime – such factors are within-year quantitative variability of meteorological elements, transformation of regime in rivers and groundwater, earthquakes and human activities.

3.1 Impact of Geological Structure and Characteristics of Stratum (Bedrock) on Development and Reactivation of Geological Processes

In engineering geology and geodynamics the stratum are considered as element, determining multi-component dynamic system of geological environment, i.e. the stratum is an important basis and determinant factor, impacting spatial development of any geological process.Substantial spatial modifications in the composition of the stratum are observed in geostructural units linked with sharp tectonic stress. Sustainability and scope and conditions of development of exogeolocgical processes and hence, resilience of slopes depends as to in which geo-structural units (orogenic or transient) the bedrock is formed and where physic-mechanical transformation is occurring (stability, deformability, shift resistance, water permeability, water resistance, moisture absorption, rheology, thixotropy and etc).

These important physic-mechanical features of the bedrock are formed as a result of historical geological processes of sedimentogenesis and diagenesis. Although, their gradual modification and transformation of engineering-geological features can occur in postgenetic conditions as well. In tectonic regime this occurs in the form of catagenesis and in the process of hypergenesis – under the impact of climatic conditions.

Thus, geological processes of any type are paragenetically linked with specific stratigraphic complex of the stratum, material composition of which and engineering-geological features vary starting from diagenesis and ending with hypergenesis. Quite frequently stratum of the same age and lithologic composition, formed in uniform paleogeographic regime and which have undergone the same way of development, currently in specific landscape-geological space acquire absolutely different engineering-geological properties. Contrasts in modification of engineering-geological prohibitio18 garemos erovnuli saagento properties of stratum are becoming more pronounced in the regime of complex tectonic regime of foldy-mountaneousterritories, like the Caucasus naoWa-wyvetiTidislocations, which have undergone complex process of block-mosaic fragmentation and scissure under the impact of lengthy and variable tectonic shifts. Activation of earthquakes and large scale gravitational processes are directly related with such active tectonic shifts and joint fissures. River Alazani upper reach is an excellent example of these processes.

The territory under consideration, which by its geological structure belongs to the most complex segment of alpine alpuri naoWa sistemis xmelTaSua zRvis moZravi sartylisurTules segments, on the background of overall geological development of the Caucasus region is formed as complex geotectonic units belonging to different type, age and having different genesis, including ancient pre-cambrian period crystallized stratum and quaternary polygenetic period sedimentation (9).

These geotectonic units are: 1. The folded-overthrust structure (megaanticlinoreum) of the Caucasus mountains formed in the process of alpine tectogenesis represents hypsometrically the tallest morphological unit representing a large horst structure, turned towards the east and creeping over the southern part of the Caucasus mountainside, along the so called “main overthrust”. The structure of the hypsometrically tallest geotectonic unit represents deeply metamorphous and crystal and intrusive Pre-Cambrian and Paleozoic rocks with intensely dislocated tectonics with mosaic breaking.

2. From the south the folded-overthrust structure of the Caucasus is bordered by a folded- overthrust system of the southern slope of the Caucasus. The two systems are separated via the “main overthrust”. This geotectonic unit penetrates the of the river Rioni basin via three tectonic zones: Mesta- , Chkhalta-Laila and -, and is represented by strong sedimentary and flysch, carbonate and volcanogenic sediments from the Upper Paleozoic through the Meso-Cainozoic age that make up the tectonically large morphological structures, which are highly complicated with tectonic overthrusts and different types of ruptures.

In its southern part the river Rioni basin is bordered by the folded-overthrust megaanticlinoreum of the Ajara-Trialeti Mountain system, which is a large morphostructure formed during the Alpine tectogenesis. The Ajara-Trialeti mountain system is made up of the Cretaceous and volcanogenic sedimentary strata, Paleocene-Early Eocene terrigenous flysch and Oligocene-Early Miocene sandy- clayey sediments. The Ajara-Trialeti folded system has a fan-like structure and highly complicated deep ruptures, overthrusts and scales and consequently, bended folds.

prohibitio19 garemos erovnuli saagento There is Southern Caucasus intermontane area known as the Georgian block between the central elevation of Caucasus and Ajara-Trialeti mountain systems. In its elevated central part the crystal basement (so called “Dzirula massif”) is outcropped; in the west and east it subsides under the Mesozoic and Tertiary sediments and in its western part gives way to the Kolkheti Valley built with Neogene and Quaternary Molasse sediments.

As the rocks in the geological area of the study area vary greatly according to their genesis, lithology, conditions of formation, age range (starting from the Pre-Cambrian age through the most upper layers of the Quaternary age) and their tectonic stress, for the creation of the special map of zoning of the risks of natural geological processes the rocks had to be grouped according to those major physical and mechanical properties which distribution pattern was formed in the relevant geotectonic environment and paleogeographic mode. For the largest taxonomic unit of such grouping we introduce the term “the engineering-geological formation”, while in the engineering-geological formations we identify the relevant lithological-genetic complexes based on their physical-mechanical properties, degree of stability and sensitivity to the geological processes of the rocks. Based on this methodology we have identified 10 engineering-geological formations and 28 lithological-genetic complexes in the study area (See Table 4).

Classification of the engineering-geological properties of the rocks conditioning hazardous geological phenomena in the river Rioni basin (drafted by E. Tsereteli)

Table 4

# Lithological-genetic engineering-geological Modern dominating Geographical complexes and their ages properties of the rocks and exodynamic processes location their stability in the massif 1 2 3 4 5 Modern bed and floodplain Continental formation High-mountainous Intense bed erosion caused by alluvial sediments of high- Loose-coarse-fractured and zone of the river the high river energy, with the mountainous rivers (>90%) loosely bound, water-resistant, Rioni basin north of transfer of sand and fine 1 sand and gravel (aQ 4). hard to moderately the parallels of the IV shingle; moderate washout of washability properties. towns of Oni and the floodplain-side banks of Tsageri. rivers during floods.

Modern bed and floodplain Strong bed and bank erosion, The area of the Loose, coarse-fractured and alluvial sediments of the flooding of significant areas of territory north of the 2 loosely bound, moderately average- and low- the floodplains in the flood parallel of town washable mountainous rivers: boulder season, development of bank Kutaisi.

prohibitio20 garemos erovnuli saagento and shingle (>70%), gravel, landslides.

4 sand, Clayey soil (aQIV ). Modern floodplain-bed Loose-loosely bound (70%) With high sensitivity to bed Within the limits of alluvial sediments of the and loose - fine-fractured, deformation and sediment- Kolkheti Valley plain zone: sand, sandy loam very low water-resistance and genesis; very powerful and clayey soil (>85%), strong washable properties. properties of river banks erosive 3 gravel, shingle (<7-10%) washout in both dimensions of 4 the critical horizon, with the (aQIV ). development and collapse of bank landslides. Above-floodplain alluvial Loose and coarse-fractured (>) Flooding and bogging the low Mountainous zone of sediments of low terraces of and loosely bound, moderately floodplain terraces in the flood the river Rioni basin 4 a mountainous zone: shingle to easily washable. season. and boulder (60-70%), sand, 1 Clayey soil, Clays (aQ IV-III). Alluvial sediments of above- Loosely bound (>75%) - Lateral erosion, bank landslides Kolkheti Valley floodplain terraces of the loosely-fractured, with low in the flood season. 5 plain zone - sand-clayey soil water-resistance and highly 1 (>75%), shingle, grit (aQ IV- washable properties.

III). Sediments of high terraces Coarse coarse-fractured (>) - Strong surface washout, gully- Mountainous zone of of a mountainous zone: loosely bound, from loose formation, with mudflow the river Rioni basin boulder-shingle, grit through slightly cemented phenomena and landslides at north of Kutaisi. 6 (>80%), with sand and conglomerates, hard to some places.

clayey joining material (aQI- moderately washable.

III). Alluvial sediments of high Coarse-fractured - loosely Weak surface washout and Within the Kolkheti terraces of the plain zone: bound, from loose to slightly gully-formation. Valley. 7 shingle and boulder (30- cemented conglomerates; 50%), sand-grit and clay and moderately washable.

clayey soil (aQI-III). Undifferentiated prolluvial- Coarse coarse-fractured (>) - Gully erosion, sedimentation of First-range tributaries mudflow sediments of the loosely bound; with non- mudflow currents, bank erosion, of the mountainous Quaternary period: unsorted uniform water-resistance and rarely -- landslide processes. zone of rivers Rioni 8 block talus and boulder moderately washable property. and Tskhenistskali. (80%), with the alternating layers of detritus-boulder

and clayey soils (PQ). Mountain zone Mild, bound (75-80%) Strong surface washout, Belt of the 9 unfragmented Quaternary loosely-fractured, non-water- landslide phenomena, gully- mountainous zone of mountain slope sediments– resistant, easily washable, formation and mudflow the river Rioni basin. prohibitio21 garemos erovnuli saagento clay and clayey soil, sandy mostly with high colloid currents. loam coarse-fractured with activity and varying coarse detritus (to 20-25%) consistency and absorbent. (dQ). Gravitational colluvial Coarse, coarse-fractured loose, Intense physical weathering, Slopes lacking high- sediments of a mountainous with high transmissibility, permanently renewable mountain vegetation zone: block talus, - with moderately washable. gravitational processes: rock cover with the 10 coarse gravel and detritus avalanche, mountain creep, inclination of over (up to 15-20%) (grQ). formation of gravitational 20°. mudflow hearths, snow avalanches. Slope elluvial-delluvial Loosely bound, with low High sensitivity to the landslide Foothills zone of sediments of the foothills of water-resistance and water- processes, gully-formation and Kolkheti Valley. the Kolkheti Valley: clay- penetrating ability, mostly of a sheet wash. 11 clayey soil with up to 5-10% soft-plastic consistence and detritus-like material. (edQ). high deformability, absorbent, with variable parameters to the shear resistance. Glacial morena sediments - Loose, coarse coarse- Erosive washout, mudflows, Alpine and Nival block talus, with clay-clayey fractured, loosely bound, mostly glacial and thermokarst zone of the river

12 soil and detritus (gQI-III). slightly condensed, at some places, soil flow. Rioni basin. moderately washable.

Fluvio-glacial sediments – Loose, coarse coarse- Strong riverbed and banks Alpine and Subalpine coarse boulder-block talus fractured, loosely bound; washout, mudflow-like zones of the river (>70%), with gravel and moderately washable. flashfloods. Rioni basin. 13 sand-clayey soil joining material and interlayers

(fgQI-III).

Molasse formation Sediments of Neogene marine-continental facies: conglomerates on clay and 14 sand cement, fine- and average-grain polymictic sandstones, clay-stones, Fragmental-cemented, semi- Foothills of the

stratified (N2p). cliffy, soaking, softly bound, Kolkheti depression. Marine molasse sediments semi-hard consistence, Racha- 15 of Neogene – alternating swellable, moderately water- Landslides, gully and sheet syncline; layers of fine- and coarse- resistant, instable over the erosion, rock avalanche. foothills of Kolkheti

prohibitio22 garemos erovnuli saagento grain sandstones and clays- slopes. depression, village stones, conglomerates Dablagomi and 2+3 (N1 ). adjacent area. Oligocene-Early Miocene Terrigenous formation Dominant landslide processes, sediments (Maykop series): Loosely bound, dense, hard- high washout of river banks, average-grain stratified consistence, swellable, mostly rock talus and rock avalanche sandstones, sometimes waterproof, colloidally active, with the average intensity of slated, peeling, jarosite, swelling, moderately water- 2.0kg/m2 a year. Surface gypsum-containing clays, resistant, with low stability, washout and gully-formation, sub-argillites; in Ajara- semi-cliffy, water-soaking, sometimes with mudflow Racha-Lechkhumi 16 Trialeti zone carbonate and with low shear resistance, processes. Syncline; foothills of gypsum-containing clays gravitational, unstable to Kolkheti depression. with conglomerate collapse with 2.0kg/m2. interlayers and streaks, with strong layers and packs of coarse-grain quartz-arkose

sandstones (P3N1) in the upper part of the section. Terrigenous-Carbonate formation Upper Cretaceous Age – Cliffy and semi-cliffy, with Gravitational rock avalanche, on The basins of the limestones of the Eocene different strengths, average 2kg/m2 a year, mudflows, rivers Rioni, complex, marls, sandstones, stability, water-resistance, rarely landslides and mountain Tskhenistskali, sandy and marl limestones, with moderate resistance to creeps, karst processes. Lajanuri, Askistskali, - 2 17 clays (K2 P2). collapse of 2.0kg/m a Ritseula, Kheora, year. Kikhula, Racha ridge; foothills of the Kolkheti Valley – villages Sajavakho, in Dapnari-Gomi area. Flysh sediments of Early Loosely bound, with little Surface washout, gully-formation, Racha-Lechkhumi Cretaceous Apt-Alpine strength, semi-cliff, partially mudflows, sensitive to syncline area, stage: stratified marls, marl soaking coefficient of 0.7- landslide processes; with average territory of villages 18 limestones, think-layer and 0.8, with moderate slope value of gravitational collapse of Orkhvi-Korenishi. sheet slated clays, with the stability. 5.66 kg/m2 a year. total strength of 80-100 m. Flysch formation Semi-cliffy, with variable Highly prone to landslide Ajara-Trialeri Upper Eocene marls with strength and stability, processes, instable to gravitational foothills in the zone 19 formanifera and lyrolepis mostly with little water- collapse, on average 3kg/m2 a year; of the Kolkheti marls, coarse-grain quartz- resistance, high softening gully-formation, surface washout Valley.

arkose and greywacke ratio (

prohibitio23 garemos erovnuli saagento sandstones, carbonate and outlets. bituminous slate clays, with conglomerate and conglomerate-breccia 3 interlayers and packs (P2 ). Carbonate formation Cliffy, with dominant Karst, particularly resistant to The middle reaches Carbonate sediments of the sediments, which are very gravitational collapse – collapse of of the rivers Rioni Early Cretaceous Age and strong and stable, water the gravitational products of 0.88 and Tskhenistskali Upper Jurassic Age: thick- soluble, non-soaking. kg/m2 a year on average; block basins, within the 20 layer and massive reef and talus and block-type landslides in area where carbonate dolomitized limestones, the zones with tectonic ruptures. rocks are spread; dolomites marls (>90%), Racha ridge, environs rarely with sandstone and of Shaori water

clay interlayers (K1+J3). reservoir, territory of Tskaltubo. Laguna formation Middle and Upper Jurassic Semi-cliffy and cliffy, of Gully erosion, highly sensitive to The river Rioni basin, color coal-containing different strengths and the landslide processes, with sediments: clays, sandstones, little water-resistance, with mudflows at some places. 21 sheet slates (J2-3). high softening ratio; soft bounded, not water- resistant, decomposable in water. Volcanic-sedimentary formation Middle Eocene basalts, Cliffy and semi-cliffy with With relatively stable slopes - with Low-mountainous andesite-basalts, mass and varying strength and the average gravitational collapse of zone of Ajara-Trialeti thick-layer breccias of stability, mostly water- 1.4kg/sm2 a year; block talus, rock northern slope. delenites and trachites, resistant. avalanches, landslides, mudflows in 22 tuffas, lava mantles, with the tectonically ruptured and tuff-conglomerates at some weathered zone. places, olitostromes, with stratified tuffas, argillites and marls in the lower part 2 (P2 ).

prohibitio24 garemos erovnuli saagento Upper Cretaceous Cliffy and semi-cliffy with Rock talus and rock avalanche over Tskaltubo region, volcanogenic sediments varying strength and the gravitational slopes, gully and lower part of the river (Mtavari stratum): water-resistance, of lateral erosions, of moderate Tskaltsitela basin. albitophyres and their tuffas, selective stability. stability, with local development of 23 tuffa-breccias, tuffa- landslide processes and block talus. sandstones, porphiries, with

limestone interlayers (K2).

Erosion-gravitational slopes, mostly Middle Jurassic – Bajocian stable, with rock avalanche porphyries stratum – lime- dominating in the weathering zone Cliffy, with high strength alkaline basalts, andesite and block talus dominating in the and stability (>70%), of Mountainous zone of basalts and andesite-dacites zone of tectonic ruptures, rarely 24 varying strength, water- the rivers Rioni and lavas, porphyries, lava landslides, surface erosion in the resistant and with selective Tskhenistkali. breccias and pyroclastolites, area lacking the vegetation cover stability, semi-cliffy. tuffas, tuffa-breccias, with and solifluction and nivation argillites and sandstones processes in the high-mountainous

(J2b). zone. Terrigenous-metamorphous formation Intense physical and frost The stratum of Lower Cliffy, mostly of low or weathering, rock avalanche; with Jurassic, strongly dislocated, High-mountainous moderate strength and active movement and accumulation metamorphized slates, zone of the rivers 25 stability; not water- of mineral mass in mudflow hearths tectonically ruptureed clay Rioni and resistant, easily of 40-50 kg/cm2 a year. Mountain slates and flaky slates, with Tskhenistkali. decomposable and subject creep, landslides and snow arkose sandstone to weathering (>80%). avalanches with dominating 1+2 interlayers (J2 ). mudflow processes. Metamorphous formation Strongly metamorphized Resistant to weathering processes, High-mountainous Paleozoic-Triassic sediments rock avalanche of coarse material zone in the river (Dizi stratum) complicated over the gravitational slopes and Tskhenistkali basin. with and tectonic Cliffy, mostly of high 26 snow avalanches mountain creeps Basins of the rivers disturbances: phyllitized strength and stability, in the zone of tectonic ruptures and Laskadula, clay slates, various-grain water-resistant. fractures, and mudflow in some Kheledula, Cholshura slated sandstones, marbled gorges and slight karsting in and Mulkhura. limestones, marble and carbonate rocks. quartzite (S2-T). Paleozoic crystal slates, Intense frost weathering and Alpine-Nival zone of Cliffy, of high strength and 27 mica slates, gneisses, nivation processes, gravitational the main Caucasus stability. phyllites, migmatites, rockfall, rock avalanches, snow ridge.

prohibitio25 garemos erovnuli saagento quartzites, amphibolites with avalanches, extremely complicated tectonic slices and overthrusts and overfaults (Pz). Magma formation Paleozoic and Alpine-cycle Nival zone of the 28 intrusive, granites, syenite, Cliffy, of extremely high main Caucasus ridge. quartz diorites, gabro-diorites, strength and stability.

granitoids (PZ-J2).

F G

3.2 The Role of GeomorphologicFactors in the Development, Forecasting and Diagnostics of Geomorphologic Factors

Basis for any economic-engineering activity of humans is a relief. Occurrence of geological disasters has direct impact on the potential of geodynamic regime of relevant territories. This is especially true in regard to such region, 70% of which belongs to the category of Alpine-Himalayan type extremely complex relief, which was formed during long historical period as a result of variable tectonic shifts and complex impact of exogenic geological processes, transforming the plastic of the relief. As a result of these processes was formed extremely contrasting primary large morpho-structural units – the system of mountains, and accumulation depressions and diverse polygenic forms, developed as a result of secondary exodynamic processes – deep gorges, formed as a result of erosion, glacier-nival, landslide-gravitational, mudslide-cumulative and karstic forms of relief. At the stage of newest tectonic movement the Caucasus highlands reached the height of 3.0- 5.0 km, while shifts depression sunk down to 0.4 – 1.5 km. such range of geotectonic shifts preconditioned clearly pronounced vertical morphological-climatic zoning and high energy of the relief, resulting in deep erosive processes and slits. Majority of old tectonic raptures were reactivated and numerous new tectonic raptures emerged, which caused activation ofearthquakes and sharp increase of geophysical fields stress.

Geomorphologic analysis reveals, that after formation of geomorphologic stages and climatic- landscape zones in the Caucasus highlands, in the final morphogenesis of relief formation is represented also exogenic morphodynamics, where genetic complexes, defining morpho-sculptural relief are formed in correspondence with morpho-clymatic situation. Within the borders of these complexes dominate those exogenic relief-formation processes and genetic types of relief, which are characteristic to relevant climatic-morphological zones. Within the territory under examination there are following complexes:

prohibitio26 garemos erovnuli saagento 1. Nival-glacial sculptural-rocky relief, with glaciers where nival-gravitational processes are dominant; the territory is also characterized with young erosive gorges and glacial mudslides. 2. High-mountainous alpine zone characterized with mountains and deep gorges, multiple Pleistocene glacier and cryogenic processes with the tiers of denuded surfaces, where deep erosive gravitational-denudation and mudslide processes and avalanches are frequently represented. 3. Mid-mountain zone where erosion-denudation forms are dominant represented with water-dividing ridges with shingling-type location, deep rivers, intensive secondary erosion, radial fragmentation of dendritic rivers; in the gorges of rivers of lower rank is characteristic occurrence of mudslide processes and karstic processes in carbonate stratum. 4. In the morphogenesis of the low-altitude mountains and foothills the most important features are morpho-structures preconditioned by new tectonics and river erosion, gorges of which are formed in the new stratum, or in deeply disintegrated depleted crust of older period stratum. In given zone landslides, river bank erosion and ravine surfaces; 5. Rivers located in intermontane plain-accumulative tectonic depression are characterized by intensive sedimentation of solid deposition, strong deformation of river bed, intensive washout of river banks, periodic flooding and swamping of floodplain.

In the geological time span exogenic geological processes are developed more intensively and rapidly, as morpho-structural hypsometric steps of given relief are located at higher levels, especially when the slopes are composed of stratum, which is sensitive to erosive-denudating processes. In such cases the slope formative processes are especially impacted by the stress, which is directly related to active tectonic shifts and the gradient of relative difference of relief altitudes, depth of erosion recession and slope inclination, integral correlation of which is expressed as energy potential of a relief. If we take into consideration, that more than two-thirds of the territory under examination is occupied by medium-altitude mountains and highlands, where annual indicators of modern vertical movement varies within the range of 15, while overall depth of erosive recession is 600-2500 meters, where consequently the gravitational field stress of slopes is increasing, it becomes clear as to how string is the energy potential of the relief. Although even in conditions of homogeneous energy potential of the relief the intensity of the slope development processes is dependent on stability of composing stratum and climatic zonality. As a result of multiannual regime-stationary surveys conducted on the territory of Georgia it was established, that geological disasters do not occur on the surfaces with inclination less than 30, except for swamped territories and high levels of groundwater, as well as erosive-settling processes and sharp changes in temperature regimes in highmountain-alpine relief and seasonal glaciations, when we can observe so called “Creep process”. On the relief with inclination of 3-80 the signs of erosion, especially in sensitive stratum and recession, as well as surface landslides are characteristic. On the slopes with inclination of 8-150 erosion is developed actively, delluvial clay sedimentation is

prohibitio27 garemos erovnuli saagento formed, in which plastic and plastic-fluid type landslides occur. On the slopes of high-mountain zone, the surface of which is the outcrop of rocky and semi-rocky stratum are formed combe rocks. On the slopes with inclination of15-250are formed plastic and creeping landslides, and in the exposed base rock the process of gravitational rockslide is practically terminated. In the high- mountain-alpine zone solifluctional processes develop intensively. On the slopes with inclination of25-350 occurs active formation of rock fragmentation and block and structural landslide occur. On the slopes with inclination of35-450occurs active formation of gravitational rock fall and landslide and rock-slides, while on the slopes with inclination of 45-650 mainly occur intensive rock slides and landslides, during which is formed actively moving colluviums and permanent enriching of mudslide prone zones with geological material. The slopes with inclination ofmore than650are in the process of permanent renewal of gravitational processes and they are characterized by rockslides, rock falls and falling of boulders with colluvial material formations. Consequently, the inclination of the surface is in direct correlation with landslide- gravitational, erosion, mudslide processes and avalanches formation and their intensity. For the purpose of establishing of the pattern of development of these processes and related risks we introduced the concept “energy potential of the relief” and we have developed categories of relief inclination. Namely: under 30- ideally flat surface; 3-80_ plain; 8-150 _ sloping; 15-250 _ weakly sloping; 25-350 _ medium sloping; 35-450– strong sloping; 45-650 _ moderately steep; 65-900 _ plateau-cornice ledges. Categorizing of the relief energy potential by the above mentioned criteria and its spatial definition on the map in correlation with sensitivity to relevant geological processes serves as effective basis for assessment of the risks of natural disasters and conducting of zoning (see diagram – correlation of geological disasters with the categories of relief energy potential).

prohibitio28 garemos erovnuli saagento

3.3 The Role of climatic-Meteorological Factors in the Development of Landslide-Gravitational and Mudslide Processes

Climatic factor, which in the geological past was the dominant factor impacting exomorphogenesis of the earth surface and formation of multi-specter sedimentary rock, continues to be the leading factor impacting formation and reactivation of current geological processes, especially such natural disasters, as landslides, mudslides and erosion wash out of rover banks. This problem is especially topical for climatically such complex region, as Georgia and namely the Rioni river basin, where more than 70% of landslide processes are provoked under the impact of climatic factor. As to the mudslides and the level of river erosion, it is totally dependent on the climatic conditions of the location, where the process provoking meteorological elements prevail (atmospheric precipitation, humidity and etc) in the regime of sharp climatic-zonal and quantitative-temporal variation in non-stationary regime. We consider, that climate, as a weather regime for certain collation, which is formed under the influence of atmospheric circulation in specific geographical environment and where certain

prohibitio29 garemos erovnuli saagento geological disasters are formed, should be viewed as a static function for assessment of background conditions. Depending on sensitivity of geological environment in different climatic areas the character and intensity of geological disasters varies under the influence of process-provoking meteorological elements (precipitation, air temperature, humidity and etc), which causes quantitative and qualitative changes and deviations and temporal recurrence due to geographic- orographic conditions, as well as global climate changes. Correlation of results of multi-annual engineering-geodynamic surveys of different scope and geomonitoring conducted on the territory of Georgia, as well as multi-annual stationary observations and data ofprocess-provoking meteorological elements confirms, that more than 70% of landslides and mudslides andtheir dynamic regime is directly related to amount of deflection of atmospheric precipitation from multiannual static norm for relevant climatic-geological environment in within-year interval (8, 10, 11). It is noteworthy, that if the rock of high sensitivity to atmospheric precipitation and groundwater is represented on a broader area within the geological transformation zone, the scale of development and activation of landslide processes becomes higher. Saturationof landslide-prone slopes by groundwater is especially clearly pronounced as a result of groundwater formed in karstic- carbonate rock, which are directly adjacent to tectonic fissure and overthrust zone and discharge in the area of landslide-prone slopes. Classical example of this is synclinal structure of Racha- Lechkumi, where cretaceous-carbonate and tertiary sedimentation stratum is adjoining with the edge of the overthrust where for several kilometers are occurring frontal landslides. Dynamic regime of formation and periodic reactivation of landslides is directly conditioned by the influence of atmospheric precipitation and energy charge of saturation of slopes, which causes changes in the consistency of the rock and reduction of resistance to shifts to the critical limit. We refer to such landslides as “climatogenic” (i.e. „consistent”) landslides. The surveys have confirmed, that the level of activation of climatogenic landslides depends on the type of atmospheric circulation regime and depending on sensitivity of geological environment the landslides can be local, regional or national (covering the while country). Maybe the criteria of quantitative distribution of atmospheric precipitation provoking landslide processes, which we have proposed may not correspond to conditions of formation and reactivation of landslides in other regions, but we consider, that proposed methodology corresponds to overall concept of „climatogenic landslides”. For the purpose of coding of spatial-temporal activation of “climatogenic landslides” and the risk of hazard in according to this methodology we introduced following categories of landslide processes: 1. Stable – when the quantitative indicator of landslide provoking atmospheric precipitation and “humidity effect” of deformable horizon for given period (year, season, month) is below the mean multiannual limiting value. 2. Background –when the volume of annual atmospheric precipitation and the “humidifying effect” of deformable horizon fits within the multiannual norm (i.e. coincides with the climatic prohibitio30 garemos erovnuli saagento static regime conditions of relevant location). In such cases and in the event of exclusion of other additional factors dynamics of the landslide processes is unfolding in accordance with the background regime. 3. Stress (exceeding the background conditions) – when the volume of annual atmospheric precipitation exceeds the mean multiannual norm by up to 200mm. in such cases the slopes with optimal receptor deformable horizon features can be observed the trend of activation of landslide processes, which exceeds the background conditions and often landslides in the state of homeostasis come into dynamic state. 4. Extreme –when activation of landslide processes starts in case of precipitation exceeding mean multi-year norm by up to 400 mm or more. In such case all stable landslides in the state of homeostasis get activated, which depends on the effect of humidification and the bodies in the dynamic state enter into extreme regime, while on the slopes with sensitive geological conditions new landslides are formed. Depending on the type of circular atmospheric regime, extreme activation of landslide processes can transform into the regional paroxysm regime and cover large areas, sometimes even the whole country. We have witnessed such paradigm on numerous occasions in Georgia, as well as in the Caucasus region. It is noteworthy, that if the process of formation-activation of landslide processes are triggered by within-year distribution of precipitation and saturation of slopes, as well as energy charge of latently flowing “humidifying effect”, which causes modification of consistency of landslide-prone stratum and reduction of lateral resistance to the critical point, transformation of mudslides is totally dependent on the volume and intensity of daily precipitation in the form of rain. For the purpose of identification of trends of landslides and mudslides, occurring in Rioni river basin and establishing of relevance of climatic factors we have analyzed data from 18 meteorological stations, located in the region under examination. Namely, we have examined the process provoking factors and parameters, which determine activation and formation of landslide and mudslides, as well as their nature and scope.

If we take into consideration the fact that more than 70% of landslides occurring on the territory of Alazani river basin are caused by climatic-meteorological conditions and activation of landslides during the recent period is confirmed to be caused by quantitative and qualitative increase of negative meteorological elements and global and regional climate changes. This explains the need to establish cerrelational regularity of development of landslide processes and parameters of climatic-meteorological elements, especially that “climatogenic landslides” have been registered in almost all climatic-meteorological zones, the energy potential of which exceeds 80and the slopes are composed of stratum, sensitive to landslide processes having features of positive receptors of collecting atmospheric precipitation and this correlation is expressed through the effect of “humidification” of slopes.

prohibitio31 garemos erovnuli saagento The correlation between activation of landslide processes and quantitative indicators of atmospheric precipitation and deformable horizon and “humidification effect” clearly demonstrates, that there is clear linkage between activation of landslide processes and the values of deviation of atmospheric precipitation from the multi-year norm. “climatogenic landslides” transform to stable condition when the quantitative indicator of atmospheric precipitation and “humidifying effect” of deformable horizon in lower than the limiting value of mean multi-annual precipitation. Also, the scope and risk of activation of landslide processes in sensitive geological environment increases proportionately to the annual volume of atmospheric precipitation. Consequently, taking into consideration the trends of development of landslides on the territory of Georgia and their dynamic regime we can identify three types, or three periods of landslides: 1. The period of maximal activation of landslide processes, which is preconditioned by the extremum of paroxysmal character of atmospheric precipitation (400-600mm and more); 2. The period of average activation of landslide processes, which mainly implies the periods between intensive activation of landslide; 3. The background condition of landslide processes. The number of landslide in given condition exceeds the number of landslide in to previous conditions. Usually landslides remain in this condition or transform to the condition of maximal activation or average activation depending on the volume of precipitation and the “humidification effect” of the slopes. The above mentioned categories are confirmed by the results of analysis of charts of deviation of landslide-provoking atmospheric precipitation form mean multi-annual norm, which were maintained by 7 meteorological stations. As the charts of all meteorological stations have confirmed, the positive within-year deviation of precipitation during the observation period exceeds the deficit of precipitation almost twice. Consequently, during 67 years in Oni region this occurred on the level of background regime of development of landslides 32 times, in Ambrolauri – 24 times during 45 years, while in Samtredia – 36 times during 68 years. Although, it should be noted, that often the quantitative data on within-year deviations of precipitation and temporal data from meteorological stations in Rioni river basin coincides. Consequently, the years, when activation of landslide processes occurs in different administrative regions is different and this should presumably be related to geographic location, vertical zonality of the relief and orographic conditions. Overall, analysis of the dynamics of activation of landslide processes has demonstrated, that in the sequence of positive balance and deficit of atmospheric precipitation the cycle of activation, suppression or temporary stabilization of landslides in different geological environment on average is within 3-8 year range (see table 5).

prohibitio32 garemos erovnuli saagento Within-year deviations of landslide-provokingprecipitation from mean multiannual norm and the diagrams of deviations of landslide-provoking atmospheric precipitation

Table 5

Positive deviations of precipitation in deficit of precipitation mm and recurrence coefficient Meteorological Observation Number <200 200-400 400- >600 Observation Recurrence station years of years 600 years and number of years 1936-1960 24 11/0,45 1/0,04 2/0,08 _ 10 1961-1980 19 9/0,47 2/0,1 _ _ 9 Oni 1981-2003 22 5/0,2 2/0,09 _ _ 14 Total 65 25/0,38 5/0,07 2/0,03 _ 33 1940-1959 19 7/0,36 2/0,1 _ _ 1942-1960 (18) 12 1963-1979 16 8/0,5 1/0,06 _ _ 1961-1980 (19) 11 Ambrolauri 1981-1999 18 4/0,2 5/0,27 _ _ 1982-1998 (16) 8 2002-2010 8 2/0,25 4/0,5 _ _ 2004-2012 (8) 5 Total 61 21/0,35 12/0,2 _ _ Total 61 36 1960-80 20 7/0,35 3/0,15 _ _ 10 1981-2000 19 6/0,31 4/0,2 _ 1/0,05 9 Lentekhi 2000-2006 6 1/0,16 1/0,16 _ 1/0,16 4 Total 45 14/0,31 8/0,17 _ 2/0,04 23 1936-1959 23 5/0,2 3/0,13 3/0,1 _ 1942-1960 (18) 10 1961-1989 28 6/0,2 3/0,1 2/0,07 1/0,03 1962-1980 (18) 13

Tsageri 1982-2006 (24) 10 Total 51 11/0,21 6/0,1 5/0,09 1/0,01 Total 60 33 1936-1959 23 5/0,2 5/0,2 2/0,08 _ 1937-1960 (23) 12 1961-1980 19 5/0,26 2/0,1 _ _ 1962-1991 (29) 17

Tskaltubo 1981-1992 11 4/0,36 3/0,27 _ 1/0,09 Total 53 14/0,26 10/0,18 2/0,03 1/0,01 Total52 29 1936-1960 24 7/0,3 3/0,12 4/0,16 _ 1937-1957 (20) 11 1961-1978 17 5/0,3 1/0,05 1/0,05 _ 1967-1980 (13) 13 Kutaisi 1981-1997 16 4/0,25 3/0,18 1/0,06 2/0,12 1984-2000 (26) 10 2002-2012 10 5/0,5 1/0,1 _ _ 2001-2012 (11) 6 Total 67 21/0,31 8/0,12 6/0,08 2/0,02 Total (70) 40 1936-1960 24 8/0,33 5/0,2 _ _ 1937-1957 (20) 12 1961-1980 19 3/0,15 4/0,21 1/0,05 _ 1967-1979 (12) 12 Samtredia 1981-2004 23 9/0,39 3/0,13 2/0,08 1/0,04 1984-2003 (19) 9 1/0,01 51 Total 66 20/0,3 12/0,18 3/0,04 Total 33 5

prohibitio33

garemos erovnuli saagento p

Deviation of landslide provoking precipitation from mean annual norm

prohibitio34 garemos erovnuli saagento p

Deviation of landslide provoking atmospheric precipitation

from mean multiannual norm

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prohibitio35 garemos erovnuli saagento p

Differently from conditions for formation of “climatogenic” landslides, which are linked with the level of saturation of slopes above the mean multiannual norm, in more than 70% of cases of transformation of mudslides the volume and intensity of torrential rains within the 24 hour interval plays decisive role. Generally potential of mudslide-provoking atmospheric precipitation is determined by their intensity and time length. Although, depending on engineering-geological conditions of mudslide locus and morphological peculiarities of catchment basin the quantitative indicators of torrential rains have different impact on the character of development of mudslide processes. In conditions of the same amount of rainwater can occur ordinary flash floods and mudslides. This depends on geological characteristics of mudslide-forming locus and its sensitivity. For example, the daily total of mudslide-forming precipitation volume is established to be: for the Carpathian Mountains – over 30 mm, Mountainous Crimea – from 25 mm to 100 mm, Dzungaria Altai Uplands – from 30- 40 mm to 70-90mm. In the Tien Shan and Pamir-Alay mountain systems as mudslide provoking precipitation is considered daily rains from 60-100mm and more, average interval of recurrence of which is once in 100 years, while in other regions of the Central Asia recurrence of mudslide provoking precipitation – 50-80mm is expected once in 20 years (селопасные районы ссср, 1976. 308с.). Establishing of the pattern distribution of mudslide-forming precipitation in the Caucasus region is quite complicated due to specificity of geographic location and complex orographic features. Quite often pluviometric gradients differ notonly from region to region, but even on the different slopes or different altitudes of the same ridge. This is the reason why the pattern of spatial-temporal distribution of torrential rains has not been fully studied. Professor I. Sulakvelidze (13) considers, that potential share of torrential rains in the total volume of precipitation in the Southern Caucasus region varies within large range depending on remoteness from the sea, orographic conditions of relief, altitudinal zonality, location of ridges and exposition. For example: for it is 80%, for Samtredia – 23%, for Tsipi (western slope of the Likhi ridge) – 12%, the Mountain Sabueti – 5%, for – 5%, – 49%, – 44%. Despite the fact, that the Caucasus, including Georgia is characterized by complex pluviometric gradient specificity of mudslide-transforming atmospheric precipitation, multiannual observations have confirmed, that collation of time intervals of atmospheric precipitation with their quantitative indicators allowed us to establish certain regularity between the volume of daily torrential rains and intensity of development of mudslides and their scope in different geological environment (14). Multiannual observations show, that in the specific geological environment of low mountainous area and foothills rocky deposition due to mudslide is formed as a result of precipitation in the amount of 20-30mm. the more the relief is inclined, the higher is the intensity of washing out. Thus, in the humid-subtropical zone of Georgia in conditions of inclination of the

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relief of around 10-200 around 200-300 tons per hectar is washed out on annual basis, while in the low-mountainous area of Imereti the volume of wash-out is around 100000 tons per hectar. As the lower limit of mudslide-forming precipitation in optimal-geological conditions in Georgia during the warm seasons (IV-X months) is considered daily precipitation of 30-50 mm. In case of torrential rains within the range of 80-100mm and more in all the catchments of the high- mountainous rivers are formed mudslides of extreme character in case of presence of geological bodies less resistant to the impact of mudslides or loose constituents of geological product. Analysis of the table of data from meteorological stations, located in Rioni river basis has demonstrated, that torrential rains of 30-50 mm, causing formation of mudslides are recurrent on almost annual basis. In the event of extreme precipitation of 50-80mm, which causes formation of mudslides in the river heads of Rioni and Tskhenistkali (Oni and Lentekhi districts) are characterized by high intensity of mudslides and the coefficient of their recurrence varies between the range of 0.11-2.6. In the event of torrential rains of 80-100mm and more the coefficient of their recurrence in the heads of the above-mentioned rivers is within the range of 0.05-0.2. In the event of extreme torrential rains (>80-100mm) the coefficient of recurrence is (0.11-0.4) and it is most frequent in the downstream area of river Rioni. Although this volume of precipitation usually causes formation of non typical muddy and rocky flows, but water and sediment containing flows. The character of distribution of mudslide-forming precipitation is clearly evident from the table No6 “daily volume of mudslide-forming precipitation and recurrence coefficient within the interval of indicated years”

Table No6: Daily volume of mudslide-forming precipitation and recurrence coefficient within the interval of indicated years

Daily volume of precipitation in mm and Number of Meteorological Observation coefficient of recurrence observation Total volume stations years years 30-50 50-80 80-100 >100

1936-1960 24 49/2.04 1/0.04 1/0.04 _ 51/2.13

1961-1980 19 39/1.9 6/0.32 1/0.05 1/0.05 47/2.5 Oni 1981-2000 19 16/0.84 3/0.16 1/0.05 _ 20/1.05

2001-2004 4 9/2.25 1/0.25 - _ 10/2.5

1936-1960 24 35/1.46 4/0.17 _ _ 39/1.42 Ambrolauri 1961-1980 19 23/1.2 10/0.52 _ _ 33/1.74

prohibitio37 garemos erovnuli saagento p

1981-2000 19 50/2.63 9/0.47 _ _ 59/3.11

2001-2011 10 30/3.0 14/1.4 1/0.1 _ 45/4.5

1955-1960 5 22/4.4 5/1.0 _ _ 27/5.4

1961-1980 19 53/2.79 10/0.11 _ 1/0.05 64/ Lentekhi 1981-2000 19 65/3.4 20/1.05 3/0.05 1/0.05 89/4.68

2001-2006 5 32/6.4 11/2.8 1/0.2 _ 44/8.8

1939-1960 21 78/3.7 3/0.14 _ _ 92/4.38

Tsageri 1961-1980 19 58/3.1 _ _ _ 73/3.8

1981-2006 25 63/2.52 3/0.12 _ - 78/3.12

1936-1960 24 149/6.2 51/2.2 12/0.5 5/0.2 217/9.0

Tskaltubo 1961-1980 19 109/5.7 35/1.8 6/0.2 2/0.11 152/8.0

1981-1992 11 45/4.1 23/2.1 8/0.73 4/0.4 80/7.1

1936-1960 24 92/3.8 33/1.38 1/0.04 3/0.13 129/5.4

Kutaisi 1961-1975 14 55/3.9 13/0.92 2/0.14 _ 70/5.0

1984-2000 16 59/3.7 19/1.19 3/0.19 2/0.12 83/5.2

2001-2011 10 62/6.2 18/1.8 2/0.2 _ 82/8.2

1936-1960 24 101/4.2 43/1.9 5/0.21 _ 153/6.37

Samtredia 1961-1980 19 84/4.4 25/1.3 5/0.26 4/0.2 118/6.2

1981-2000 19 88/4.6 26/1.4 2/0.11 1/0.05 117/1.33

2001-2005 4 30/7.5 11/2.7 1/0.25 _ 42/10.5

Thus, we have geologically processed and tested in practice the volume of annual precipitation, exceeding the mean annual precipitation, which causes formation or provokes mudslides in specific geological environment, or the volume of torrential rains, which cause transformation of mudslides. But to establish the pattern of development and reactivation of landslide-mudslide processes in specific geological environment for the long-term period it is necessary to have long-term climate-change forecasts, which should cover at least 25-30 years. Elaboration of forecasts of spatial-temporal pattern of development of landslide-mudslide processes and determination of hazard risk index remains a serious challenge, as we do not have a

prohibitio38 garemos erovnuli saagento p uniform approach and methodology. At the same time preparation of long-term forecasts is related to obtaining of information, its processing and development of geoinformation electronic data base on time, location and scope of multi-specter factors and process-provoking abiotic and biotic agents. As of today the National Environmental Agency has fully processed and documented information related to all key natural geographic-geological factors, causing or provoking formation of landslide-mudslide processes, as well as those qualitative and quantitative parameters of those meteorological elements, which cause deviations from the threshold values and hence cause activation or dissipation and stabilization of landslide-mudslide processes. Consequently, today we possess information on the pattern and intensity of development of different geological processes in specific geological environment and specific spatial dimension, as well as those additional factors and criteria, which cause activation or provoke the processes. To establish the trend of temporal dynamics of mudslide-landslide processes in long-term perspective, we need to prepare climate-change long-term forecasts, where the main accent shall be made on the annual deviations from the mean multiannual norm (for landslides), while for mudslide processes we need to determine daily volumes and recurrence in the values, that the Agency uses to determine the pattern of development of landslide and mudslide processes. Hence, for the purpose of indepth analysis of the landslide-mudslide risks it is expedient to have long-term forecasts of climate-changes related to spatial-temporal development of landslides and mudslides taking into consideration criteria, that the Agency possesses currently. In the beginning of 2013 the chief geologist of the Project on Developing of climate resilient flood and flash flood and geological disaster management practices on behalf of the Geological Service of the National Environmental Agency notified the project leaders on the above mentioned conclusions, but the latter did not consider it expedient to seek solutions to this problem.

4. Principles of Elaboration of Landslide and Mudslide Risk Assessment and Zoning Map

The task of assessment of risks of geological disasters in high-mountainous regions and zoning of the territory is a challenging task, especially when we have to deal with such complex geological occurrences, which are preconditioned by interrelated multi-component determinant and stochastic factors. This issue is especially problematic for such complex region, as Rioni river basin mountainous zone, where the risk of landslide-mudslide processes is extremely high. In the scientific literature in the process of assessment of risks of natural disasters are used three key components – the risks, vulnerability and elements under risk (Van Gesten, 2008). The risk is perceived as the occurrence, which may cause negative impact and is characterized by temporal probability and intensity. We consider, that in regard to geological hazards we should also consider the spatial dimension as well. prohibitio39 garemos erovnuli saagento p

Vulnerability implies physical, social, economic and ecological conditions, which contribute to increase of probability of negative impact of hazards (UN International Strategy for Natural Disaster Risk Reduction 2004). Vulnerability is related to the level of losses, incurred as a result of certain intensity of natural disasters. In the process of assessment of vulnerability should be identified the population, engineering facilities and infrastructure, which is under the risk of natural disaster. Consequently, risk management structure should include risk assessment, as well as risk management through analysis of such qualitative and quantitative information on the territory under consideration, as determination of types of geological disasters, establishing of preconditioning and provoking determinant and scholastic factors, inventory of facilities subjected to the risks, assessment of the level of vulnerability and estimation of possible losses. It is noteworthy, that all types of geological hazards are characterized by a spatial component, which needs to be analyzed for the scope and recurrence. The final goal of multi-specter geological risk assessment is elaboration of the map of zoning of geological disaster risks, which shall serve as basis for elaboration of long-term geological disaster risk reduction strategy on national and regional level. Quantitative and qualitative assessment of natural disaster risks is extremely important for the purpose of provision of information to the population subjected to such risks. This also allows for establishing of risk criteria, establishing the early notification system and elaboration of adaptation-technological measures and identification of priority activities on the level of municipalities. Unfortunately despite the fact, that major part of the population of the planet periodically finds itself in emergency situations due to geological disasters, till the 70s of the XX century there was little scientific information on geological disaster quantitative and qualitative assessment methodology, intensity of geological disasters and their recurrence (exclusion was information related to earthquakes). As a breakthrough in given area can be considered the year 1980, when under the aegis of UNESCO-UNEP the leading scientists of more than twenty countries elaborated and published their work in given area (1984, 2 volumes). The publication covers issues related to patterns of development of landslides and mudslides and methodology for conducting of regional and local research, issues related to forecasting of landslides and mudslides and protection from them, factors promoting to their formation, as well as legal and administrative aspects. The monography also contains results of research of landslides and mudslides in Georgia, principles of zoning, risks of such disasters and possible losses by regions. Lately there have been serious developments in the methodology of zoning of geological disasters, including landslides and mudslides. Despite this there are still major differences in the approaches towards methodology and procedures of regional risk mapping. In our opinion this is caused by insufficiency of information on process-causing permanent determinant factors, as well as qualitative, quantitative and statistical information on stochastic process-provoking agents and lack of cause-and-effect analysis.

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Despite the fact, that assessment of risks of landslide-gravitational and mudslide processes in high-mountainous area and elaboration of disaster management plans is extremely important, methodological research proposed in given area is still insufficient and assessment criteria is often not adequate. It would have been impossible to elaborate Rioni river basin climate resilient flood and flash flood and geological disaster management practices and zoning of the territory according to the relevant risks for the purpose of protection of population and engineering facilities, subjected to high risks without data, obtained through specialized engineering-geological surveys, that have been conducted previously (the scale 1:200000-1:10000), as these surveys allowed us to collect information on determinant factors causing disasters in geological environment, while stationary observations allowed us to collect statistical data on process-provoking agents. On the basis of analyzing of the above referred data we prepared the map of geological hazards and risks of the region under the observation. As the basis for the mapping served classification of stratum according to their composition, stability, geotectonic properties and sensitivity to geological disasters. We consider, that overall strategy of assessment of landslide-gravitational and mudslide risks should first of all identify such criteria of risk management, which shall allow for assessment of key factors, causing specific disasters, as well as process-provoking agents, which shall allow to assess caused or expected physical, social and environmental damage, the level of vulnerability and elements under risk. We have elaboratedlandslide and mudslide risk scenarios for Georgia as a result of analysis of key factors, causing these processes and process-provoking meteorological elements, which are variable in time and space. The above mentioned factors are used to determine the level of damage, caused to the territories as a result of landslides and mudslides in homogeneous geological environment taking into consideration probability of the period of occurrence of these disasters, intensity and elements under the risk (such as population, agricultural lands, engineering facilities and etc). Consequently, in the process of assessment of landslide and mudslide risk management in homogeneous geological environment and specific climatic environments we use several criteria: hazard, vulnerability and facilities under risk (6,11). Under the hazard is implied spatial probability that a certain territory can be subject to the impact of geological disaster. Under vulnerability we consider two aspects: the level of damage to the territory, prone to certain geological disasters and elements subject to the risk of geological disasters. For the purpose of zoning of landslide-prone territories we have used the term “landslide potential”, which is expressed as intensity of the process (severity of the risk) and activeness (frequency of recurrence), developed in homogeneous geological environment and specific climatic conditions. We have assessed severity of landslide processes by three indicators: prohibitio41 garemos erovnuli saagento p

1. The total area of landslide processes, occurring in certain geological environment divided by the total of the territory under consideration; 2. The total of landslide bodies divided by the total territory under consideration; 3. the areas with homogeneous geological properties, where there is probability of development of new landslides or activation of landslides in the homeostatic state under the impact of additional natural-technogenic factors, i.e. the areas where there is probability of formation of landslides or activation of landslides in homeostatic state divided by the total area under consideration. By adding all the three above mentioned indicators we receive the coefficient from 0 to 1. For the purpose of zoning of territories by mudslide risk we have used the “mudslide risk coefficients” (Ks); These coefficients are: 1. The total of the mudslide-forming water courses divided by those water courses,

flowing into the basin, where the mudslides have not occurred (Ks= n1/n2); 2. The total area of water courses within specific geological environment divided by the total area of the river basin (Ks= tz/P) The total mudslide-transformational water courses divided by the total area of the river basin (Ksz fs F); 3. The total area of the active loci, contributing with mineral products to formation of mudslides divided by total catchment area (Ksz fm/F2); apart from the above mentioned coefficients in the process of assessment we take into consideration: 4. Frequency of formation of mudslides in specific geologic environment within a time unit; 5. Maximal volume of the mass, washed out by the mudslides (in thousand m3); 6. Facilities, which are within the mudslide-prone area. Consequently, the map of risks of mudslides and landslide has been elaborated on the basis of assessment of spatial multi-criteria elements. The risks are classified into 4 categories: 1. High; 2. Medium, 3. Low, 4. No risk. 1. The high risk category is assigned to those areas, where the key components of geological environment (stratum, relief, energy potential) are extremely amenable to formation of different geological processes and are characterized by the high coefficient of damageability (over 0.5) and ability of extreme activation of processes averagely with the interval of 8-11 years; 2. The medium risk category is assigned to those territories, where the coefficient of damageability from landslide-mudslide processes is within the range of 0.1-0.5 and the probability of extreme activation is around 10%; 3. The low risk category is assigned to those territories, where the coefficient of damageability from landslide-mudslide processes is less than 0.1% and the risk of occurrence of landslides and mudslides does not exceed 1%.

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4. To the last category are assigned territories, where without additional unforeseen process-provoking agents formation of mudslides is not probable.

5.Landslide and Mudslide Mitigation Measures

a) Landslide Mitigation Measures

Out of diverse exodynamic processes, which take place in Rioni river basin floods and flash- floods are in direct cause-and-effect relationship with landslides and mudslides. Among landslides, occurring on the territory of the river basin the most numerous are so called coastal landslides, genesis of which is related to the erosive washout of the foothills, side erosion, which causes disruption of gravitational balance of the slopes and development of landslide processes. The above described process is ongoing especially actively during the floods and flash floods. The mechanism of formation of “coastal landslides” is impacted by the inclination of slopes, geological composition, location of so called critical horizon of erosive washout, geodynamic potential of water flow and etc. Coastal landslides, as geological occurrence accompanying floods and flash floods, are the main subject of the below referred adaptation measures. Floods and flash floods are also indirectly impacting so called climatogenic landslides. This adaptation measures are also extended to secondary landslide processes and relevant measures are to be conducted on identified seismsmotectonic landslide-prone slopes. For the purpose of introduction of effective practice of management of floods, flash floods and such hazardous geological processes, related to them as landslides and mudslides, long-term climateforecasts are of crucial importance. The National Environmental Agency taking into consideration the global climate change trends has elaborated hydrometeorological forecasts, according to which expected increase of water discharge in the upper part of River Rioni is going to increase by 26% by 2050, which shall be followed by reduction of water discharge by 10% by 2100. The above provided hydrological indicators, which are derived on the basis of precipitation forecasts, are reference point for planning of adequate adaptation measures for mitigation of increased risk of landslide and mudslide processes. There are numerous classifications of landslide-mitigation measures, which can generally be divided into preventive and engineering-protective measures. Apart from the above-mentioned, there are passive and active landslide hazard mitigation measures. There are following types of passive landslide-preventive measures: restrictive measures (restricting cutting of slopes, agricultural activities, development, destroying of vegetation cover, irrigation, blasting and etc) and regulating measures (reduction of the scope of economic activities, recommendations for retaining sustainability of slopes), adoption of legislation, afforestation of slopes and etc. to active, prohibitio43 garemos erovnuli saagento p i.e. engineering-protective measures belong construction of special anti-landslide slope fortification walls and other constructions, diversion of rivers and etc. Terzaghi (Terzaghi, 1948) also divides anti-landslide measures into two categories: 1. Measures targeted towards prevention of reduction of slope stability coefficient; and 2. Measures targeted towards increasing of slope stability coefficient. Designation of preventive measures is conducting of such measures prior to formation or activation of landslide processes, which shall ensure increase of slope stability coefficient. Apart from the above mentioned, there is classification of landslide-prevention measures by such aspects, as the scope of measures to be conducted, projected time of effectiveness of measures (temporary, palliative) and capital measures, designated for ensuring long-term stability of slopes. Quite often we have to deal with complex of causes, promoting to formation of landslides and consequently, to attain optimal results landslide-prevention measures should be of complex character as well. Such complex measures are related to substantial expenditures, which is the main impediment for conducting of landslide-prevention and protection measures on the level of municipalities. The optimal solution is when notwithstanding such complex approaches, the volume of works to be implemented is minimal, but they ensure sufficient stability of slopes thus preventing formation of landslides. Probably this can be attained through indepth study of local conditions and continuous monitoring of processes. Specific anti-landslide measures and constructions should be selected on the basis of slope stability reports. Among anti-landslide measures conducted for the purpose of protection of population and facilities located in Rioni river basin should be named measures targeted towards neutralization of coastal landslide, as in the process of floods and flash floods this genetic type of landslides are the most typical for this area. Second most widespread genetic type of landslides in this region are so called climatogenic landslides and preventive measures are mainly focused on drainage of slopes. Tectogenic and seismogenic block landslides are clearly visible in the relief and as a rule are characterized by large dimensions. By their dynamic they mainly belong to so called “extinct” landslides. In majority of cases on such landslide-prone areas occur secondary climatogenic landslides. In such cases anti-landslide measures should be of complex character. Lately alongside such preventive measures of natural disasters, as construction of engineering-protective facilities more attention is paid to awareness rising of population regarding risks of natural hazards, which promotes to sharp reduction of cases of loss of life and material losses. Despite this taking into consideration global trends of climate change, in our opinion engineering measures should be implemented more actively too. In the table provided below we list anti-landslide measures, which should be implemented in regard to different genetic types of landslides (Table 7). Measures to be implemented in regard to

prohibitio44 garemos erovnuli saagento p specific landslides are reflected in the landslide cadastre and the table on “Facilities under the impact of landslide processes and measures to be implemented”. Measures reflected in the table, except for measures planned as a result of engineering- geological surveys, are mainly proposed on the basis of experts‟ experience, or recommendations of normative documents (standard 2.01.15-90: engineering facilities for protection of territories from disastrous geological processes). In case of coastal and climatogenic landslides proposed measures are mainly focused on elimination of causes of their formation.

Anti-landslide measures and structures

Table 7

Genetic types of landslide Anti-landslide measures to beimplemented Comments

1 2 3

I. coastal landslides Riverbank and slope protection walls, gabions and In the event of need fascines, geotechstile nets, organizing of cunettes, conducting of additional erosion-protective covers, filling in of rifts, diversion of anti-climatogenic landslide water courses, leveling of watercourses, flow-diversion measures dams.

II. climatogenic landslides Mountain,catch water drain and drainage canals, drainage of surface and groundwater, open and closed drainage systems; capitation of water sources; removal of landslide-prone dirt, terracing of surface, organizing of banquettes, filling in of rifts, silicatization of sand-clay ground and electro- chemical solidification; afforestation of landslide- prone slopes bio-engineering measures, slope protection walls (abutments),; measures restricting agricultural activities and regulating measures

III. Tectoseismogenic slope protection walls (abutments); In the event of need landslides* buttresses, banquettes, counter-banquettes, conducting of additional fortification of cliffy slopes with anchors anti-climatogenic and and piles; anti-gravitational metal nets and coastal landslide enclosures; pouring of cement into rifts andmeasures bituminization

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* In theIIIgenetic category of landslides are included rockslides.

b) Flood Prevention Measures

Floods and flash-floods often become the main cause of formation of mudslides and landslide-gravitational processes ongoing on the slopes often contribute to such occurrence and formation of solid component of mudslides. High energy of mountainous relief, tectonicfeatures of mountains and mountain massives positive vector of neotectonic shifts and climatic- meteorological conditions predetermine intensity of denudation processes in Rioni river basin, as a result of which on the slopes and gorges accumulates large volume of solid material, which is washed out during the mudslides. According to global climate change forecasts by 2050 the number of torrential rain days in Rioni river basin shall increase substantially. In Rioni river basin there is large number of settled areas and communication and economic facilities, falling within the zone of transit of mudslide flows and accumulation of mudslides. In high- mountaneous areas there are conducive conditions for formation of so called glacial mudslides. Glaciar mudslides are characterized with extremely high kinematic energy and consueuently, destructuve power. Coincidence of period of torrential rains and intensive melting of snow is especially dangerous. Due to the above mentioned it is necessary to conduct effective anti-landslide measures in the region. Mudslides in Rioni river basin are of structural or turbulent character, that‟s why we need to differentiate measures to be implemented and adopt individual approaches. Also, different relief and climatic conditions of the catchment area and local specificities need to be taken into consideration. Anti-mudslide measures have been implemented for over a century, but scientifically proven and well tested methods have been developed only in the second half of the XX century. The documents elaborated in that period serve as main guidelines for planning of such measures (such as standard 2.01.15-90 – engineering protection of territories, structures and facilities from hazardous geological processes; or V.D. Lomtadze, Engineering Geology – engineering geo- dynamics, 1977; and General scheme of anti-erosion measures in Georgia). We also use recommendations of reports, prepared by Geological Service of Georgia, Cadastre data and results of surveys, conducted in Rioni river basin in 2013, focused on research of mudslides and possible hearths of landslides. Measures, to be implemented for prevention of mudslides on specific territories are listed in the table provided below. prohibitio46 garemos erovnuli saagento p

Mudslide prevention measures and structures Table 8

Purpose of measures Protective measures Comments

1 2 3 Retention of mudslide flows Water retention reinforced-iron and stone dams and abutments

Diversion of mudslide flows to Diversion canals and bridges bypass engineering facilities and structures

Diversion of mudslide flows to Diversion and retention dams and dykes . conductive channel

Reduction of dynamic of mudslide Organizing of dike dam cascade; flows terracing of slopes and watercourses, agri and forest melioration

Retaining of permeability of Periodic cleaning of mudslide courses and mudslide courses removal of slime and sediment load Prevention of mudslide-forming Flashflood regulating dams and dikes flash floods

Reduction of the volume of solid Regulation of surface water flows on slopes,Given measure is mainly components of mudslides reduction of solid sediments designated for the throughafforestation, truncation and otherstructural mudslide anti-erosion measures formation foci

Forecasting mudslides Organization of monitoring and notification service

Thus, as a summary of measures targeted towards protection of population of Rioni river basin from mudslides, we can state, that effective implementation of the above mentioned measures depends not only on the availability of financial-material resources, but on organizational and methodological support as well, main components of which are the following:

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1. Establishment and functioning of monitoring and early notification system in regard to hazardous geological processes of regional and local dimension; 2. Development of material-technical basis for monitoring of landslide and mudslide processes; 3. Increasing awareness and preparedness of local population; 4. Increasing of the role of local municipalities and delegation of relevant functions.

6. State of Affairs from the Standpoint of Landslides and Mudslides and the Risk of their Occurrence by Municipalities

6.1 Oni Municipality

Geographical Location

Oni Municipality administratively belongs to Racha-Lechkumi- Kvemo region. The total area of the municipality is 1712 km2, the population is 8372 persons; population density per 1 km is 5,4 persons. Number of settled areas – 66 villages and 1 city. The territory is located in the River Rioni catchment area and includesmountainous Racha depression and the territory located upstream of river Rioni.Morphologically it is located on the southern slope of the Greater Caucasus and from the north-east it is bordering with the main watershed on the Caucasus Crest, while on the south and south-east it is bordering with Kvemo Racha depression and Racha Ridge.

Geomorphogical peculiarities of the area

The relief of the area is mountainous and highly diverse. The southern slope of the main Caucasus Ridge and the Lechkhumi Ridge belong to the high-mountainous Apline and Sub-Apline landscapes, while certain elevated sections of the Racha Ridge are of a sub-apline landscape type. Hypsometrically lower part of the area is occupied by the gorges of river Rioni and its tributaries. The northern high- mountainous part of the area has a glacial nival and erosive-glacial relief, which is intensely broken. The depth of erosive cutting is more than 1000 m here, and the slope inclination is 40-60°. The absolute height of the main Caucasus Ridge and Shoda-Kedela goes up to 3500-4000 m (the height of the Shoda mountain is 3609 m).

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The northern part of the region includes high-mountainous erosive-denudation relief of deep gorges that is developed over the substrates of the Jurassic system. The mild forms of the relief in the given part of the region are the result of the influence of the erosive processes on intensely dislocated mica sandstones and clay slates of the Lias Age. The relief is broken with a dense river network. The gorges are mostly V-shaped, but in places where the clay slates are dominant the rivers form trough-like gorges. For instance, the width of the river Rioni floodplain around the village Ghebi is 150 m; it is 280 m between village Ghebi and village Chiora and it is 230 m at village Chiora.

Average-mountain mountain-gorge denudative relief with dominating erosive and landslide processes. The given type of relief is prevalent in the central and southern parts of the region and it is an immediate eastern continuation of the Racha-Lechkhumi syncline depression. The given type of the relief is developed over the substrate of the clay-sandy and carbonate sediments of the Upper Jurassic, Cretaceous and Tertiary Ages. The old-landslide forms of the relief and modern active landslides are widely prevalent in the area. Such relief is developed on the slopes of the gorges of the rivers Rioni, Jejora and their tributaries. The given kind of the relief is common in the areas of villages Korta, Skhieri, Shardometi, Bajikhevi, Parakheti, Chorda, Somitso, Kvemo Bari and others. The slope profile here shows the trace of the landslide processes, as it is wavy-and-stepped. 20-50-m-high walls have been developed in the part of the region that is made up of the mass limestones (villages Khirkhonisi, Skhieri), with the colluvial grounds in their basis being the hearth of inception and development of the erosive and landslide processes.

The central and southern parts of the territory belonging to the middle-mountain zone are characterized by vertical erosive break-ups ranging between 300-600 m. The slope inclination is 30-45°. in addition to the erosive processes the relief of the average-mountain portion shows the traces of karst processes. The river terraces in the river Rioni gorge have survived in the areas adjacent to villages Skhieri, Kristesi, Somitso, Komandeli and others. The first above-floodplain terraces are prevalent along the river Rioni in the areas of Oni and Ambrolauri municipalities located at 3-4 m above the modern bed. The town of Oni is build over these terraces.

Karst relief developed over the substrate of the Cretaceous and Tertiary Carbonate rocks. Within the area of the Cretaceous and Tertiary carbonate sediments of the region karst formations represented by caves and karst cones are developed. The karst formations developed over the Lower prohibitio49 garemos erovnuli saagento p

Cretaceous carbonate substrate are highly prevalent in the extreme eastern part of the northern slope of the Racha Ridge, around mountain Khikhata and Khirkhonisi where these forms are developed as caves or karst cones. They are also spread over the areas of villages Putieti, Mtiskalta, Usholta, Shkmeri, Kharistvali, Zemo Bari, Kvemo Bari and Mukhli. The great number of karst formations is the result of the massiveness of Barrem limestones.

Tectonics and geology

The territory is characterized by fairly stressed tectonic conditions. It is crossed by three lateral young and old ruptures, which are complicated by thrusting and disjunctive dislocations of different directions and is well seen in the relief. The following large tectonic units can be identified among them: the extreme northern part of the Main Caucasus Ridge, which covers the heart of the crystal slates anticlinorium in the central zone of the Caucasus; folded system of the southern slope of the Great Caucasus, which, across the area spreads as a wide strip from north-east of south-east and is represented by the Lower and Middle Jurassic clay slates of Kazbegi- zone; it is also represented by the Shovi-Pasanauri sub-zone of -Tianeti zone made up with the Upper Jurassic and Cretaceous carbonate flysch sediments, while the south-western part of the area is bordered by Chkhalta-Laili zone represented by the Upper Paleozoic and Triassic metamorphic clay slates. Almost over all the area of the north-eastern part of the area Jurassic porphyrite stratum spreadsfrom east of west, while the southern and south-western part of the area is occupied by the Gagra-Java zone Racha- Lechkhumi synclinorium sub-zone. The tectonic movements, which continue to present, have influenced the seismicity of the area. The epicentre of the earthquakes registered in the region lies within the study area. Almost the entire region is located within 6-7-point-intensity earthquake zone. The earthquakes promote the inception and development of dangerous geodynamic processes in the study area and are a temporary contributors to the development of the mountain creeps of large and small landslide bodies.

The geological makeup of the area is comprised of the formations of the Jurassic, Cretaceous, Tertiary and Quaternary systems represented by cliffy, semi-cliffy, coarse-fractured and clay rocks.

The Upper Lias sediments are known as “Sori stratum” with lithology made up of the alternating layers of clay slates and sandstones. prohibitio50 garemos erovnuli saagento p

The Middle Jurassic sediments are highly prevalent in the high-mountainous portion of the Oni District represented by the formations of Aalenian and Bajocian Ages.

Lithological makeup of The Aeolenian sediments is sandstones and clay slates, while the lithology of the Bajocian porphyrite stratum is represented by the rocks of effusive formation: porphyries and their pyroclastolites, tuffas, tuffa-breccias, tuffa-conglomerates and tuffa-sandstones. Together with the Aalenian sediments they are prevalent in the gorges of the rivers Sontarula, Sakaura, Chala and Jejori as well as across the Racha Ridge.

The Upper Jurassic sediments, which are the formations of Cellovial-Oxford Age are spread over the northern wing of Zemo Racha syncline (in the upper reaches of the river Rioni flow). They are represented by thick-layer marls, carbonate slates and limestone interlayers, and by dark grey clays and carbonate sandstones over the southern wing.

The formations of the Oxford-Thitonian Age run as a continuous line along the northern wing of the Zemo Racha syncline. They are represented by limestones with marl interlayers, carbonate and sandy limestones, micro-conglomerates and breccias limestones, while over the southern slope their lithology comprises carbonate slates, slate clays, sandy limestones and carbonate sandstones.

Apt-Albine Age sediments are represented by clays, sandy-clay slates and argillites, which alternate with sandstones.

The Cenomanian sediments are prevalent in the gorge of the river Kheuri and are made up of glauconitic sandstones. the Tertiarysystem sediments. The Paleocene-Eocene formations are represented by carbonate facies, thick-layer and massive limestones, marls and sandy limestones. They outcrop around village Chordi.

The “Maykop Series” formations of the Oligocene-Lower Miocene Age are widely spread in the study area. Their outcrops have been observed around villages Zemo Bari, Parakheti, Seva, Chordi, etc. The Maykop Series is mostly represented by slated clays and sandstones.

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The Quaternary sediments are made up of elluvial, delluvial, colluvial, alluvial, prolluvial and glacial-and-fluvioglacial formations and differ significantly from one another with their physical- mechanical and engineering-geological properties.

The alluvial sediments are represented by the above-floodplain terraces of the river Rioni, with three above-floodplain terraces identified. They are located at different heights from the riverbed and are made up of boulder and shingle, with gravel and clay loam joining materials. The remnants of the oldest third terrace in the area of Zemo Racha are seen on the right side of the river Rioni gorge developed around village Sori, while on the left side they are developed around the town of Oni and then run through the river Jejora gorge, between the villages Zhashkva and Pipileti, where they have survived over small areas.

The second terrace of the river Rioni is spread over small areas around village Sori. It survives at about 50 m above the modern bed. Its length is 800-900 m and its width is 50-60 m. These sediments are built with well-treated boulders and shingle and sandstones and sand-gravel and porphyrite stratum of the Bajocian Age, cemented with clay and clay loam. Their strength is 6 to 7 m.

The second terrace of the river Rioni in the area of the town Oni is located over the washed out surface of the porphyrite stratum of the Bajocian Age. It survives at the height of 70-80 m from the modern bed and covers about 1.5 km2 area. It is made up of boulder and shingle with sand-gravel and clayey soil joining materials.

The first above-floodplain terrace around village Sori is spread across about four kilometers; its width is 300-400 m. It is located at the height of 4-6 m from the current riverbed and is represented by poorly sorted shingle with boulder accretions and sand-gravel with the clay and clay loam joining material. The terrace is covered by strong delluvial sediments.

The fluvio-glacial sediments developed in the region are prevalent around the town of Oni. They would develop as a result of disintegration of steep and gullied slopes and are spread in the villages of Kheiti, Khirkhonisi, Zhashkva, Kristesi, on the right flank of the river Kheori, over the left slope of the river Rioni, in the river Jejori water catchment basin, etc. The mentioned formations are of large sizes and are located over an uneven surface and are made up of block talus and clay loams what can be associated with the early glaciation cycle. The product of disintegration of the old fluvio-glacial

prohibitio52 garemos erovnuli saagento p sediments is the landslide bodies developed at about 200 m above the Jejora riverbed in villages Somitso and Shardometi.

The product of old fluvio-glacial sediments is villages Somitso, Shardometi and others.

Large accumulations of colluvial sediments in the region are observed in the areas where Cretaceous limestones and sandstones are prevalent. The thick material accumulated at the bottom of the walls is represented by of lithologically different rocks of the block talus and fractures. The colluvial sediments in some areas of the region are represented by relatively small fractures and detrital material, which are often cemented with clay material. The thickness of the colluvial sediments at the bottom of the walls is highly variable and ranges from 5-10 to 80 m. The material accumulated at the bottom of the walls and steep slopes is particularly thick.

The delluvial sedimentsare mainly represented by clay and clay loam ground containing accretions of cliffy and semi-cliffy rocks: grit and detritus, with rare accretions of stone circles. The delluvial sediments are widely spread in the region and attain quite high thicknesses over the both flanks of the river Rioni. Similarly thick delluvial sediments are developed over the flanks of the river Kheori gorge, around village Bokva.

Over the delluvial sediments at the mouths of almost all gorges and slopes in the region there are landslide bodies developed, the n’th part of the majority of which reaches the bed of the gorges and form favorable conditions for the inception and development of hearths of mudflow. This process is further exacerbated by high steepness of the slopes, their lithological composition and circulation of underground waters.

The modern Elluvial-Delluvial formations are widely prevalent across the region. These sediments are represented by two varieties: in the area with cliffy rocks, their lithology is primarily detritus and block talus with clay and clay loam joining material, while in the area where semi-cliffy and clay rocks are spread, they are represented mainly by clay and clay loam ground with grit and detritus accretions. The thicknesses of these sediments vary highly and are within 2-20 m.

The modern Elluvial sediments are mostly prevalent in the watershed ridges. Lithologically they are represented by two varieties: where the carbonate, terrigenous-metamorphous and volcanogenic-

prohibitio53 garemos erovnuli saagento p sedimentary cliffy rocks are prevalent the elluvial sediments are represented by detritus and block talus with the clay and clayey soil as joining material, while in the areas where the carbonate-terrigenous, laguna, flysch and terrigenous semi-cliffy formations are prevalent the elluvial sediments are represented by clay and clayey soil with the grit and detritus as joining materials. Their thickness varies between 2 and 5 m.

The Prolluvial sediments in the region are mostly prevalent at the confluences of the mudflow currents of the river Rioni and near the confluences of small gullies in the river Rioni basin. The Prolluvial sediments are mainly represented by poorly sorted gravel and shingle with the sand and clay loam joining material.

Hazardous Geological Processes

Relief of Upper Racha Oni Municipality is characterized by high geodynamic potential which is preconditioned by the following: high inclination of slopes (30-450 and more); high frequency of hydrographic network; activation of subsurface erosion, high sensitivity of stratum towards geological processes and climatic-meteorological factors, large volume of Quaternary period sedimentation (8-25m) and etc. The above mentioned factors precondition the large scale of hazardous geological processes. On the territory of Oni municipality different hazardous geological processes are represented at a more-or less different scale. Among them the most hazardous and damaging processes are: erosion, mudslides and gravitational (rockslide, rockfall) processes. Hazardous geological processes occurring in the region, the area of their occurrence and geodynamic features of these processes coincide with specific zones of geological-geomorphologic conditions. Apart from natural conditions, which impact development of hazardous geological processes, anthropogenic factor is becoming one of the most important factors contributing to their severity. Among such anthropogenic factors are residential and industrial construction, use of forest massives and etc. below we provide characteristics and description of hazardous geological processes. The Cadastre of landslides and mudslides on theterritory of Oni municipality has been developed on the basis of survey of hazardous geological processes, occurring on given territory. In the process of identification and assessment of causes of hazardous geological processes the issues, related to sensitivity of composing stratum are playing important role.

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In given regard it should be noted, that quarts-arkosic sandstone and limestone and marls of Jurassic-Cretaceous period create cliffy slopes, which create the zone of rockslides and rockfalls. Quite often such zones represent the locations of formation of mudslide flows and feed solid components into these flows. On the territories, composed of terrigene-carbonate formation semi-rocky stratum, such as clay-slate and marl, are the most conducive conditions for formation of mudslides and landslides. As to sedimentation of Quaternary period, represented by Elluvial-Delluvial, Elluvial- Proluvial and Fluvio-Glacial genesis loosely-coupled argillo-arenaceous stratum erosive processes are the most widespread. Below we provide data on the scope of spread of certain geological processes and the trends of their development. Erosion processes occurring on the territory of Upper are of diverse character. Namely, there is subsurface erosion, side erosion (washout of river banks) and surface erosion (soil erosion). One of the main factors, causing subsurface erosion is availability of erosion-sensitive stratum of the water course bed (clay-slate, slate, elluvial-glacial deposits), high energy of water flow and excessive atmospheric precipitation. Subsurface erosion is occurring in almost all small and large river beds and ravines. Subsurface erosion is especially strong in the period of spring showers and melting of snow. Side erosion is mainly characteristic in the beds of Jejora, Gharula, Chanchakhi, Kheuri and Sontarula tributaries of river Rioni, where the river banks are mainly composed of Elluvial- Proluvial and glacial deposits. Side erosion is mainly present on plains and floodplain terraces, which are located on the territories, adjacent to villages Sori, Shardometi, Parakheti, Sevas Sromisubani, Khvaskhkieti, Zudali, Bokva, Skhieri, Komandeli, Nigvznara, Ghari, Sheubani, Tsmendauri, Samitso, Pipileti, Sorgiti, Nakieti, Chinchvisi, Utsera, Saglolo, Glola, Shovi, Chiora, Gona and town of Oni. Quite often side erosion provokes landslides, as in the process of flash floods occurs erosion of slope bases and gravitational balance is undermined. Frequency of gullying erosion is mainly preconditioned by the prevalence of Elluvial- Diluvial deposits, abundance of atmospheric precipitation and shallow location of groundwater. The latter is discharged into erosive crevices. Gullying erosion is especially activated during the spring showers and the period of snow melting. Landslide processes. All landslides, occurring in the region are divided into groups dependingon engineering-geological complex, with which the landslides are linked. Landslides, which develop in the deposits of Oligocene-Lower Miocene period, so called Maikop Clays are characterized by large size (10-900ha). Such landslides develop on the sandy- argillaceous and sandy substrates. In dry condition Maikop clays are characterized with high solidity. By mineral composition they belong to montmorillonites, but they are highly sensitive when absorbing moisture and are easily transformed into landslides. By dynamic the landslide prohibitio55 garemos erovnuli saagento p formed in the Maikop clays are either active, or temporarily stable. Such landslides are occurring on the territories, adjacent to villages Samtisi, Kvemo Bari, Bajikhevi, Farakheti, Shromisubani, Kvashkieti, Simitso and Zhashkva. Landslide bodies on the territory of villages Samtisi, Bajikhevi, Farakheti, Shromisubani and Samitso (see pictures 1 and 2) are tectoseismogenic, characterized by high power and are caused by reduction of stability of stratum, depletion of parental material of slopes, saturation of stratum and quaternary period deposits with ground and surface water and intensive side erosion of the slopes caused by flash floods. Landslide bodies on the territory of Kvemo Bari, Kvishketi and Zhakva are characterized by medium strength and mainly develop in the Quaternary stratum. Causes of these landslides are: saturation of quaternary clay soils with surface and ground water; intensive erosion of slope bases in the period of flash floods; high sensitivity of clay soils and anthropogenic load on the slopes.

Picture#1Picture#2

Villages Parakheti, Bajikhevi, Shromisubani and Samitso are located within the high risk zone, while villages Kvemo Bari, Kvasha, Zhashkva are located within medium risk zone. Village Samtisi is located within the low risk zone. Landslides are also widespread in Lower Oligocene and Cretaceous deposits. By their size these landslides are quite large (100000 - 900000m3). By the mechanism of movement they mainly belong to sliding type of landslides. Landslides develop on limestone, marl, sandstone, carbonate clay and conglomerate substrates. By their dynamic they are active, or temporarily stable. Landslides of plastic relocation are relatively rare. In majority of cases they are surface type, although in some cases they may seize part of depletion mantle. Overall, surface mudslides by

prohibitio56 garemos erovnuli saagento p their dynamic belong to category of active mudslides. They are represented on the territory, adjacent to villages Samtisi, Zemo Bari, Kvemo Bari, Gomi, Utseri and Shkmeri. Territory of villages Zemo Bari, Kvemo Bari, Gomi and Utseri are located within the high risk zone, while Samtisi and Skmeri are located within the low risk zone. Landslide bodies on the territory of villages Samtisi and Gomi are tectoseismogenic, are characterized by huge power. The reason of their formation and activation is reduction of stability of stratum, sharp incline of slopes, depletion of composing stratum and high saturation of base rock and quaternary deposits with ground and surface water. Landslides occurring on the territory of villages Zemo Bari, Kvemo Bari and Shkmeri are characterized by medium power and are mainly occurring in the quaternary deposits. Main reasons of their formation are: high saturation of base rock and quaternary deposits with ground and surface water, intensive erosive washout of slope bases in the period of flash floods, high sensitivity of clay stratum and anthropogenic load. Landslides occurring in the zone of location of Cimmerian-titonic stratum are of extremely large size and are occurring on clay, sandstone and conglomerate substrate. These landslides by their dynamic are in active or temporarily stable condition. Landslides occur in Deluvium clay stratum located near villages Shardometi, Parakheti, Seva, Zhakva and Bajikheivi. Territories of villages Parakheti and Bajikhevi are located within the high risk zones, while villages Seva, Zhakva and Tskhmori are located within the medium risk zone. Village Shardometi is located within the low risk zone. Landslides on the territory of village Tskhmori are tectoseismogenic and characterized by huge power. The reason of their formation and activation is reduction of stability of stratum, sharp incline of slopes, depletion of composing stratum and high saturation of base rock and quaternary deposits with ground and surface water. Reasons of formation of landslide bodies on the territories adjacent to villages Seva and Shardometi are: high saturation of base rock and quaternary deposits with ground and surface water, intensive erosive washout of slope bases in the period of flash floods, high sensitivity of clay stratum and anthropogenic load. Landslide occurring in the deposits of Colluvium-Oxford period are represented on the territories adjacent to villages Kvemo Bari, Tskhmori, Chibrevi, Seva, Komandeli (see picture 3) and Khirkhonisi where they occur on sandstone, clay-slate, conglomerate, carbonate and clay deposits, characterized by high sensitivity. Landslides occurring on the territories adjacent to villages Chibrevi, Tskhmori and Kvemo Bari are tectoseismogenic, characterized by huge power. Main causes of these landslides are: reduction of solidity of stability of stratum, sharp incline of slopes, depletion of composing stratum and high saturation of base rock and quaternary deposits with ground and surface water, high saturation of base rock and quaternary deposits with ground and surface water, intensive erosive washout of slope bases in the period of flash floods. prohibitio57 garemos erovnuli saagento p

Landslides located on the territory of Seva and Khirkonisi are of medium strength and occur mainly in the Quaternary stratum. Reasons for their formation are: high saturation of base rock and quaternary deposits with ground and surface water, intensive erosive washout of slope bases in the period of flash floods, high sensitivity of clay stratum and anthropogenic load. Villages Chibrevi andKhirkonisi are located within the medium risk zone. Landslides occurring on the territories characterized with stratum of Mid Jurassic period and baios agestratum are represented on the territory of village Sakao (picture 4), Mazhieti, Sorgiti, Psori and Jinchvisi. Landslides occur on tuff, tuff-breccia and porfirit substrate. Products of their depletion are characterized with medium sensitivity. Landslides by their dynamic are in active and temporary stable condition. Landslides are characterized by medium strength and are mainly occurring in the quaternary stratum. Main reasons of their formation are: sharp inclination of slopes, intensive depletion of stratum and excessive saturation of quaternary stratum by surface and ground water.

picture #3 picture #4

VillagesSakao and Majhieti are located within the high risk zone, while village Fsori is located within the medium risk zone. Villages Jinchvisi and Sorgiti are located in the low risk zone. Landslide developed in the Middle and Lower Jurassic period stratum occur in villages Mazhieti, Khideshlebi, Ghunda, Chordi and Psori. They occur in the depletion mantle of clay-slate and sandstone stratum, which is characterized by medium sensitivity to landslide processes. Old landslide bodies periodically get activated. Reasons of formation of landslides are: reduction of stability of stratum, sharp incline of slopes, depletion of composing stratum and high saturation of base rock and quaternary deposits with ground and surface water. Villages Mazhieti and Khideshlebi are located within the high risk zone. Villages Ghuncha, Chordi and Psori are located in the medium risk zone.

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Among important factors, causing landslides are lithologic specificities. Depletion plays decisive role in formation of slopes and preconditions their state. Highly dispersed structures are no lessimportant, as they are less stable on the slopes. Superposition of stratum has important impact on formation of landslides. Climatic factors play important role in formation of landslides on the territory under examination. Ground water also causes formation of plastic landslides. Side erosion, occurring in the process of flash floods also contributes to landslide processes. The role of anthropogenic factor in the formation of landslides should be stressed too. Economic and engineering activities on the territory of the region cause disruption of balance on the slopes, which triggers formation and activation of landslides.

Mudslides. Complicated orography, morphometry, geomorphologic and geological conditions of the upper reach of Rioni river, as well as specificity of circulatory atmospheric processes promote to intensive formation of mudslides. Mudslides occur in Oni Municipality almost on annual basis, but the most dangerous mudslides are those, which are formed on the same location once in 11-25 year cycle. It is noteworthy, that strong mudslides do not occur simultaneously on the tributaries of Rioni and they are formed depending on micro and mezzo circulatory atmospheric processes. Although it should be noted, that spring torrential rains, caused by entering of warm atmospheric masses on the territory of Shoda-Kedela Ridge in their turn promote to intensive melting of the snow cover and formation of mudslides in the river gorges. On the background of general flooding this also causes pulsating flash floods, activation of side erosion, intensive washout and landslides on the slopes and erosion of plains and floodplains. Mudslides in Rioni river basin mainly occur in the river gorges and foothills. In relatively short period of time they have large destructive power and they represent serious risk to population and engineering communications. On the territory of Oni municipality mudslides rarely contain only mud and they are rather of stony-muddy composition. The solid component is fed into these mudslides by landslide bodies, located on cliffy slopes. Mudslides cause demolition of river banks, roads, bridges, damage agricultural lands and represent hazard to settled areas. In the spring of 2005 climatic conditions caused intensive melting of snow in the upper reach of Rioni. Strong floods were followed by 2-4 hour long flash floods due to blocking of gorges by mudslides. Flash floods caused substantial damage to population residing in the town of Oni and the region itself. 30 houses were demolished and agricultural land was damaged. In Oni municipality generally occur mudslides containing solid components. Currently the population of the region is mostly threatened by the mudslides in the following gorges: village Ghebi – 3 mudslide gorges, which destroyed several houses. Mudslide gorges which mainly develop on the north and west of village Ghebi damage the highway and agricultural land plots. River Kheuri creates risks to village Zudali (see picture 5). In village Little Ghebi Larkhishou gorge represents risk to population and the bridge, crossing Rioni (see picture 6). prohibitio59 garemos erovnuli saagento p

F

Picture #5 Picture #6 In the north-east of village Dididze Ubani river Chishura, which is left tributary of river Rioni represents risk to the population, the bridge and agricultural land plots. River Bdgviora crossing the village Glola for many years represents risk to the population of the village, holiday camp “Shovi”, the road and the bridge (see pictures#7 # 8).

Picture #7 Picture #8 In village Glola in Bokvistskali gorge in the spring of 1988 occurred devastating flash flood, caused by obstruction of the river bed with rockslide and its breakthrough at a later stage. Such mudslides and flash floods occur in the mountain rivers almost on annual basis. Village Utsera is located within the zone of high risk due to Mushvani gorge, which is located to the west of the village, as in the river headis accumulated large volume of deposits, representing high risk and having potential of transforming into a mudslide. Such mudslide can cause catastrophic results not only to the village, but to the population, located downstream of river Rioni. Similar processes can occur on almost all mountain rivers.

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The vegetation cover on the territories, described above is quite poor as a result of intensive cultivation of land plots. Intensity of surface washout is increased, due to which the probability of occurrence of landslides increases too. Mudslides are also formed under the impact of landslides, as they play important role in feeding of solid components into the mudslides. At the same time it should be noted, that surface washout and landslide processes mainly occur in delivium and eluvial-deluvial formations. Due to this in the solid mechanical mass of the mudslides prevail clay fractions. After examination of geological section of given locations it was established, that such mudslide sediments are composed of fine-grained materials (sand, sludge) and such solid components (stones, sand, gravel), which can move freely on the bottom of the flow. On the debris cone sometimes we can observe large rocks, which have broken off under the impact of velocity of the flow. In Oni municipality are also represented several water flows bringing down stones, which are formed in the terraced deposits of rivers. They occur in such areas as Tsola gorge (the right tributary of river Jejora), temporary flows, coming down from Tsmendauri terrace on the territory of the town of Oni and etc. it should be noted, that number of such gorges is quite limited. Such flows are characterized by minor turbidity, as they contain small amount of fine grain fractures and are mainly containing solid material. Climatic conditions of the region play important role in formation of mudslides. During the warm seasons atmospheric precipitation is high and torrential rains occur quite often, which causes high surface flows. Formation of mudslide processes is also influenced by erosion-denudational relief spread on large territory, which is characterized by sharp incline of slopes and high energy of rivers. Majority of mudslides occurring on the territory of Oni municipality are of turbulent type and water is the main moving power in such cases. Although it should be noted, that some mudslides are of structural character and they are usually formed in extreme situations. Such mudslides occurred in previous years during the heavy snowfall in village Ghebi and other villages. Such mudslides occur as a result of high saturation of steep slopes and disruption of local balance, due to which large sticky mass starts moving towards lower benchmark at high velocity. It is noteworthy, that majority of mountain river gorges do not have debris cone and they directly flow into large rivers through narrow river bed and obstruct them, as a result of which large territories are flooded. Length of passage of mudslides occurring in the region does not exceed 1-1,5 hours. Turbulent flows contain 40% of solid material. The ability of transportation of this material is predetermined by the water mass and such solid material is gradually accumulated alongside with movement of water flow. Such processes mainly occur in summer period and have large spread and frequency.

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In the mudslides of structural character composition of solid material exceeds 60%. They occur mainly in the spring, more rarely in the fall and they are usually large by their scope. Material transported to the accumulation zone is usually spread on small area and creates elevations on the relief. Preventive measures need to be conducted in the mudslide-prone gorges. Such measures should be of complex character taking into consideration, that erosion, landslide and rockslide processes are characteristic on given territories. Among such measures should be cleaning of slopes from mudflow, afforestation of such areas, terracing of slopes and etc. Taking into consideration all the above mentioned and results of field surveys we came to conclusion, that out of 43 settled areas of Oni municipality, impacted by disastrous geological processes 18 settled areas are located within the high risk zone, 17 settled areas are located within the medium risk zone and 8 settled areas are located within the low risk zone. (Seetable) Out of 66 settled areas within the scope of spread of disastrous geological processes and the overall level of their activation, 35 settled areas and adjacent territories are within the high risk zone. 22 settled areas and adjacent territories are within the medium risk zone and 10 settled areas and adjacent territories are within the low risk zone.

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Facilities under the risk of landslides, located in Oni municipality and measures to be implemented Table 9

Number of Damage caused by Preventive measures to be Settled areas Number of landslide Total area of households landslides Dynamic status of a conducted # bodies and their landslides residing in landslide body and the geographical location (ha) the settled level of risk area 1 2 3 4 5 6 7 8 Oni Municipality

1 Village north-east exposition 183,24 98 Within the scope of Old landslide bodies, Regulation of the ground Shardometi of the left slope of river the landslide contour temporarily stable, with water level on the slopes Rioni, western part of are located 23 low dynamics; risk through construction of village Shardometi households and level – medium drainage system agricultural lands

2 Village Chibrevi River Murekhani, the 69 1 Within the scope of Old landslide bodies, Currently there is no need left tributary of river the landslide contour temporarily stable, with of conducting of landslide- Rioni; eastern are located 5 houses low dynamics; risk preventive measures exposition slope and agricultural lands level – medium

3 Village 3 landslide bodies, 2 of 161,5 111 Houses, road and 2landslides are active, Ground water is regulated Farakheti them located on the agricultural lands are with high dynamics, 1 through drainage system; right slope of river damaged; 22 houses landslide is periodically landslide-prone slopes are

Mukhrani, west are under the risk; 3 active, with medium truncated; construction of 2 exposition slope and 1 households have been dynamics; risk level – protective structures on the landslide is located to resettled. medium gorge of river Mukhrani on the left of river the area of location of Cheshora on the slope landslides; due to their size of western exposition and power of the landslide conducting of protective measures is practically

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impossible

4 Village Seva 2 landslides on the 80,85 40 Within the scope of Old landslide bodies, Regulation of ground water right western the landslide contour temporarily stable, with levels on the slopes; exposition slope of are located 32 low dynamics; risk afforestation of slopes; river Cheshora households and level – medium conducting of coast- agricultural lands protecting works for the purpose of reduction of side erosion

5 Village Left tributary of river 46,15 3 Agricultural lands and Old landslide bodies, Due to sharp incline of Shromisubani Rioni; the left western 4 houses were active, with high slopes conducting of anti- exposition slope of damaged. 4 dynamics; risk level – landslide measures is not river Kheuri households residing in high expedient these houses were resettled.

6 Village Lachta- Middle and lower part 110,56 129 Within the scope of On the slope is Currently there is no need Sheubani of the right slope of the landslide contour represented an old of conducting of landslide- river Rioni of south- are located 85 houses landslide body, preventive measures east exposition and agricultural lands temporarily stable, with low dynamics, risk level – medium Village Sakao 7 Left slope of western 42,2 115 The landslide Contemporary Diversion of ground water, exposition of river periodically damages periodically active restoration of forest cover

Sakaura gorge villages of Sakaura landslide with medium

gorge and the road, dynamic; risk level – connecting with the high regional center

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8 Sakao-Mazhieti Left Village lope of 4,3 The landslide damages Contemporary Slope-fortification works connecting road western exposition of Sakao-Mazhieti periodically active are not expedient due to river Sakaura gorge connecting road landslide with high complex relief; the road dynamic; risk level – should be moved further high away from the slope

9 Village 2 landslides on the left 93.9 84 13 houses, agricultural 1 landslide is active, Regulation of ground water Khideshlebi slope of river Sakaura land plots and with medium levels on the slopes; gorge of west and agricultural lands have dynamics; 1 landslide is afforestation of slopes; south-west exposition been damaged temporarily stable with low dynamics. Risk level – high

10 Village Mazhieti 2 landslides on the left 125,6 60 22 houses, located on Old landslide body Regulation of ground water slope of south-west the landslide-prone with local activation levels on the slopes; filling exposition slope of slope have sustained areas, of medium in of landslide crevice; river Sakaura and the damage of different dynamics, risk level – truncation and stripping of right slope of south- degree; 3 households high the slope east exposition of river were resettled Badeura, which is left tributary of river Sakaura

11 Village Upper and middle part 75,3 43 The landslide Old landslide body, Regulation of ground water Khirkhonisi of the left slope of represents risk to active, with low levels on the slope

north-east exposition agricultural lands and dynamics; risk level – of river Rioni major part of the medium population (30 households)

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Village Somitso 12 Left slope of north 314,45 5 The population of the Old landslide body, Due to complex character of exposition of river village has been active, with medium the landslide, its large size Rioni resettled during dynamics; risk level – and the fact, that the

previous years; the high territory is not settled, landslide damages conducting of landslide agricultural lands and preventive measures is not local road expedient

13 Village Lower part of the left 50,55 35 The landslide damages Old landslide body, Regulation of ground water Komandeli slope of River Rioni, the road, 25 houses partially active, with levels on the slope through north exposition are located on the medium dynamics; risk construction of drainage

landslide-prone slope level – medium system; construction of coast-protective structure on the left coats of river Jejora alongside the active part of the landslide.

14 Village medium and upper part 74 17 The landslide damages Old landslide body, Regulation of ground water Zheshkva of the left slope of left agricultural lands, the periodically active, levels on the slope through tributary of river Rioni crown of the slope and with medium construction of drainage river Chalistskali 12 households residing dynamics, risk level – system; truncation of the in the district medium slope, construction of coast- Kalmakhelidze protective structure on river Chalistskali for reduction of erosion

15 Village The right slope of west 52.26 20 Causes damage to Old landslide body, Conducting of landslide Kvashkieti exposition of river agricultural lands temporarily stable, with preventive measures is not

Kheuri, left tributary of low dynamics, risk expedient river Rioni level – medium

16 Village The right slope of west 287 20 Causes damage to Old landslide body, Regulation of surface water

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Tskhmori exposition of river agricultural lands. Out with locally active flow (drainage of slopes); Chalistsklai, left of 25 households areas, with medium afforestation of slopes; tributary of river Rioni residing on the slope, dynamics, risk level – filling of landslide crevices 8 households, located medium and tamping and terracing

within the tip of the of landslide mass landslide are under the high risk

17 Village Pipileti The left slope of river 75,65 22 Causes damage to Old landslide body, Currently there is no need Jejora, left tributary of agricultural lands. stable, with low of conducting of landslide- river Rioni Minor deformations dynamics; risk level – prevention measures are identified on the low houses, located on the slope

18 Village Sorgiti Middle and lower part 52 3 Within the scope of Old landslide body, Regulation of surface water of river Jejora slope, the landslide contour stable, with low flows with drainage

left tributary of river are located 11 houses dynamics; risk level – channels

Rioni and agricultural lands low

19 Village Zemo The right slope of west 80,1 36 Within the scope of Old landslide body, Regulation of surface water Bari exposition of river the landslide contour stable in the middle and and ground water flows Berula, left tributary of are located 25 houses upper part. Tip of the with drainage system on the river Rioni and land plots. landslide is active and it right bank of river Berula, Damage is caused to is washed out by river alongside the tip of the agricultural lands Barula. Risk level – landslide located in the lower medium part of the landslide

20 Village Kvemo 2 landslides on the 107,8 31 12 houses and Old landslide body, Collection of all ground and Bari right south-west and agricultural lands are with locally active karst water surface outlets left north-west damaged areas, with medium into one capital isolated

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exposition slopes of dynamics, risk level – watershed; diversion of river Berula, left medium water from the slope; tributary of the river terracing and afforestation Rioni of landslide-prone slope

21 Village Samtisi Right north-east 48,11 16 Within the scope of Old landslide body, Currently there is no need exposition slope of the landslide contour stable, with low of conducting of landslide- river Barula gorge, left are located dynamics, risk level – prevention measures tributary of river Rioni agricultural lands; low does not cause damage to settled area

22 Village Utsera Right south-east 10,47 325 Causes damage to 1 stable and 1 Capital repairs of catch exposition slope of agricultural lands and periodically active, water cistern and regulation river Rioni, 2 represents risk to 10 with medium dynamic, of ground water levels; landslides are households located at risk level – medium construction of protective identified the bottom of the structures at the bottom of slope the slopes for protection of population

23 Village Gomi 2 landslide bodies on 39,35 85 Within the scope of Both are old landslides, Restoration of water supply the right south and the landslide contour with periodically system pipe and drainage of south-east exposition are located 7 houses. activated areas, with ground water; slopes of river Water supply system medium dynamics; risk implementation of Gomrula, left tributary and the local road is level – medium landslide-preventive of river Rioni damaged measures on the second landslide is notpossible due to its complex character, large size and sharp incline of slope

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24 Village Jinchvisi Left slope of north-east 14,75 65 Within the scope of Old landslide body, Currently there is no need exposition of river the landslide contour stable, with low of conducting of landslide- Gomrula, left tributary are located 6 houses dynamics, risk level – prevention measures of river Rioni and agricultural lands low

25 Village Psori 2 landslides on the left 78 5 Within the scope of Both landslides Organizing of drainage south-east exposition the landslide contour aretemporarily stable system on the slope for

slope of river Jejora, are located 20 houses with low dynamics; risk regulation of ground and left tributary of river and agricultural lands level – medium surface water flows Rioni

26 Village Left south-east 37,88 15 On the slope, damaged Old landslide body, Filling in of landslide Bajikhevi exposition slope of by landslide are periodically active, crevices, truncation and river Chale, left located 15 houses, with medium stripping of the slope, tributary of river Jejora land plots and dynamics, risk level – organizing of drainage for agricultural lands high regulation of ground water

27 Village Chordi Rightnorth-west 82,87 In the 70s of the Old landslide body, Currently there is no need exposition slope of previous century temporarily stable; risk of conducting of landslide- river Chale, left activated landslide level – high prevention measures tributary of river Jejora damaged the whole territory of the village and all residents of the village were resettled

28 Village Shkmeri 2 landslides on the left 29,25 15 Causes damage to Current periodically Regulation of ground and north-west exposition agricultural lands, active landslide with surface water through slope of river Kheura, does not represent risk medium dynamics; risk drainage and water left tributary of river for the population, level – low diversion channels; Rioni represents risk to the construction of protective local road structures on the left bank

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of river Kheura

Ghunda 29 Left north-east 134.32 7 Causes damage to Old landslide body, Currently there is no need exposition slope of agricultural lands and temporarily stable; with of conducting of landslide- river Jejora represents risk to 11 low dynamics; risk prevention measures households located on level – medium the landslide-prone slope

Facilities under the risk of mudslides, located on the territory of Oni Municipality and measures to be implemented Table 10

Settled areas Geographical Areas, The volume of Damage caused by Period of recurrence Preventive measures to be # location (name o covered with mudslide mass mudslides of mudslides and the conducted the main river mudslide as a formed as a level of risk that basin and result of result of facilities are tributary, where single single subjected to transformation of occurrence occurrence mudslide (ha) (m3) occurred)

1 2 3 4 5 6 7 8 Oni municipality

1 Village Sori River Samperavis 4,35 150 000 Causes damage to The mudslide Periodic cleaning and Ghele, the right agricultural lands, passage occurs leveling of the river bed is tributary of river represents risk to 1 seasonally, once in recommended; mudslide Rioni household residing on 2-3 years; risk level sediments should be

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the right side of the – medium removed; continuous gorge monitoring of the gorge should be conducted

2 Villages Seva, River Cheshora, 1,4 40 000 Causes damage to The mudslide Periodic cleaning and Farakheti and the left tributary agricultural lands and passage occurs deepening of the river bed New Chordi of river Rioni bridge pillars seasonally, once or and removal of mudslide twice a year; risk sediments level – high

3 Villages Bokva, Left tributary of 7.0 250 000 Represents risk to the The mudslide Periodic cleaning and Kheiti, river Rioni river population residing passage occurs deepening of the river bed Kvashkieti and Kheuri and its on the edge of the seasonally, once or and removal of mudslide Zudali right tributary gorge, agricultural twice a year; risk sediments; continue river Chiori gorge lands, road level – high monitoring on the gorges connecting the villages and the bridge 4 Villages Left tributary of 0,5 15 000 Causes damage to Periodic cleaning and Zhaskhva and river Jejora river agricultural lands, The mudslide leveling of the river bed Pipileti Chalistskali road connecting the passage occurs and removal of mudslide villages and the seasonally, once or sediments is bridge twice a year; risk recommended level – high

5 Town of Oni Usakhelo gorge - 0,4 10 000 Causes damage to The mudslide Cleaning of the river bed right tributary of Oni-Iri connecting passage occurs from inert material, river Jejora highway and the seasonally, once a fortification of banks and bridge year; risk level – construction of capital high bridge

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Periodic cleaning and 6 Village Nakieti Right tributary of 0,2 7 000 Represents risk to The mudslide leveling of the river bed river Rioni river population residing passage occurs and removal of mudslide Vuzhanuli gorge on the edges of the seasonally, once in sediments is gorge and Oni- 2-3 years; risk level recommended Ambrolauri highway – medium

7 Village Utsera Left tributary of 3,5 110 000 Represents risk to The mudslide Periodic cleaning and river Rioni river population residing passage occurs deepening of the river bed Usakhelo gorge on the edges of the seasonally, once a is recommended; gorge and bridge year; risk level – protective structures

high should be constructed on the edges of the gorge

8 Village Utsera right tributary of 2,85 100 000 Causes damage to The mudslide Periodic cleaning and river Rioni river forest massives, Oni- passage occurs deepening of the river bed

Beglori gorge Shovi connecting seasonally, once or and removal of inert

road and the bridge twice a year; risk material level – high

9 Village Saglolo Right tributary of 0,7 30 000 Periodically damages The mudslide Periodic cleaning and river Chanchakhi Oni-Shovi connecting passage occurs deepening of the river bed

river Iline gorge road and the bridge twice a year; risk and removal of inert level – medium material and cleaning of road

10 Represents risk to The mudslide Periodic cleaning and Left tributary of population of the passage occurs 2-3 deepening of the river 16.0 1 000 000

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Village Glola river Chanchakhi village and Shovi times a year; risk bed, removal of mudslide river Bdgviora holiday camp, level – high sediments (it should not gorge highway and the be dumped into the river bridge bed of river Chanchari); continuous monitoring of the gorge

11 Village Glola Left tributary of 0.3 5500 Represents risk to The mudslide Periodic cleaning of the river Chanchakhi population of the passage occurs once gorge from mudslide river Patara Tskaro village and a year; risk level – deposition gorge agricultural lands medium

12 Resort Shovi Right tributary of 0,8 35 000 Causes damage to the The mudslide Periodic cleaning of river Chanchakhi road and the bridge; passage occurs twice facilities and local road river Usakhelo represents risk to the a year; risk level – from mudslide gorge territory of resort high depositions; periodic Shovi deepening of the river bed and removal of sedimentation; construction of protective structures at the pillars of the bridge

13 Resort Shovi Left tributary of 1,6 60 000 Causes damage to the The mudslide Periodic cleaning and river Chanchakhi road and t represents passage occursonce deepening of the river bed river Chkoguri risk to the territory of or twice a year; and removal of inert gorge resort Shovi risk level – medium material; continuous monitoring of the gorge

Oni-Ghebi Right tributary of Causes damage to The mudslide Cleaning and deepening of 14 connecting river Rioni river 2,2 25 0000 forest massive, Oni- passage occurs 2-3 the river bed, fortification highway Shkiroluri gorge Ghebi highway and times a year; risk of edges of the gorge and the bridge level – high restoration of a bridge

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15 Village Chiora Right tributary of 3,0 130 000 Causes damage to The mudslide Periodic cleaning of the river Rioni river forest massives and passage occurs once river bed, removing of Shliroruli gorge represents risk to or twice a year; risk debris cone and mudslide pillars of Chiori level – medium deposition bridge

16 Village Chiora Left tributary of 3,4 145 000 Represents risk to The mudslide Periodic cleaning and river Rioni agricultural lands and passage occurs once leveling of the bed, Tsiskviliskari 25 households or twice a year; risk removal of inert material, gorge residing on the right level – high which should be placed edge of the gorge along the gorge, construction of protective structures to reduce risk that population is subjected to

17 Village Chiora Left tributary of 1,7 70 000 Periodically damages The mudslide regular cleaning and river Rioni river road connecting passage occurs once deepening of the bed; Kholi gorge villages Chiora and or twice a year; risk periodic cleaning of road Ghebi level – medium from mudslide sediments; continuous monitoring of the gorge

18 Villages Ghebi Right tributary of 7,0 300 000 Damages forest The mudslide Periodic cleaning of the and Chiora river Rioni river massives passage occurs 2-3 bed from mudslide debris Lagaruli gorge times a year; risk and sediments level – medium

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19 Villages Ghebi Right tributary of 3,5 170 000 Damages forest The mudslide Conducting of and Chiora river Rioni river massives passage occurs 2-3 mudslideprevention Shoduri Khevi times a year; risk measures is impossible due gorge level – medium to complicated relief. Periodic cleaning of road from mudslide debris

20 Village Ghebi Right tributary of 2,9 110 000 Damages local road The mudslide Additional bank river Rioni river and bridge, represents passage occurs 2-3 fortification works and Lartkishou gorge risk to population times a year; risk cleaning of the bed residing alongside the level – high edge of the gorge Bank fortification works 21 Village Ghebi left tributary of 5,5 200 000 represents risk to The mudslide have been conducted on river Rioni river population, passage occurs once the right side of the river

Cheshura agricultural lands and or twice a year; risk bank and concrete walls highway level – high were built; no additional works are needed currently

22 Village Ghebi Left tributary of 2,0 50 000 Represents risk to The mudslide Periodic cleaning and river Rioni river population and passage occurs 2-3 deepening of the gorge Usakhelo gorge agricultural lands. 7 times a year; risk through removal of inert households were level – high material resettled

23 Village Ghebi Left tributary of 1,7 55 000 Represents risk to The mudslide Periodic cleaning and river Rioni river population (15 passage occurs 2-3 deepening of the gorge Usakhelo gorge households) and times a year; risk through removal of inert agricultural lands. level – medium material

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24 Village Tsedisi Left tributary of 0.5 15 000 Periodically damages The mudslide Periodic cleaning of the river Jejora river Iri-Ioni connecting passage occurs once highway and the bed Tsedisi Ghele highway in 3-4 years; risk level – medium Damages forest Right tributary of 3.2 140 000 massive; in case of The mudslide Conducting of mudslide river Rioni river excessive atmospheric passage occurs once preventive measures is 25 Sheusuri precipitation of snow or twice a year; risk impossible due to melt the mudslide level – medium complicated relief transports huge volume of solid material into Rioni river bed

26 Right tributary of 2.0 90 000 Damages forest The mudslide Conducting of mudslide river Rioni river massive; does not passage occurs o2-3 preventive measures is not Rubodzali represent risk o times a year; risk expedient settled area level – medium

The mudslide 27 Left tributary of 1.5 40 000 Damages forest passage occurs once Conducting of mudslide

river Sakaura river massive; does not or twice a year; preventive measures is not Chabalakhi represent risk o expedient settled area The mudslide 28 River Khojara, left 0.7 15 000 Damages forest passage occurs once Conducting of mudslide tributary of river massive; does not or twice a year; preventive measures is not Sakaura represent risk o expedient settled area

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6.2 Ambrolauri Municipality

Geographical Location

Ambrolauri municipality is located on the southern slope of the Central Caucasus. On the north and north-west the municipality is surrounded by the Lechkumi Ridge, while from the south it is surrounded by Racha Ridge. Ambrolauri municipality is part of Rioni river basin catchment area, includes Kvemo Racha valley and upper and middle part of river Rioni. Total area of the municipality is 1142.1 km2, number of villages – 69, 1 township, 1 city, population is 15019 persons, population density - 16,3 persons per km2

Geomorphologic Specificities of the Territory

On the territory of the municipality are represented following geomorphologic districts and types of relief: In the northern part of the region and northern periphery of Kvemo Racha valley is represented by high-mountainouserosion-denudational relief, which is developed on Jurassic and Cretaceous period substrates. The region is characterized by streamline rounded forms of relief, which can be attributed to the impact of erosive processes on strongly-dislocated stratum of flysch and lias epoch of the Lower Jurassic and Cretaceous periods. The relief is intersected by tributaries of river Rioni – Asakisttskali, Rtsiula, Lukhunistskali and other deep gorge rivers and tributaries. The gorges are in majority of cases V-shaped. In those areas, where the clay-slate stratum is dominating, the gorges are vessel-shaped. The central and southern part of the territory belongs to medium-mountain zone. In the oligocene-miocen sediments of the Quaternary period is developed medium-mountain erosive hilly relief. Soft and streamline forms of the relief are formed due to sharp changeability of limestone from north towards the south, which is clearly expressed in Rioni gorge, in the area of Khidikari. Sediments of different lithological composition are represented in the region in the form of different micro relief. Relatively stable areas, composed of chokrak sandstone, conglomerates and limestone, together with Oligocene period sandy-argillaceous deposits create 25-30 meter cornices in the zone of villages Lower Sharva, Bareuli and Sadmeli. Relief of given type is characterized with minor ravination (depth of crevices in 300-600meters). Slope inclination is around 30-450.Relief of medium-height mountains is erosive-denudational and karstic, while river Rioni gorge is denudational-erosive and there river terraces are retained. Due to the fact, that carbonate deposition of cretaceous and quaternary period is widespread in the region, we can identify karstic forms, which have developed on complex and asymmetric monoclonal and anticlinal structures of the Racha Ridge (Saint George Mountain, Nakerala, Satsalike, Khikhata, Lodomisi and etc). Absolute altitude of Racha Ridge is increasing from north to the south

prohibitio77 garemos erovnuli saagento p direction, where there are giant clifts, overlooking and Mukhuri depression. The northern wing of the Trialeti Ridge is a creviced mildly inclined plateau with numerous karst funnels, which were formed due to prevalence of barem limestone, their outcrops and humid climate. On the Saint George Ridge, which from the north is bordering to river Shareula canyon, while from the south it is surrounded by Nakerala Ridge, there are numerous karstic funnels, diameter of which is around 1-3 meters, while in some cases it reaches 25-100 meters. Depth of such funnels is from 40-60 meters to 200-300 meters. Mountain Khikhata plateau has similar relief. Karstic formations are less frequent on the limestone stratum of its steep slopes. On the substrate of alluvium deposits the relief of river gorges is terraced. Alluvium terraces are widely represented form on Rioni gorge. In the gorge of the region there are 5 terraces, which are spread from the lowest point of the gorge up to 130-140 meters. First terraces of the floodplain are represented on the territories of Oni and Ambrolauri municipalities, alongside rivers Rioni and they are around 3-4 meters above from the current river bed. Cities Oni and Ambrolauri are built on these terraces. Hypsometric location of terraces on the left bank of Rioni is the following (above Rioni river level): floodplain terrace – 1-2 meters; I terrace 3-4 meters; II terrace – 10-15 meters; III terrace – 50-60 meters; IV terrace – 130-140 meters. Below Khidikiri Kldekari terraces of river Rioni are clearly pronounced on the territories of Ambrolauri, villages Bareuli and Ghadishi. Length of I, II and III terraces reaches several hundred meters, while their width is several dozens of meters. It is noteworthy, that on the III terrace, located near the town of Ambrolauri alluvion reaches 2 meters. On the right slope of river Rioni gorge from Khidikari Kldekari till the village Sairme, hypsometric location of terraces above the river level is the following: floodplain terrace – 2-3 meters; I terrace – 10-15 meters; II terrace – 25-30 meters; III terrace – 55-60 meters, IV terrace – 126-130 meters. None of the terrace stretch over this distance as an uninterrupted line. They are crossed by right tributaries of Rioni, that is why the right terraced slope of the gorge is represented as series of hillocks going down towards the river bed.Rioni terraces are retained only on these hillocks. Complete sequence of terraces is represented on the watershed of Kvatskhuti and Dzirageuli rivulets and Dzirageuli, Bostani, Charjo and Chkvishi hillocks. Incomplete sequence of these terraces is represented on the territory of Sadmeli, Toli and Kvishari. I terrace is represented best of all. It goes as almost uninterrupted line from Khidikari Kldekari and along the right slope till the estuary of the river Sharula. I terrace is stretched along 9-10 kilometers from village Kvatskhuti (crossing the estuary of river Ritseuli) till village Bostana. On this stretch its maximum width reaches 1 kilometer. I terrace is also represented near the villages: Chorjo, Kvanchkara, Toli, Chrebalo and Kvishari. Terrace near the village Kvishari is the widest and so called Kvishari plains are located on this terrace. Its maximum width is around 1 kilometer. prohibitio78 garemos erovnuli saagento p

As to other terraces, they are represented only on the above mentioned hillocks. On some occasions terraces are represented as very narrow line, although majority of them are suitable for settlement due to their relief. Terraces have not retained their initial appearance due to active landslide processes occurring in the region. Fragments of II terraces of river Rioni are retained alongside the road in village Bostana, where the height of the terrace is 35-40 meters. The terrace occupies around 500m2. Width of the terrace is around 7.5-8.0 meters. Karstic relief formed on the carbonate substrate of Cretaceous and tertiary period. In the area of carbonate deposits of cretaceous and tertiary period are widely represented karstic formations in the form of karstic funnels and caves. Karstic formations of the Lower Cretaceous period are broadly represented on the northern slope of Racha Ridge, in the lower part of Nakerala, Khikhata and Lodomisi, where there are numerous caves and karstic funnels. They are also represented on the territories of villages Skhartali, Tskadasi, Zemo and Kvemo Tlughi, Ukeshi, , Saint George Ridge and river Sharaula. Their large number is attributed to large volume of barem limestone, where ground water rich with carbon dioxide alkalizes calcium from limestone, which causes formation of large cavities in the limestone. Diameter of numerous karstic funnels on the territories adjacent to river Sharaula reaches 1- 3 meters, more rarely around 25-100 meters, while their depth varies from 40-60 meters to 200- 300 meters. On the territory of Satsalike ridge and mountain Khikhata, where the slopes have sharp incline, karstic formations are relatively rare. On the territories where Neocom and Turon-Santonian period limestone is widespread, karstic formations are well represented. In villages Nikortsminda and Cheliaghele they are well represented, while such formations are more rare in the Lower Cretaceous massive limestones.

Tectonics and geology The territory is characterized by fairly stressed tectonic conditions. It is intersected by three lateral young and old global ruptures, which are complicated by thrusting and disjunctive dislocations of different directions well seen in the relief. The following large tectonic units can be identified among them: the extreme northern part of the Main Caucasus Ridge, which cinoruses the heart of the crystal slates anticlinorium in the central zone of Caucasus; folded system of the southern slope of the Greater Caucasus, which, across the region, as a wide strip spreads from north-west of south-east and is represented by the Lower and Middle Jurassic clay slates of Kazbegi-Lagodekhi zone, as well as Shovi-Pasanauri sub-zone of Mestia-Tianeti zone, which is built with the Upper Jurassic and Cretaceous carbonate flysch sediments, while the south-western part of the area is bordered by the Chkhalta-Laili zone represented by the Upper Paleozoic and Triassic metamorphic clay slates. Almost over all the area of the north-eastern part of the area there are Jurassic porphyrite stratum spreading prohibitio79 garemos erovnuli saagento p from east of west, while the southern and south-western part of the area is occupied by Racha- Lechkhumi synclinorium sub-zone of Gagra-Java zone.

The tectonic movements that continue to present have marred the seismicity of the area. The epicenter of the earthquakes registered in the region lies within the study area. Almost all of the region is located within 6-7-point-intensity earthquake zone. The earthquakes promote the inception and development of dangerous geodynamic processes in the study area and are a temporary contributing factor for the development mountain creeps with of large and small landslide bodies.

In the extreme northern part of the region, at the mouths of the river Ritseula, the Middle Lias sediments are rare. Lithologically, they are represented by the rhythmic alternations of highly metamorphous dark grey clay slates, aspide slates and sandstones.

The Upper Lias sediments known as “Sori stratum” is prevalent in the northern part of the area and is represented by clay slates, limestones and sandstones.

The Middle Jurassic sediments are prevalent in the central and northern part of the district and are represented by the formations of Aalenian, Bajocian and Bathonian Ages.

The Aalenian sediments are lithologically built with sandstones and clay slates, while the Bathonian porphyrite stratum is lithologically represented by the rocks of effusive formation: porphyrites and their pyroclastolites, tuffas, tuffa-breccias, tuffa-conglomerates and tuffa-sandstones. Together with the Aalenian sediments they are prevalent in the gorges of the rivers Lukhunistskali, Ritseuli and Askistskali.

The Bathonian sediments survive only as a fragment over the southern wing of the Racha-Lechkhumi syncline and in Shaori tectonic sub-zone. The lithology of the rocks comprises clay slates and sandstones.

The formations of the Chimeric Age make up the northern flank of the Racha-Lechkhumi syncline, near villages Tsesi and Mukhli. They are represented by a color stratum – sandstones and marl clays.

The Lower Cretaceous sediments – the Valanginian-Hauterivian and Barrem formations outcrop over the both flanks of the Racha-Lechkhumi syncline, in the basins of the rivers Shareula, Ritseula

prohibitio80 garemos erovnuli saagento p and Askistskali, where they are mainly represented by massive dolomitized thick-layered limestones, quartz-arkose sandstones, micro-conglomerates and marl limestones.

The Apt Age sediments outcrop in the gorges of the rivers Znakura, Askistskali, Ritseula and Shareula and around villages Kvatskhuti and Nikortsminda, where they are represented by stratified marl limestones and clay marls.

The Upper Cretaceous Cenomanian sediments are prevalent in the gorges of the rivers Askistskali, Ritseula, Lukhunistskali, Znakura and Shareula, where they are represented by glauconitic sandstones.

Turon-Danish sediments are quite widely prevalent in the region, in particular, in the catch basin of the river Rioni and they arerepresented by pink and white massive limestones.

The sediments of the Tertiarysystem. The Paleocene-Eocene formations are represented by carbonate facies, thick-layer and massive limestones, marls and sandy limestones. On the left flank of the river Rioni, they outcrop west of village Itsa and west of village Baji, and on the right flank of the river Rioni, they outcrop in the area of Kvemo and Zemo Chkvishi.

The formations of “the Maykop Series” of the Oligocene-Lower Miocene Age are widely prevalent in the study area. Their outcrops have been observed in the catch basins of the rivers Askistkali, Ritseula and Lukhunistskali and around villages Tsesi and Mukhli. The Maykop Series is mostly represented by slated clays and sandstones.

The Quaternary Sediments are widely prevalent in the region. They are mostly represented by old and modern alluvial, colluvial, delluvial and prolluvial sediments.

The old alluvial sediments can be seen in the gorge of the river Lukhuni, near village Likheti, on the right flank of the river Lukhuni, along 1.5 km of the motor road. At this point they survive at the height of 35 m from the modern bed of the watercourse and are represented by boulders and shingle with clay and sandy joining material. The thickness of the terrace is 6-6.5m.

The old alluvial sediments survive in Shaori cave occupying 16 km2. Lithologically, the alluvial sediments are presented by clays and clay loams, with rare sandy and sandy-and-shingle interlayers.

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Large amounts of modern alluvial sediments are found in the beds of large rivers in the region. The alluvial sediments all over the beds of the river Rioni and its large tributaries are represented by sands, boulders and shingle and rarely, by block talus.

It is also worth noting that west of the town of Ambrolauri, in the small left tributaries of the river Rioni, the talus trains occupying 0.2-0.3 km2 can be observed. Their strength reaches 10-15 m.

Large accumulations of colluvial sediments in the region can be observed in the areas where Cretaceous limestones and sandstones are prevalent. The thick material accumulated at the bottom of the walls is represented by the block talus and fractures of lithologically different rocks. The colluvial sediments in some areas of the region are represented by relatively small fractures and detrital material, which are often cemented via clay material. The thickness of the colluvial sediments at the bottom of the walls varies highly and ranges between 5-10 to 80 m. Particularly thick is the material accumulated at the bottom of the walls and steep slopes.

The delluvial sedimentsare widely prevalent in the region and reach quite great thicknesses over the both flanks of the river Rioni. Particularly thick is the Quaternary cover developed on the right flank of the river Rioni located in the tectonically stressed area with thrusting and disjunctive dislocations, e.g., in the area of Kvishnari, Gendushi, Zemo and Kvemo Zhokhsha, Khvanchkara, I Tola, II Tola, etc. Their thickness at these locations reaches 30-35 m and they occupy several scores of square kilometers. The landslides developed here belong to the type of complex landslide bodies and are tecto-seismogenic landslide bodies.

Similarly thick delluvial sediments are developed at the bottom of Udo-Klde walls, north-west of the village Korti and in the area of villages Skhvava, Potskhvrevi mountain, etc.

Over the delluvial sediments near the mouths of almost all gorges in the region and on slopes there are landslide bodies developed, the n’th part of the majority of which reaches the beds of the gorges and create favorable conditions for the inception and development of the hearths of mudflow in the ravines. This process is further exacerbated by sharp steepness of slopes, lithology of the rocks, conditions of circulation of underground waters, etc.

The modern Elluvial-Delluvial formations are widely prevalent across the region. These sediments are represented by two varieties: in the area with cliffy rocks they are lithologically composed of detritus prohibitio82 garemos erovnuli saagento p and block talus with clay joining material, while in the area where semi-cliffy and clay rocks are prevalent, they are represented mainly by clay and clay loam ground with grit and detritus accretions. The thicknesses of these sediments vary greatly in the range of 2-20 m.

The modern Elluvial sediments are mostly prevalent on the watershed ridges. Lithologically they are represented by two varieties: where the carbonate, terrigenous-metamorphous and volcanogenic- sedimentary cliffy rocks are prevalent the elluvial sediments are represented by detritus and block talus with the clay and clay loam ground joining material, while in the areas where the carbonate- terrigenous, laguna, flysch and terrigenous semi-cliffy formations are prevalent the elluvial sediments are represented by clay and clay loam ground with the grit and detritus joining materials. Their thickness varies between 2 and 5 m.

The prevalence of the Prolluvial sediments in the region is limited. They are mostly prevalent at the estuaries of the mudflow currents of the river Rioni and in the small gullies of the river Rioni basin. The Prolluvial sediments are mainly represented by poorly sorted gravel and shingle with the sand and clay loam joining material.

Disastrous Geological Processes

Kvemo Racha region can be considered as having high geodynamic potential due to the following factors: high inclination of slopes (25-400and more), high density of the river network, deep erosive crevices, large volume of quaternary deposits, reaching 5-20 meters and more. The above mentioned factors precondition frequency and scale of disastrous geological processes. On the territory of Ambrolauri Municipality occur almost all disastrous geological processes, characteristic to mountainous regions, out of which the most dangerous are: landslides, mudslides, rockfalls, rockslides and erosion. Disastrous geological processes, occurring in the region, the area of their occurrence, their character and geodynamic features coincide with zones, having specific geological-morphological conditions. Below we provide description of certain disastrous geological processes. On the basis of research of disastrous geological processes, occurring on the territory of Ambrolauri municipality was elaborated cadastre of mudslides and landslides. In the process of researching and establishing reasons and factors, causing disastrous geological processes establishing of the level of sensitivity of composing stratum towards specific disastrous geological processes is of extreme importance.

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It should be noted, that quarts-arkosic sandstone of Jurassic-Cretaceous age, limestone and marl create clifty slopes, that represent the zone of development and accumulation of rockslides and rockfalls. Products of gravitational processes often become reason for formation of mudslides and feed solid components into them. On the territories, composed of semi-rocky stratum of clay- slate, slate and marl of terrigenous-carbonate formation are conducive conditions for formation of landslides and mudslides. As to sediments of quaternary period, which create zones where loosely-coupled sandy- argillaceous stratum of elluvial-delluvial and ellivual-proluvial genesis, in such areas occurs erosion of three types: subsurface erosion, side erosion (erosion washout of river banks) and surface erosion. Below we provide data on the areas of occurrence of specific geological processes and trends of their development. Erosion: on the territory of Kvemo Racha water-born erosion is represented in its broad variety, including subsurface erosion, lateral erosion (washout of rover banks) and surface erosion (soil erosion). Main factor causing subsurface erosion is presence of stratum, which are sensitive to water- born erosion (clay-slate, slate, alluvial-glacial deposits), high energy of water flow and atmospheric precipitation. Subsurface erosion occurs in almost all small and large estuaries, gorges and ravines. Subsurface erosion is especially acute during spring rains and snow melt period. Frequency of gullying erosion is mainly determined by the volume of elluvial-delluvial sedimentation, abundance of atmospheric precipitation and surface location of groundwater. The ground water is discharged into erosive crevices and ravines. Gullying erosion becomes stronger during spring rains and melting of snow cover. In Kvemo Svaneti depression major part f ravines have developed as a result of washout of deposition. Side erosion is most clearly pronounced in the river beds of Rioni, Sharula, Krikhula, Khoteura, Lukhunistskali, Ritseula and Asakistskali. In these areas river banks are mainly composed of alluvial-proluvial sedimentation. Side erosion mainly occurs on floodplain and plain terraces, which are located near the following villages: Tsesi, Likheti, Uravi, , Dzirageuli, Kvatskhuti, Sadmeli, Chorjo, Khvanchkara, Toli, Chrebalo, Kvishari, Bugeuli and city of Ambrolauri. Quite often side erosion provokes landslides, as in the process of flash floods occurs erosion of the tip of landslides and slope bases are washed out. In the period of floods and flash floods, when the water levels and water discharge increases substantially due to increase of velocity of the water flow, banks are intensively washed out. Landslide processes: landslides occurring in the region have different granulomeric consistency and dynamics depending on engineering-geological formation and complex that they are linked to.

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On Sarmatian depositslandslides develop on large-grained sandstone and clay substrates, represented on both banks of river Rioni. Landslides occur on the territories of villages Kvanchkara, II Toli, Lower Zhoshka, Upper Zhoshka, Didi Corjo, Bostana, Sadmeli, Begeuli, Kedisubani and Gori. These landslides mainly develop on delluvial-elluvial and delluvial formations. Landslides that develop in quaternary stratum and they often seize depletion mantle as well. By the mechanism of movement majority of them are of creeping type. Landslides are mainly moving in clay stratum, which are characterized by high sensitivity. Main reason of formation of landslide bodies, which occur in Sarmatian deposits near villages Kvanchkara, Lower Zhoshki, Upper Zhoshki and Sadmeli is reduction of stability of composing stratum, sharp inclination of slopes and climatic-meteorological conditions. Main precondition for developing of landslides is intensive erosion wash out of slope bases in the period of flash floods, high sensitivity of clay stratum and anthropogenic load (incorrect cultivation of slopes, heavy constructions and etc). Landslides occurring on the territories of villages II Toli, Bostana, Bageuli, Kedisubani and Gori have huge power and they mainly develop in the quaternary period stratum. By their movement mechanism they are of creeping type and they move on the surface of Sarmatian clay, which is characterized by high sensitivity. Other reasons for formation and activationoflandslides on the settled territories are: sharp inclination of slopes, weak physico-mechanical properties of rocky stratum due to its depletion, excessive saturation of quaternary and base rock by ground and surface water. Out of the above mentioned villages following villages are under the high risk: Lower Zhoskhki, Sadmeli and Bageuli villages and adjacent territories. Villages Kvanchkara, II Toli, Kedisubani, Gori and Didi Chorjo and adjacent territories are under the medium risk. Village Bostana is under the low risk. For the purpose of reduction of dynamics of the landslide processes and ensuring stability of slopes it is expedient to conduct following measures: - In the gorges of rivers, where the landslide tips are under intensive erosion impact – construction of bank-protective structures; - on the slopes should be organized drainage and water diversion channels for the purpose of regulation of surface and ground water flows; - terracing of slopes, planting of perennial species and restoration of forest cover. Description of measures to be conducted on each landslide body is provided in the cadastre of landslides. Landslides, developed on the sandstone, limestone, clays and conglomerate substrates of Middle Miocene deposits are characterized by creeping-sliding type of movement. Majority of landslides are formed in delluvial and elluvial-delluvial formations. Landslides of this type occur on both banks of river Rioni on the territories of villages Lower Sharva, Upper Shavra, Khonchiori,

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Upper Zhoshka, Lower Chvishi, Kvanchkara, Patara Chorjo, Bareuli, Dzirageuli, Saketsia, city Ambrolauri (see picture 12), Kvatskhuti, Krikhi and Akhalsopeli. Landslides occurring on the territory of villages Dzirageuli, Kvatskhuti and Krikhi are tectoseismogenic and the reason of their formation and activation is reduction of stability of stratum due to discontinuous and sliding dislocation, sharp inclination of slopes, depletion of composing layers and excessive saturation of stratum and quaternary deposits by surface and ground water. Landslides occurring on the territories of villages Lower Shavra, Patara Chorjo, Lower Chkvishi, Upper Zhoshka, Bareuli, Khonchiori, Saketsia and Akhalsopeli are of medium power (5- 10 meters) and occur mainly in the quaternary stratum. Reasons for their formation are: excessive saturation of quaternary stratum with surface and ground water, intensive erosion of slope bases in the period of flash floods, high sensitivity of clay soils and anthropogenic impact on slopes. Villages Upper Zhokhi is within the high risk, villages Dzirageuli, Kvatskhuti, Krikhi, Lower Shavra, Khvanchkara, Bareuli and Akhalsopeli and adjacent territories are within the medium risk, while villages Saketsia, Khonchiori, Kvemo Chvishi and Patara Chorjo are under the low risk zone. Landslides, which develop in Maikop layer (Oligocene-Lower Miocene). By the structure the landslide bodies, which are most widespread are of creeping type, while asequent and insequentlandslides are less frequent. Such landslides develop on the sandy-argillaceous and sandy substrates. In dry condition Maikop clays are characterized with high solidity. By mineral composition they belong to montmorillonites, but they are highly sensitive when absorbing moisture and are easily transformed into landslides. By dynamic the landslide formed in the Maikop clays are either active, or temporarily stable. Such landslides occur on the territories near villages Kvishari, Gendushi (Pictures#9 #10),I Toli (picture#11),Didi Chorjo, Baji, Lower Savra, Gviara, Kldisubani, Kvatskuti and Mukhli.

Picture#9 picture #10 Landslide bodies occurring on the territories of villages Ghviara, Kldisubani, Kvatskhuti, Ghendushi, I Toli, Didi Chorjo and Mukhli are tectoseismogenic, powerful and main reasons of

prohibitio86 garemos erovnuli saagento p their formation and activation are: reduction of stability of stratum due to discontinuous and sliding dislocation, sharp inclination of slopes, depletion of composing layers, excessive saturation of stratum and quaternary deposits by surface and ground water, intensive erosion of slope bases in the period of flash floods. Landslides on the territory of villages Kvishari, Baji and Lower Shavra are characterized by medium power and mainly occur in the quaternary stratum. Reasons for their formation are: excessive saturation of stratum and quaternary deposits by surface and ground water, intensive erosion of slope bases in the period of flash floods, high sensitivity of clay soils and anthropogenic impact on the slopes.

Picture#11 picture#12 Villages Kvishari, Ghendushi and I Tola are located within the high risk zone, villages Baji, Lower Shavra, Didi Chorjo, Kvatskhuti and Mukhli are located within the medium risk zone. Population residing in villages Ghviara and Kldisubani has been completely resettled due to high activeness of landslide processes in the 70s of the previous century. Landslides occurring in Middle and Lower Eocene and Upper Cretaceous deposits. By the mechanism of movement they mainly belong to the sliding type of landslides. Landslide processes develop in limestone, sandstone and marl substrates. By their dynamics majority of t hem are active. Landslides located in the area of above mentioned depositions by the type of their movement belong to sliding type, while landslides of plastic movement are less frequent. In majority of cases landslides are of surface type, although some of them also seize part of depletion mantle. Surface landslides by their dynamic mainly belong to active type of landslides. Such landslides are occurring on the territory of villages Zemo Chkvishi, northern part of I Toli, northern part of Kldisubani and Futieti. Territories of Upper Chvishi and I Toli are located within the high risk zone, while village Futieti is located within the low risk zone. Landslide occurring in the deposits of Colluvium-Oxford period are represented on the territories adjacent to villages Mukhli and Tesi and river Satiskvilo Ghele and Rioni gorges. prohibitio87 garemos erovnuli saagento p

Landslide processes occur on sandstone, clay-slate, conglomerate, carbonate and clay deposits. Landslides occurring in the base rock are tectoseismogenic, powerful and main reasons of their formation and activation are: reduction of stability of stratum due to discontinuous and sliding dislocation, sharp inclination of slopes, depletion of base rock, excessive saturation of stratum and quaternary deposits by surface and ground water, intensive erosion of slope bases in the period of flash floods. Villages Mukhli and Tsesi and adjacent territories are located within the medium risk zone. Landslides occurring in the sori deposits of Lower and Middle Jurassic period are represented on the territories adjoining to villages Uravi and Abari. Landslide occurs in clay-slate and sandstone substrates. Landslides are of medium size, not deep. Reasons for formation of landslides in the quaternary deposits of Jurassic stratum are: tectoseismogenic, powerful and main reasons of their formation and activation are: sharp inclination of slopes, depletion of composing layers, excessive saturation of stratum and quaternary deposits by surface and ground water, intensive erosion of slope bases in the period of flash floods. Landslides occur on the territory under examination due to natural, as well as anthropogenic factors. Lithological properties of stratum play important role in formation of landslides. Depletion has decisive impact on formation of slopes and determines their condition. Sensitivity of clay base rock plays important role as well, as such soil transforms into dynamic state easily under the impact of slope gravitation. Correlation between the inclination of slopes and direction of stratum has important influence too. Local climatic-meteorological conditions play important role in formation and reactivation of landslides in Ambrolauri Municipality. Ground water is one of important factors in the process of formation of landslides, which causes formation of plastic landslides. Side erosion, occurring in the process of flash floods plays important role too. The role of anthropogenic factor in the process of formation of landslides should be stressed too. Economic and engineering activities undermine balance on the slopes, which causes development and activation of landslide processes. Mudslides. Mudslide processes are widespread on the territory of Ambrolauri Municipality. Mudslides mainly occur in the gorges located in the mountains and foothills, where they cause substantial damage to population and engineering communications. In the region mainly occur muddy and stony-muddy flows, which mainly feed on landslide processes, occurring on the river banks. Mudslides damage road, agricultural lands, bridges and villages. (See picture#13). On the territory of Ambrolauri municipality mainly occur muddy and stony-muddy flows. Such mudslides occur in gorges of rivers Ghviara, Toli, Znakura, Pepela. These mudslides occur in tertiary and quaternary stratum, which is easily saturated and washed out. The sediment that is transported by mudslides consists of thick sandy-argillaceous mass. prohibitio88 garemos erovnuli saagento p

Mudslides of stony-muddy character are most frequent in the region. Mudslides and flash floods occur in mountain rivers almost on annual basis. In 2005 landslide mass, accumulated in the area of village Ghendushi blocked the gorge, due to which mudslide of catastrophic power was formed. Similar situation occurred in 2001 in the gorge of river Asakistskali. In 2007 in the river Lashisghele gorge powerful mudslide occurred repeatedly (see picture#14), which subjected population residing on the left edge of the George to a serious risk. In March of 2010 on the territory bordering villages and Bageuli occurred a large plastic landslide, on the body of which near the estuary of river Naboslevi developed a mudslide. The height of the mudslide mass was 8 meters. Mudslides reach II terrace of river Rioni. Similar mudslides occurred in given gorge in 2003 and their transformation is always linked with activation of landslide processes. In 2013 rockslide occurred in the river Ghviarula gorge, due to which population of villages Ghviara and Bostana were subjected to risk. In the river head is accumulated huge mass of unstable stratum and mudslide can cause catastrophic results not only to adjacent villages, but to the population residing in the lower part of Rioni gorge as well.

picture #13picture#14 On the territory of Ambrolauri Municipality mudslides are formed under the impact of landslides, as they impact formation of mudslides and feed solid material into the flows. It should also be noted, that surface washout and landslides mainly occur in delluvial and elluvial-delluvial formations. That is why in the mudslide mass prevail clay fractions. Usually after passage of mudslide is formed a hilly relief. As a result of examination of sections it was established, that such mudslide sediments are composed of fine-grained materials (sand, sludge) and such solid components (stones, sand, gravel), which can move freely on the bottom of the flow. On the debris cone sometimes we can observe large rocks, which have broken off under the impact of velocity of the flow.

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Mudslides are also formed under the influence of erosion-denudation relief, spread on large territory, characterized with sharp inclination of slopes and high energy of water flow. Majority of mudslides occurring on the territory of Ambrolauri municipality are of turbulent type and water is the main moving power in such cases. Although it should be noted, that some mudslides are of structural character and they are usually formed in extreme situations. Such mudslides occurred during previous years in villages Chorjo, Upper Zhoshkashi, Bugeuli and others as a result of abundant precipitation. It is noteworthy, that majority of mountain river gorges do not have debris cone and they directly flow into large rivers through narrow river bed and obstruct them, as a result of which large territories are flooded. Length of passage of mudslides occurring in the region does not exceed 1-1,5 hours. Powerful mudslides usually occur after large amount of precipitation occurs after lengthy drought. Turbulent flows contain 30-40% of solid material. The ability of transportation of this material is predetermined by the water mass and such solid material is gradually accumulated alongside with movement of water flow. Such processes mainly occur in summer period and have large spread and frequency. In the mudslides of structural character composition of solid material exceeds 60%. For the purpose of protection of population and engineering facilities on the mudslide-prone gorges should be conducted preventive and engineering-protective measures. Such measures should be of complex character taking into consideration, that erosion, landslide and rockslide processes are characteristic on given territories. Among such measures should be cleaning of slopes from mudflow, afforestation of such areas, terracing of slopes and etc. As a result of processing of data obtained as a result of the field work we came to the conclusion, that out of 39 settled areas, located in Ambrolauri Municipality 11 are located within the high risk zone, 20 are located within the medium risk zone and 8 are located within the low risk zone. See table #11. From the standpoint of spread of geological processes, their intensity and the level of activation, out of 70 settled areas 31 settlements and adjacent areas are under the high risk. 20 settlements and adjacent areas are under the medium risk and 19 settlements and adjacent areas are under the high risk. See engineering-geological map.

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Facilities under the risk of landslides, located on the territory of Ambrolauri Municipality and measures to be implemented Table 11

Settled area Number of landslides Total area Number Damage caused by landslides Dynamic status of Preventive measures to be # and their geographical of of households landslides and the risk conducted location landslides residing in level (ha) the settled area 1 2 3 4 5 6 7 Ambrolauri Municipality

1 Village Upper Upper part of the right 201,66 48 Damage is caused to Old landslide body, in Organizing of drainage Chvishi south-west exposition agricultural lands, on the tip the middle and lower channels for the purpose of slope of river Rioni, of the landslide are located parts are located regulation of ground and north-west part of remnants of 5 houses, activated areas. Is surface water; afforestation of village Upper Chvishi population has been resettled. characterized with active areas of the landslide 10 households remain within medium dynamics; the risk zone risk level – medium

2 Village Lower 2 landslide bodies- the 29,85 110 agricultural lands are located 2 old landslide bodies, Currently preventive measures Chvishi right slope of north-east within the risk zone temporarily stable; don‟t need to be conducted exposition of the right risk level – low tributary of river Rioni river Obinela

3 Village Lower part of the right Damage is caused to Old landslide body of Construction of river bank Kvishari slope of south-east agricultural lands, 450 meter creeping type, the tip protective structure alongside exposition of river Rioni; 104,90 110 long section of Ambrolauri- of the landslide is the tip of the landslide for

southern part of village Kutaisi highway activated; is reduction of side erosion; Kvishari down to the characterized with diversion of surface and ground Rioni river bed high dynamics, risk water (reduction of level),

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level – high organizing of drainage trenches

4 Village Upper part of the right 56,52 23 Damage is caused to Old landslide body, Due to complex character of Ghendushi slope of south-east agricultural lands, local road; periodically activated, the landslide and its size exposition of the right 6 households have been with medium conducting of landslide-

tributary of river Rioni resettled; 20 households, dynamics; risk level – preventive measures is river Asakistskali; residing below the tip of the high practically impossible

northern part of village landslide are under the risk Ghendushi

5 Village Upper The slope of south-east 152,83 86 Damage is caused to Both landslides are in Organizing of drainage for the Zhoshka exposition of the right agricultural lands and yards; the active phase, one purpose of regulation fo ground tributary of river Rioni 25 households residing on the with high dynamics and surface water; terracing and river Lashisgele; 2 left edge of river Lashisgele and the other with afforestation fo slopes with landslides are under the risk low dynamics; risk perennial species; conducting of level – high anti-ersosion measures on river Lashisghele gorge

Surface and ground water 6 VillageLower 2 landslide bodies on the 125,43 66 Damage is caused to Both landslides are diversion; terracing and packing Zhoshka right east exposition and agricultural lands and yards; periodically active, of dirt; afforestation; river bank left wets exposition 45 households, the local road with medium protective structure built on the slopes of the right and the village cemetery are dynamics; risk level right edge of river Asakistskali

tributary of river Rioni located within the risk zone; high for the purpose of mitigation of river Asakistskali 7 households have been side erosion is working resettled effectively currently

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7 Village I Tola 2 landslide bodies on the 163,6 129 Ambrolauri-Kutaisi highway Both landslides are Diversion of ground water right slope of west and the central gas pipeline is periodically active, through organizing of drainage

exposition of river Rioni periodically damaged; 15 one is with highly system; restoration of forest and left slope of south households are located within active dynamics and cover; construction of bank exposition of river the risk zone; 2 households the other is with low protection structure on the Asakistskali, which should be resettled dynamics; risk level - right side of Rioni includes small part of high village Chebralo

8 Village II Tola 3 landslide bodies on the 116 145 Damage is caused to One stable and two Concentration of ground and right slope of east agricultural lands and 250 active landslides with surface waters and their exposition and north- meter section of the local high dynamics; risk discharge into the gorge; east exposition of the road level – medium construction of bank protection

right tributary of river structures alongside the gorges Rioni river II Toli gorge and river beds for reduction of 3 erosion

9 Village Right slope of south- 114,13 231 Damage is caused to 2 old landslide bodies, Restoration of old drainage Kvanchkara west exposition of river agricultural lands, road periodically activated, system, conducting of Rioni, 2 landslides connecting villages with medium melioration works, organizing Kvanchkara and Chorko; 6 dynamics; risk level – of culvert and water discharge houses are damaged medium collectors, canals and drainage

10 Village Lower Lower part of the left 118,82 36 10 houses are damaged, local Old landslide body, Organizing of drainage system Shavra slope of north-west road is within the risk zone temporarily stable, on the slope for the purpose of exposition of river Rioni, with low dynamics; discharge of ground and surface western part of village risk level – low water

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Shavra

11 Village Baji Lower part of the left 148,26 71 6 houses are damaged; 17 Old landslide body, Organizing of drainage system slope of north-west households, a cemetery and periodically active, on the slope for the purpose of

exposition of river Rioni local road is within the risk with medium discharge of ground and surface zone dynamics; risk level – water; filling-in of landslide medium crevices; truncation of the slope

12 Village Upper part of the left 65,17 31 4 houses and agricultural Old landslide body, Organizing of drainage system Ghadishi slope of west exposition lands are damaged; 3 periodically active, on the slope for the purpose of of river Rioni households and local road are with medium discharge of ground and surface within the risk zone dynamics; risk level – water; leveling of landslide medium terraces, truncation of the slope

13 Village 2 landslides, middle and 106,85 59 Damage is caused to Old landslide body, Organizing of drainage system Bareuli lower part of the left agricultural lands, local road periodically active, on the slope for the purpose of slope of Rioni of north and bridge; 1 household has with medium discharge of ground and surface

exposition; includes both been resettled; 11 households dynamics; risk level – water; conducting of bank edges of Sapovnela gorge are located within the risk medium protection works on both sides zone of the gorge alongside the river bank

14 Village Patara Right slope of south- 15,36 58 Houses and agricultural lands Old landslide body, Currently preventive measures Chorjo west exposition of river are potentially under the temporarily stable, don‟t need to be conducted Rioni, south part of landslide risk with positive village Patara Chorjo dynamics; risk level – low

15 Village Didi 3 landslides; right slope 142 68 Damage is caused to the 2 landslides are Regulation of ground water

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Chorjo of river Rioni of south cemetery, agricultural lands periodically active, 1 through organizing of drainage exposition and left slope and local road; landslide stable, with medium system; conducting of erosion- of river Chorjo of west represents risk to 15 houses dynamics; risk level – preventive measures in the exposition and Kutaisi-Ambrolauri medium gorge; prohibition of cultivation

highway of land on the surface of the

landslide

16 Village Middle and lower part of 118,45 119 Currently disastrous Old landslide body, Currently preventive measures Bostana the right slope of south- geological processes on the temporarily stable, don‟t need to be conducted west exposition of river slope are not activated and no with low dynamics; Rioni damage is caused risk level – low 2 landslides; upper part 17 Village of the left slope of west 79,7 159 Damage is caused to 2 old landslide bodies; Organizing of drainage on the Bugeuli exposition of river Rioni; agricultural lands; in the one active with high slopes for the purpose of at the river head of lower part of the landslide dynamics; another discharge of ground water; Naboslevi gorge and left body the landslide mass is with locally activated filling and leveling of landslide slope of east exposition periodically transformed into areas; with low crevices of Bugeuli rivulet a mudslide, representing risk dynamics; risk level – to 8 households located on high the left edge of Naboslevi gorge

18 Road Lower part of left slope 40,36 Periodically damages 250 Old landslide body, Implementation of capital connecting of north-east exposition meter section of the road active, with high measures is not expedient or

villages of river Rioni connecting villages Bageuli dynamics; risk level – possible due to the size and

Bageuli and and Saketsia medium active dynamics of the Saketsia landslide; in the event of damage of road it should be leveled and ballasted

19 Village Right slope of south-east 82,95 93 Damages agricultural lands Old landslide body, Organizing of drainage on the Kldisubani exposition of river Rioni and road; due to high periodically activated slopes for the purpose of

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activation of landslide in the lower part; discharge of ground water; processes in the 70s of the with medium afforestation of slopes previous century 65 dynamics; households were resettled One landslide is organizing of culvert and water 20 Villages 2 landslides; right slope 406,45 220 Damage is caused to stable, another is discharge collectors, canals and Sadmeli and of south-west exposition agricultural lands; 8 houses periodically active, drainage; redistribution of Dzirageuli of village Rioni are within the risk zone with medium landslide mass and slope paving; dynamics; risk level – afforestation of the landslide high

21 Village 2 landslides; upper part 27,8 43 Damage is caused to local One landslide is Diversion of ground water and Kedisubani of the left slope of north road and the cemetery; 11 temporarily stable, filling and leveling of landslide exposition of river Rioni; households residing on the another is active, is crevices northern part of village tip of the landslide are characterized with Kedisubani within the risk zone regressive development, with medium dynamics; risk level – medium 10 houses and agricultural Old landslide body, Organizing of drainage system 22 Village Upper Right slope of right 208,25 56 lands are damaged with locally activated for removing of ground water Shavra tributary of river Rioni areas; with medium and karst water; terracing of river Shareula . dynamics; risk level – surface on the landslide body medium and planting of perennial species

23 Village Jvari 2 landslides; left slope of 53,6 70 Causes damage to local road One landslide body is Regulation of ground water river Zankura and left and agricultural lands; temporarily stable, levels and surface water flows; slope of left tributary of represents risk to 11 another is with truncation and stripping of the

river Zankura river households located near the locally activated slope Satseria Ghele tip of the landslide areas; with medium dynamics; risk level –

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low

24 Village Right slope of west 58,25 124 represents risk to population Old landslide body, Regulation of ground water Znakva exposition of river of the village, local road and with locally activated levels and surface water flows Znakura gorge agricultural lands areas; with low through organizing of drainage dynamics; risk level – medium

25 Village Left slope of north-east 139,6 107 represents risk to population Old landslide body, Organizing of drainage system Saketsia exposition of Rioni gorge of the village and agricultural with locally activated for removing of ground water; lands areas; with low terracing of surface on the dynamics; risk level – landslide body and planting of medium perennial species

26 Village Right slope of north-east 10,8 71 Causes damage to local road Old landslide body, Regulation of surface water Khonchori exposition of left and cemetery with locally activated flows and slope paving tributary of river Rioni areas; risk level – river Znakura low

27 Village 2 landslides; left slope of 73,2 23 Houses and agricultural lands One landslide body is Restoration of old drainage Akhalsopeli south-east exposition of are damaged; one household contemporary, system for the purpose of left tributary of river is under the high risk; 2 periodically active regulation of surface water Krikhula river Khoteura households areunder the with medium flows; filing in of ravines and and left slope of north- medium risk and 22 dynamics; another is truncation and stripping of the east exposition of river households are under the low an old landslide body slope Krikhula risk with locally activated areas; with medium

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dynamics; risk level – medium

28 Village Krikhi Right slope of west 24,9 65 Damages local road and road Old landslide body, Diversion of ground water with exposition of river leading to the cemetery tip of the landslide is drainage system; planning and Krikhula (Ghvedieti activated and is terracing of slopes landslide) washed out by river Krikhula; with low dynamics; risk level – medium

29 Village Gori 2 landslides on the left 98,23 28 25 houses and agricultural One landslide body is Regulation of ground water slope of river Rioni of lands are damaged active with high through organizing of drainage north and exposition and dynamics; another is system; restoration of forest north west exposition temporarily stable cover in the middle and lower with locally activated part of the slope; construction areas; with low of bank protection construction dynamics; risk level – on the left bank of Rioni for medium prevention of erosion

30 Village On the slope with old 114 161 21 houses located in the Old landslide body Regulation of surface water Kvatskhuti landslide are identified 2 lower part of the landslide with locally activated flows in the area of the old activated landslide areas; and agricultural lands are areas; with low landslide and discharge of the right slope of south-east damaged dynamics; risk level – water into the nearest ravine; exposition of river Rioni, medium construction of river bank central part of village protection structure on the Kvatskhuti right bank of Rioni alongside the tip of the landslide

31 Village Tsesi 2 landslides on the right 24,7 212 7 houses and 200 meter Both landslides are Conducting of amelioration slope of south exposition section of Oni-Ambrolauri periodically active, works; organizing of culvert of river Rioni and left highway are damaged with medium and water discharge collectors,

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slope of west exposition dynamics; risk level – canals and drainage; terracing of of right tributary of river medium slopes and afforestation M Rioni river Tsiskvilis Ghele

32 Village 3 landslides on the east 82,8 19 Agricultural lands and local 2 landslides have Regulation of surface water Mukhli and west exposition road is damaged periodically activates flows and ground water; slopes river Cheshura areas with medium building of bank protection gorge and the left slope dynamics; one structures on both banksof river of north-east exposition landslide is stable, Chonishura for reduction of of river Rioni risk level – medium side erosion

33 Village Urevi 2 landslides on the right 160,21 153 Landslide processes cause 2 old landslide bodies Regulation of surface water slope of east-west damage to local road and with locally activated flows; construction of bank exposition of river agricultural lands; 15 areas; with medium protection structure on the left Lukhunistkali households are within the dynamics; risk level – edge of river Lukhinistskali for risk zone; 2 households were high reduction of side erosion resettled

34 Village 2 landslides on the left 63,13 77 Landslide processes cause One landslide body is Regulation of ground water on Khimshi slope of north-east damage to local road and stable; another is the slope; construction of exposition of left agricultural lands; 17 stable with locally landslide prevention structure tributary of river Rioni households residing on the activated areas; with alongside the gorge river Pepeliskhevi and slope of an old landslide are low dynamics; risk left slope of north-west subjected to risk level – low exposition of river Rioni

35 Village Abari Right slope of east 13,73 55 Causes damage to agricultural Old landslide with Regulation of surface water exposition of river lands and yards, represents locally activated flows on the slope; construction Lukhuni risk to Uravi-Amrolauri areas; risk level – of landslide prevention highway and 15 households medium structure alongside the gorge of

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residing on the slope river Lukhuni for reduction of side erosion

36 City of Ambrolauri, left II 3,1 804 Landslide represents risk to Contemporary construction of landslide Ambrolauri terrace of river Rioni, highway and the building of landslide with high prevention structure alongside the territory of former agricultural vocational dynamics; risk level – the left bank of river Rioni for agricultural vocational education institute; the active medium reduction of side erosion; filling education institute. zone of the landslide is in of landslide crevices and gradually advancing on the ravines road

Facilities under the risk of mudslides, located on the territory of Ambrolauri Municipality and measures to be implemented Table 12

Areas, Administrative Geographic location covered Volume of Damage caused by Period of recurrence # units and settled (name of the main with mudslide mudslides of mudslides and Preventive measures to be areas river basin and mudslide as sediments risk that they conducted thetributary where a result of transported as present to facilities the mudslide was single a result of transformed) occurrence single (ha) occurrence (m3) 1 2 3 4 5 6 7 8 Ambrolauri municipality

1 Includes village Left tributary of 0,9 22 000 Washout of river banks Passage of mudslide Conducting of bank Baji and adjacent river Rioni river and seizing of agricultural flows occurs protection measures and territories Apanata gorge lands seasonally once in 2 periodic cleaning of the years; risk level – gorge medium

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2 Village Chrebalo Right tributary of 3,0 80 000 Washout of river banks on Passage of mudslide Cleaning of river river Rioni river the territory of village flows occurs Asakistskali river bed; Asakistskali Zhoshki; represents risk to seasonally once in 2 part of solid material agricultural lands and years; risk level – needs to be removed population residing on the medium while part should be used right bank of the river for construction of river bank fortification gabions

3 Villages Right tributary of 0,85 25 000 The gorge is landslide and Passage of mudslide It is recommended to Ghendushi and river Asakistskali mudslide prone, it flows occurs organize stanks in the Zhoshka river Lashisghele represents risk to the seasonally once in middle and lower parts of gorge population residing on the 3-4 years; risk level the gorge for interception right bank of the river and – high of mudslides the road, connecting villages

4 Village II Tola Right tributary of 0,3 8 000 The gorge is landslide and Passage of mudslide It is recommended to river Rioni river II mudslide prone, it flows occurs build bank protection Toli gorge represents risk to the seasonally once in structure on the right population residing on the 3-4 years; risk level edge of the river for right bank of the river and – medium protection of population 250 meter long section of and the road the road, where intensive erosion processes are occurring

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5 Villages Ghviara Right tributary of 0,1 2 500 Damages agricultural lands Passage of mudslide Depending of the river and Bostana river Rioni river and the road; the bridge flows occurs bed and leveling of the Ghviara Ghele on Kutaisi-Ambrolauri seasonally once in 2 river bed and removal of highway and represents years; risk level – mudslide deposits; proper risk to the population high bank protection structure residing on the river bank needs to be built

6 Villages Right tributary of 2,0 70 000 Represents risk to the Passage of mudslide Removal of inert material Kldisubani and river Rioni river population residing on the flows occurs and deepening of the river Sadmeli Ritseuli left bank near the debris seasonally once in 2 bed; inert material can be cone, agricultural lands years; risk level – used for organizing of and bridge on the highway high gabion protective walls

Passage of mudslide 7 Village Likheti Right tributary of 0,6 15 000 Represents risk to the flows occurs Bank protection

river population of village seasonally once in 2 structures should be Lukhunistskali river Likheti and concrete constructed on both banks years; risk level – Kheoristskali bridge high of the river, bridge pillars should be fortified; the river bed should be periodically cleaned from solid sediments Passage of mudslide 8 Village Abari Right tributary of 0,3 6 000 Represents risk to the flows occurs Cleaning and deepening

river Lukhunistskali population of village seasonally once in 2 of the gorge and building a nameless rivulet Abari of bank protection years; risk level – medium structures on both banks of the river

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Passage of mudslide 9 Ambrolauri- Uravi Right tributaries of 0,4 10 000 Mudslides periodically flows occurs Periodic cleaning of

connecting road river Lukhunistskali damage Ambrolauri- seasonally once in 2 gorges and removal of – 4 nameless gorges Uravi connecting road inert material from the years; risk level – medium road

Passage of mudslide 10 Village Bugeuli Left tributary of 1.0 30 000 The gorge is landslide and flows occurs cleaning of gorge and

river Rioni river mudslide prone, it seasonally once in removal of inert material Naboslevi gorge represents risk to the 2-3 years; risk level population residing on the – medium left bank of the river and agricultural lands, as well as local road Passage of mudslide 11 Villages Znakva Left tributary of 1,9 60 000 Represents risk to flows occurs removal of inert material

and Saketsia river Rioni river agricultural lands, road seasonally once in from the gorge and Znakura connecting villages and 2-3 years; risk level deepening and leveling of the bridge – medium the bed; removed inert material can be used for building of banquette and fortification of vertically cut edges Passage of mudslide 12 Villages Khotevi Left tributary of 2,2 90 000 Represents risk to flows occurs Periodic removal of inert and Akhalsopeli river Krkhula river agricultural lands, road seasonally once in material from the gorge Khoteura and its connecting villages and 1-2 years; risk level right tributary river the bridge – medium Passage of mudslide 13 Villages Krokhi Left tributary of 1,25 38 000 Washing out of river flows occurs Continue periodic and city of Rioni river banks represents risk to seasonally once in removal of inert material

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Ambrolauri Krirkhula population residing on the 1-2 years; risk level from the gorge river bank in Ambrolauri – medium

Statistics of disastrous geological processes identified on the territory of Oni and Ambrolauri municipalities (1987-1998)

Table #13

Years Landslide Newly- Mudslides Passage of Rockslides Rockfalls Flooding Settled areas Information s formed mudslide and facilities source landslides within the

risk zone Municipality Municipality

1987-88 160 9 46 22 12 21 85 45 1989-91 179 19 50 5 17 19 16 56 1992-95 179 - 50 8 5 8 15 12 1996 179 - 50 14 5 6 22 16 Information Oni 1997 179 - 51 5 5 6 55 9 bulletins 1998 179 - 51 4 4 6 17 7 Total 179 28 51 58 48 21 85 67 State Department of Geology 1987-88 166 7 17 12 2 7 25 54 Tbilisi, 2000

1989-91 177 11 17 3 2 9 4 48 1992-95 181 4 17 - - 5 5 16

1996 181 - 17 7 - 3 10 1 1997 181 - 17 - 1 3 20 10

Ambrolauri Ambrolauri 1998 181 - 17 2 1 2 10 6

Total 181 21 17 24 6 9 25 71

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Statistics of disastrous geological processes identified on the territory of Oni and Ambrolauri municipalities by settled areas Table 14 Years settled area Geological process Caused damage Information source

Landslide Agricultural lands, bridges, roads, Mudslide communications, death toll, 58 1997 Oni district, 67settlements Erosion villages were badly damaged, 11 Floods villages were moderately damaged Report for the years 1996- 98

Landslide Almost all villages were damaged, Mudslide bridges destroyed and deformed, 1997 Ambrolauri district, 71 settlements roads damaged. 3 households were resettled Report for the years 1996- 98 1998 Oni district, villages Shardometi, Farakheti, Zudali, Landslide 11 settlements, 7 were damaged; 5 Seva, Tskhmori, Mazhieti, Khideshlebi, Nakieti, Mudslide settlements were flooded; geological Report for the years 1996- Ghari, Nigvznara and town of Oni Floods monitoring is conducted over 60 98 settlements

1998 Ambrolauri districtvillages Tsesi, Kvatskhuti, Landslide 10settlements; all the 10 were Report on the Natural Saketsia, Sadmeli, Tola, Bugeuli, Kvishari, Abari, Mudslide damaged; 6 households were resettled Disatsers of the 1998 Likheti and town of Ambrolauri

2000 Ambrolauri district villages Tola, Zhashka. Zhoshka Landslide 3settlements, all the settlements Report on the Natural and Skvava were damaged Disasters of the 2000

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2004 Ambrolauri district villages Mukhli, Tsesi, Lirkheti, 37 landslides 27 settlements, 281 buildings, 7 km Information bulletin Abari, Uravi, Khimshi, Kvatskhuti, Itsa. Gori, 6 mudslides of roads, 3 bridges,387,5ha of “Natural Disasters” for the Akhalsopeli, Krikhi, Skhvava, Sadmeli, Znakva, 1 flood agricultural lands, 27 settled areas and year 2005 Saketsia, Ghviara, Khvanchkara, I Tola, II Tola, 13 bank washout areas 278 buildings are under monitoring Chorjo, Zhoshka, Kvishari, Ghendushi, Ghadishi, Baji, Lower Shavra, Tlughi, Velevi, Betlevi, Nikortsminda and town of Ambrolauri 2004 Oni district villages Ghebi, Chiora, Glola, Utsera, 33 landslides 23 settlements, 216 buildings, Information bulletin Mazhieti, Nakieti, Lagvanta, Ghari, Khideshlebi, 9 mudslides 10 bridges, “Natural Disasters” for the Gomi, Komandeli, Nigvznara, Pipileti, Psori, 5 floods 9 km of roads, 170 ha of land plots year 2005 Tskhmori, Tsedisi, Parakheti, Seva, Shardometi, 10 bank washout areas have been damaged, 21 town of Oni settled areas and 214 buildings are under monitoring 2004 Oni district village Ghari Mudslide 12 households and 8 sawmills are Overall status of disastrous under the risk geological processes in Oni district, 2004

2004 Oni district villages Ghebi, Chalebis Ubani, Chiora, Mudslide 18 settlements, bridges, roads, Overall status of disastrous Glila, Gona, resort Shovi, Saglolo, Utsera, Nakieti, agricultural lands, population geological processes in Oni Lagvanta, Komandeli, Nigvznara, Shardometi- district, 2004 Parakheti bridge, Gomi 2005 Ambrolauri district villages Likheti, Tsesi, Khimshi, 25 landslides. 21 settlements, 70 houses, out of Information bulletin Gori, Skhvava, Krikhi, Ghviara, Sadmeli, Znakva, 1 mudslide, side erosion which 16 destroyed and needs to be Natural Disasters, 2006 Bugeuli, II Tola, I Tola, Kvishari, Ghadishi, Shavra, due to flash floods, floods moved to geologically stable area, as Baji, Patara Oni, Khotevi, Ghendushi, Zhoshka a result of floods was damaged a 1870 meter long stretch of lands; 2360 meter long land stretch is under the risk; landslides have caused damage to 49,5 ha, 74,5 ha of lands is under the risk; 2750 km of road was damaged 2005 Ambrolauri districtvillage Ghendushi Landslide 7 houses were destroyed Information bulletin on Natural Disasters, 2005

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2005 Ambrolauri district villageZhoshka Landslide 54 houses are under the risk Information bulletin on Natural Disasters, 2005 2005 Ambrolauri district villageUpper Zhoshka Landslide 6 households were moved to Information bulletin on geologically stable area Natural Disasters, 2005

2005 Oni district villages Ghebi, Chiora, Glola, Utsera, 6 landslides, side erosion 14 settlements, Information bulletin on Majhieti, Nakieti, Khideshlebi, Lagvanta, caused by flash floods 136 houses, as a result of flash flood Natural Disasters Komandeli, Ghari, Akhali Chordi, Shardometi, was damaged 10350 meters long Bokva and town of Oni stretch of land; 11800 meters long land stretch is under the risk; landslides damaged the territory of 4 ha; 6 ha is under the risk; 8,470 km of road is damaged 2005 Oni district village Ghebischalebi Ubani Mudslide 18 households Information on Racha- Lechkumi Kvemo Svaneti region, 2005 2005 Oni district village Ghebi and population residing Mudslide 12 households Information on Racha- on the bank of Lartkishou river Lechkumi Kvemo Svaneti region, 2005 2005 Oni district village Chiora Mudslide 8 households Information on Racha- Lechkumi Kvemo Svaneti region, 2005 2005 Oni district village Ghari Side erosion causes as 4 buildings are destroyed, 34 houses Information on Racha- aresult of flash flood in are under the risk Lechkumi Kvemo Svaneti river Gharula region, 2005

2005 Oni district village Glola Mudslide 1 building was destroyed, 11 are Information on Racha- damaged seriously; road and other Lechkumi Kvemo Svaneti communications were damaged; 4 region, 2005 households are under the risk

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2005 Oni district village New Chordi Flash flood, mudslide 28 households are under the risk Information on Racha- Lechkumi Kvemo Svaneti region, 2005 2005 Oni district village Shardometi Flash flood, mudslide 15 households are under the risk Information on Racha- Lechkumi Kvemo Svaneti region, 2005 2006 Ambrolauri district village Tsesi, Khimshi, Sadmeli, 7 landslides, 3 17 settlements,1350 meters of road, Information bulletin on Likheti, Skhvava, Gori, Ghviara, Znakva, Bugeuli, I mudslides, 9 areas 34,5 ha of agricultural lands, 1610 Natural Disasters, 2007 Tola, Kvishari, Ghadishi, Zhoshka, Tskimori washed out meters of territory and a bridge is 4 floods damaged; 84 houses and water supply system was damaged 2006 Oni district villages Ghebi, Chiora, Glola, Utsera, 7 landslides, 3 Damage was caused to 15 settlements, Information bulletin on Gomi, Khideshlebi, Zhizhoreti, Ghari, Lagvanta, mudslides, 9 areas 5050 meters of roads, 11 ha of Natural Disasters, 2007 Lancha, Komandeli, New Chordi, Shardometi, washed out agricultural lands, 1000 meter long Tskmori and town of Oni 4 floods stretch of land, bridge, buildings, high voltage transmission lines, 8 sawmills and 130 households 2007 Ambrolauri district villages Tsesi, Khimshi, I Tola, 4 landslides 5 settlements, 17 households under Information bulletin on Kvishari, town of Ambrolauri 1 river bank washout the risk. 1 house destroyed; 550 Natural Disasters, 2008 meters of the roads and land plots are damaged Oni district villages Ghebi, Glola, Khideshlebi, 3 landslides 6 settlements, 16 houses, 2000 meters Information bulletin on Komandeli, Lachta, Shardometi 2 river bank washout of roads, land plots, bridge passages Natural Disasters, 2008 2007

2008 Ambrolauri district villages Tsesi, Khimshi, I Tola, 6 landslides 7 settlements, 8 households, 300 Information bulletin on Kvishari, Kvanchkara, Zhoshka, town of Ambrolauri 2 mudslides meters of roads, land plots, Natural Disasters, 2009 1 river bank washout agricultural lands

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2008 Oni district villages Ghebi, Glola, Khidashlebi, 3 landslides Roads, bridges, land plots, agricultural Information bulletin on Komandeli, Lachta, Shardometi 1 mudslide lands Natural Disasters, 2009 2 river bank washouts

2009 Ambrolauri district village Uravi, Likheti, I Tola, II 9 landslides 6 settlements, population, roads, land Information bulletin on Tola, Bareuli, Kedisubani, Kvanchkara, Ghendushi, 4 mudslides plots, agricultural lands, bridge Natural Disasters, 2010 Gori, Krikhi, Khidikari, Akhalsopeli 4 river bank washouts passages

Oni district villages Pipileti, Khidashlebi, Parakheti, 3 landslides 7 settlements, population, roads, land Information bulletin on 2009 Ghebi, Glola, Chiora 3 mudslides plots, agricultural lands, bridge Natural Disasters, 2010 3 river bank washouts passages 1 rockfall 2009 Oni district village Ghebi mudslide 6households were resettled to Conclusions for the year geologically stable area 2009

2010 Ambrolauri district village I Tola, II Tola, 5 landslides 12 settlements, 70 households, 2250 Information bulletin on Khedisubani, Krikhi. Kvanchkara, Uravi, 2 mudslides meters of roads, 30 land plots, Natural Disasters, 2011 Ghendushi, Likheti, Chrebalo, river Asakistskali, 5 river bank washouts agricultural lands, bridge passages Krikhula

2010 Ambrolauri district village I Tola 1 landslide 2households were resettled to Conclusions for the year geologically stable area 2010

2010 Ambrolauri district village Akhalsopeli 1 landslide 1 household was resettled to Conclusions for the year geologically stable area 2010

2010 Ambrolauri district village Bareuli 1 landslide 1 household was resettled to Conclusions for the year geologically stable area 2010

2010 Oni district villages Utsera, Gomi, Parakheti, 4 landslide 10 settlements, 36 households, 2680 Information bulletin on Shardometi, Komandeli, Chiora, river Kholi gorge, 6 mudslides meters of roads, agricultural lands, 3 Natural Disasters, 2011 Glola, Patara Tskaro, river Bdghviora, Ghebi, left 1 river bank washout bridge passages, 1 high voltage tower slope of river Rioni, Amrolauri-Oni highway

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2010 Oni district village Shromisubani 1 landslide 3households were resettled to Conclusions for the year geologically stable area 2010

2010 Oni district village Sakao 1 landslide 1 household was resettled to Conclusions for the year geologically stable area 2010

2010 Oni district village Mazhieti 1 landslide 6households were resettled to Conclusions for the year geologically stable area 2010

2011 Ambrolauri districtvillages Lower Zhoshka, I Tola, 8 landslides 19 settlements, 95 households under Conclusions for the year Chrebalo, Kvatskhuti, Sadmeli, Gori, Gorisubani, 1 mudslide the risk; roads, land plots, bridge 2011 Khimshi, Itsa, Akhalsopeli, Znekva, Chkvishi, passages; 11 households were Velevi, Likheti, Uravi, Jvarisa, town of Ambrolauri resettled to geologically stable area

2011 Oni district villages Utsera, Kvemo Bari, town of 3 landslides 4 settlements, 14 households under Conclusions for the year Oni 1 mudslide the risk; roads, land plots, bridge 2011 passages, agricultural lands

2012 Ambrolauri district villages Kvatskhuti, Tsesis, 7 landslides 23 settlements,, Information bulletin on Znakva, Saketsia, Upper Shavra, Kvishari, 4 mudslides 64 households under the risk; roads, Natural Disasters, 2013; Ghendushi, I Tola, II Tola, Lower Zhoshka, Uravi, 4 river bank washouts land plots, bridge passages, Conclusions for the year Krikhi, Kvanchkara, Kvishari, river Lukhinistskali, agricultural lands 2012 river Krikhula, river Naboslevi gorge, river Ghendushi gorge, Liketi, Tsesi, Gori, Tsakhi, Ghviara, town of Ambrolauri 2012 Oni district villages Zemo Bari, Kvemo Bari, Sakao, 6 landslides 9 settlements, 65 households under Information bulletin on Khideshlebi, Sheubani, Sori, Ghebi, river Lartkishou 2 mudslides the risk; roads, land plots, 1 bridge, Natural Disasters, 2013; gorge, Komandeli 2 river bank washout agricultural lands; 1 household was Conclusions for the year resettled to geologically stable area 2012

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Ambrolauri district villages, II Tola, Krikhi, 19 landslides 20 settlements, 3 households were Conclusions for the year 2013 Kvishari, Tsesi, Kvatskhuti, Patara Chorjo, Sadmeli, 2 mudslides resettled to geologically stable areas 2013 Uravi, Akhalsopeli, Betlevi, Lower Sharvra, Upper 2 river bank washouts Zhoshka, Mukhli, Khimshi, Gori, town of Ambrolauri 2013 Oni district villages Zemo Bari, Sheubana, Lachta, 14 landslides 15 settlements,57 households are Conclusions for the year Khuruti, Khideshlebi, Mazhieti, Tsmendauri, 1 mudslide under the risk; 4 households were 2013 Shromisubani, Parakheti, Chiora, Pipileti, Sorgiti, 2 river bank washouts resettled to geologically stable areas Gomi, Shardometi, Sori

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6.3 Forecasts Related to Development of Disastrous Geological Processes on the Territories of Oni and Ambrolauri Municipalities

On the territories of Oni and Ambrolauri Municipalities by physical-geographical conditions we can identify following territories: humid climate zone with moderately cold winter and hot, relatively dry summer; and humid climate zone with moderately cold winter and warm long summer. Shaori depression is characterized by the coldest winter. Due to global climate change and warming effect forecasts of disastrous geological processes that may develop on the territories of Ambrolauri and Oni municipalities are the following: climate warming may cause substantial deviation from the normal climatic conditions, established in the region. Mean annual temperature may increase, which in its turn shall cause reduction of precipitation and increase of droughty days. In conditions of global warming torrential rains shall become more frequent on the slopes of Rioni river basin, majority of which are populated. Flash floods, developed as a result of torrential rains shall cause gullying of the slopes and increase probability of the washouts and formation of mudslides. On the other hand, probability of deep penetration of atmospheric precipitation into the surface layers shall reduce, which shall cause reduction of water levels and create conducive conditions for reduction of activeness of surface landslides. In regard to tectoseismogenic landslides we can state, that where conditions of penetration of atmospheric precipitation into the crevices and gulliesshall remain same, the level of activeness of landslide bodies shall remain within the range of mean multiannual indicator. Reduction of ground water levels may have positive impact on the stability of those slopes, where occur both deep and surface landslides and which are populated. Landslide processes are impacted by high seismic activity. Due to such processes many old landslides are reactivated. Taking into consideration, that on the territories of the above mentioned municipalities landslides are widespread, it shall be necessary to conduct capital, as well as simple preventive measures, which should be planned on the basis of monitoring results.

6.4

Geographic Location

Lentekhi municipality is located on the southern slope of the Caucasus Ridge and represents one of the highestmountainous regions in Georgia. On the south-east and the south the region is

prohibitio112 garemos erovnuli saagento p surrounded by the Lechkumi Ridge, while on the north it is surrounded by the Egrisi Ridge; on the west – the Codori Ridge, while on the north is located the Caucasus main watershed. On Lentekhi municipality main hydrographic unit is river Tskhenistskali. In Lentekhi into river Tskhenistkali are flowing rivers Khedeula and river Laskadura, after which river Tskhenistskali is flowing out of Kvemo Svaneti depression, from then onwards it is known under the name of Rtskhmeuli gorge, which connects Kvemo Svaneti and Tsageri depressions. It has submeridian direction and it continues flowing for 16 kilometers from township Lentekhi till town of Tsageri. Kvemo Svaneti depression is spread on 80 kilometers from the west to the east. Total area of Lentekhi municipality is 470km2. The largest settlement is township Lentekhi. There are 61 villages in the municipality, population is 8643 persons, Population density is 18,4 persons per 1km2.

Geomorphological peculiarities of the area

In Lentekhi municipality, the relief developed over the substrate of average- and high-mountain Jurassic cliffy rocks is represented by a geomorphological unit of Kvemo Svaneti mountain pit. Kvemo Svaneti mountain pit is made up of two gorges (gorges of the river Tskhenistskali and the Kheledula, the right tributary of the river Tskhenistskali), which, in the mutually opposite directions, are directed towards Lentekhi settlement.

The river Tskhenistskali within the Kvemo Svaneti mountain pit often changes its direction and the gorge below the river Shushara tributary acquires a lateral direction and up to village Mele flows through a canyon-like gorge, then, in the area of villages Chikhareshi and Makhashi, the gorge floodplain widens at the expense of the talus trains of the tributaries and inclined surfaces of the slope. The widened section, which is an alluvial terrace genetically, runs for 9-10 km up to the village of Chvelieri. There are erosive steps over the slopes of the said section of the gorge, which are clearly seen north of village Lemzagori.

Up to Lentekhi settlement, below village Chvelieri the gorge of the river Tskhenistskali is narrow and the water current flows through the cliffy rocks.

The gorge of the river Kheledula is the western part of Kvemo Svaneti mountain pit. The gorge has a prominent flat floodplain with the width of 0.5-0.7 km. Similar to the gorge of the river Tskhenistskali,

prohibitio113 garemos erovnuli saagento p here too, there are river terraces and talus trains with sloping surfaces developed on the right slope of the gorge.

The most important tributary of the river Kheledula is the river Skilori which starts at the Svaneti Ridge and flows through the cut-down trough down to village Mananaura.

The forms of the Old-landslide relief can be observed in the upper parts of the gorges of the rivers Mukhra, Kheshkuri and Ashkhashuri, which are the tributaries of the river Tskhenistskali and in the upper parts of the gorges of the rivers Tekali, Margouli, Tskhenishuri, Ghobishuri and Shushari flowing from the Lechkhumi Ridge.

The Rtskhmeluri gorge links the mountain pits of Kvemo Svaneti and Tsageri and spreads for 16 km from Lentekhi to Tsageri. From west it is bordered by the branches of the Odishi Ridge and from east it is bordered by the branches of the Lechkhumi Ridge. Both slopes of the Rtskhmeluri gorge are broken with the gorges of the tributaries of the river Tskhenistskali, with the river Devashi and river Khopuri being the largest among them, with the traces of the Quaternary glaciation surviving in the upper parts of their gorges.

The Rtskhmeluri gorge is developed in the slates of the Lower Jurassic Age, sandstones and only in the lower section the river crosses the Middle Jurassic porphyries and Cretaceous limestones stratum. Over the slopes along this section of the gorge, there are erosive steps at high elevations, with villages Lagharvashi, Rtskhmeluri and others located on them.

There is a typical canyon formed at the crossing of the northern wing built with the limestones of Lechkhumi syncline, so called “Muri narrow gorge”. The steeply inclined, almost hanging limestone strata form a narrow partition-like relief form, with the Muri Fortress erected on it.

In general, it can be said that the Kvemo Svaneti region has high geodynamic potential due to high inclination of the slopes (30-50° and more), dense river network, great depth of erosive cutting, great thickness of the Quaternary sediments (5-20 m and sometimes more). These factors condition the frequency and large scale of hazardous geological processes.

Tectonics and geology

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The main part of the Kvemo Svaneti territory is included in Chkhalta-Laili zone of the southern slope of the folded system of the Caucasus mountains that is separated by deep ruptures from its bordering zones in north and south. In the given region, the strongly folded and metamorphosed geosyncline formations of Dizi series are elevated to great level. Out of the folds present in the region the anticlines of Lamanashuri, Khopuri, Tsiplakakia, Laskadura and Lekaldi are worth noting. The said structural units are built with a range of fine folds and sub-lateral, steeply sloping ruptures with little amplitudes.

The territory of the Lentekhi municipality is made up of various sediments of different ages, from Paleozoic to modern sedimentary and metamorphosed rock complexes.

The Middle Paleozoic-Triassic sediments the river Tskhenistskali basin is represented by strongly dislocated metamorphosed rocks of Dizi series, predominantly with normal-terrigenous sediments represented by clay phyllitized slates, phyllites and different-grain carbonate sediments, represented by marbled limestones and marble. The lower layers of Dizi series are built with tuffas, tuffa-breccias and tuffa-sandstones.

The Jurassic system – the Jurassic rocks occupy the largest area of Svaneti. The Lower Jurassic rocks are mainly represented by slates, the Middle Jurassic rocks are represented as slates and sandstones, as well as Bajocian porphyrite stratum, while the Upper Jurassic rocks are represented by carbonate- terrigenous sediments.

Intrusive formations. On the territory of the Lentekhi municipality both deep intrusive massifs and sub-volcanic bodies as well as bodies with different compositions and ages associated with the strata of the Paleozoic and Jurassic Ages are widely prevalent and present.

The cutting bodies represented by base and acid rocks are: granitoids, gabro-diabases and porphyries.

The Quaternary sediments. A complex set of denudation and accumulation processes in the conditions of the intensely broken relief of the region causes the accumulation of loose sediments in the floodplain beds of the river and at the bases of the slopes. Fluvio-glacial, alluvial, prolluvial, delluvial, colluvial and other sediments with mixed genesis are prevalent here.

The UpperQuaternary sediments as water-glacial sediments, are quite widely prevalent in the gorge of the river Tskhenistskali and are represented by unsorted, weakly worked boulders and shingle and

prohibitio115 garemos erovnuli saagento p block talus. Alluvial sediments are present as terrace sediments built with shingle, gravel and sand. The delluvial-prolluvial formations have a limited distribution.

The Modern sediments are represented by fluvio-glacial formations found in the floodplain beds of almost all gorges of the main rivers and their tributaries. Lithologically, the rocks of the said genesis are represented by block talus and gravely material and weakly worked shingle and sandy loam.

The prolluvial sediments build the talus trains of mudflow currents, which sometimes have great thicknesses.

The delluvial sediments are prevalent on almost all slopes lower parts of which are covered with thick trains at some places.

Disastrous Geological Processes

On the territory of Lentekhi Municipality occur almost all disastrous geological processes, characteristic to mountainous regions, out of which the most dangerous are: landslides, mudslides, rockfalls, rockslides and erosion. Disastrous geological processes, occurring in the region, the area of their occurrence, their character and geodynamic features coincide with zones, having specific geological-morphological conditions. Apart from natural processes, which predetermine development of disastrous geological processes, such anthropogenic factors, as industry and construction, use of forest resources and etc. are other cause of these geological disasters. Below we provide description of certain disastrous geological processes. On the basis of studying of disastrous geological processes, occurring on the territory of Lentekhi Municipality was developed cadastreof landslides by settlements, which includes 54 landslides. Also, cadastreof mudslides was developed by river basins, which includes 34 mudslides. In the process of researching and establishing reasons and factors, causing disastrous geological processes establishing of the level of sensitivity of composing stratum towards specific disastrous geological processes is of extreme importance. It should be noted, that quarts-arkosic sandstone of Jurassic-Cretaceous age, limestone, marl and rocky stratum of volcanogenic formation, such as lava breccias, andesite and andesite-basalt create cliffy slopes, that represent the zone of development and accumulation of rockslides and rockfalls. Products of gravitational processes often become reason for formation of mudslides and feed solid components into them.

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On the territories, composed of semi-rocky stratum of clay-slate, slate and marl of terrigenous-carbonate formation are conducive conditions for formation of landslides and mudslides. As to sediments of quaternary period, which create zones where loosely-coupled sandy- argillaceous stratum of elluvium-delluvial, ellivual-proluvial and fluvial-glacial genesis, in such areas is characteristic erosion of three types: subsurface erosion, side erosion (erosion washout of river banks) and surface erosion. Below we provide data on the areas of occurrence of specific geological processes and trends of their development. Erosion: on the territory of Kvemo Svaneti erosion is represented in its broad variety, including subsurface erosion, lateral erosion (washout of river banks) and surface erosion (soil erosion). Main factor causing subsurface erosion is presence of stratum, which are sensitive to water- born erosion (clay-slate, slate, alluvial-glacial deposits), high energy of water flow and atmospheric precipitation. Subsurface erosion occurs in almost all small and large estuaries, gorges and ravines. Subsurface erosion is especially acute during spring rains and snow melt period. Lateral erosion is most clearly pronounced in the river beds of Tskhenistskali, Kheledula, Laskadula gorges and river beds of their tributaries. In these areas river banks are mainly composed of alluvial-proluvial and glacial sedimentation. Lateral erosion mainly occurs on floodplain and plain terraces, which are located near the following villages: Chvelieri, Khofuri, Kheledi, Mami, Tsiflakakia, Lesemi and Mele, where in September of 2013 as a result of flash flood was washed out the landfill of solid hazardous waste, located on the territory of the right bank of river Tskhenistskali (see pictures#15 - #16)

Picture #15picture #16 Quite often side erosion provokes landslides, as in the process of flash floods occurs erosion of the tip of landslides and slope bases are washed out. In the period of floods and flash floods,

prohibitio117 garemos erovnuli saagento p when the water levels and water discharge increases substantially due to increase of velocity of the water flow, banks are intensively washed out. Observations conducted in the previous years have demonstrated, that in May of 1987River Tskhenistskali washed away 4-8 meters of river bank near the village Chvelieri, while during one year was washed away 23-25 meter long stretch near the village Khopuri. Gullying erosion: Frequency of gullying erosion is mainly determined by the volume of elluvial-delluvial sedimentation, abundance of atmospheric precipitation and surface location of groundwater. The ground water is discharged into erosive crevices and ravines. Gullying erosion becomes stronger during spring rains and melting of snow cover. In Kvemo Svaneti depression major part f ravines have developed as a result of washout of deposition. Landslide processes: landslides occurring in the region are preconditioned by diversity of factors. Among them are: complex relief, morphological properties, hydrological and climatic conditions and their negative impact on physic-mechanical properties, side erosion and anthropogenic factor. Within the territory of Lentekhi municipality as a result of landslides are damages houses, roads and certain districts of villages. Landslideprocesses mainly develop in the quaternary period elluvial-delluvial formations, while certain local landslides also occur in stratum of Jurassic and Cretaceous period. Lithologically landslide deposits contain clays and gravel material. Landslides are mainly concentrated alongside the river beds of Tskhenistskali and Kheledula, in the lower part of slopes, on the territories near villages Khacheshi, Kheledi, Lesema (see picture#17), Laskadura, Melura, Babili (see picture#18),Pakhi, Nanari, Tekali, Mami, Shkedi, Natsuli, Mele, Zhakunderi and Leshuri. Majority of landslides have developed on terrigenous-metamorphic sediments of the Jurassic and Cretaceous period (clay-slate, slate, sandstone, marl and limestone) and elluvial- delluvialformations, developed on them.

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Picture #17picture #18

landslides differ by the mechanism of movement, which is preconditioned by such factors, as energy of the relief, sensitivity of composing stratum, frequency of tectogenic and exogenic crevices, the level of their muddingб climatic conditions, anthropogenic factor and etc. In the above mentioned stratum creeping type of landslides is widespread, that are characterized by spread on large areas, from 10 hectares (villages Makhashi and Chikareshi) up to 150 hectares (villages Melura and Tsana). Average power of landslides is 3-5 meters, rarely up to 20 meters (villages Melura and Panaga), in some areas we come across complex landslides (villages Tekali, Mami and others). On certain localities were identified surface (climatogenic) landslides. Territory of Lentekhi municipality is characterized by large volume of precipitation. Surface water penetrating into the stratum causes reduction of physic-mechanical properties and stability of slopes. Increasing of the ground water levels causes increasing of hydrostatic pressure. Quite often the above mentioned factors cause formation of surface (so called climatogenic) landslides. Landslides occurring in the region can be divided into surface, relatively deep and deep landslides. The deepest landslide (up to 20 meters) has developed on Lower Lias and Disi stratum and topsoil developed on their substrate. By age we identify old, contemporary and new landslides. Majority of contemporary and new landslides are active or partially stable. Small landslides, of under 1 hectare are mainly identified alongside the river beds of tributaries and slopes alongside the roads. By the mechanism of movement they are creeping or sliding. Frequently reason for formation and activation of landslides is washout of the tip of the landslides by rivers Tskhenistskali, Koruldashi, Kheledula and Laskadula, which is in its turn related to flash floods. Such events occur near the villages Mami, Babili, Panagi, Lower Tsanashi, Dzughareshi, Lesema, Khacheshi, Shtvili, Mananuri and Laskadula. Mudslides: Mudslide processes are widespread on the territory of Lentekhi Municipality. Mudslides mainly occur on slopes of sharp inclination, which are sensitive to depletion processes. Mudslides mainly develop on clay-slate and slate stratum of Jurassic period, which easily succumb to destructive exodynamic processes and contribute to accumulation of depletion material. In Kvemo Svaneti depression are widespread almost all types of mudslides. In the tributaries of river Tskhenistskali mudslide foci are located in the river heads, as well as the middle parts of rivers. Majority of them contain loosely-coupled solid material accumulated as a result of depletion and gravitation processes. In majority of rivers, where mudslides are formed (river Tskhenistskali, Kheledula, Laskadula and Devashi) the transit sections are either very short, or nonresistant. The latter is happening

prohibitio119 garemos erovnuli saagento p when the flows are relatively short (Mele gorge, Pishoki gorge (picture #21),Bibili gorge and etc) and the zone of formation of a mudslide immediately passes to attenuation phase. In Lentekhi municipality are represented mudslide forming foci of different genetic type, such as: erosive-gravitational, erosive-landslide, landslide, gravitational-landslide and gravitational. 13 out of them are of erosive-gravitational origin, 8 – landslide origin, 6 – erosive- landslide origin and 7 – landslide-gravitational origin. Frequently formation of mudslide flows is caused by accumulation of large masses of soil in the river beds, resulting from landslide-gravitational processes. Due to this periodically are formed stanks, disruption of which creates powerful mudslide flows with large volume of stratum at the debris cone (reaching several thousand of m3). Such mudslide occurred in 2005 near the estuary of river Kheledula, Sgumrashura, Mamiskhevi and Laskadula gorges. The volume of debris cone of river Laskadula was 120000m3, Tekalistskali - 15000m3, Shushariskevi - 22000 m3. It should be noted, that as a result of washout of the base of the debris cone main mass of the sedimentation was washed out by rivers Tskhenistkali and its tributaries. Solid component of mudslides occurring on the territory of Kvemo Svaneti contains stones or mud-and-stones. Stones are brought down by mudslides in the upper part of Tskhenistskali gorge in those areas, which are composed of rocky stratum. Out of all 34 mudslides, registered in the region 27 are of muddy-stony consistence (rivers Laskadula, Babiliskhevi, Mukhra, Khanashuri), while the rest are of watery-stony consistence (Leshuristskali, Patara Kheledula, Gvimbrala, Ghobishuri (Pictures #19 #20),Tskhemuristskali, Kvedreshi and Lamanashuri (Picture #22).

Mber of mudslide

Picture# 19Picture#20 Distribution of the number of mudslide forming foci in the catchment area is the following: on 26 mudslide forming basins is one focus, while in 5 basins there are from 2 to 3 foci (rivers Megulo, Pishkori, Ghobishuri, Rtskhmeluristskali and Tskhenishuri). In two basins are around 4-5 foci (rivers Laskadura and Kheshkuri).

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Picture#21Picture#22 The total area of 16 mudslide-forming foci is under 1.0km2, while total area of 18 foci is under 5.0km2. as to the volume of transported sediments on the debris cone, it is different and according to data collected during the previous years the volume of transported sedimentation is: 15 mudslide forming river (Babiliskhevi, Chveliskhevi, Gvimbrala, Tskhenishuri) - 5000m3, 11 gorges (Meliskhevi, Mamiskhevi, Meluriskhvi, Khanashuri, Pishkori, Mergulo, Kheshkuri) – from 5000 to 10000m3, while on the zone of discharge of mudslides on rivers Teklistskali, Panagistskali, Tsanashura, Sgimrashura, Shushara and Tvibra the volume of sediments is 10000m3. Frequency of annual passage of mudslides varies and in the event of conducive conditions in majority of gorges it is 1-2 a year, rarely 2-3 times and mudslides are formed mainly in the river beds (Mergouli, Patara Kheledula, Meluriskhevi, Mamiskhevi and Tvibra). There are some exclusions as well, when limited precipitation deters formation of mudslides. As a result of monitoring, conducted in 2013 it was established, that during the year under consideration formation of mudslides and the level of their activeness was lower than the mean annual. Minor mudslides occurred on rivers Babiliskhevi, Devashi, Lakanshura, while mudslides of stony consistence occurred in the upper part of rivers Zeskho, Ghobishura, Koruldashi and etc. We can conclude, that majority of debris cone of mudslides is covered with grass and underbrush, which confirms, that in 2013 in these gorges mudslides have not occurred. During last decades the deposit of mudslides transporting stones and rocks have substantially narrowed Tskhenistskali river bed and the river was shifting its position. Similar is occurring in rivers Devashi, Pishoki, Ghobishura, Rtskmeluristskali and Khopuristskali estuary. Mudslides cause substantial damage to infrastructure of the municipality (Lentekhi- Koruldashi road, Sachapano bridges, power transmission lines and etc), houses, different facilities, land plots and agricultural lands.

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Rockslides and rockfalls: rockslides and rockfalls mainly occur alongside cliffy slopes of Kvemo Svaneti depression and as a rule they are spread sporadically. Relatively small areas of rockslides and rockfalls are identified alongside the roads, where gravitational geological processes cause obstruction of road shoulders and cuvets, which deters proper use of roads. Rockslidesand rockfallsare impacted by sharp inclination of slopes, low resistance of stratum to depletion, formation of clefts and seismic shocks. Rockslides develop in different stratigraphic- lithological units in the mountain missives of clefty rocky and semi-rocky composition. Rockslides and rockfalls mainly develop in tuff-breccia, tuff-sandstone and porphyritic layers and granitoid stratum of Paleozoic period. On slopes built with tufogenic stratum some cones of rockfalls are of triangle shape and granulometrically consist of inhomogeneous rocks and shingle. Rockslides and rockfalls occur on slopes of river gorges Tskhenistskali, Zeskho, Kheshkuri, Laskadula and Khopuristskali. On the basis of observation data, collected by the National Environmental Agency was elaborated forecast of climate trends in Lentekhi municipality for the end of the XXI century. It is the following: mean annual atmospheric temperature shall increase from 9.10 to 12.60, annual total precipitation shall reduce from 1197mm to 1127mm. Presumably number of days of strong rainfall shall increase. Number of dry years shall increase. According to data for the period of 1956-2000 frequency of dry years increased from 53% to 62%, while the mean flow of river Tskhenistskaliincreased from 61m3 to 87m3. Above mentioned expected climate changes shall have impact on almost all exogenic geological processes. Along with increase of dry years the climate shall become relatively continental and intensity of physical depletion shall increase, which shall cause increase of the frequency of mudslides with prevalence of solid components and mudslides of muddy consistence. Increase of number of rainy days, as forecasted shall cause influx of rain water in the clefty ground, which shall cause surface (climatogenic) landslides and rockslides. Torrential rains and increase of temperature shall cause intensive melting of glaciers, which shall increase the capacity of transportation of water flows, frequency of mudslide passages, intensiveness of river bank washouts and increase of volume of solid sediments, which shall have negative impact on functioning of infrastructure of the region. Atmospheric precipitation in the form of torrential rains shall have the most impact on the dynamic of climatogenic (surface) landslides, while it shall have less impact on deep landslides, activeness of which is related to ground water, located in deep stratum.

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Facilities of Lentekhi Municipality under the landslide risk and measures to be implemented Table 15

Number of landslides Total area Number of Damage caused by Dynamic status of a Measures to be and their of households landslides landslide and the risk implemented # Settlement geographical location landslides residing in the level settlement (ha)

1 2 3 4 5 6 7 8 Lentekhi municipality

1 Village Sasashi Left slope of river 5.25 318 Causes damage to houses One active and one Planning of slopes, Tskhenistskali gorge, and forest massives temporarily stable; risk diversion of surface water, river Mushvaleduri level – medium drainage basin, 2 landslides

2 Village Tsanashi Left slope of river 49.6 232 Causes damage to houses 2stabilized, with locally Regulation of surface water Tsamnashuri, of population of villages active areas; risk level – flows, construction of river Tsamnashuri river upper and lower medium Kheledula river bed basin, 3 landslides Tsanashi. fortification structure

3 Village Right slope of river 6.0 333 Caused damage to 5 One old landslide with Regulation of surface water Zhakhunderi Pishkori gorge, eastern houses locally active areas; flows, drainage of ground part of Zhakhunderi, 2 another contemporary; water landslides risk level – medium

4 Village Makhashi Right slope of river 10 2 Caused damage to 4 One old landslide with Not expedient due to high Tskenistskali gorge, 1 houses locally active areas; risk geodynamic potential of the landslide level – low slope and large area of

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spread

5 Village Melura Right slope of river 160 54 Caused damage to 29 One old landslide with Drainage of ground water, Tskhenistskali gorge, 1 houses and agricultural locally active areas; risk diversion of surface water landslide lands level – high 6 Village Kekhura Right slope of river 4.5 57 Caused different Contemporary, partially Tskhenistskali gorge, 1 category of damage to stabilized, risk level – Not expedient due to high landslide 22 houses high geodynamic potential of the slope and large area of spread

7 Village Pakhi Left slope of river 3.2 65 Contemporary, with Not expedient due to high Kheledula gorge , 1 Caused damage to 32 active, risk level – high geodynamic potential of the landslide houses and agricultural slope and large area of lands spread

8 Village Panaga Left slope of river 5.0 156 Caused damage to 150 Contemporary, with Regulation of surface water Tskhenistskali gorge, 1 meter section of active, risk level – high flows, drainage of ground landslide Lentekhi-Chikareshi water

9 Village Chikareshi Head of the river 10 287 The landslide crosses Contemporary, with Regulation of surface water Tvibra, 1 landslide river Tvibra and forms active, risk level – high mudslide; damaged 23 houses

10 Village Lurji Right slope of river 7.0 104 old landslide with locally Regulation of surface water Tskhenistskali gorge, 1 Caused damage to 4 active areas; risk level – flows and construction of landslide houses and agricultural high river bank protection lands structure

11 Village Bavari Left slope of river 31.5 103 Represents risk to the Contemporary, partially Regulation of surface water Kheleula, 1 landslide highway, damaged 4 stabilized, risk level – flows and construction of houses medium river bank protection

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structure

12 Village Tsana Left slope of river 150.0 61 Damages Lentekhi- Contemporary, partially Not expedient due to large Koruldashi gorge, 1 Koruldashi road; stabilized, risk level – spread landslide damaged 3 houses medium

13 Village Bughleshi Right slope of river 0.96 19 Damaged 4 houses and Contemporary, partially Regulation of surface water Tskhenistskali gorge, 1 land plots stabilized, risk level – flows and bank landslide medium consolidation. 14 Village Babili Right and left slopes 211.5 297 Damages Lentekhi- One old and 2 of river Tskhenistskali Chikareshi road, 20 contemporary landslides Not expedient due to high gorge, 3 landslide houses and agricultural with active areas; risk geodynamic potential of the lands level – medium slope and large area of spread

15 Village Chukuli Right slope of river 142.5 119 Destroyed 6 houses; Contemporary, partially Not expedient due to Tskhenistskali gorge, 1 represents risk to 28 stabilized, risk level – complex character of the landslide and houses; caused human high landslide and large area of mudslide death spread of the landslide

16 Villages Leksura, Right slope of river 303.0 385 Damaged local roads and Old landslides , Not expedient due to high Gulida, Melura Tskhenistskali gorge, 44 houses temporarily stabilized, geodynamic potential of the 4 landslides risk level – medium slope and large area of spread 2 contemporary active 17 Village Tekali Left slope of river 70.6 91 Damages Lentekhi- landslides ; risk level – Not expedient due to high Tskhenistskali gorge, Tekali road, forest cover, medium geodynamic potential of the 3 landslides damaged and destroyed slope and large area of 17 houses spread

18 Village Mele River Mele catchment 2.0 276 Damages 10 residential Contemporary, partially Regulation of surface water area, 1 landslide houses and land plots stabilized, with active flows areas; risk level – medium

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19 Village Mami Right slope of river 36.5 83 Damages forest massives, Contemporary, partially Not expedient due to Tskhenistskali gorge, 400 meters section of stabilized, with active complex character of the left slope of river Tekali-Mami road and areas; risk level – medium landslide and large area of Kelashi, 3 landslides damaged 14 residential spread of the landslide houses

20 Village Shkedi Left slope of river 293 damaged 3 residential Contemporary, partially Regulation of surface water Tskhenistskali gorge, 4.5 houses and agricultural stabilized; risk level – flows, conducting of 1 landslide lands medium drainage works

21 Village Shtvili Right slope of river 1.6 18 Destroyed 5residential Contemporary, with Construction of bank- Tskhenistskali gorge, houses and agricultural active areas; risk level – protecting structure 1 landslide lands medium 22 Village Tvibi Left slope of river 0.9 77 damaged 6 residential Contemporary, with Not expedient due to high Mukhara, 1 landslide houses and represents active areas; risk level – geodynamic potential of the risk to the population of low slope district Ghvaduri Not expedient due to high 23 Village Khacheshi Slopes of river 5.3 84 Damaged 6 residential Contemporary, partially geodynamic potential of the Kheledula gorge, 3 houses and represents stabilized, with active slope landslides risk to the road and areas; risk level – medium agricultural lands Not expedient due to high 24 Village Zeskho Slopes of river 28.75 28 Damages Mele- Contemporary, active geodynamic potential of the Tskhenistskali gorge, Koruldashi road, forest with stabilized areas; risk slope 4 landslides massives ; damaged 2 level – medium houses

25 Village Chvelieri Catchment area of 30 161 Damages forest massives, Contemporary, with Not expedient due to high river Chvelieri, 1 represents risk to the partially stabilized areas; geodynamic potential of the landslide population; damaged 20 risk level – medium slope and large area of residential houses spread of the mudslide

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26 Village Mananauri Right slope of river 0.96 17 represents risk to the Contemporary, stabilized; Construction of bank Kheledula gorge, 1 road, agricultural lands risk level – low protective structure landslide and 2 houses alongside the river

27 Village Lesema Left slope of river 3.0 230 Damaged local roads, Contemporary, partially Construction of erosion- Kheledula gorge, 1 more than 20 houses and stabilized; risk level – preventive structure on the landslide agricultural lands medium left side of river Kheledula

28 Village Lekosandi Left slope of river 1.5 125 Damaged and destroyed Contemporary, partially Regulation of surface water Mauldi gorge, 1 6 houses; damages the stabilized; risk level – low flows landslide forest cover

29 Estuary of river Left slope of river 4.0 4 Damages 60 meter Contemporary, active; Planning of relief, Khoruldashi Khoruldashi, 1 section of Lentekhi- risk level – high construction of bank landslide Koruldashi road protection structure

30 Village Right slope of river 0.8 52 Represents risk to the Contemporary, active; Regulation of surface water Matskhvarlameziri Tskhenistskali, 1 residential houses and risk level – medium flows . landslide land plots construction of bank 31 Village Dzughareshi River patara 15.0 Damages forest massives Contemporary, active; protection structure Kheledura gorge risk level – medium

32 River Nashalisghele Left slope of river _ Damages forest massives Contemporary, active; Planning of surface, estuary Tskhenistskali gorge risk level – medium construction of erosion protective structure on the river Tskhenistskali banks

33 Village Laskadura Left slope of river 97 Destroyed 12 houses and Contemporary, active; Not expedient due to high Laskadula gorge, 1 4.5 represents risk to other risk level – medium geodynamic potential of the landslide houses slope and large area of

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spread of the mudslide

34 Village Lemzagori Right slope of river 28.0 124 Damages village road Old landslide, temporarily Drainage of ground water, Tskhenistskali gorge, and houses stable, risk level – restoration of forest cover 1 landslide medium

35 Estuary of river Left slope of river 3.75 _ Damages forest massives Old landslide, partially Regulation of surface water Laslashi Tskhenistskali gorge, stable, risk level – flows . 1 landslide medium

Facilities of Lentekhi Municipality under the mudslide risk and measures to be implemented Table 16

Geographical Areas, covered Volume of Damage caused by Period of recurrence of Measures to be implemented location with sediments mudslides mudslides and the risk Settlement (name of the main level mudslide as a resulting # river basin and the result of from single tributary, where the mudslide was single occurrence of transformed occurrence a mudslide (ha) (m3) 1 2 3 5 6 7 8 9 Lentekhi Municipality Township River Laskadura 2.2 120 000 Represents risk to Once a year; the risk Cleaning of river bed; Lentekhi population of township level is low after periodic rehabilitation of Lentekhi implementation of bank protective structure river bank fortification works

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1. Village Babili Rive 1.3 40 000 Periodically damages Once or twice a year; Cleaning of the gorge from Babiliskhevi local roads and Lentekhi- risk level – high mudslide deposits; proper Koruleshi highway use and maintenance of mudslide diversion structure

2. Village Babili River Lakari 0.55 11 000 No damage identified 3-4 times a year; risk No damage to population level – medium identified, consequently conducting of measures is not expedient 3. Village Chvelieri River Chvelieri 0.2 6 000 Causes damage to 2-3 times a year; risk periodic cleaning of river population and road level – medium bed and construction of bank protective structure

4. Village Tekali River 1.55 25 000 Caused damage to Once or twice a year; ---- ,, ---- Tekalistskali residential houses risk level – medium 5. Village Leusheri River 0.75 12 000 No damage identified, Once or twice a year; Apart from conducted Gheshuristskali represents risk to risk level – low measures gabions need to be agricultural lands and made local road 6. Village Panaga River Panagis 0.5 1000 Land plots, bridge and Once or twice a year; periodic cleaning of river Ghele pipe bridge risk level – high bed, rehabilitation of bank protective structure 7. Village Tsanashi River 1.6 10000 No damage identified, Once or twice a year; periodic cleaning of river Tsanashura represents risk to risk level – high bed, construction of gabions population

8. Village Kheledi River Patara 1.2 1500 No damage identified, 3-5 times a year; risk

Kheledula represents risk to land level – high ---- ,, ---- plots and local road

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9. Village Gvimrala River Gvimrala 2.05 2000 No damage identified, Occurs on annual basis; Ghele represents risk to risk level – medium ---- ,, ---- population 10. Village Khopuri River Khopuris 3.75 5000 Information is not Once or twice a year; periodic cleaning of river Ghele available; represents risk risk level – high bed, restoration- to population rehabilitation of the bank protective structure 11. Village Tvibi River Mukhra 0.85 3000 Damaged land plots, road 2-3 times a year; risk Bank protective gabions are and bridge level – high constructed

12. Village Mami River Dabieri 1.4 4500 Damages forest cover 2-3 times a year; risk Not expedient due to high level – low geodynamic potential of the mudslide flow

13. Village Chvelevi River Chvelpis 4.8 4000 Damages local road and 2-3 times a year; risk Construction of bank Khevi land plots level – high protective gabions

14. Village Luji River Kheshauri 2.9 8000 No damage identified, Twice a year; risk level Bank protective structure represents risk to – high should be rehabilitated population and land plots

15. Village Sasashi River Murgouli 1.5 6500 Damages Lentekhi- Twice a year; risk level periodic cleaning of river Sasashi road and bridge – medium bed, rehabilitation of bank protective structure 16. Village Sasashi River 5.0 10000 Damages agricultural Once or twice a year; River bed was deepened, Zgimrashura lands and population after construction of gabions organized bank protective structure risk level – high

17. Village Sasashi River Laslashi 0.9 8000 No damage identified, 2-3 times a year; risk periodic cleaning of river

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represents risk to level – medium bed, construction of gabions population of village Sasashi

18. Villages River 7.2 5000 Damaged and buried Once a year; risk level periodic cleaning of river Jakhunderi and Pishkorisghele houses and cemetery, – high bed, monitoring Chukuli population was resettled observations from the risk zone

19. Village Kheria River 0.82 2500 No damage identified, Once or twice a year; Construction of bank Kjeriastskali represents risk to risk level – medium protective gabions agricultural lands 20. Village Chikareshi River 6.7 800 No damage identified, Once or twice a year; periodic cleaning of river Khanashuri represents risk to risk level – high bed, construction of bank population protecting structure

21. Village Shkedi River 3.6 2500 Damaged land plots and Once a year; mudslide- bank protecting measures Tskhenishura a bridge preventive measures were conducted; monitoring were conducted; risk should be established level – medium 22. Village Ghobi River 6.4 4800 Damaged forest cover Twice a year; risk level Is not expedient due to high Ghobishura and road to village – low geodynamic potential of a Natsuli mudslide flow 23. Village River 0.15 4200 No damage identified, Twice a year; risk level periodic cleaning of river Rtskhmeluri Rtskhmeluristska represents risk to – medium bed, construction of bank li population protecting structure 24. Village Kvedreshi River 0.4 2500 No damage identified Once a year; risk level ---- ,, ---- Kvedreshistskali – low 25. Village Mami River 1.1 8000 Information is not Three times a year; risk Construction of bank Mamiskhevi available; level – medium protective gabions 26. Village Mele River 1.15 10000 Information is not Three times a year; risk Is not expedient due to high Meleskhevi available level – medium geodynamic potential of a

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mudslide flow 27. Village Lekosandi River 1.7 42000 Information is not Once in 3-5 years; risk periodic cleaning of river Mauldiskhevi available; represents risk level – high bed, monitoring to agricultural lands 28. Villages Kheledi, River Kheledula 4.4 110000 Damaged houses, roads, Once in 3-5 years; risk Restoration-fortification of Khacheshi, different infrastructure level – high protective structure Tsakhashi, township Lentekhi 29. Village Mami River 0.7 14000 Information is not Once or twice a year; Bank protective structure Lamushuristskali available; represents risk risk level – high has been built to agricultural lands 30. Village Mazashi River 0.75 15000 Information is not Once or twice a year; periodic cleaning of river Mazashisgele available; represents risk risk level – medium bed, rehabilitation of bank to population protecting structure 31. Village Khacheshi River Tvibledi 2.9 75000 Information is not Once in 2-3 years; risk periodic cleaning and Ghele (left available; represents risk level – medium deepening of the bed tributary of to agricultural lands Kheledula) 32. Village Khacheshi Left tributary of 0.40 12000 Information is not Once in 2-3 years; risk periodic cleaning of river riverKheledula available; represents risk level – low bed, deepening of the bed to the road

33. River 0.25 1000 Once or twice a year; periodic cleaning of river _ Lamanashuri risk level – bed, construction of bank protecting structure 34. River Lakhashuri 2.65 90000 Damages Tsageri- _ ----- ,, ------,, ----- Lentechi highway 35. Damages agricultural periodic cleaning of river River Devashi lands, Tsageri-Lentechi ----- ,, ----- bed, deepening of the bed 1.5 45000 highway and a bridge

Statistics of disastrous geological processes identified on the territory of Lentekhi municipalities by settled areas

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Table 17

Geological processes Years Settlements Caused damage Information source

1 2 3 4 5 Till 1980 No data available on Lentekhi municipality Mudslides – 50, No data available Information bulletin – 2000 settlements Landslides -84

1980-86 23 settlements of Lentekhi municipality Landslides – 10, Mudslide 7,5 km road and 5 bridges Information bulletin – 2000 passages – 30, rockfalls – were damaged; 4,5 10. kilometers of river banks were washed out

1987-88 56 settlements of Lentekhi municipality Landslides – 23, Mudslide 8.5 kilometers of road and Information bulletin – 2000 passages – 45, Rockslides 9 bridges were damaged; – 2, in 1987 from the risk Rockfalls – 12. zone were resettled 1089 households; in 1988 within the high risk zone were 226 houses 1989- 23 settlements of Lentekhi municipality Landslides – 2, Mudslide 2,0 km of road Information bulletin – 2000 1991 passages – 23, Rockfalls – 7, river bank washouts - 3.0km

1992- Lentekhi municipality, villages Guida, Landslide – 1, Mudslide 3,0 km section of road Information bulletin – 2000 1995 Ghaghma Leksura, Khakhura, Chikareshi passages– 28, Rockslide – and partsof township and etc 1, Rockfalls – 12, river Lentekhi were damaged; bank washouts - 3.0km river banks were washed out 1996 18 settlements of Lentekhi municipality Mudslide passages – 5, 1.0km of road and 2 Information bulletin – 2000 Rockfalls – 3, river bank bridges were damaged

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washouts - 3.0km

1997 23 settlements of Lentekhi municipality Landslides – 8, Mudslide 2.0km of road, 3 bridges Information bulletin – 2000 passages – 14, Rockfalls – and 61 residential houses 12, river bank washouts - were damaged 4.5km

1998 7 settlements of Lentekhi municipality Landslide – 1, Mudslide 1.5km of road was Information bulletin – 2000 passages– 10, Rockfalls– damaged. 2, river bank washouts - 2.0km

2004 Natsuli, Ghobi, Mele, Lekosandi, Sasashi, Landslides – 3, Mudslide 7.3km of road, 7 bridges, Information bulletin – 2004 Luji, Chvelpi, Panaga, Leusheri, Tekali, passages – 14, river bank 215 residential houses and Mami, Chvelieri, Durashi, Sakhdari, Babili, washouts – 13 locations buildings were damaged; Ghaghma, Leksura, Melura, Tsanashi, side erosion of banks - 22 Kheledi, Naghomari, Khopuri, Mazashi, km township Lentekhi; total number of settlements – 28 . 2005 Local councils: Chikareshi, Zhakunderi, Landslides, erosion, 11 651residential houses, 6 Information bulletin – 2005 Choluri, Kheledi, Rtskhmeluri, Khopuri, foci of mudslides bridges 46 km of road and township Lentekhi 6 power transmission towers were damaged 2006 Local councils: Rtskhmeleuri, Khopuri, Mudslides – 4, landslides 53 residential houses, 3 Information bulletin – 2006 Kheledi, Choluri, Zhakunderi, Chikareshi – 2, erosion – 4, bridges, 8 sawmills, high voltage power transmission tower, hospital, cemetery were damaged; 183 houses within the risk zone 2007 Villages Babili, Luji, township Lentekhi Landslides, mudslides, 500 meters of road, 1 Information bulletin – 2007

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river bank washouts bridge passage, 17 residential houses 2008 Villages Babili, Luji, Sasashi, Chikareshi, Landslides, mudslides side 1.5km of road, 2 bridges, Information bulletin – 2008 Shkedi, township Lentekhi erosion 45 residential houses were damaged 2009 Villages Sasashi Lemzagori, Chukuli, Landslides– 7, Mudslides residential houses, roads, Information bulletin – 2009 Babili, Leksura, Gulida, Melura, Khopura, – 9, river bank washouts – agricultural lands, land Gvimrala, Chikareshi, Panaga, Mazashi 11 plots were damaged; 4,5 km of river banks were washed out 2010 Villages Sasashi, Babili, Lemzagori, Gulida, Landslides, Mudslides, 126 residential houses Information bulletin – 2010 Zhakhundeli, Melura, Khopuri, Panaga side erosion were damaged; 1.1 km of river bank was washed out 2012 Villages Leksura, Gulida, Melura, Sasashi, Landslides – 4, Sections of Lentekhi- Information bulletin – 2012 Shkedi, Gvimrala, Laskadura, township Mudslides – 5, rockslides Tsageri and Lentekhi- Lentekhi – 2. Chikareshi road, bridge and 16 residential houses were damaged 2013 Villages Khekhura, Babili, Chukuli, Landslides– 6, Mudslides– Sections of Lentekhi- Materials of field work – 2013 Leksonadi, Luji, Panaga, Mami, Leusheri, 9, Rockslide – 2, river Korunladhi road, river Durashi, Shtvili, Tsanashi bank washouts – 1.3.km Tskhenistskali bank protection structure, residential houses and subsidiary facilities were damaged

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6.5 Tsageri Municipality

Geographic location

Tsageri municipality is located on the Southern slope of the Greater Caucasus. Western border of the municipality goes alongside the eastern slope, southern border goes along river Rioni gorge, eastern border goes along the watershed ridge located near villages Sairme, Kveda, Chvishi, Tabori and Ghendushi, while the northern border goes alongside the eastern slope of Lechkhimi ridge. Total area f the municipality is 755.4 km2 . There is one city, 15 village councils and 58 villages in the municipality. Population is 16622 persons, population density is 22 persons per square kilometer.

Geomorphologic characteristics of the area

The complex geology and tectonics, climate and human economic activity condition the nature and geomorphological peculiarities of the relief in Lechkhumi.

Depending on the tectonic regime, geology, lithological-structural peculiarities of the rocks and dominant types of denudation processes on the territory of the municipality, the following geomorphological regions and types of relief can be identified:

1. The high- and average-mountainous relief of the Lechkhumi Ridge developed over the substrate of the Middle Jurassic porphyritic stratum and Cretaceous carbonate sediments.

2. The average-mountainous erosive-karst relief of Askhi and massifs developed over the substrate of the Upper Jurassic limestones.

3. The Zubi-Okureshi mountain pit area with the erosive-accumulation relief developed over the substrate of the Cretaceous and Upper Jurassic limestones

4. Racha-Lechkhumi syncline Geomorphological area with the erosive-accumulation relief developed over the substrate of the Tertiary sediments.

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High- and average-mountainous relief type of Lechkhumi Ridge developed over the substrate of the Middle Jurassic porphyry stratum and Cretaceous carbonate sediments

The said morphological area, in addition to Lechkhumi Ridge, comprises the Gormaghali Ridge. The absolute levels here are within the range of 1500-1800 m. The relief-forming element in this region is the denudation processes. The dominant relief forms are gravitational and karst forms. The given region is characterized by the mountain-gorge relief. The major rivers are the Lajanuri, Tskhenistskali, Rioni and their tributaries.

The river Lajanuri has developed a V-shaped gorge and the inclination of its slopes is 25-40°. Below health resort Lashichali the river has developed a wide floodplain with the width of 70-80 to 100-150 m. Out of the hazardous geological processes typical to the given geomorphological region sheet and linear erosion and mudflows are most common, while the landslide processes are less frequent.

Average-mountainous erosive-karst relief of Askhi and Khvamli massifs comprises the eastern and southern parts of Tsageri municipality. The limestone massif of Khvamli is connects to the Lechkhumi Ridge, which is located between the rivers Tskhenistskali and Rioni, from village Nakuraleshi to village Tvishi. Out of hazardous geological processes, karst, erosive and gravitational processes are pronounced here.

The geology is represented by the Jurassic, Cretaceous and Paleogenic sediments; in a lithological respect, the sediments are represented by tuffa-sandstones, tuffa-breccias, limestones, marls and marl limestones. Such lithological variety of the rocks is clearly evidenced by the type of the relief.

The Zubi-Okureshi mountain pit covers the gorge of the river Tskhenistskali around village Zubi- Okureshi. The basin is characterized by hilly and sometimes by stepped relief. The surface is broken with many gorges and gullies with the depth of their erosive cut-down of which is up to 10 m. Karst funnels can be observed in the peripheral sections.

The river Tskhenistskali has a meridian direction. The width of the floodplain is 50-80 m. The above- floodplain terraces built with the averagely treated shingle and boulder are at 3-5 m above the riverbed.

From east and west, Zubi-Okureshi basin is bordered by erosive-gravitational walls which height is 10- 15 to 50-70 m. At the base of the wall there are thick colluvial and delluvial-colluvial sediments.

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Adjacent to the Zubi ravine, the river Tskhenistskali is joined by the river Jonoula from the right side. From the west the river basin is bordered by Askha massif and by the low-mountainous area of Tsageri mountain pit from the east. The lower reaches of the Jonoula gorge is worked in limestones stratum of Askha abutment and is an asymmetrical gorge with its left flank being relatively steep. Above village Chkumi, the river Jonouli for 7 km flows through quite a wide flat-bed gorge. The right slope of the river Jonouli gorge is characterized by landslide-block slopes.

One of the typical morphological elements in the river Rioni gorge is Tvishi narrow mountain pass where the gorge is developed in the limestones and is characterized by quite deeply cut canyon-like forms. The flanks of the gorge in their upper part are transformed into the plain relief shapes. The Tvishi mountain pit is bordered by erosive-gravitational walls. The bedrocks here are covered by strong colluvial and delluvial-colluvial train with its thickness reaching 15 m. The landslide processes are widely common here (Orkhvi-Tvishi). The erosive processes are prevalent almost everywhere. There are mountain creeps and rock avalanche cones along the walls.

The Racha-Lechkhumi syncline spreads from the middle reaches of the river Jonouli to the basin of the river Lajanuri. The geology of the given region is represented by the Tertiary sediments.

In the Racha-Lechkhumi syncline in the Tsageri municipality there are two morphological units identified: Tsageri and Orbeli mountain pits. The first one covers the gorge of the river Tskhenistskali and another one -- the gorge of the river Lajanuri.

The Tsageri mountain pit is located in the middle reaches of the river Tskhenistskali. The absolute levels of the riverbed within it range from 400 to 500 m. From north-west the basin is bordered by the branches of Egrisi Ridge and by the abutments of Askha and Khvamli massifs from the south-west. The length of the basin is 12 km and its width is 10 km. The major part of the Tsageri basin is made up of the rocks of terrigenous and carbonate formations, with their age from Oligocene through Sarmat. The basin has a hilly relief with widely spread landslide sites.

The river Lajanuri has a large floodplain spreading over a great distance, which is built with boulder- and-shingle sediments.

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In the area of villages Orbeli and Usakhelo the gorge of the river Lajanuri widens and forms the Orbeli mountain pit. The morphology of the basin is characterized by river terraces and widely common landslide processes. Below the Lajanuri water reservoir the river flows into the antecedent low mountain pass which is cut down into the Lebechin anticlinal ridge. The depth of the gorge is 600-800 m. The landslide processes are widely common here.

Tectonics and geology

According to the tectonic zoning of the territory of Georgia the territory of Tsageri municipality is located in Gagra-Java zone of the folded system of the southern slope of the Great Caucasus.

The description of Individual folds is provided below:

1. Lajanuri anticline and Lajanuri syncline are observed around village Lajani and are spread from north-west of south-east. Lajanuri anticline is made up of the stratum of Bajocian porhyrites and Lower and Upper Cretaceous sediments. Lajanuri syncline trough is made up of the Upper Cretaceous sediments.

2. Dekhviri anticline. The axis of the anticline runs through village Dekhviri. The fold continues up to the river Lajanuri. In the central part of the anticline the sediments of Maykop facies and Oligocene clays are outcropped. 3. The Nasperi syncline can be observed on the area of village Nasperi and is widely prevalent. The fold trough is made up of Sarmat sediments. In the east the fold is complicated by relatively small folding. 4. Zogishi anticline is a much compacted anticline located between two syncline folds (Sairme and Ghvardia) made up of the Upper Cretaceous and Paleogenic sediments. 5. The Sairme syncline is a relatively flat fold with its trough made up of the Middle Eocene sediments.

The geology of the territory of the municipality is represented by the rocks dating back from the Jurassic through the Quaternary.

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The Jurassic system

The Jurassic sediments are represented by the Middle and Upper Jurassic volcanogenic sediments and so called color stratum.

Middle Jurassic – Bajocian (J2bi) is represented as a thickvolcanogenic stratum. It is prevalent in the northern, western and southern parts of the territory and covers the gorges of the rivers Tskhenistskali, Jonouli, Lajanuri and Rioni.

The Upper Jurassic is represented as a Kimmeridgian-Titon (J3km-t)color stratum. Lithologically it is represented by clays, sandstones and conglomerates. These sediments are of different colors.

The Cretaceous system

The Cretaceous sediments cover Racha-Lechkhumi syncline and are widely prevalent. There are three strata identified in the Cretaceous sediments: the Lower Carbonate, Middle Terrigenous and Upper Carbonate.

The Lower Cretaceous sediments – the sediments of the Valanginian-Hauterivian stage (K1v-h)are spread as a narrow strip around village Okureshi. Lithologically these sediments are mainly represented by sandstones, dolomitized and crystal limestones.

The sediments of the Barrem stage (K1b)are spread as a narrow strip in the southern and south-western part of the territory around villages Tabori, Lukhvano, Nakuraleshi and Tsiperchi. These sediments are represented by dolomites, dolomitized limestones and limestones.

The Apt Age sediments (K1ap) represented by marl limestones, stratified marls and rarely by limestones, continue the Barrem stage in conformity, over the both wings of Racha-Lechkhumi syncline.

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The Alb sediments (K1al) continue the Apt sediments with conformity at all locations. The Albine Stage is represented by marl and clay formations.

Thesediments of the Cenomanian Stage (K2cm) outcrop in the basins of the rivers Tskhenistskali, Lajanuri and Rioni. The Cenomanian sediments are representedby glauconitic sandstones, with tuffa interlayers at some places, and rarely by Carbonate sediments – sandy and marl limestones.

The sediments of Turon-Datum Stage (K2t-d) are widely prevalent. Their outcrops can be observed on Lebechini anticline wings, in the gorges of the rivers Rioni and Lajanuri, north of village Tvishi, and in the gorge of the river Tskhenistskali in the north. The said sediments are represented by mass limestones.

The Tertiary system

The Tertiary sediments spread on the territory of Tsageri municipality are presented by the sediments of almost all stages, from Paleocene through Sarmat. The sediments of the same age are found in the structure of Racha-Lechkhumi syncline.

1 The Lower Paleocene (P1 )sediments – dense crystal limestones penetrate the northern wing of Racha- Lechkhumi syncline as a narrow strip.

2 1 The Upper Paleocene-Lower Eocene (P1 -P2 ). The sediments of this age almost everywhere continue the Lower Paleocene. These sediments are litholologically represented by limestones, marl limestones and rarely by sandy marls.

2 The Middle Eocene (P2 )sediments are driven over the both wings of Racha-Lechkhumi syncline as a narrow strip. These sediments are litholologically represented by greenish marl limestones, marls and sandy limestones.

3 The Upper Eocene (P2 )is presented by think-layer grey marls with marl limestone interlayers. These sediments are quite widely prevalent.

1 The Oligocene (Maykop stratum) (P3-N1 ). The sediments of this age around Racha-Lechkhumi syncline are widely prevalent. Their outcrops are found on the territories of Kveda Lukhvano, Aghvi,

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Tskhukureshi, Ghvishiri, Usakhelo, Surmushi, Orbeli and Chkhuteli. These sediments are represented by non-carbonate clays with the interlayers and packs of carbonate clays.

1 The Lower Miocene (Sakaraulo horizon) (N1 sk). The outcrops of the sediments of this age are mainly found in Dekhviri anticline and can also be found in the wings of Racha-Lechkhumi syncline. These sediments are litholologically represented by the Maykop-type clays, yellowish-gray thin-layer fine- grain sandstones.

2 Kotsakhuri-Chokrak horizons (N2 ks-č) are represented by clays, sandy clays, clay sandstones and marls. These sediments are found in great amounts in the structure of the wings of Racha-Lechkhumi syncline.

2 The sediments of the Karagan-Concian horizons (N2 kg-kn) are widely prevalent in the areas of villages Utskheri, Lailashi, Tsilamieri, Makhashi and Tabori. These horizons are lithologically represented by coarse- and fine-grain sandstones and carbonate clays.

3 The sediments of the Upper Miocene-Sarmat Stage (N1 s) are not so widely common. The sediments of this age are found within the villages: Kenashi, Sanorchi and Nasperi, where they are a part of the structure of Sanorchi syncline. Lithologically they are mainly represented by clays and sandstones.

The Quaternary sediments. The Quaternary sediments build the terraces on the both slopes of the river Tskhenistskali gorge, and modern Quaternary sediments are prevalent at the bottom of the walls of the gorges of the rivers and gorge slopes. These sediments are represented by elluvial, delluvial, colluvial, alluvial and prolluvial varieties.

Hazardous geological processes

Tsageri municipality is among those leading with intense hazardous geological processes and damage inflicted to the public-economic facilities in the country. The following hazardous geological processes occur here: landslides, mudflows, rock avalanche, water erosion, karst and piping processes.

Historically the development and activation of the natural geological processes in Lechkhumi have been common. Over the observation period 8 to 12-year cycle of extreme intensification of these

prohibitio142 garemos erovnuli saagento p processes has been observed. Recently the periodicity in the frequency of the activation of processes has been broken and almost annually extreme occurrence of the said processes are found.

One of the major reasons for the above-mentioned, in addition to the complexity of the relief, geological makeup and climatic peculiarities is the anthropogenic impact on the geological environment.

Based on the field and laboratory studies under the Rioni basin project and by means of the employment of the distant methods 101 landslides have been described and registered in the cadaster in theTsageri municipality area.

Landslide processes. The geological makeup, hydrogeological and relief conditions of the territory of the Tsageri municipality condition the wide prevalence of landslide processes in the area. In addition to the natural conditions one of the factors contributing to the development of the landslide processes is human economic activity.

The area of the Lechkhumi municipality is 755.4 sq.km, while the area damaged by landslide processes is 3866.5 ha.

The landslides associated with the Jurassic sediments are common in the areas of villages Kulbaki, Isunderi, Zubi, Orbeli, Tvishi, Korenishi, Orkhvi and Okureshi. The major causes for the origination and development of the landslide processes in the areas where the Jurassic sediments are prevalent are the erosion washout of the slopes during the flooding and floods, significant incline of the surface and marginal humidification of the slope sediments. Most of the landslides are superficial and shallow and are developed in the elluvial-delluvial sediments, which are represented by clay loams and clays with 10-15 to 20-25% accretions of detritus and grit. The landslides are mostly plastic and are developed over the slopes with the inclination of 15-30°. The landslides damage and threaten the residential houses and Kutaisi-Ambrolauri road in village Tvishi. The following settlements are located in the high-risk zone of landslides: Orkhvi, Tvishi and Orbeli. Villages Kulbaki, Isunderi and Korenishi are located in the medium-risk zone of landslides.

The landslides associated with the Cretaceous sediments are spread in the environs of villages Zogishi, Kveda Sairme, Aplani, Tabori and Orbeli. The landslides are associated with the erosion- denudation slopes mostly inclined by 15-25°. Most of the landslides develop in the delluvial prohibitio143 garemos erovnuli saagento p sediments; however, Sairme landslide covers both, the Quaternary rocks and bedrocks. The landslides are mostly flow slides, either active, or slightly active. The reasons for the landslide processes over the slopes built with the Cretaceous sediments are the lateral erosion of the rivers mostly during the floods and flashfloods and deteriorated mechanical properties of the grounds caused by the humidification of the slope clay sediments. The rocks are characterized by moderate resistance to the denudation processes. The following settled areas are located in the landslide risk zone: Tabari, Alpana, Sairme and Zogishi.

The landslides associated with the Paleocene-Eocene sediments are spread on the territories of villages Tskhukureshi, Nakurasheli, Ghvishiri, Kulbaki, Orbeli, Chkhuteli, Larchvali and Aghvi.

The reasons for the formation of landslide processes, in addition to the great inclination of the slopes and local climatic-meteorological conditions is widely prevalent clay and semi-cliffy weathered rocks and anthropogenic impact. The grounds are sensitive to the landslide and other denudation processes. Villages Orbeli, Chkhuteli, Larchvali, Aghvi, Ghvishiri and Nakuraleshi are located in the high landslide risk zone. Village Tskhukureshi is located in relatively lower, medium-risk zone of landslides. In village Larchvali landslides pose danger to the Kutaisi-Tsageri motorway. As for Chkhuteli landslide, it damages the connecting road of Tsageri and village Orbeli.

The landslides are developed in elluvial-delluvial clays and clay loams with 10-15% of rocky detritus and grit accretions. The slope sediments slide over the bedrocks and sometimes over the Quaternary alluvial sediments. Both flow slides as well as plastic landslides take place here. They pose danger to residential houses as well as to agricultural lands and engineering facilities.

The landslides developed in the Oligocene and Miocene sediments are found in the areas of villages Kveda Ghvishiri, Tskhukureshi, Surmushi, Usakhelo, Kveda Lukhvano, Saletodiano, Aghvi, Larchvali (See Fig. 23 and 24), Dekhviri, Bardnala, Chkhuteli (See Fig. 25), Orbeli (See Fig. 26) and Laskhana. The major causes for the development of the landslide processes are high sensitivity of the slope sedimentary rocks to humidification, improper cultivation of slopes, as well as the lateral erosion of the rivers mostly during the floods and flashfloods – washout of slope bases. According to the mechanism of movement the landslides developed here are mostly flow slides or plastic landslides. In terms of power the landslides here are mostly of an average depth, but the landslides in villages Lukhvano, Chkhuteli and Orbeli have great depths (>10 m). There was village Rekha adjacent to

prohibitio144 garemos erovnuli saagento p village Saletodiano, which was fully land-slid in 1987, and the village residents were taken to safe locations. Villages Usakhelo, Lukhvano and Dekhviri are located within the high-risk landslides zone.

sur. #23 sur. #24

sur.#25sur.#26

The landslides developed in the Miocene clay-sandstone formations occur in villages Dekhviri, Utskheri, Lesindi, Lailashi, Usakhelo (See Fig. 27 and 28), Ghvirishi, Orbeli, Tsilamieri, Tabori, Surmushi, Nasperi, Sanorchi, Lukhvano.

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The lithology of Miocene sediments is represented by clays, clay sandstones and sandstones. The complex is characterized by wide prevalence of landslide processes, which mostly occur in the middle and lower sections of the slopes. The development of landslides is promoted by the excess amounts of ground water in the slopes. The ground water levels vary from 0.5 to 6-8 m and are characterized by variable regime. The strength of landslide bodies also varies. Particularly strong landslides occur in villages Gveso, Tsiperchi, Lailashi and Lesindi. These villages are distinguished by high potential for the landslide development.

It is recommended to take preventive, as well as capital measuresto maintain the stability of the landslide-prone slopes.

sur. #27sur. #28 Mudflows. The mudflow processes are widely prevalent in the area subject to the study. As the mudflows have high velocity and energy, they pose particular danger to the settled areas and economic and engineering facilities.

The formation of the mudflow processes is promoted by the easily washable weathered and coarse- grain material accumulated over the gorge slopes and high inclination of the slopes.

The mudflow currents on the territory of Tsageri municipality are found in the gorges of the rivers Tskhenistskali, Jonouli, Lajanuri and Rioni.

In the gorge of the river Jonouli which is made up of marl limestones, marls and limestones, mostly stone-and-water currents are formed. The strengths of the talus trains of the mudflow currents vary from 1 to5 m. The talus trains are lithologically represented by coarse material, with accretions of prohibitio146 garemos erovnuli saagento p block talus and small amount of clay loam joining material. The mudflow currents pose danger to the village roads, household plots and population during the flashfloods.

The mudflow currents developed in the gorge of the river Tskhenistskali pose danger to villages Kveda Lukhvano, Saletodiano, Bardnala, Namkashuri, Kveda Aghvi and Lajana (See Fig. 29 and 30) and Kveda Tsageri. The mudflow development here is promoted by the gravitational processes, landslides and weathered material accumulated over the slopes in great amounts. The frequency of the formation of mudflow currents for the majority of them is once or twice a year.

sur #29 sur#30

Mudflow current deflectors and mudflow blocking units and anti-landslide measures and forestation of the slopes are seen as anti-mudflow measures. The mudflow currents developed in the gorge of the river Lajanuri often damage the motorways, and building mudflow carrying engineering facilities is considered as a measure against them.

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Facilities of Tsageri municipality under the risk of landslides and measures to be implemented Table 18

Settlements Number of landslides Total area of Number of Damage caused by Dynamic state of Preventive measures # and their landslides households landslides landslides and risk levels to be conducted geographical location (ha) residing in the settlement

1 2 3 4 5 6 7 8 Tsageri municipality

1 Village Kulbaki River Jondoula gorge, 6.65 64 2 households have been 1 landslide in the process Regulation of surface 3 landslides resettled from the landslide of stabilization, 1 mildly water, river bank risk zone; 3 houses, active, risk level – medium solidification agricultural lands and land plots under the risk G 2 Village Lowe Right slope of River 299 55 25 households have been 2 active landslides 1 Regulation of surface Lukhvano Tskhenistkali gorge, 3 resettled from the landslide landslide in the process of and ground water, landslides risk zone; 5 houses, stabilization, with active construction of agricultural lands and land areas; risk level – high barrages in the river plots and Tskaltubo-Tsageri beds road is under the risk

3 Village Zaragula Right slope of River 8 30 5 houses and agricultural Contemporary, active; risk Regulation of surface Usakhelo gorge, 1 lands are under the risk level – high water flows, landslide prohibition of cultivation of the slope

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4 Village Gveso Right slope of River 126 68 Landslide damaged 9 Contemporary, active; risk Planning of the slope, Tskhenistkali gorge, 1 residential houses; 6 houses. level – high regulation of surface landslide Land plots and the road is and ground water under the risk

5 Township Tsageri Right slope of River 3.6 650 1 household has been Temporarily stable, risk Planning of the slope, Tskhenistkali gorge, 1 resettled from the landslide level – low regulation of surface landslide risk zone; Land plots are water flows under the risk

6 Village Chkuteli Left slope of River 143 309 50 households have been 3 active, 1 with locally Regulation of surface Tskhenistkali gorge, 4 resettled from the landslide active areas; risk level – and ground water, landslides risk zone; 10 households, high planning of the land plots and Tsageri-Orbeli surface, construction road are under the risk of barrages in the river beds

7 Village Laskhana Left slope of River 56.85 66 1 house damaged, 3 houses 3 active, 1 landslide in the Regulation of surface Tskhenistkali gorge and agricultural lands are process of stabilization, risk and ground water, under the risk level – high filling in and leveling of crevices, prohibition of cultivation of the slope

8 Village Bardnala Right slope of River 98 101 8 houses and agricultural 1 active landslide, 1 mildly Regulation of surface Tskhenistkali gorge, 4 lands are under the risk active, risk level – medium water flows, landslides construction of barrages in the river beds 5 houses have been moved to 2 active landslides, 1 Regulation of surface 9 Village Tsiperchi Right slope of River 52.45 101 safe zone; 1 house and local periodically active, 1 in the water flows,

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Tskhenistkali gorge, 4 road is under the risk process of stabilization; risk construction of landslides level – high barrages in the river beds, prohibition of cultivation of the slope

10 Village Larchvali Right slope of River 130.9 49 5 houses were destroyed by a 3 active landslides, 1 mildly Regulation of surface Tskhenistkali gorge, 5 landslide, 22 houses, land active, in the process of and ground water, landslides plots and highway are under stabilization; risk level – filling in and leveling the risk high of crevices, prohibition of cultivation of the slope Regulation of surface 11 Village Kvemo Left slope of River 60 103 3 houses were destroyed by a 2 active landslides; risk and ground water Aghvi Tskhenistkali gorge, 2 landslide, land plots are level – high . landslides under the risk

12 Village Lasuriashi Left slope of River 32.8 206 1 house moved to safe zone; Landslides are active; risk Organizing of drain Tskhenistkali gorge, 2 20 houses, land plots and level – high channels near the lad

landslides forest under the risk plots; filling in of

clefts, tamping and terracing Upper part of the left Regulation of surface 13 Village Dekhviri slope of River 78 97 4 houses badly damaged; 2 active, 2 in the process of and ground water Tskhenistkali gorge, 4 school, agricultural land and stabilization; risk level – landslides forest under the risk high Regulation of surface 14 Village Lesindi Upper part of left 219.75 50 32 houses are moved away 3 active landslides, 1 and ground water; slope of river from the risk zone; 23 stabilized; risk level – high conducting of Lajanuri, 4 landslides houses, land plots and local measures on 2

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roads are under the risk landslides not expedient Upper part of the left 15 Village Sanorchi slope of River 95.5 50 Residential houses, land 2 active, 1 periodically Regulation of surface Tskhenistkali gorge, 4 plots, agricultural lands activated; risk level – high and ground water, landslides prohibition of cultivation of the slope

16 Village Nasperi upper reach of 121 108 5 houses need to be moved 3 active, 1 periodically Regulation of surface Ustkhera gorge (right to stable location; 4 houses, activated; risk level – high and ground water, tributary of Rioni) 5 land plots and agricultural planning of the slope landslides lands are within the risk zone Village Utskheri 17 Upper reach of 141.65 111 2 houses, land plots and 2 active, 2 stabilized, 1 Regulation of surface Ustkhera gorge (right agricultural lands are mildly active risk level – and ground water, tributary of Rioni) 5 within the risk zone high filling in and leveling landslides of crevices, conducting of measures on 2 landslides not expedient

18 Village Tsilamieri Lower part of right 78 48 5 houses need to be moved 2 active, 1 mildly active Regulation of water slope of river Lajanuri to stable location; 48 risk level – high flows on the slope, gorge, 2 landslides houses, agricultural lands draining of lakes and local road are under the formed on the risk landslide

19 Village Latsoria Right slope of river 11.55 101 Residential houses, 2 active, 1 mildly active Resettlement Lajanuri gorge, 3 agricultural lands and risk level – high ofpopulation from

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landslides forests landslide-prone zone; regulation of surface water flows

20 Village Spatagori 82.8 126 Residential houses, 4 active, 1 temporarily Regulation of surface Left slope of river agricultural lands and local stable, risk level – high and ground water, Lajanuri gorge, 5 road prohibition of landslides cultivation of the slope, restoration of forest cover 13 houses need to be 21 Village Usakhelo 254.95 189 moved to stable location; 22 3 active, 2 in the process Regulation of surface Right slope of river houses, agricultural lands of stabilization, risk level and ground water, Lajanuri gorge, 5 and local road are under the – high construction of landslides risk barrages in the river beds; on 1 landslide the above measures were not effective

22 Village Leshkeda 1.9 49 Recommendation was Active, risk level – high Capturing of ground Right slope of river provided to move 5 houses water, regulation of Lajanuri gorge, 1 to stable location; 5 houses surface water flows landslide and agricultural lands are within the risk zone

23 Village Lailashi 141 290 2 houses need to be moved 1 active, 1 in the process Regulation of surface Right slope of river to stable location; of stabilization, risk level and ground water, Lajanuri agricultural lands and local – high filling in and leveling impoundment, 2 road are under the risk of crevices landslides Village Surmushi Left slope of river 4 households have been 3 active, 1 periodically Regulation of surface 24 Khelichuri (left 81.5 85 resettled from the landslide active, risk level – high water flows, planning

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tributary of river risk zone; 4 households, of the slope, drainage Lajanuri) 4 landslides land plots and local roads of water from lake, are under the risk resettlement of population from the landslide risk zone

25 Village Tabori River Rikistskali and 134 83 Agricultural lands 2 active, 1 temporarily Regulation of surface Tetrighele gorges (left stable, risk level – and ground water, tributary of river medium prohibition of Khelichuri) 3 cultivation of the landslides slope Agricultural lands, local Regulation of surface 26 Village Isunderi Right slope of river 21,25 70 road 2 stabilized, risk level – and ground water Tskhenistkali gorge, 2 medium landslides Regulation of surface 27 Village Zubi 97.65 251 1 house moved to safe zone; 1 active, 2 stabilized, risk and ground water Right slope of river land plots , agricultural level – medium Tskhenistkali gorge, 2 lands and local road are landslides under the risk

28 Village Shua Aghvi Left slope of river 12.8 42 3 houses were moved to 1 in the process of Regulation of surface Tskhenistkali gorge, 1 safe zone; 10 houses, land stabilization, risk level – and ground water, landslide plots , agricultural lands medium solidification of river are under the risk Rguani banks Regulation of surface 29 Village Zeda Aghvi Left slope of river 95.4 25 2 houses, land plots , 1 active, 2 temporarily and ground water Tskhenistskali gorge, 3 agricultural lands and local stabilized, risk level – high landslides road are under the risk agricultural lands Regulation of surface 30 Village Kenashi Upper part of 15 22 1 active, risk level – high and ground water left slope of river Tskhenistskali gorge, 1

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landslide 3 active, risk level – high 31 Village Upper River Gvrishi gorge 89.1 69 46 households have been Measures on 2 Ghvrishi (right tributary of river resettled from the landslide landslides hall not be Utskheris ghele) 3 risk zone; 8 households, land effective, water landslides plots are under the risk should be regulated on one landslide

32 Village Lower Left slope of Utskheris 35.2 87 agricultural lands, village 1 active, 1 stabilized, risk Regulation of surface Ghvrishi ghele (right tributary road level – medium and ground water of river Rioni) 2 landslides agricultural lands, village 33 Village River Gvishiris ghele 50 72 road 1 active, 1 mildly active, Regulation of surface Tskhukhusheri gorge, 2 landslides risk level – high and ground water, prohibition of cultivation of the slope village road mildly active, risk level – Regulation of surface 34 Village Lower Right slope of river 60 52 high water Sairme Rioni, 1 landslide

Right slope of river agricultural lands stabilized, risk level – Regulation of surface 35 Village Korenishi Rioni, 1 landslide 25.5 120 high water

Active, risk level – high Regulation ground 36 Village Orkhevi Lower part of left 400 142 40 residential houses, land water and slope of river Rioni, 1 plots, Kutaisi-Ambrolauri atmospheric landslide highway precipitation water

37 Village Tvishi Lower part of right 133.75 241 residential houses, land 2 active, risk level – high Periodic cleaning of slope of river Rioni, 2 plots, Kutaisi-Ambrolauri the highway, landslides highway regulation of surface

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and ground water Active, risk level – high 38 Village Orbeli Right slope of river 225 453 62 households have been Detailed engineering- Lajanuri resettled from the landslide geological surveys due risk zone; 10 households, to complex nature of land plots are under the risk the landslide . Active, risk level – high Regulation of surface 39 Village Khoji Left tributary of River 5.0 57 Damages agricultural lands and ground water Utskheri gorge

40 South-east part of Lower part of the left 48 158 Damages agricultural lands Stabilized, risk level – low Measures don‟t need village Zogishi slope of river Rioni to be implemented gorge Kutaisi-Ambrolauri highway Active, risk level – high Regulation of surface 41 Village Alpana Lower part of the right 99 89 water slope of river Rioni gorge

3866.5 5139

F Facilities of Tsageri municipality located within the zone of mudslide processes and measures to be implemented Table 19

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# Administrative region; Geographical location Areas, covered Volume of Damage caused by Period of recurrence of Measures to be settlement (name of the main with mudslide sediments mudslides mudslides and the risk level implemented river basin and the as a result of resulting from tributary where single single mudslide transformation occurrence occurrence of occurred) (ha) a mudslide (m3) 1 2 3 4 5 6 7 8 Tsageri municipality construction of 1 Village Kulbaki River Tskhenistskali 0,08 1600 Information is not Once or twice a year, risk mudslide passage basin, right tributary of available level – low structure river Jonoula

2 Village Lower River Tskhenistskali 0,1 3500 Damaged residential 2-3 times a year, risk level – Construction of Lukhvano basin, right tributary of houses, agricultural lands high mudslide canal, river Namkashuri and local road periodic cleaning of the bed construction of 3 Village River Tskhenistskali 0,01 180 Damages local road 1-2 times a year, risk level – mudslide passage Saletodiani basin, left tributary of medium structure (Upper Likhvano) river Nacharashvili Ghele Damages local road 4 Village Chkumi River Tskhenistskali 0,04 800 Once in 2-3 years, risk level Construction of basin, left tributary of – medium mudslide diversion river Jonoula structure and gabions

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5 Village Tsiperchi right tributary of the 1,15 34000 Tsageri-Tskaltubo Once in 2-4 years, risk level construction of river Tskhenistskali highway, local road of – medium erosion-prevention village Tsiperchi barrages

6 Village Chalistavi Tskhenistskali river 4,15 145000 River bed is cleaned, Once a year Protective measures basin, river banks solidified with don‟t need to be Namkashuri banquettes, pillarsof conducted Tsageri-Tskaltubo bridge protected

7 VillageKvemo Left tributary of river 0,35 8800 Damages local roads and Once in 3-5 years, risk level Construction of Aghvi Tskhenistskali agricultural lands – medium mudslide passage structure and periodic cleaning of the bed construction of 8 Village Kvemo river Tsulashi, left 1,3 52000 Damages local roads and Once in 1-2 years, risk level mudslide passage Aghvi tributary of river agricultural lands – medium structure Tskhenistskali

9 South part of Tskhenistskali river 0,25 5000 Damages Tsageri- Once in 2-3 years, risk level Periodic cleaning of village Isanduri basin; right tributary of Tskaltubo highway; banks – medium the bed river Tskhenistskali solidified with banquettes, river Rachkha pillars of Tsageri- Tskaltubo bridge protected

10 Village Kvemo Tskhenistskali river 1,3 40000 Damages land plots and Once a year, risk level – low Construction of Tsageri basin; right tributary of local road mudslide passage river Tskhenistskali structure and periodic cleaning of the bed

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11 Village Gveso Tskhenistskali river 0,15 3500 Land plots, agricultural Once in 1-2 years, risk level Construction of basin; river Gveso lands; crossing on the – high barrages in the bed, gorge, right tributary highway is arranged periodic cleaning of Tskhenistskali

12 No the north of Tskhenistskali river 0,12 3000 Damages the local road Once in 2-3 years, risk level Construction of Fortress Muri basin, left tributary of – medium mudslide passage river Tskenistskali structure and periodic cleaning of the road

13 Village Orbeli Lajanuri river basin, 0,5 6000 Damages road connecting Once a year, risk level – high Construction of river Mukvauli Ghele, Orbeli and resort mudslide diversion right tributary of river Lashichala structure and periodic Lajanuri cleaning of road

14 Village Orbeli Lajanuri river basin, 0,35 8000 Damages road connecting Once in 2 years, risk level – Construction of right tributary Orbeli and resort medium mudslide diversion Lashichala gabions and periodic cleaning of road

15 Village Orbeli Lajanuri river basin, 0,36 7000 Damages road connecting Once in 1-2 years, risk level Construction of right tributary Orbeli and resort – medium mudslide diversion Lashichala gabions and periodic cleaning of road

16 Village Orbeli Lajanuri river basin, 0,45 10000 Damages road connecting Once in 2-3 years, risk level Construction of right tributary Orbeli and resort – medium mudslide diversion Lashichala structure and periodic cleaning of road

17 Village Orbeli Lajanuri river basin, 1,4 42000 Damages road connecting Once a year, risk level – high Construction of right tributary Orbeli and resort mudslide diversion

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Lashichala structure and periodic cleaning of road Periodic cleaning of 18 Village Bardnala Tskhenistskali river 1,5 38000 Represents risk to Occurs seasonally, risk level the bed basin, river Sakhraula population residing on the – medium Ghele, right tributary edge of the gorge; on of river Tskhenistskali Tsageri-Tskhaltubo highway was built mudslide passage structure, which reduced the risk to the minimum Periodic cleaning of 19 Village Lailashi Lajanuri river basin 4,8 145000 Agricultural lands and Once in 2-3 years, risk level the bed river Khelichuri, left local road – medium tributary of river Lajanuri river Lajanuri Periodic cleaning of Represents risk to Once in 2-3 years, risk level the bed ; building of 20 Village Lajana 60 1 200 000 population and Tsageri- – high mudslide diversion

Alpani road gabions on both banks

Statistics of disastrous geological processes identified on the territory of Tsageri municipalities by settled areas Table 20

Geological years settlement Caused damage Sourcesof information processes

1987- Tsageri municipality Landslides - 178 Within the risk zone are 45 Information bulletin of State 1988 Mudslides - 28 settlements, 123 km of roads, 26 Department of Geology, 2000

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bridges 1989- Tsageri municipality Landslides - 188 Within the risk zone are 37 @@ 1991 Mudslides - 28 settlements, 20 of road, 1 bridge “

1992- Tsageri municipality Landslides - 174 Within the risk zone are 46 1995 Mudslides - 28 settlements, 2 kmof roads, 1 bridge

“ 1996 Tsageri municipality Landslides - 174 Within the risk zone are 52 Mudslides - 28 settlements, 54 kilometers of road, 4

bridges “ 1997 Tsageri municipality Landslides - 178 Within the risk zone are 37 Mudslides - 28 settlements, 50 kilometers of road, 4 bridges, water supply system, 50 “ houses were flooded, Tskaltubo- Tsageri highway was damaged 1998 Tsageri municipality Landslides - 180 Within the risk zone are 16 Mudslides - 2 settlements, 21 kilometers of road, Report on Natural Disasters for the 131 houses damaged, 90 houses under years1996-98 the risk, 8 houses moved to safe area, 40 ha of vineyards and 35 ha of arable land was damaged 2000 Tsageri municipality Landslide 40 houses destroyed, more than 100 houses under the risk, highway and Report on Natural Disasters for the roads damaged years1996-98 2003 Village Lasuriashi Landslide Within the risk zone are 56 houses, 1 Engineering-geological assessment Mudslide bridge of landslide, which occurred in village Lasuriashi on January 7 of 2003

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Villages Chkuteli, Kveda Tsageri, Landslides - 42 Within the risk zone are 29 2004 Tsiperchi, Bardnala, Larchvali, Zubi, Mudslides -5 settlements, 443 buildings, 3 bridges, Report on Natural Disasters for the Okureshi, Gveso, Aghvi, Nasperi, Flooding - 4 10,2 km of roads; 23 settlements may years 2004 Dekhviri, Makhashi, Lasuriashi, Orbeli, River bank be under the risk; 422 buildings are Tsageri, Lajana, Gagulechi, Surmushi, washout – 5 areas under monitoring; 21 buildings have Ghu, Usakhelo, Latsoria, Lukhvano, Rockfall – 1 area to be moved to safe location Khoji, Tsilamieri, Spatagori, Tvishi, Korenishi Villages Chkuteli, Lisuriashi, Orbeli, Landslides - 25 Within the risk zone are 25 2005 Lajana, Lashichala, Sanorchi, Aghvi, Mudslides - 3 settlements, 90 buildings, 10 Report on Natural Disasters for the Kenashi, Lukhvano, tsilamieri, River bank buildings have to be moved to safe year 2005 Doghureshi, Gveso, Lesindi, Larvachi, washout – 3 areas zone, 4,6 km of road has been Visual engineering-geological Zubi, Tsiperchi, Batdnala, Ghvirishi, Flooding – 1 area damaged, the school building is observations spatagori, Laskhana, Khoji, Utskheri, under the risk (in village Lasuriashi) Latsoria Villages Orbeli, Spatagori, Lesindi, Within the risk zone are 26 InformationBulletin of Monitoring 2006 Usakhelo, Surmushi, Aghvi, Gagulevhi, Landslides - 27 settlements, 492 buildings, 66 and Forecast Center for the year Latsoria, Lajana, Tsilamieri, Khoji, Mudslides - 2 buildings need to be moved to safe 2006, Tabori, Laliashi, Dekhviri, Tvishi, River bank location, 3,4 km of road, agricultural Visual engineering-geological Orkhevi, Okureshi, Chkuteli, Laskhana, washout – 1 area lands, 1,5 km of river banks were observations and conclusions on Zubi, Gveso, Tsiperchi, Larchvali, washed out (village Orbeli) disastrous geological processes Makhashi, Lasuriashi, Okureshi occurring in Tsageri Municipality B Villages Lajana, Orbeli, Usakhelo, Landslides - 21 Within the risk zone are 22 InformationBulletin of Monitoring Latsoria, Chkuteli, Lasuriashi, Dekhviri, Mudslide - settlements, 78 buildings, 9 buildings and Forecasts Center for the year Aghvi, Lesindi, Larchvali, Chkumi, 1Flooding – 1 area need to be moved to safe location, 4 2007, Gveso, Kveda Tsageri, Chalistavi, River bank houses and 1 school, roads and Visual engineering-geological Ghvirishi, Tsilamieri, Makhashi, washout – 3 areas agricultural lands are under the high observations and conclusions Sanorchi, Nasperi, Laskhana, Okureshi, risk Lukhvano

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Villages Lajana, Orbeli, U sakhelo, Landslides - 37 Within the risk zone are 28 2008 Latsoria, Chkuteli, Lasuriashi, Dekhviri, Mudslide - 1 settlements, 273 houses, 44 houses InformationBulletin of National Aghvi, Lesindi, Larchvali, Chkumi, Flooding – 2 area need to be moved to safe place, 12 Environmental Agency for the year 2008 Ghvirishi, Tsilamieri, Surmushi, River bank km of road, rope bridges, 280 meters Chalistavi, Tsiperchi, Bardnala, washout – 4 areas of water supply pipe, 60 ha of Visual engineering-geological Gagulechi, Zubi, Makashi, agricultural lands were damaged observations and conclusions Tskhukusheri, Nasperi, Spatagori, Kveda Tsageri, Sanorcho, Gveso, Alpana Villages Lajana, Orbeli, Okureshi, Landslides - 25 Within the risk zone are 22 2009 Tvishi, Usakhelo, Chkuteli, Aghvi, Mudslides - 2 settlements, houses, local roads, InformationBulletin of National Lesindi, Larchvali, Ghvirishi, Tsilamieri, River bank water supply facilities, highway, Environmental Agency for the year

Surmushi, Chalistavi, Spatagori, washout – 3 areas agricultural lands 2009

Leshkeda, Zubi, Isunderi, Gveso, Visual engineering-geological Tsiperchi, Bardnala, Kveda Tsageri, observations and conclusions Latsoria Villages Larchvali, Orbelii, Lesindi, Within the risk zone are 26 2010 Usakhelo, Surmushi, Spatagori, Landslides - 31 settlements, 129 houses, 35 houses InformationBulletin of National Tsiperchi, Lukhvano, Kveda Tsageri, Mudslides – 4 need to be moved to safe location, 8 Environmental Agency for the year Lajana, Lashichala, Orkhevi, Tvishi, Flash flood – 3 km of roads, 6 bridges, agricultural 2010 Lailashi, Zubi, Nakuraleshi, Okureshi, Flooding – 2 areas lands were damaged Visual engineering-geological Bardnala, Leshkeda, Nasperi, Chalistavi, Rockslide - 1 observations and conclusions Sanorchi, Gveso Villages Khoji, Ghu. Usakhelo, Alpana, Within the risk zone are 21 2011 Orbeli, Aghvi, Sanorchi, Naspieri, Landslides - 21 settlements, 62 houses, 3houses need Visual engineering-geological Isunderi, Dekhviri, Cjkuteli, Tvishi, Mudslides - 1 to be moved to safe location, local observations and conclusions , 2011 Flooding – 1 area Orkhvi, Tskhukhusheri, Kveda Tsageri, roads and agricultural lands were Kveda Ghvirishi, Gagulechi, Lasuriashi, damaged Chalistavi, township Tsageri, Larchvali

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Villages Larchvali, Dekhviri, Orkhvi, Within the risk zone are 34 2012 Tvishi, Alpana, Makhashi, Sanorchi, Landslides - 30 settlements, 138 houses, 20 houses InformationBulletin of National Sairme, Nasperi, Ghvirishi, Surmushi, Mudslides - 2 need to be moved to safe location, 5 Environmental Agency for the year River bank 2012 Leshkada, Spatagori, Usakhelo, Lajana, km of road and agricultural lands Orbeli, Latsoria, Tabori, Chalistavi, washout – 1 area were damaged Visual engineering-geological Okureshi, Zubi, Tsiperchi, Lukhavno, Rockfall – areas observations and conclusions Laskhana, Chkuteli, Aghvi, Lailashi, Gveso, Kveda Tsageri, Ghu, Bardnala, Sairme Villages Sanorchi, Nasperi, Ustkheri, Within the risk zone are 18 2013 Leshkeda, Surmushi, Khoji, Dekhviri, Landslides - 41 settlements, 112 houses, 44 houses InformationBulletin of National Laskhana, Chkuteli, Gveso, Sairme, Mudslides - 2 need to be moved to safe location, Environmental Agency for the year

Alpana, Kveda Tsageri, Tsiprechi, River bank local roads, agricultural lands 2013

Larchcvali, Orbeli, Usakhelo, township washout – 2 Field observation data Tsageri areaskarstic occurrence - 1

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6.6 Forecasts of Occurrence of Disastrous Geological Processes on the Territories of Lentekhi and Tsageri Municipalities

On the basis of surveys conducted by the Institute of Hydrometeorology were elaborated climate change forecasts for Lentekhi Municipality by the end of XX1 century. The forecast are the following: mean annual temperature shall increase from 9.10 to 12.60, annual total for atmospheric precipitation shall reduce from 1197mm to 1127mm. Presumably shall increase the number of days, when torrential rains occur. Also, number of dry years shall increase. On thebasis of data for the years 1956-2000 we can state, that frequency of dry years increased from 53% to 62%, while mean annual discharge of river Tskhenistskali increased from 61m3to 87m3. The above mentioned climate changes shall have impact on more or less all exogenic geological processes. With increase of the number of dry years intensity of chemical depletion shall increase, while increase of share of fine-grained clay fractions in the depletion product shall cause increase of clay materials and muddy-stony content in the solid components of mudslides. Increase of number of rainy days, as forecasted shall cause influx of rain water in the clefty ground, which shall cause surface (climatogenic) landslides and rockslides. Torrential rains and increase of temperature shall cause intensive melting of glaciers, which shall increase the capacity of transportation of water flows, frequency of mudslide passages, intensiveness of river bank washouts and increase of volume of solid sediments, which shall have negative impact on functioning of infrastructure of the region. Atmospheric precipitation in the form of torrential rains shall have the most impact on the dynamic of climatogenic (surface) landslides, while it shall have less impact on deep landslides, activeness of which is related to ground water, located in deep stratum. The territory of Tsageri municipality is one of the most complicated territories in the country from the standpoint of the scale of disastrous geological processes (floods, flash-floods, landslides, mudslides, rockslides, river bank washouts), their recurrence and damage caused by them to engineering facilities and population. Due to global climate change and warming effect forecasts of disastrous geological processes that may develop on the territories of Lentekhi and Tsageri municipalities are the following: climate warming may cause substantial increase of mean multiannual temperature. Abundant atmospheric precipitation in the form of torrential rains shall not penetrate deeply into the ground water, which creates conducive conditions for formation of mudslides. Flash floods, developed as a result of torrential rains shall cause gullying of the slopes and increase probability of the washouts and formation of mudslides. On the other hand, probability of deep penetration of atmospheric precipitation into the surface layers shall reduce, which shall cause reduction of water levels and create conducive conditions for reduction of activeness of surface landslides.

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Activation of natural disasters in the recent period can be attributed to increase of frequency of their recurrence and overall sensitivity of geological environment, sharp deviation of meteorological elements from the mean multiannual norms as a result of global climate changes, increase of frequency of earthquakes in the Caucasus region, high anthropogenic load, unsystematic urbanization, construction, intensive development of agricultural lands, cutting of forests and etc. In regard to landslides, related to tectonic disruptions, when conditions of penetration of precipitation into the ground remain the same, activation of landslides is less likely and it shall remain within the range of mean multiannual indicators. Reduction of ground water levels may have positive impact on damage, caused to buildings by contraction of soil. Similar processes may be occurring in the deep landslides, where reduction of ground water levels shall have positive impact on stability of landslide-prone slopes. On the background of climate change floods and concurrent erosion (side and surface) and accumulation processes shall be activated. Taking into consideration, that landslide and mudslide processes occur on the territory of Tsageri Municipality are quite widespread, for the purpose of improvement of geodynamic situation and its mitigation and stabilization it is necessary to conduct preventive, as well as capital measures. It should be noted, that permanent monitoring should be conducted and early notification system should be established for the purpose of timely notification of population regarding expected disasters.

6.7 Tskaltubo Municipality

Geographical Location

Tskaltubo municipality is located within river Rioni catchment area. From the west and north-west the municipality is bordering with and Tsageri municipalities, while from the north it is bordering with Ambrolauri Municipality. From the east geographical border of the municipality goes along river Rioni and from the east it is bordering with the Racha Ridge and Tkibuli depression. Total area of the municipality is 701km2 . Population is 17000 persons, municipality includes 17 communities and 49 villages. Population density is 24.1 persons per 1.0km2.

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Table 21.

# Territorial units Area in ha 1 Tskaltubo 3252 2 Dghnurisi community 4475 3 Mekveni community 4821 4 Opurchketi community 7013 5 Rioni community 5514 6 Gumbri community 4793 7 Gvishtibi community 2858 8 Village Tskaltubo community 4721 9 Tskhunkuri community 4632 10 Maolavi community 5740 11 Village Partskhanakanevi 5319 12 Kvitiri community 2598 13 Mukhiani community 3249 14 Village Geguti 3144 15 Parkieti community 2581 16 Village Opshkviti 2433 17 Village Sakulia 2957

Geomorphological peculiarities

Municipality area covers part (north-eastern end) of the Kolkehti Valley, part of a hilly piedmont and part of Samgurali and Racha Ridges. The absolute levels vary from 20-22 m to 1770 m. The diversity of the relief is due to the complex geological-tectonic structure, wide prevalence of exodynamic geological processes, anthropogenic impact on the geological environment, etc. The following geomorphological regions and forms of relief are distinguished in the Tskaltubo area: 1. Kolkheti Valley area with the erosion-accumulation relief, 2. hilly piedmont area, the low-mountainous erosion- denudation and karst relief developed over the substrate of the sediments of the Upper Cretaceous and Tertiary carbonate and terrigenous formations, 3. mid-mountain denudation relief of the eastern end of the Khvamli Ridge and south-western branch of the Racha Ridge.

1. The geomorphological region of the Kolkheti Valley covers the territory of the Valley proper, as well as the terraces of a piedmont strip. The relief of the Valley was formed as a result of the accumulation processes of the river Rioni and its tributaries in the tectonic mountain pit.

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The major part of the Valley on the territory of the Tskaltubo municipality is characterized by a plain surface, which is slightly inclined southwards where the Kolkheti natural landscape is effectively fully transformed and is represented by technogenic landscape specific to agricultural, urban and industrial landscapes. The absolute levels on the Valley vary between 20 and 150 m. On the northern periphery of the Valley River Rioni II and III above-floodplain terraces with the relative height of up to 30-50 m broken due to the erosive processes are prominent in the relief.

2. The hilly piedmont covers the area between the 120-500 m absolute levels. The so-called “hilly plain” of Tskaltubo-Simoneti is located within the northern and north-eastern boundaries of the relief and is formed as a result of the erosive breaking-up of the right above-floodplain terraces of the rivers Rioni, Kvirila and their right tributaries. The “hilly plain” is a group of individual low hillocks and hills with flat crests.

3. Khvamli ridge eastern end and Racha ridge south-western branching mid-mountainous denudative relief, north of Kutaisi the watershed of River Rioni and Tskhenistskali is the Samgurali ridge, while the watershed of Riv. Rioni and Riv. Mtischala Racha ridge nameless continuation that passes along Riv. Rioni up to Kutaisi.

The Samgurali Ridge with its height increasing northwards from 494 m (mountain Sataplia) to 880 m (mountain Etseri) is broken with V-shaped gorges and other linear and erosive formations. The drainage of the eastern slope of the Ridge is accomplished through the right tributaries of the river Rioni – Sakalmakho Ghele, Rudua, Okinkila, Satopavi and other small gorges, while the most water- abundant tributary of the Rioni from the left side is the river Lekhidaria. The slopes of the gorges of the rivers from the city of Kutaisi to village Zhoneti is sloping and rarely steep, and from Zhoneti to Mekvena the inclination of the slopes increases sharply and they descend into the gullies with a steep angle. Particularly steep are the slopes of the right tributaries of the river Rioni, sometimes even with 50-60° inclination. The cutting depth of the gullies varies from 10-15 m to 120-150 m.

On the territory of the Tskaltubo municipality, particularly in its northern part, karst cones are widely prevalent majority of which are dry with the water circulating in them only during heavy rains or snow melting. The Lower Cretaceous limestones are almost fully covered with certain karst formations.

There is a lake on the territory of Tskaltubo, which is fed with karst waters, which flow into the lake as three griffins. There is a karst cavity north-east of the lake with Vaznari stream feeding the lake. prohibitio168 garemos erovnuli saagento p

During heavy rains the karst is unable to carry the water current and the latter flows back to one of the districts of the city where there is a hospital nearby. The current floods the hospital and residential houses with their adjacent plots of field. The same situation is observed in the area adjacent to the city (coordinates: 303443-4689975), where during the heavy and long rains the karsts are filled and the water current overflows from the karst surface flooding 5 families living nearby and the farming plots. The karst cave on the territory of village Kumistavi, after restoration, has been used as a sightseeing object.

Tectonics and geology

Large part of the Tskaltubo municipality area is located in the central elevation zone of the Caucasus intermontane region (Georgian Block). Tectonically, the south-western part of the municipality belongs to the western Molasse subsidence zone.

The following major tectonic structures are represented on the territory of the Tskaltubo municipality: The Oncheishi tectonic block spreads from Okriba elevation over the study area. The block includes Khvamli anticline, which is the extreme northern fold of the said Block and is built with the Bajocian volcanogenic sediments. It should be noted that the structural plan of Okriba elevation adjacent to villages Mekvena, Oncheishi, Derchi and Dghnorisi creates a fairly complex geological situation. The complexity of the situation can be explained by numerous splitting ruptures with widely prevalent exodynamic phenomena.

Oncheishi anticline spreads over the left slope of the river Rioni along the distance of 12-15 km and width of 2-2.5 km.

Derchi anticline is spread in the northern limestones of village Derchi. The angle of inclination of the anticline wings is 15-20°. Dzmuisi stratum sediments with the thickness of 40-50 m are found in the trough of the anticline.

Dghnorisi anticline spreads south-west of the Derchi anticline. It is spread locally and is made up of sandstones, conglomerates and sheet clay-slates.

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Namokhvani anticline fold spreads near village Namokhvani, along the Kutaisi-Oni motorway. Its direction is north-west with the angle is 280°. The width of the fold is 4.0 km and it gets gradually covered with young sediments east of the river Rioni.

On the territory of the Tskaltubo municipality there are rocks aged from the Jurassic through the Quaternary period.

The rocks of the Middle Jurassic-Bajocian(J2bi) stratum are lithologically represented by tuffa- breccias and rarely tuffas, tuffa-sandstones and tuffa-porphiries. The total strength of these sediments is approximately 2000 m.

The sediments of the Dzmuisi stratum (J2ltdz), which are sheet slates, argillites and sandstones are represented in the Rioni gorge in the area of villages Gumati-Rioni. The strength of the sandstones is less than that of the argillites. The argillites are of a sheet type in the weathering strip. The total strength of the complex is 300-350 m. Intense folding is typical to these rocks, which is sometimes complicated by shallow tectonic ruptures. The rocks are cliffy rocks with average strength.

The outcrops of the Upper Jurassic(J3) sediments are found on the left slope of the river Rioni, north- west of the city of Kutaisi and on the territory of village Gelati. Lithologically these sediments are represented by clays (making 75% of the whole section). Rarely, the interlayers of sandstones and conglomerates can be observed in the clays. The thickness of these sediments varies from 200 to 250 m depending on the location.

The carbonate formation of the Jurassic Age(K2)on the territory of theTskaltubo municipality is represented by dolomites and dolomitized limestones. These sediments are joined with the limestones of the Barrem Stage and are called Neocomian sediments. The Neocomian sediments outcrop on the surface in the gorges of Tskaltubo-Khomli-Kumistavi and rivers Rioni and Tskaltsitela, north-west of Kutaisi. Lithologically, the sediments of the given age are mostly represented by crystal limestomes and rarely by dolomites. The total thickness of the stratum ranges between 50-150 m. The limestones that make up 85-90% of the sediments of this stratum are crystal, in some places -- dolomitized, solid and very solid, thick and with massive layers. The sediments of Apt-Cenomanian Age are spread over small areas. Their outcrops are found north and north-west of Kutaisi. Lithologically, these sediments are represented by limestones, marls, glauconitic sandstones and rarely by clays and conglomerates. The thickness of the complex is 10-60 m. The rocks are slightly dislocated. The inclination of the rock prohibitio170 garemos erovnuli saagento p layers is from 5-8 to 20-25°. The rocks of the intrusive formation of the Upper Cretaceous Age on the territory adjacent to the city of Kutaisi are represented by light grey teschenites, which are coarse- grained, massive and solid. The so called Mtavari stratum is spread on the territory adjacent to village Kvakhchiri and Tskaltubo town. Lithologically, this complex is represented by tuffa-breccias, tuffa-sandstones, tuffas and mantles of basalts. The total thickness of the rocks is 300-350 m. The rocks are strongly dislocated.

The Maastrichtian-Danish sediments of the Upper Cretaceous Age on the Tskaltubo municipality area are widely prevalent. Lithologically, the complex of the said rocks is made up of limestones with the accretions of the marl layers. The Maastrichtian sediments are represented by stratified limestones, marl limestones and rarely by the accretions of marl layers. The sediments of Danish Age are represented by thick-layer karsting limestones, with rare accretions of thin marl layers. The thickness of the complex is 50-250 m.

The sediments of the Paleogenic Age (P) on the territory of the municipality are spread in the river Rioni gorge, north of Kutaisi, on the territories of villages Gumati, Opurchkheti and in their adjacent area. Lithologically these sediments are represented by basalts as individual blocks and rarely as veins. Sometimes they spread as effusive mantles with their thickness rarely exceeding 40m.

The Delluvial-Prolluvial sediments of the Quaternary Age are prevalent in the mountainous part of the municipality, in the lower part of the slopes. According to the structure, two groups of the said sediments can be identified: the first group is predominantly represented by coarse formations with the total thickness of 15-20 m and rarely over 20 m. another group is represented by connected rocks with the accretions of fractured material. Lithologically this group is represented by clays and clay loams and rarely by sandstones with the accretions of detritus. Overall thickness of the said sediments varies from 10 to 20 m.

Dangerous Biological Processes

Dangerous geological processes on the territory of Tskaltubo Municipality are broadly expanded and diverse. Among them the most damageable are landslide, erosion, rock avalanche and karst related processes.

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Formation and development of a dangerous geological process are connected with geological and geomorphological conditions of a concrete place that precondition growth of the dangerous geological processes. Activation of geological processes frequently is provoked by impact made by men on geological environment that is enshrined in the processing of slopes, apportion of the ones, deforestation, etc. In the development of dangerous geological processes triggering role plays sensitiveness of rocks constructing a place against geological process. On the territory under examination are represented following types of rock stratum: Jurassic and Cretaceous quartz-arkosic sand-stones, lava breccias and tuff-breccias that create clifty relief, where surface stratiform sediments are wiped out and thereby, outcrop surface rocks. Debilitation of toughness of such sediments happens in the band of tectonic disruptions, characterized with rock avalanches and rockfalls. Basically semi-rock-type areas with comparatively less hard rocks – clay-shale, marls and rocks of terrigenous formation are subject to landslides and torrents. These sediments are characterized by high sensitiveness and complaisant to environmental conditions. In-depth and riverside erosion is common to all small and big rivers flowing through the study area. River Rioni robustly erodes its banks in the section of villages Opurchkheti-Zarati- Rioni, where water torrent shifted to the left bank in 60-70 m. distance, provoking so called riverside landslides and erosive processes. Resultant to the riverside erosion a landslide destroyed one residential house and damaged 5 houses on the territory of village Zarati. Landslide effects. On the territory of Tskaltubo Municipality landslide processes are widely unfolded that is the most prevalent dangerous geological effect, which is induced by various factors: hard geological-geomorphological, hydrogeological and climate conditions, also, economic activities of the people. Consequent to the effect made by the landslides there are a lot of facts of damage and destruction of houses, damage of roads and other household communication. Landslides are widely spread in cover rocks of Quaternary age that are basically represented in elluvial-delluvial formations. Sufficiently strong landslides (5-10 m. in depth) are in the area of expansion of Mid-Jurassic sediments.

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Landslides developed in the Quaternary period sediments are generally based on clay-loamy and road-metal gravel soils. It‟s frequent to encounter landslides of rock avalanche type developed in basic rocks, which are of tectonic origin and lithologically presented as loamy with inserts of large clastic fraction particles and products of exhaustion shell of basic rocks. On the territory of Tskaltubo Municipality landslides are spread over the both slopes of river Rioni Gorge. On the right bank of the river landslides are mainly of rock avalanche type (villages Namokhvani, Bentkoula, Mekvena, Gumati (photos № 31, № 32), Jimastaro), and on the left bank there are creeping landslides, which cluster is represented in clay-loamy and shallow road-metals. Such types of landslides are spread in villages Rioni, Sormoni, Opurchkheti, Zarati, Derchi and Dghnorisa. Major part of landslides are formed in the Mid-Jurassic age, in the precipitations of so called

Dzmuisi waters(J2dz)that are represented in the exhausted weak laminated clay-shale and clays with particles of thin-stratum sandstones. According to the mechanism of moving, landslides are of various nature that is conditioned by shells‟ sensitiveness against the landslide processes, frequency of shell gapping, climate-related factors, etc. Expansion of landslides of rock avalanche type is limited (villages Namokhavi, Bentkoula, Mokvena). Out of 21 landslides enrolled in the landslides‟ registry 17 are of creeping nature. Area of landslides is changing within 3.58 hectares-185 hectares (village Derchi). Strength of the landslide bodies is changing from 2.5-3.0 m.(village Sormoni) to 18-20 m. (Derchi, Dghnorisa). In the end of 80th of the last century landslides of rock avalanche type moved to the territory of Mekveni village. Rock avalanche crossed the motor road, blocked Rioni River and thereby, was created kind of a big lake that endangered settlements located on the banks of the river and Gumati Power Station dam, but there was no sudden breakage of rock avalanche wall. The river itself broke through a wall of rock avalanche and pending danger was naturally elevated.

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Photo #31 Photo #32 On the sidelines of Kutaisi-Ambrolauri motor road there are encountered comparatively small-sized landslides that were developed due to the apportion of slopes while constructing roads and which damage the motor road (see, photo # 33). Activation of such landslides has place mainly during the continuous rainfalls. Penetration of heavy atmospheric precipitations into the landslide soil weakens linkage between components of the soil and makes it heavier that provokes gravitational disbalance. These landslides are attributed to the surface landslides. In Rioni Gorge during floods and water influx occurs erosion of the slope bases (subsurface erosion) that provokes gravitational disbalance and development of landslide process. The described types of genetic landslides are numerous on the sides of river gorges and on the slopes of irrigation and derivation canals (see, photo #34). Major part of landslides are formed in the Mid-Jurassic age, in the precipitations of so called

Dzmuisi waters(J2dz)that are represented in the stratum clay-shale and mudstones with particles of thin-stratum sandstones and area occupied by them amounts to 317 hectares. These precipitations are featured by high sensitiveness. Index of landslide damage of the territory (villages Namokhvani, Bentkoula, Mekvena) in this area is 0.25. Total area of landslides spread in these precipitations amounts to 113.7 hectares.

Photo #33 Photo #34

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On the territory of Tskaltubo Municipality in 2013 resultant to the field work there were revealed and described 17 creeping landslides, 3 rock avalanches and 5 runny-plastic landslide bodies, 14 landslide sections are active, 3 out of them are strongly active (villages Gumati, Derchi and nearby Dghnorisa), 5 settlements and regions are fallen in the average activeness zone (Kutaisi City – Rua Street, Kutaisi-Oni motor road, villages Zarati, Rioni, Kutaisi City – Kazbegi Street). The zone of lower landslide danger includes villages Sormoni, Bentkoula, Jimastaro and Nogha territories. In total on the territory of the Municipality in 2013 landslides damaged 47 and destroyed 4 residential houses. In the zone of damage risk still are 38 houses. Rock avalanche-type landslides formed on the right slope of river Rioni Gorge (Namokhvani, Bentkoula, Mekvena) partially are connected with tectonic disruptions of Bayos volcanogenic row. As a result of tectonic movement rocks are utterly broken-gapped. Depth of gap penetration is great, atmospheric precipitations fallen in the open gaps promptly flow to the bottom and unload on the level of local erosion basis. In these sediments practically there are no underground waters. Movement of landslide bodies is mostly provoked by gravitational power ensued due to the steep slant of the slopes. Presently, the above mentioned landslides are in a stable condition. In favorable conditions (earthquake) activation of presently stable landslide bodies is expectable that might occur temporary block of the Rioni river similarly to the above mentioned case.

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Facilities of Tskaltubo Municipality located in the landslide-prone areas and measures to be taken Table #22

Total area of Preventive Quantity of Damage inflicted by Dynamic state of # Administrative Geographic location of landslides measures/actions to be households landslide s landslides and risk district Settlement landslide body (hectares) taken residing in a levels settlement

1 2 3 4 5 6 7 8 Tskaltubo Municipality 1. Kutaisi City, Northern periphery of 3.3 hectares 30 Landslide masses With slowed dynamic Organize diversion of Rua Street the city blocked river-bed and of average risk (5 surface waters families in a zone) 2. Village Gumati Basic part of the 45.0+3.0+15.0=6 182 8 damaged houses, 3 2 areas with active Takeaway of surface (3 sectors) inhabited territory 3.0 hectares sectors of Kutaisi-Oni dynamic and with waters and periodic motor road high level of risk renovation works

3. Kutaisi-Oni Adjacent to village 6.7hectares Motor car (Kutaisi- With average Regulation of surface motor road Opurchkheti territory Oni) dynamic and risk waters and its factor organized takeaway to the ravine

4. Village Zarati Main part of the village 48 hectares 158 10 houses severely With average Constructing a territory damaged, internal dynamic and risk drainage network community roads and factor (a lot of would improve sowing lands residential houses are quality of the in the zone) steadiness only partially

5. Village Sormoni Western part of the 11.5+1.0+1.1=13. 116 Community road is With minor dynamic Regulation of surface

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(3 sectors) village Sormoni and 6hectares damaged and 4 and low risk factor waters and terracing by-canal side residential houses of this part of a slope (not-significantly), motor road

6. Village Rioni Southern-eastern part 80 hectares 443 Old school is Being in low dynamic Constructing a deep of the village damaged, farm house and of average risk drainage network and and residential houses regulation of surface (1 destroyed, 10 streams damaged)

7. Village Almost whole territory 25 hectares 27 2 residential houses With low dynamic Removal of surface Bentkoula of the village are damaged and risk factors waters and their (residential houses are organized takeaway in the zone) from the slope

8. Village Derchi Main part of the 185 hectares 120 Severely damaged 6 Low dynamic and Constructing a inhabited territory houses, internal high risk factors drainage network and community roads and forestation of sowing lands uninhabited sectors 9. Village Western and eastern 54+27=81 251 3 houses are damaged Low dynamic and Removal of surface Dghnorisa (2 part of the village hectares and community average risk factors waters and their sectors) traffic roads takeaway to the ravine, constructing a drainage network at separate buildings 10. Village Jimastaro Western periphery of 7.5+ 5.0+1.5=14 120 1 residential house is Low dynamic and low Organized takeaway (3 sectors) the village hectares destroyed, 3 houses risk factors of surface waters and and internal arranging drainages community roads are around the residential damaged houses

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11. Kutaisi City, Northern-western 100m2 50 2 residential houses With active dynamic Removal of surface David and periphery of Kutaisi are damaged and and high risk factors waters and Kostantine Street supporting walls construction of a new – Kazbegi Street main wall 12. Adjacent to Right side of the 5.1 hectares _ Motor road is Stable and low risk Regulation of surface village Nogha Kutaisi-Nogha motor damaged factors waters through an territory road organized takeaway

13. Village Mekvena Left side of the Kutaisi- 26.0 hectares _ Residential houses are With low dynamic Cleaning periodically Oni motor road damaged (7 families) and risk factors slid masses and motor road

14. Village Left side of the Kutaisi- 26.0 hectares _ 1 residential house is With slowed dynamic Regulation of surface Namokhvani Oni motor road, slope destroyed, 2 damaged and low risk factors waters and unload of part of the village them in a ravine

Statistics of geological processes registered in Tskaltubo Municipality by separate settlements Table #23

Settlements Geological Inflicted damage Source of information processes 1 2 3 4 5 Villages Derchi, Mekvena, It was recommended to resettle 152 families. Information bulletin of 1981- Opurchkheti, Vanischala, It was recommended to resettle 12 families. 1998. Landslide, karst 1998 Kumistavi, Chuneshi, Kvilishori, 180.2 hectares were damaged. Town of Tskaltubo.

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Villages Opurchkheti, Zhoneti 8 families were flooded and should be resettled. Bridge Information bulletin of on the river Rioni in village Mamatsminda was 2005. 1998-

2005 Flooding, landslide destroyed. Section of Kutaisi-Ambrolauri motor road of 150-200 m. length, 140 hectares.

Villages Gumati, Land slid on the Kutaisi-Ambrolauri motor road Information bulletin of Jimastaro,Opurchkheti, Derchi section of 100m. length. A residential house by the 2006 (monitoring). road side was damaged. On the territory of village 2006 Landslide Derchi 2 residential houses were destroyed and 70- 80m. length motor section became out of order; 120 hectares of lands were damaged.

Village Rioni, Kutaisi-Ambrolauri 5 residential houses were damaged and became Information bulletin of motor road, Kutaisi, Rua Street. inappropriate for living in village Rioni, 2 houses were 2007 (monitoring). damaged. 5 sections of motor road of total 160 m. 2007 Landslide length, land space of 15.0 hectares. 5 residential houses were under risk (Kutaisi, Rua Street).

Village Gumati, adjacent to railway Severely damaged 7 residential houses, damaged 10.0 Information bulletin of . station Rioni territory, erosion of Landslide hectares of lands, river Rioni moved to the right side 2008 (monitoring) 2008 . . banks by river Rioni Erosion of banks and eroded 32.4 hectares of the sowing land

Villages Zarati, Rioni. Landslide formed, destroyed one residential house and Information bulletin of 2009 Landslide damaged 17.2 hectares of sowing land. 2009 (monitoring). Village Zarati, erosion of the right 4 damaged residential houses are to be taken to the Information bulletin of bank of river Rioni adjacent to the solid ground. Right bank erosion of river Rioni by 2010 (monitoring). Rioni railway station. railway station Rioni is continuing and 4.5 hectares of Landslide 2010 space is eroded, also bank erosion is in process on the Erosion of banks left bank of village Zarati. There is detected a gradual activation of bank landslides.

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Kutaisi City, Rua Street, villages 5 residential houses are in the landslide zone on Rua Information bulletin of Dghnorisa, Zarati. Street. Landslide is growing its scale. In Dghnorisa 2 2009 (monitoring). 2011-

2012 Landslide residential houses were severely damaged, 4 houses are in a dangerous zone. 4.5 hectares of land was damaged. Village Gumati (Jimastaro), village 8 severely damaged residential houses are to be taken Information bulletin of Derchi to the solid ground (village Gumati), also, 4 families 2013 (monitoring). 2013 Landslide (village Derchi) are to be resettled on the solid ground, 62.9 hectares are damaged. Quantity of landslides - Total Damaged (landslide area) – 576.7 hectares Quantity of damaged houses -216 21

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6.8 Samtredia Municipality

Geographical location

Samtredia Municipality occupies a part of Western Georgia territory, which is bounded on the south by northern hillside of Adjara-Trialeti ridge, on the west and on the east by rivers Khevistskali and Kumura, and on the north by the administrative border of . Samtredia Municipality comprises of 12 communities and 48 villages. Area of the Municipality is 282 km2. Population counts 60476 residents. Density of population is 1 km2and amounts to 166 residents. Below is a table with information on settlements and areas occupied by the ones.

Areas of Town of Samtredia and its rural communities

Table #24

# Community, Town, Village Areas (hectares)

1 Town of Samtredia 3198.49 2 Village 168 3 Gomi Community 2533.64 4 Village Gormaghali 1018.89 5 Tolebi Community 1321.03 6 Sajavakho Community 858.78 7 Opeti Community 1684.22 8 Village Gamochinebuli 696.66 9 Didi Jikhaishi 4251.97 10 Village Ianeti 2014.17 11 Village Bashi 2622 12 Etseri Community 1374.28 13 Melauri Community 1364.27 14 Ghaniri Community 2080.77 15 Nabakevi Community 2265.43

Geomorphological peculiarities of the territory

The relief of the Samtredia municipality territory is fairly diverse and is divided into lowland, piedmont and mountainous districts. The lowland occupies the major part of the Samtredia municipality. The area foothill strip is also fairly wide. The plain emerged as a result of the erosion and prohibitio181 garemos erovnuli saagento p accumulation action of the rivers Rioni, Tskhenistskali, Gubistskali and others. The terraces formed with the action of these rivers spread up to Kutaisi. The surface of the terraces is flattened and is slightly bogged at some places. The absolute levels of the lowland vary from 16-20 m (in Samtredia) to 100-130 m. The elevated weakly inclined terraced lowland comprises the II and III above-floodplain terraces of the rivers Rioni and Tskhenistskali, with their relative height varying from 10-15 m to 35- 50m. It should be noted that the II terrace is flattened and almost unbroken, while the III terrace and upper IV terrace are slightly broken with gullies and streams with the depth of erosive cutting of 10-20 m.

The hilly piedmont covers the above-mentioned inclined plain relief and lowland from north, east and south. This place presents a group of individual low hills and flat plateau-like crests. The absolute levels vary from 80-90 m to 120-500 m, which towards the territory of village Sajavakho, gradually decreases (to 70-80 m).

4 to 5 river terraces can be observed in the river gorges. Their relative heights vary within the limits of 3-5, 8-12, 15-20, 25-35 m respectively (the rivers Khevistskali and Kumuri). On the territory of Samtredia municipality, there is a low-mountainous part of -Imereti Ridge (northern wing), where the absolute levels reach 800-1000 m.

The northern slope of the ridge is broken with deep V-shaped gorges of such rivers as the Kvershaveti, Sulori, Kumuri, Khevitskali and others. It should also be noted that the piedmont longitudinal branches belong to an ordinary low-mountainous zone (650-1000 m), while the average height of all lateral branches is 1000-1500 m and that of the average-mountainous relief is 1500-2000 m. The slope inclination in the hilly foothill varies from 8-10 to 30-32°, and that in the high-mountainous zone changes to 35-45°. Only rarely does the inclination increase to 50°.

Tectonics and geology

Tectonically, Samtredia municipality is located in the western molasse subsidence of the intermontane area of the South Caucasus. The southern part of the municipality is located in the northern sub-zone of the folded system of the Lesser Caucasus. The Pontic marine molasses of the Upper Eocene-Sarmat Age outcrop over the flanks of the western subsidence zone. The degree of folding of these molasses is complex – a plicated-block one. Specific blocks are separated with ruptures. prohibitio182 garemos erovnuli saagento p

The folded Ajara-Trialeti system is isolated from the intermontane area with a large shearing, which runs from village in the northern part of the folded system to village Dapnari (central part of Surami-Gokishuri). The angle of dip of the shearing varies from east of west from 60° to 10-5°.

Several large folds of a linear direction inversed northwards are found in the northern sub-zone of Ajara-Imereti folded system, which are complicated with upthrusts and ruptures forming the linear zones of fissures, which greatly reduce the strength of the natural massifs of the strong cliffy rocks and break them. In terms of seismicity the territory belongs to a 7-8-point seismic zone. The geology of the territory of Samtredia municipality is represented by the sediments from the Cretaceous through the Quaternary Age.

The Upper Cretaceous sediments(K2). In the study area, the Upper Cretaceous sediments are the oldest in terms of geological age; they outcrop on the left flank of the river Rioni gorge. The distribution area of these sediments is small. Their surface outcrops are seen as a narrow strip east of village Dapnari. They spread over 2.5 km length and 0.7-0.75 km width. The sediments are represented by thin-layer limestones and marls with thin-layer limestone sandstones spread next to them in the section. The total thickness of the sediments varies from 20-25 m to 200-250 m.

2 3 The Eocene sediments(P2 -P2 ) are widely spread on the territory of the municipality. These sediments build the northern slope of Ajara-Imereti Ridge, from the territory of village Vazisubani up to the administrative boundary of and beyond.

2 The Upper Eocene sediments(P2 ). Within the limits of the Samtredia municipality these sediments spread from village Vazisubani to the territory of village Mtisdziri. The length of the distribution of these sediments (within the municipality boundaries) is 20-22 km and the width varies between 0.8-2.0 km. The sediments are represented by stratified tuffa-breccias, sandstones and tuffas. The upper part of these sediments is represented by coarse-layer tuffa-breccias, which at some places are covered with andesites. The thickness of these sediments reaches 3500 m.

3 The area of distribution of the Upper Eocene sediments(P2 ) on the territory of the municipality is not large. The sediments spread from west of south-east. The length of their distribution is 8-9 km and the

prohibitio183 garemos erovnuli saagento p width varies from 0.4 km to 1 km. The sediments are represented by light grey thin-layer clays, marls and sandy marls. The total thickness of the layers of these sediments is 20-180 m.

1 The Pliocene sediments(N2 Pn) are mostly washed out and survive only as individual fragments. These sediments lie over the Sarmat and sometimes older sediments with angle unconformity. The individual outcrops of these sediments are found on the territory of Samtredia-.

Such outcrop is observed on the territory of village Dablagomi. The length of the outcrop is 2.5 km and its width is 0.7 km. The sediments are represented by weakly cemented conglomerates, sandstones and clays. Clays dominate in the middle and lower parts of the geological section. The thickness of the sediments is 80-100 m.

The unbroken Modern Quaternary sediments (Q). The Quaternary cover is represented by elluvial- delluvial and sometimes by colluvial, clay and clay-detritus formations. These sediments spread in almost all gorges and at the bottoms of the mountain slopes, but are characterized by interrupted and sharply varying thicknesses varying from 1.0 m to 20 m or in some places even higher.

The Modern alluvial sediments(alQ4).The Modern alluvial sediments are represented by shingle, sands or sandy loams. A thick boulder of flow or sedimentary rocks spread together with these sediments. The shingle in the beds of the rivers and floodplain are unbounded and are slightly bounded over the above-floodplain terraces. These sediments build the beds of the river Rioni and its tributaries and floodplains. The total thickness of these sediments varies from 5-10 m to 50 m.

The unbroken Delluvial-Prolluvial Quaternary sediments(d-pQ4). These sediments are represented by detritus and clastic material, spread together with clayey soils and clays with sandy loam. At the bottoms of steep slopes, in addition to the mentioned sediments, coarse material ca also be found.

The unbroken Elluvial-Delluvial Quaternary sediments(edQ4). The unbroken Quaternary sediments are represented by clay loams and clays, rarely by sandstones with detritus and grit. The thickness of these sediments varies from 5-10 m to 15-20 m.

The thickness of the Delluvial-Prolluvial sediments over the mountain slopes and in the gorges varies from 2-3 m to 6-10 m.

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Hazardous geological processes The studies performed on the territory of the Samtredia municipality have demonstrated that the hazardous geological processes are quite diverse with the following processes being most notable: landslide processes, bank washout, surface erosion, linear erosion, karsting and rare mudflows.

Bank washouts (the lateral erosion by the rivers) mostly occur over the plain relief, on the both banks of the river Rioni, from village Odilauri through the territorial border of the municipality. Particularly large-scale bank washouts are registered on the territories of Akhalsopeli, Dapnari and Sajavakho with scores of hectares of agricultural land areas washed out by the rivers. Zemo , Kveda Kude and Tsiagtubani are badly damaged by the sheet wash. Here, the Quaternary slope sediments are fully washed out and outcrop on the surface as thick-layer sandstones of the Eocene. Mudflow streams are rare and are mostly prevalent in the area with Pontic sediments (village Dablagomi).

Landslide processes. Landslide is the most common exodynamic geological process prevalent on the territory of the municipality. The area of the landslide distribution mainly covers the left bank of the river Rioni above the floodplain terrace. This location represents a low hilly piedmont of the northern wing of the Guria-Imereti ridge. Geologically, the hilly piedmont is built with the Upper Cretaceous, Middle and Upper Eocene, Pliocene (Pontic) sediments and slope sediment sediments survived on their substrate. The landslides in these sediments occur effectively everywhere in the surface sediments of the terrigenous-volcanogenic and sedimentary formations. Their structure depends on the kind of the weathering crust. The areal hearths of weathering are built with clay and detritus and macro fragmental elluvial soils. This was originated in the thickness of the volcanogenic sedimentary rocks of the Middle and Upper Eocene. Both the landslides with complex movement and simple flow slides are registered in the hilly piedmont. The landslides are almost always consequential and move in the direction of the inclination of the bedrocks. The sliding surface of a landslide body usually follows the contact of the fissure zones of weathering. The landslides are characterized by clearly outlined boundaries and stepped surface. The complex landslide bodies were originated as a result of the flow-plastic landslides. The landslide circus is located in the extreme upper part of the slope (Mtisdziri landslide. See Fig. 35), while the gletcher-type ground current spreads in the middle and lower parts of the latter. The thickness of the landslides similar to the above-mentioned type is 12- 15 m, and their volume is from several thousands to one million cubic meters and sometimes, higher. The landslides of the similar type are originated as a result of intense humidification of the landslide

prohibitio185 garemos erovnuli saagento p soil with atmospheric and ground waters (landslide in village Abasha. See Fig. 36) and great inclination of the slope (25-35°).

sur. #35sur. #36 The causes of the landslides developed in the slope clay sediments originated over the substrates of the cliffy sediments of the Cretaceous age is the humidification of the sensitive loamy soils with atmospheric precipitations and the action of ground waters, as the level of ground waters is highly variable resulting in sliding the grounds over the contact of cliffy bedrocks and delluvial clay loam.

The landslides in the bedrocks (there are two of them within on the study area – in Nigorzgvari and Mtisdziri) are developed in the area of the volcanogenic-sedimentary formation and tuffogenic rocks. These landslides have predominantly emerged in intensely fissured and weathered cliffy grounds that due to the great inclination of the slopes are subject to great tensions resulting in the fissures over the slope and reduced stability of the cliffy rock massifs ultimately creating the preconditions for the emergence of a landslide.

The landslide affected areas and the houses damaged or demolished due to the landslides are distributed unevenly on the territory of the municipality. Over the terraces of the river Rioni with an almost plain relief bank washouts and partially flooding can be found, while the landslides associated with the geological complexes of different ages and represented by the Upper Cretaceous, Eocene and Pliocene sediments are widely prevalent in the hilly part. prohibitio186 garemos erovnuli saagento p

Overall, 32 landslide-prone sites have been identified on the municipality territory. The cadastral description of the landslide-prone sites will be represented together with the text, which, in addition to the detailed description of the landslides contains major recommendations for the improvement of the stability of the landslide-prone slopes.

According to the type of movement of the landslides on the territory of the hilly piedmont three types of landslides can be identified: (1) flow landslides, (2) flow-plastic landslides, and (3) avalanche-type landslides. According to their dynamics there are active and stabilized landslides. Active landslides are activated annually or seasonally (landslides of Nigorzghva or Mtisdziri). While Stabilized landslides have shifted in equilibrium phase and the activation of new powerful factors is necessary for their activation (villages Zemo Abasha, Chognari and others).

The Upper Cretaceous sediments (K2 ) occupy the least area of the hilly piedmont (approximately 1-1.2 km2). The landslides at this location cover the area of 15.5 ha. The volume of the land-slide affected mass varies from 132 000 m3 to 750 000 m3. These landslides are spread in the area of village Dapnari and east of the village. As a result of the landslide activity 4 residential houses were ruined and 3 residential houses have been damaged. The ratio of damage of the Cretaceous sediments is 0.12.

2 The Middle Eocene sediments (P2 ) are the most widely prevalent with minor landslide damage in the study area. They are distributed over the area of 49.7 km2. The cause of landslide processes development is the humidification of the slope grounds with the atmospheric precipitations. The area damaged by the landslide is 1.0 km2. A total of 10 landslide bodies have been emerged in the said sediments. The landslides occur in villages Tolebi, Nogha, Nigorzghvavi, Kvakude and Dabla Gomi. 32 residential houses have been damaged and ruined due to the landslides, and 12 houses are at risk of damage. The ratio of damage due to the landslide within the zone of distribution of the said sediments is 0.02.

3 The Upper Eocene sediments (P2 ) and the elluvial and delluvial sediments developed over their substrate have been damaged the most due to the landslide processes. These sediments occupy 27.6 km2 of the territory of the municipalities. The total number of the landslide bodies is 19, and the area covered by the landslides is 17.3 km2. These sediments are represented by marls, clays and thin-layer sandstones. Villages Dabla Gomi, Dapnari (See Fig. 37), Nogha, Kvakude, Zemo Abasha, Patara Opeti, Gormaghala (See Fig. 38), Didi Opeti and Mterchveuli are located in the landslide activity area. prohibitio187 garemos erovnuli saagento p

The reason for the development of landslide processes in the given location is primarily the variation of the ground water level and maximum humidification of the ground with the atmospheric precipitations.

sur. #37sur. #38 Landslide affected areas vary from 4.0 to 29 ha (village Patara Opeti). The volume of the landslide mass varies from 96 000m3 to 1 320 000m3. The coefficient of the areal damage of the territory where the said sediments are spread is 0.64.

Out of the complexes damaged by the landslides on the territory of Samtredia municipality the Pontic 1 2 (N2 pn) sediments occupy the least area in the municipality their distribution being 17.6 km out of which 0.6 km2 area is damaged by the landslide action. The damage ratio is 0.08. The most widely spread is the landslide in Mtisdziri (57 ha). The reason for the landslide process here is the concurrence of the directions of the slope inclination and inclination of the layers of the bedrocks (sandstone).

Landslide mass is approximately 1 400 000m3. Four residential houses have been ruined due to the landslide and 3 other houses are in the danger zone.

23 flow slide bodies and 9 block-type landslides have been identified on the territory of the municipality. Out of 9 landslide bodies 3 are very active (in Nigorzghva, Mtisdziri, Mterchveuli).

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Overall, 5 villages are at high risk of the landslide action on the territory of Samtredia municipality: Gadaghma Nigorzghva, Dapnari, Gamochinebuli, Mterchveuli and Mtisdziri.

Villages Tolebi, Nogha, Kvemo Abasha, Didi Opeti, Tsiagtubani and Dabla Gomi (a total of 6 settlements) are at average risk of the landslide action.

Villages Pirveli Nigorzghva, Kvakude, Zemo Abasha and Gormaghali are at a low risk of the landslide action. A total of 36 houses have been ruined and 32 houses are damaged in the Samtredia municipality. At present, 40 houses are at risk.

The basis of the landslides in all of the above-listed villages is small and average gullies, with the major of the landslide mass flowing into them. The gullies are narrow and V-shaped. After the landslide mass gets in the gullies, the latter are often blocked. Sometimes, the clay material in the watercourse swells with the surface runoff and the mudflow currents are originated in the gully. Such a phenomenon took place on the territory of Nigorzghva, where the torrent mass blocked the motorway and silted and damaged the yards and residential houses. Similar occurrence was observed in Dablagomi where the mudflow current overfilled the ditch with the length of 60-80 m. The cutting width was 3-3.5 m and the depth was 3.0 m. The torrent current damaged the internal village road, silted the yards and ground floors of the houses.

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Facilities of Samtredia Municipality located in the landslide-prone area and preventive measures to be taken Table #25

Total area of Preventive Quantity of Damage inflicted by Dynamic state of # Administrative Geographic location of landscapes measures/actions to be households landslide phenomena landslide body and district Settlement landslide body (hectares) taken residing in a risks of damage settlement

1 2 3 4 5 6 7 8 Samtredia Municipality 1. Village Zeda Far southern and eastern 10.0+9.5+3.5+4= 98 Homestead plots, 2 Two sectors are Removal of surface Tolebi (4 sectors) part 27 hectares residential houses, active, two waters, drainage of of village Tolebi areas for sowing temporarily in stable underground waters, (agricultural lands) condition, landslide fortification of river risk in both sectors is Khevistskali erosive average part

2. Village Nogha Western periphery of 17.0+13.5=30.5 218 Agricultural lands, Temporarily stable, Removal of surface (2 sectors) village Nogha hectares homestead plots, 3 with average risk waters houses are damaged

3. Village Central part of 3.5+18.5=22 78 Damaged residential Temporarily stable, Regulation of surface Gadaghma inhabited area hectares houses and 3 families with high risk (5 waters and their Nigorzghva have been resettled families) takeaway to the (2 sectors) ravine 4. Village I Southern part of the 20 hectares 92 Minor damages are In a stabilization Removal of Nigorzhgva village detectable on phase, risk is low underground waters residential houses in possibly maximum scale will considerably rise

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quality of steadiness of the slope

5. Village Kvakude Northern outlandish 4+4+4.2=12.2 29 Internal community Temporarily stable, Removal of surface (Korei part of the village hectares road, part of with average risk watersand planting of settlement) homestead plot and 1 perennial trees (3 sections) family are damaged

6. Village Zemo Eastern part of the 5.5+19.0=24.5 115 Internal community Temporarily stable, 2 Removal of surface Abasha (2 village hectares road and sowing lands houses in low risk watersand arranging sectors) are damaged zone drainage network around the houses

7. Village Patara Southern-western edge 28.5 hectares 68 Motor road and Slight dynamic is Regulation of surface Opeti of the village sowing lands identified, cemetery waters and 2 families are in risk zone

8. Village Kvemo Northern periphery of 22+7.5=29.5 115 Internal community Slight dynamic with Regulation of surface Abasha the village hectares road and 6 residential average risk waters (2 sectors) houses are slightly damaged

9. Village Western and eastern 21+3+2=26 351 Internal community Low dynamic with Constructing a Gormaghali (3 periphery of the village hectares road and sowing lands low risk drainage network sectors) around the buildings and regulation of surface waters would somehow rise quality of steadiness of the slope 10. Village Dapnari Western periphery of 15.5 hectares 210 Main traffic road With active dynamic Arranging drainage

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the village between villages, 2 and high risk on the slope and houses are destroyed, organized takeaway 3 under threat of surface waters

11. Village Southern and eastern 18+6+24 hectares 115 Two residential With average Regulation of surface Gamochinebuli part of the village houses are damaged, 2 dynamic and high watersand (2 sectors) houses are in a risk constructing a landslide zone drainage network around the buildings 12. Village Didi Northern-eastern 6.0 hectares 55 2 sectors of the Low dynamic with Regulation of surface Opeti periphery of the village internal community average risk watersand road are damaged constructing a drainage network around the buildings 13. Village Southern part of the 2.5-11=13.5 56 Severely damaged 2 With average Regulation of surface Mterchveuli (2 village hectares residential houses, 10 dynamic and high watersand sectors) houses are under risk (1 sector) constructing a threat, road is being drainage network destroyed around the buildings 14. Village Northern part of the 12.5 hectares 71 Community road is Low dynamic and Regulation of surface Tsiagtubani village damaged and up to 17 average risk zone watersand houses are in the constructing a risky zone drainage network around the buildings 15. Village Dabla Southern and eastern 7.5+3.0+4.0+3.0= 364 2 residential houses Two sectors with Regulation of surface Gomi (4 sectors) peripheries of the 17.5 hectares are damaged, 3 are average dynamic, 2 – watersand village under threat, with active in average constructing a homestead land plots risk zone drainage network 16. Village Mtisdziri Southern periphery of 57.0 hectares 321 4 houses, homestead In active dynamic and Cleaning of the slope the village plots and sowing high risk via removing lands are destroyed underground waters

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Statistics of geological processes registered in Samtredia Municipality by separate settlements Table #26

Years Settlements Geological Inflicted damage Source of information processes 1 2 3 4 5 Villages Dapnari, Nigorzghva, Dozilo sector, 4 residential houses, agricultural sowing lands, Engineering-geological Tolebi-Bughnara, Gomi, Kormaghali, Nola, localroads and motor roads, 386.6 hectares were plan of 1968-1970 1968- 70 Zemo Abasha, Gamochinebuli (sector of Landslide damaged. Tskhvaradze).

Villages Dapnari, Nigorzghva, Opeti, In the mentioned period it was recommended to Engineering-geological Tsiagtubani, Gomi, Kormaghali, Tolebi, resettle 392 families. visual conclusions 1971-

98 Zemo Abasha, Gamochinebuli, Mterchveuli, Landslide compiled in various years. II Nigorzghva.

Villages Nigorzghva, Opeti Recommendation on the resettlement was given Information bulletin of 2005 Landslide to 4 families, 39.5 hectares were damaged. 2005 (monitoring)

Villages Opeti, Recommendation on the resettlement was given Information bulletin of 2006 Landslide to 7 families, 23.0 hectares were damaged. 2006 (monitoring)

Villages Ilori, Tolebi (Vazisubani settlement) Tskhenistskali River moved to the left side and Information bulletin of caused erosion on 450-500 meters of the territory 2007 of Ilori (Samtredia) cemetery. A stone dam is Erosion of fixed there now, 1.5 hectares of the area is 2007 banks eroded. Also, Khevistkali River eroded right bank in Vazisubani Settlement, flooded 3 residential houses and adjacent land plots, area of 31.6 hectares. 2008 Samtredia, “Komakhouri” cemetery adjacent Erosion of Rioni River moved to the right side at the Information bulletin of

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territory village Vazisubani, Dapnari banks “Komakhouri” cemetery by 40-50 m. and eroded 2008 (monitoring) Landslide 900-1000 meter section of the bank; eroded 5.0 hectares of land. Likewise, the same year landslide damaged 2 residential houses on the vil.Dapnari-Opeti road, 3 houses turned out to be under threat; 13.0 hectares of land were damaged.

Village Dapnari Landslide destroyed 2 residential houses and Information bulletin of damaged 3 ones, 120 m. length of motor road was 2009 (monitoring) Landslide damaged, 22.5 hectares of land were damaged.

Villages Zeda Gomi, Dapnari, Akhalsopeli, Because of the damage undergone Information bulletin of Ianeti recommendation on the resettlement was given 2010 to 4 families, 27.5 hectares were damaged. Due to the bank erosion of river Rioni mast of high voltage became threatened. Thus, it was Zeda Gomi recommended to dislocate the mast. On the landslide, 2010 territory of Ianeti-Akhalsopeli as a result of bank erosion of erosion a section of 50-60 m. of the mainstream banks gas pipeline was uncovered, thus recommendation was given to dislocate the one. Threat to be flooded was created to 3 families, it was recommended to erect a bank protecting construction, 28.0 hectares were damaged.

Village Gomistemi Landslide Recommendation on the resettlement was given On-site call in 2011 2011 to 4 families, recommendation on fortification to 2 families, 21.0 hectares were damaged.

Community of village Gamochinebuli Landslide Recommendation on the resettlement was given On-site call in 2011 to 2 families, 12.0 hectares were damaged.

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Community of village Gormaghali Landslide Recommendation on the resettlement was given On-site call in 2011 to 4 families, 25.0 hectares were damaged.

Community of village Opeti Landslide Recommendation on the resettlement was given On-site call in 2011 to 6 families, 13.0 hectares were damaged.

Village Dobilo, Nigorzghva-Chognari Road Landslide Landslide damaged and made inappropriate for Information bulletin of living 2 residential houses, 28.2 hectares of land 2012 were damaged. Land slid on the Nigorzghva- 2012 Chognari Road that damaged 25-30 m. of the motor road, 1 residential house became threatened, 31.6 hectares of land were damaged.

Village II Nigorzghva Landslide damaged and almost destructed 4 Monitoring reports of houses. It was recommended to move the 2013 2013 Landslide damaged houses to the solid ground/stable territory; 36.0 hectares were damaged. Quantity of landslides - Total Quantity of damaged houses - 459 Damaged (landslide area) – 366.98 32

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6.9 Forecast on development of disastrous geological processes on the territories of Tskaltubo and Samtredia Municipalities

Resultant to the global heating processes one can imagine the forecast on the development of dangerous geological processes on the territories of Tskaltubo and Samtredia Municipalities as it is specified below: In Georgia on the whole and naturally on the territories of Tskaltubo and Samtredia Municipalities global heating is enshrined in the growth of average temperature, drop in precipitations, increase of the quantity of drought days and atmospheric precipitations, basically, pouring rains. During the pouring rains precipitations are not well soaked into the soil that promotes favorable conditions for developing torrents. Preclusion of penetration of atmospheric precipitations into the surface soil obviously would drop the level of underground waters that, on its hand, would create a condition to slow down the activeness of surface landslides. In relation to landslides connected with tectonic disruptions, where conditions for penetration of atmospheric precipitations into the gapped soil remained the same, probability of landslide processes is quite low and it might remain on the average multiyear background level. Instability of underground water levels (drop) might have positive effect on damages provoked by shrinkage processes of premises. Landslide processes in the deep landslide bodies might develop similarly, where drop in the level of underground waters would positively impact the steadiness of landslide slope. In case if the given scenario re climate changes plays out this would increase frequency of floods and activation of its collateral erosive and accumulative processes. Taking into account the circumstance that landslide processes are widely spread on the territories of the given municipalities it will become necessary to take both capital-engineering and simple preventive measures for the implementation of which it is necessary to choose a place and a type of measures that might be done through conduction of monitoring surveys.

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7. bibliografia gamoyenebuli sakvlevi teritoriis Sesaxeb.

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