Water Management in the South Caucasus USAID Contract No. OUT-LAG-I-804-99-00017-00

FINAL REPORT

Sedimentation of the Kura River In the South Caucasus

Prepared for: U.S. Agency for International Development Mission for the South Caucasus

Prepared by: Development Alternatives, Inc. Tblisi, Georgia

October 2002

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Water Management in the South Caucasus

November 9, 2002 Mr. Peter Argo Director Office of Energy & Environment U.S. Agency for International Development 20 Telavi Street, 5th Floor Tblisi 380003 Georgia

Final Report Sedimentation of the Kura River

Dear Mr. Argo,

We are pleased to provide the USAID Caucasus Mission with the attached report titled Final Report on “Sedimentation of the Kura River in the South Caucasus ” for the project activities conducted to date in as part of the Water Management in the South Caucasus Project.

This report is part of a series of activities for Water Resource Management in the Kura-Aras River Basin that address technical and related policy and institutional conditions and experiences relevant to achieving the objectives of the Project.

This report summarizes some of the tasks completed as part of the Activity 1, Monitor Water Quantity and Quality in the Kura-Aras Basin. This report was prepared by the Dr. Gregory L. Morris with the cooperation of the Hydrometeorological Services in Armenia, Azerbaijan, and Georgia.

This report is intended to be a focal point of discussions with the Hydrometeorological Services in each country to increase the dialogue for sustainable water management in the South Caucasus. The report provides detailed recommendations that will be considered for implementation.

We are pleased to distribute this report to the interested parties in the region on behalf of USAID. Thank you for your assistance in support of this project.

Sincerely,

Paul C. Dreyer, PE Chief of Party

Enclosure cc: Dr. Michael Boyd, USAID/Armenia Mr. William McKinney, USAID/Azerbaijan Mr. Edwin Stains, DAI/Bethesda D331 DCover83

14 Paliashvili Street, Tblisi 380079 Georgia AUA Center Building; 9 Alex Manukian Street, Suite 207; Yerevan 375070 Armenia Caspian Business Center; 40 Jafar Jabbarli Street, Suite 604; Baku 370000 Azerbaijan TABLE OF CONTENTS

EXECUTIVE SUMMARY Introduction...... ii Reservoir Sedimentation and Loss of Water Supply ...... iii Sediment Problems Below Dams ...... iv Reservoirs and Water Quality in Kura River ...... iv Recommendations for Sedimentation Problems Below Dams ...... v Recommendations for Sedimentation Problems Above Dams ...... v

1. INTRODUCTION...... 1 1.1. Scope and Purpose of Study ...... 1 1.2. Sponsorship ...... 1 1.3. Limitations...... 2

2. STUDY AREA DESCRIPTION ...... 2 2.1. Study Area Location ...... 2 2.2. Climate...... 2 2.3. Kura River ...... 3 2.4. Reservoirs Along Kura River ...... 5

3. EROSION AND SEDIMENT YIELD...... 5 3.1. Methods...... 5 3.2. Erosion Conditions in Georgia...... 6 3.3. Sediment Yield from Kura Basin in Georgia...... 6 3.4. Erosion Conditions in Azerbaijan ...... 7

4. RESERVOIR OPERATIONS...... 8 4.1. Services Provided and Service Area ...... 8 4.2. Reservoir Inflow and Discharge...... 9 4.3. Reservoir Level ...... 10 4.4. Reservoir Operation and Kura Flow...... 10

5. WATER QUALITY...... 11 5.1. Water Quality Data...... 11 5.2. Reservoirs and Water Quality ...... 14 5.3. Water Quality and Reservoir Stratification ...... 15

6. SEDIMENTS AND SUSTAINABLE USE ...... 16 6.1. Sedimentation and Reservoir Life ...... 16 6.2. Reservoir Bathymetric Data ...... 16 6.3. Bed Material Sediment Data...... 16 6.4. Sediment Trap Efficiency ...... 17 6.5. Suspended Sediment Data...... 17 6.6. Trends in Suspended Sediment Yield ...... 18 6.7. Reservoir Half-Life...... 19

7. APPENDICES ...... 20

i SEDIMENTATION OF KURA RIVER BASIN IN THE SOUTH CAUCASUS

EXECUTIVE SUMMARY

Introduction

Azerbaijan has 135 reservoirs with over 0.5 million cubic meters of storage capacity, many of these located within the Kura River Basin. Of the 21.6 km3 of reservoir storage nationwide, 85% (18.4 km3) is contained in three reservoirs on the Kura River as shown in Table E1. These three reservoirs are located one after the other, with Mingechevir Reservoir being the most downstream.

Table E1: Summary of Reservoirs on Main Stem of Kura River. Maximum Original Hydropower Name Year Built Irrigation Water Level, m Capacity Mm3 Capacity, MW Varvara 1956 18 60 16.5 Yes Mingechevir 1953 83 16,600 380 a/ Yes Enikend 1998 104 158 150 No Shamkir 1980 158 2,677 370 Yes Totals 19,495 816.5 Abbreviations: Mm3 = million cubic meters, MW = megawatt, a/ Enlargement from 360 to 380 MW capacity under construction.

Azerbaijan has approximately 1.4 million hectares under irrigation and its agricultural economy depends heavily on reservoirs, with Minge chevir alone irrigating about half the total area. There are no reservoirs on the main stem of the Kura River in Georgia, although hydropower reservoirs exist on some tributaries, and considerable unexploited hydropower potential exists in Georgia.

Reservoirs strongly affect both hydrologic conditions and the sediment balance along the river system below the dam. The river downstream is deprived of sediments, promoting erosion and degradation of the river bed. On the other hand, elimination of flood flows by the reservoir can cause sediments to accumulate. An important example of this has occurred at the mouth of the Kura River, formerly about 4 meters deep, which is now reportedly only 0.5 to 1.0 meters deep because of sediment accumulation. Because of flow regulation and irrigation diversions, annual floods no longer scour sediment from the river mouth. The resulting shallow water and river mouth bar impede sturgeon from entering the river.

ii Reservoir Sedimentation and Loss of Water Supply

The useful life of large reservoirs is generally limited by the rate of sediment accumulation. In large reservoirs, such as those on the Kura River, the volume of sediment that will accumulate is so great that removal is not feasible. As a rough rule of thumb, reservoir operations will become seriously affected when half of the volume has become sedimented. To maintain the long-term functioning of this nationally important water supply infrastructure, it is necessary to determine appropriate strategies for dealing with sedimentation. Presently available data are rather limited, and there has been no systematic nationwide survey of reservoir sedimentation problems. However, the available information points to the the following situations.

Assuming that sediment yields do not increase, the available data indicate that sedimentation problems will not seriously affect the largest reservoirs during the next 100 years, but many smaller reservoirs may be affected.

· Smaller reservoirs in Azerbaijan may be expected to experience serious sedimentation problems during the next 50 years. A number of reservoirs are already more than 30 years old, sediment yields are high in the semi-arid and arid climate and mountainous terrain, and erosion is increasing by the effects of desertification.

· Simulations in this report indicate that Shamkir Reservoir, on the Kura River upstream of Mingechevir, will lose about half of its storage volume to sedimentation by year 2100.

· Simulations in this report indicate that Mingechevir Reservoir will have lost about half of its capacity by year 2500.

· Geyranbatan Reservoir supplying water to Baku has already experienced localized sedimentation problems which have interfered with the water supply to Baku.

Lacking a nationwide survey, at present there is no knowledge on which reservoirs are most affected by sedimentation, which are not, and how serious the problem may become at sites other than the Kura River reservoirs analyzed in this report.

Although reservoir sedimentation is a rather long-term problem, there are very good reasons to start now to identify those reservoirs with serious sedimentation, and to make a preliminary identification of sediment control strategies.

· Sediment and water management. In many cases, the only effective means to manage sedimentation is to avoid sediment accumulation in the first place. Another strategy when water supplies decline due to sedimentation is to better manage the available water resource. Development of sediment control strategies requires a good knowledge of hydrologic and sediment-production processes within the watershed above the reservoir. In the case of the Kura River reservoirs that are critical to Azerbaijan, this requires data-gathering and data- sharing cooperation between both Azerbaijan and Georgia.

iii · Planning future infrastructure. Extensive long-term investment needs to be made in irrigation and other water resource infrastructure. Before such investment is made, it should be ascertained that the water supplies will also be available in the long-term. It would be a waste of resources to construct costly irrigation improvements in an area which will face severe water shortages several decades in the future due to reservoir sedimentation.

· Raising dams. One sediment management strategy is to raise the level of the dam, thus enlarging the volume of the reservoir by inundating additional areas. If this strategy is to be used in the future, the affected lands should be identified now, so that costly new infrastructure and settlements are not placed in areas to be inundated in the future.

· New reservoirs. When new reservoirs are constructed, in some instances it is possible to design them so that sediment accumulation is reduced. However, these designs require the availability of adequate hydrologic and sedimentation data. Sediment surveys at existing reservoirs are required to develop sediment yield estimates for the proper design of new reservoir sites. One new reservoir is currently under construction in Azerbaijan.

Sediment Problems Below Dams

The primary downstream sediment problem related to the reservoirs is the accumulation of sediment at the mouth of Kura River, which impedes the migration of sturgeon and possibly other species. This is an immediate problem which may be considered important given the threatened status of salmon in the Caspian Sea, and the historical importance of the Kura River as a spawning habitat.

River mouth sedimentation results from elimination of high flows along the Kura River by the reservoirs; current flows are no longer large enough to scour sediments from the river. River sedimentation problems of this type below dams are addressed by establishing a schedule of reservoir releases to provide periodic flushing flows. The releases should be scheduled to optimize fish passage and minimize impacts to other users. Available preliminary information suggests that an opportunity exists to satisfy environmental needs much better than at present by optimizing the release schedule. More detailed information and hydraulic modeling will be required to address this issue and analyze alternatives.

Reservoirs and Water Quality in Kura River

The existing reservoirs along Kura River act as traps for both sediment and a number of other pollutants. The total storage capacity of these is about 1.5 times the total annual flow of the Kura River at Mingechevir, and the inflowing waters can be retained for many months in these reservoirs prior to being released downstream. In general, the available information indicates that the quality of water exiting the Mingechevir reservoir is of relatively good quality with low BOD5, high dissolved oxygen, and lacking contaminants such as DDT. However, the water continues to exhibit nutrient enrichment. While industrial discharges throughout the entire region have been largely eliminated by depressed economic conditions, because of pollutant trapping in the reservoirs, even many industrial

iv pollutants would have been greatly reduced by the reservoirs. Thus, contaminants in the lower Kura River may have originated more from Azerbaijan and Armenia (via Aras River) rather than from Georgia.

Recommendations for Sedimentation Problems Below Dams

1. Sedimentation Assessment at Kura River Mouth. Undertake a preliminary assessment of the ecological, water allocation and hydraulic issues associated with changing the release schedule at Mingechevir dam to enhance the downstream environment, focusing on increased water depth at the Kura River mouth during the period of sturgeon migration. This would focus on a collection and organization of existing data, interaction with local environmental and water management experts, limited field sampling (sediments and cross-sections), and preliminary computations with a sediment transport model.

This assessment will require approximately six months of effort. Once the general feasibility has been determined and possible conflicts identified, the follow-up activity would involve the final analysis and negotiations required to modify the operational rule for the Kura River reservoirs.

Recommendations for Sedimentation Problems Above Dams

To help preserve the existing reservoirs against sedimentation, and to aid the orderly development of any new water supplies, the following strategies are recommended.

2. Preliminary Assessment and Prioritization. Collect the available information from all existing and proposed reservoirs, to determine their relative susceptibility to sedimentation. These data should include water inflow, reservoir volume, watershed area, sediment yield data as available, year built, etc. Analysis of these data will indicate which reservoirs will have the most severe problems in the next 50 years, and which will not begin develop problems until much further in the future. Select approximately a dozen reservoirs for more detailed study . Because of its importance in checking the sedimentation inflow along the Kura reservoir, both Shamkir and the Ayrichay Reservoir (near Seki) should be included in the study to better define sediment yield above Mingechevir. This assessment can be developed by collecting and synthesizing existing data, and may be completed in approximately two months.

3. Reservoir Surveys. Ideally, all reservoirs should be surveyed and the data placed into electronic format for contouring and volume computations. The final data may be presented in a GIS format. This project should be initiated with the priority reservoirs selected under recommendation No. 1, including Shamkir and Arichay Reservoirs. Thereafter, as feasible, perform surveys at other sites where good original top ographic data exists as a means to determine long-term sediment yield in different parts of the country. Finally, surveys should be performed at as many of the remaining reservoirs as possible.

v It is estimated that approximately 10 reservoirs would be surveyed. Working efficiently and with modern equipment, an average field time of approximately one week per reservoir should be adequate, with an equal amount of time for data reduction and reporting. Because of their larger size, approximately two weeks field time will probably be required at Shamkir and three weeks at Mingechevir Reservoir.

4. Sediment Management Strategies. Analyze each of the priority sites with high potential for sedimentation problems to determine: when sedimentation is likely to become a problem, the types of problems anticipated, and sediment management strategies. This analysis will be based on all the available hydrologic data plus the information collected in steps No. 1 and No. 2, above. This analysis will require an average of approximately one to two weeks of effort per reservoir, depending on information availability.

vi 1. INTRODUCTION

1.1. Scope and Purpose of Study

A reconnaissance level study was undertaken to assess sedimentation conditions within the Kura River basin in Georgia and Azerbaijan, particularly as it relates to the Mingechevir and other reservoirs on the main stem of the Kura within Azerbaijan. Based on this, develop preliminary recommendations to address sedimentation and reservoir management issues which were identified.

This assessment was performed during two weeks between September 21 and October 5, 2002. Field activities undertaken included visits by automobile to representative portions of the Kura, Alazani and Ay richay watersheds, visit by automobile to three Kura River reservoirs in Azerbaijan (Shamkir, Enikend, Mingechevir) and portions of their irrigation areas, collection of hydrologic and operational data in both Georgia and Azerbaijan, and interviews with personnel in both countries.

Reservoirs interrupt the flow of sediment along the river, creating sedimentation impacts both above and below the dams. The reservoirs created upstream of the dams act as sediment traps, and sediments will eventually accumulate until it seriously interferes with reservoir operation. River channels below the dam are affected by the reduced sediment load, a consequence of sediment trapping within the reservoirs, plus the altered streamflows below the dam caused by reservoir operation and irrigation withdrawals.

This report represents an overview assessment of the sedimentation impacts associated with the reservoirs on the main stem of the Kura River in Azerbaijan. The study area includes the watershed of the Kura above Mingechevir which delivers sediment to the four main-stem reservoirs, the reservoirs themselves, and potential impacts to the river channel below the dams to the Caspian.

1.2. Sponsorship

This work was undertaken as part of the “Water Management in the South Caucasus” project, funded by the U.S. Agency for International Development (USAID) under contract to Development Alternatives, Inc. (DAI). The study was conducted by Dr. Gregory L. Morris, PE principal of Gregory L. Morris & Associates of San Juan, Puerto Rico.

Page 1 of 26 1.3. Limitations

There are serious data limitations throughout the region, and the data-collection system has suffered by the break-up of the USSR and resulting collapse of economic activity within the region. As a result, reliable and current data are generally not available. Therefore, the findings and recommendations of this report are based on three sources: interpretation of the limited existing data, information from interviews, and field observations. Despite the lack of statistical data, there was general agreement among the three sources of information with respect to the major issues presented in this report.

2. STUDY AREA DESCRIPTION

2.1. Study Area Location

The Kura River watershed drains portions of five countries, and flows eastward into the Caspian Sea. The entire watershed of the Kura River, including the Aras River which drains most of Armenia and enters the Kura downstream of the reservoirs, is illustrated in Figure 1. The breakdown of the entire Kura basin, by watershed and country, is summarized in Table 1. Figure 2 illustrates the location of the Kura River reservoirs, and a satellite image of this area is presented as Figure 3.

Table 1: Watershed Areas of Kura River above the Caspian Sea (km2). Country Kura River above Mingechevir Kura River at Mouth Azerbaijan 14,600 56,700 Georgia 34,700 34,700 Turkey 5,600 28,200 Armenia 7,700 29,800 Iran 0 39,500 TOTAL 62,600 188,900

2.2. Climate

Georgia is moist with a moderate climate. While the Black Sea coast is warm enough t o be classified as sub-tropical, the Kura watershed is colder and winter snows can be expected, although at lower elevations (Tbilisi, Alazani valley) it does not snow every year. Total annual

Page 2 of 26 rainfall within the Kura basin in Georgia is on the order of 600 to 700 mm/year. In the Alazani watershed rainfall is higher, averaging about 800 mm/year in the area of Telavi and over 1,000 mm/yr in the mountains.

Precipitation patterns for three stations in Georgia are summarized in Figure 4. Bolnisi and Achalciche are in the Kura watershed, and Telavi is in the Alazani watershed. Daily data in Figure 5 show that precipitation is well-distributed throughout the year. The highest flows are generally associated with rain-on-snow events in the late spring and the most intense rains are from convective storms. Annual long term rainfall data at Akhaltsikhe, Georgia were observed for trends. A slight declining trend in rainfall was observed in Figure 6. A test of statistical significance was not performed.

The climate in Azerbaijan is generally much drier than Georgia with semi-arid conditions prevailing over much of the country. Moist areas occur along the border with Georgia, particularly in the Ay richay River watershed, and in the higher mountains. However, along the Kura River rainfall decreases from about 600 mm/year near Shamkir Reservoir, to about 150 mm at the Caspian coast. The principal tributary to the Kura below the dams is the Aras River, draining primarily from Armenia (see Figure 1).

2.3. Kura River

The Kura River is used as a water supply for irrigation and industrial processes and also as a receiving body for municipal and industrial wastewaters, both treated and untreated. Contamination from industrial activities is now very low due to the closure of most factories in the watershed following breakup of the USSR. However, cities continue to discharge municipal wastewater into the Kura River , and wastewater treatment plants generally do not exist or do not operate. Because the hydrometerological data collection systems also suffered from the economic collapse within the region, there are currently few data available to assess contamination issues.

The Kura River is directly related to one of the principal economic issues affecting the Caspian Sea, which is the dramatic decline in the sturgeon fishery. In the early 1900s the Kura River was an important sturgeon fishery, at that time producing about half of the world’s supply of caviar. Today production from the Kura River is insignificant and most production is from the Volga River. (The Cousteau Society, 1998).

The discharge of the Kura River into the Caspian Sea is heavily influenced by upstream withdrawals. Thus, while its normal discharge may be on the order of 26 km3/year (DAI/USAID, 2002), the Caspian Environmental Programme (1999) used an annual discharge of approximately 16 km3/year, which represents approximately 6 per cent of the total terrestrial inflow into the

Page 3 of 26 Caspian Sea as shown in Table 2. However, the present flow may be significantly less than this due to additional upstream irrigation withdrawals.

Table 2: Mean Annual Inflow into Caspian Sea (Caspian Environmental Programme, 1999) Mean Annual Inflow River Km3 Percent of Total Volga 228.6 81.6 Kura 16.6 5.9 Ural 8.4 3.0 Terek 6.8 2.4 Sulak 4.2 1.5 Samur 1.7 0.6 Iranian & other rivers 10.0 3.6 Ground water 4.0 1.4 Total 280.3 100.0 Note: Rainfall is about 22 cm/year and evaporation about 80 cm/year averaged across the entire Caspian.

Streamflow in the Kura is of prime importance to the sturgeon fishery because high flow rates are required to prevent sedimentation of the river mouth. Sturgeon migrate along deep channels, and their migration is blocked by shallow water or whitewater rapids. The principal human impacts to rivers which have led to the decline in Caspian sturgeon include:

· Overfishing.

· Dams which affect both upstream migration of adults and the downstream migration of juveniles.

· Altered flows which allow sedimentation within the river. In the Kura River flows are altered by both reservoir operation and irrigation withdrawals below the dams. Greatly reduced flows allow the accumulation of sediment at the river mouth (creation of a mouth bar) which can block upstream fish passage. During the Soviet period it was determined that a depth of 1.78 m should be maintained at the mouth of the Kura River to sustain fish passage. However, in recent years depths as shallow as 0.5 m have been reported.

· Contamination of rivers can kill either adult or young fish, prevent adults from reaching spawning grounds, weaken fish making them more susceptible to disease, and produce genetic defects.

Page 4 of 26 Dam construction has had a particularly severe impact on sturgeon, and it is believed that without fish farming operations, some species of Caspian sturgeon would already be extinct.

2.4. Reservoirs Along Kura River

There are reportedly 135 reservoirs in Azerbaijan with a storage capacity in excess of 0.5 Mm3, but it is not known how many of these are in the Kura watershed. There are four reservoirs on the main stem of the Kura River in Azerbaijan, as summarized in Table 3 and located in Figure 2. The largest reservoir is Mingechevir, which receives water from both the Kura and the Alazani Rivers and required three years to fill (1953 to 1956). Two smaller reservoirs located upstream of Mingechevir, Enikend and Shamkir, do not receive runoff from the Alazani River . The small Varvara Reservoir is below Mingechevir Reservoir. The total storage volume for these reservoirs is equivalent to about 1.5 years of river flow at Mingechevir Reservoir.

Table 3: Summary of Reservoirs on Main Stem of Kura River. Original Maximum Year Original Total Hydropower Name Water Level, Usable Irrigation Built Capacity Mm3 Capacity Capacity, MW m a/ Mm3 Varvara 1956 18 60 ? 16.5 Yes Mingechevir 1953 83 16,600 b/ 8,700 380.0 c/ Yes Enikend 1998 104 158 136 150.0 No Shamkir 1980 158 2,677 1,400 370.0 Yes Totals 19,495 10,236 816.5 Abbreviations: Mm3 = million cubic meters, MW = megawatt, a/ Baltic datum. The present Caspian level is at about -28 m on the Baltic datum. b/ The original total volume has also been reported as 16,100 Mm3. c/ Enlargement from 360 to 380 MW capacity under construction.

3. EROSION AND SEDIMENT YIELD

3.1. Methods

To perform a preliminary assessment of erosion conditions, road trips in Georgia were made to Gudauri, Bolnisi, Armenian border at Sadakhlo, Alazani basin and downstream along the Kura River to Red Bridge at the Azerbaijan border. In Azerbaijan travel included the Ayrichay basin plus the route from the Georgia border to Baku. Although erosion is a natural process,

Page 5 of 26 human activity can greatly accelerate erosion rates. The purpose of these field visits was to look for indicators of accelerated erosion, and if present to recommend general control strategies.

3.2. Erosion Conditions in Georgia

There was generally evidence of only moderate rates of accelerated erosion within most of the Kura watershed in Georgia. There is good vegetation cover, rainfall is rather well- distributed throughout the year, there is little evidence of gullying, and row crops are concentrated on soils which are nearly flat. In a few locations there is evidence of recent river incision (down cutting at bridge piers), but it is not a general phenomena, and observations do not suggest that bank erosion rates are unusually high within the local geomorphic context. As a result, there is little soil conservation work that could be performed to significantly reduce sediment yield in most areas of the Kura River basin within Georgia.

However, in some areas high rates of soil and stream bank erosion were observed. Massive erosion was observed at and above the upper limit of forest vegetation in the Caucasus, at elevation ranges of about 1,500 to 1,900 m along the Aragvi River near Gudauri (see photograph in Figure 7). For security reasons it was not possible to ascend into these elevations in the Caucasus of the Alazani River basin, but the heavy silt loads in the streams draining the mountains in this area suggest that erosional processes are accelerated within the mountains in this area as well. Thus, there may be greatly accelerated erosion rates at higher elevations within the Caucasus. The massive gullying observed in the area of Gudauri, once started, is most difficult and costly to stop. This type of erosion is initiated by concentration of runoff along foot paths and animal trails, and destruction of protective vegetation.

In the drier area east of Rustavi and near Algeti, stream incision was readily apparent. Essentially all of the serious and incipient erosion problems observed in this area of Georgia were observed on grazing lands. At several road crossings, accelerated erosion below culverts was observed (see photograph in Figure 8). Gullying was also observed in this area.

Any soil conservation efforts in the Kura/Alazani watershed should focus on: (1) grazing lands , and (2) road construction, particularly at stream crossings . Although there was relatively little evidence of erosion from row crops, it should also be recognized that much of the land was fallow due to economic decline.

3.3. Sediment Yield from Kura Basin in Georgia

Suspended sediment yield from gage stations in the Kura River watershed within Georgia were compiled and provided by Hydromet. Data were from gage stations having at least 5-years

Page 6 of 26 of record. Bed material load was not measured or estimated for these stations. These sediment yield estimates are based on data collection during the USSR period. It was reported that sediment concentration was normally measured at 10-day intervals by sampling at discrete depths and locations within the stream cross-section, but that more frequent sampling was used during periods of high flow. A sediment rating curve was used to estimate yield for the unmeasured period. These data are presented graphically in Figure 9 showing sediment yield as a function of watershed size.

Sediment yields in excess of 400 t/km2/yr are reported at four stations, and three of thes e are on the Aragvi River where massive gullying was observed (recall Figure 7). Sediment yields are otherwise under 300 t/km2/yr. These values appear consistent with conditions observed in the field. They are also generally consistent with the sediment yield of 320 t/km2/yr estimated to enter Mingechevir reservoir based on gage station data in Azerbaijan, as subsequently presented in Table 10.

3.4. Erosion Conditions in Azerbaijan

Erosion conditions within the moist port ions of the Alazani River watershed within Azerbaijan and tributary to the Mingechevir reservoir were not remarkably different than those observed in Georgia. However, Azerbaijan is generally drier, reducing vegetative growth and making the soils more susceptible to damage by overgrazing and erosion. Problems with gully erosion were observed, and the severity of the erosion problem tends to increase as moisture levels decline.

Erosion problems within the area tributary to Mingechevir Reservoir are primarily associated with grazing lands. The streams draining the Caucasus and comprising the northern portion of the Ayrichay River watershed in particular are areas of high sediment yield. The Town of Saki is constructed on a huge alluvial fan created by sediment outwash from the Kishchay River draining the Caucasus Mountains (see photograph in Figure 10).

A small tributary to the Ayrichay River , near its confluence with the Alazani River, was observed to have experienced bank erosion and channel widening on a massive scale due to a heavy rainfall which occurred several days prior to the site visit. Banks were still actively caving in and trees had obviously just fallen into the stream. This appears to be the result of stream incision and disconnection of the stream from the floodplain. As a result, flood flows are no longer able to overflow and dissipate their energy onto the floodplain, and instead this energy is directed against the vertical stream banks, eroding the banks and causing the river to widen dram atically (see photograph in Figure 11).

Page 7 of 26 Moving in the direction of Baku and downstream of Mingechevir Reservoir, climatic conditions are drier and erosion is generally worse. While the irrigated areas are on relatively flat soils with little erosion pot ential, a considerable amount of hilly land is cultivated for rain fed crops. On these sloping soils there appears to be no effort to apply basic soil conservation techniques such as contour ploughing and long furrows were frequently observed to run downslope (see photograph in Figure 12).

In Azerbaijan, desertification is a serious problem due to factors including excessive grazing pressure plus over-irrigation which leads to soil salinization. The land area within the Azerbaijan coastal zone (within 100 km of Caspian shoreline) affected by different classes of desertification has been reported by the Casp ian Ecological Programme (1998): Degraded vegetation ...... 7,987 km2 Water erosion...... 2,892 km2 Wind erosion ...... 281 km2 Soil flooding & salinization...... 3,269 km2 Technogenic desertification...... 1,178 km2 Desertification due to flooding and soil salinization has been caused by several factors including the rise in groundwater levels by excessive irrigation and increases in the Caspian Sea level. Estimates of desertification areas outside of the 100 km wide coastal zone were not available.

Increased erosion rates due to desertification is not a direct threat to the Kura River reservoirs because it primarily occurs downstream of the dams. However, the desertification process is directly related to the Kura River reservoirs inasmuch as the poor management of reservoir irrigation water is a primary cause of soil salinization. This poor water management is one of the most serious desertification problem within the country because it affects the most productive (irrigated) soils. Accelerated erosion due to desertification undoubtedly affects other reservoirs within Azerbaijan.

4. RESERVOIR OPERATIONS

4.1. Services Provided and Service Area

The Kura River reservoirs primarily provide hydropower and irrigation supply. Flood control is provided as a by -product of these operations, and recreational use is inconsequential. Reliable data on the area under irrigation are reportedly not available. However, irrigated area

Page 8 of 26 was considered to ha ve declined significantly due to the combination of loss of markets and other dislocations following breakup of the USSR, plus widespread problems of soil salinization. Salinity impaired soils were readily evident during the field visit as shown in the photograph in Figure 13). Perhaps half of the irrigated land is now dedicated to low-value crops, pasture and forage, and cotton is the single largest row crop .

All four Kura River dams are operated by the electrical power authority. Reportedly, each year’s operational procedure is developed by consultation between the power authority and irrigators based on an estimate of expected inflow from snow pack plus other hydrologic parameters. About 9 km3 of water per year should be released to the Kura River for environmental uses, including the scouring of sediment at the river mouth to maintain a depth of at least 1.78 m at the point of discharge into the Caspian Sea. This depth is required to permit the passage of sturgeon.

4.2. Reservoir Inflow and Discharge

Flows along the Kura River and its tributary, the Alazani River, are highly seasonal, as illustrated by the data in Figure 14. The inflows from ga uged streamflow stations above Mingechevir Reservoir for the period 1970-1990 plus 1992-1994 were compiled by Mammadov (2002) and are summarized in Table 4. These are the major tributaries to the reservoirs. Information on the ungauged tributary area was not available, but as compared to the ga uged area it constitutes a small and relatively dry portion of the total water shed above Mingechevir dam.

Table 4: Gauged Inflow into Mingechevir Reservoir, 1970-1990, 1992-1994. Gauge Station Mean Annual Inflow (km3/yr) Percent of Ga uged Inflow Kura at Khuluf 8.16 69 Ala zani at Ayrichay 3.39 28 Iori at Kesamen 0.21 2 Gangachay at Zurnabad 0.13 1 Totals 11.89 100 Source: Compiled by Mammadov, 2002.

Discharges from Mingechevir to the Kura River, Shirvan Canal, Karabakh Canal and evaporation were compiled by Mammadov (2002) for the years 1964 to 1975 and are summarized in Table 5. Data were incomplete for other years.

Page 9 of 26 Table 5: Discharges from Mingechevir Reservoir, 1964-1975. Discharge Mean Annual Inflow (km3/yr) Percent of Gaged Inflow Kura at Yevlakh 9.11 77.0 Shirvan Canal 0.81 7.0 Karabakh Canal 1.26 11.0 Evaporation 0.59 5.0 Totals 11.77 100.0 Source: Compiled by Mammadov, 2002.

4.3. Reservoir Level

Long-term data on the average level of Mingechevir Reservoir, by year, are presented in Figure 15. Seasonal or daily data on reservoir level were not available. The reservoir has not been full (to elevation 83 m) since 1998. The original stage-volume curve for Mingechevir Reservoir is presented in Figure 16. All levels for Mingechevir and the other reservoirs are established on the Baltic vertical datum. The level of the Caspian Sea is at about -28 m on the Baltic datum.

4.4. Reservoir Operation and Kura Flow

There are about 1.5 million hectares of irrigated land in Azerbaijan, although not all of it is currently irrigated. About 1 million hectares of land is irrigated by the Mingechevir Reservoir, and about half of this area is reported to have serious salinization problems. The reservoir delivers water by two irrigation canals and this irrigation water is not used for power generation. There are additional irrigation withdrawals from the Kura River below the dam.

Current irrigation deliveries from Mingechevir to its two irrigation canals are about 3.7 km3/year. This is equivalent to a water application 0.37 m deep over the 1 million hectare irrigation area. Information on additional withdrawals for irrigation from Kura River downstream of the reservoir was not available, and in general the data on irrigation deliveries and the crops under irrigation was reportedly incomplete due to poor reporting procedures.

Mingechevir Reservoir provides most of the storage capacity along the Kura River (recall Table 3). Flow along the Kura is River highly altered by the reservoir, as illustrated in Figure 17. For the year shown (1987), the inflow to Mingechevir Reservoir from the Kura River was 12.7 km3 (inflow from Alazani River and other tributaries is not shown), and the discharge to the river was 9.3 km3. At the river mouth, following inflow from the Aras River, the discharge of the Kura River had increased to 13.0 km3.

Page 10 of 26 Under current conditions a significantly smaller amount of water is discharged to the river below the dam than in 1987, as illustrated by the data presented in Figure 18. The available data also indicate that irrigation deliveries from Mingechevir Reservoir have increased in recent years as shown in Figure 19, coinciding with reduced releases to the river . This change in reservoir operations is associated with two serious problems: sturgeon passage at the river mouth and soil salinization, as follows:

· Decreased river flow has resulted in sedimentation by fine sands and muds at the river mouth, with depths as small as 0.5 m, as compared to the depth of 1.78 m previously established as the minimum required to maintain sturgeon passage.

· Increasing irrigation deliveries combined with reduced acreage under irrigation can contribute to rising groundwater levels and promote soil salinization.

The reason for increased irrigation deliveries is not clear, but factors may include increased leakage from canals, a tendency by farmers to apply excess amounts of irrigation water, plus year -around irrigation of forage crops as opposed to seasonal irrigation of cotton. Because of the large implications to productive land and to important environmental issues related to the Caspian Sea ecosystem, this issue warrants immediate attention.

5. WATER QUALITY

5.1. Water Quality Data

There are no functional water quality stations along the Kura River in Georgia. Limited water quality data for Azerbaijan were available for this report. Water quality data for the Alazani River, before it enters the Mingechevir Reservoir, is summarized in Table 6. Water quality data are available for Kura River at Mingechevir Reservoir, below the reservoir is summarized in Table 7. These data indicate that water of high quality is discharged by the reservoir, although nitrates and dissolved solids appear somewhat high. For both sets of data, the percentage oxygen saturation based on the reported temperature and dissolved oxygen concentrations were computed and these values are included in the tables. Oxygen levels are very close to saturation (>90%) in many of the samp les, and the lowest value is 76 per cent saturation.

Page 11 of 26

Table 6: Selected Water Quality Data for Alazani River below c onfluence with Ayrichay River above Mingechevir Reservoir. (Summarized from Mammadov, 2002)

Date (day / month / year) Parameter 2/2/91 10/4/91 8/6/91 4/8/91 6/10/91 5/12/91 5/2/00 5/4/00 9/7/00 8/10/00 Temperature, ºC 2.4 4.6 16.4 26.2 14.9 3.5 10.0 13.0 18.0 18.0 Suspended Solids, mg/L 199 235 971 24 120 175 64 193 159 402 pH 8.3 8.2 8.4 8.3 8.4 8.6 8.1 8.1 8.5 8.4 Dissolved Oxygen, mg/L 12.7 12.1 9.2 7.2 9.2 12.7 10.0 9.2 7.8 7.2

O2 Percent Saturation a/ 92% 94% 94% 89% 91% 96% 88% 87% 82% 76% BOD -5, mg/L 0.9 1.2 1.2 1.9 1.4 0.7 1.2 1.4 1.7 2.6 TDS (sum of ions), mg/L 466 423 317 367 323 415 425 406 278 403

PO4 , mg/L 0.044 0.041 0.091 0.081 0.106 0.073 0.003 0.002 0.005 0.007

NO2, mg/L 0.002 0.007 0.011 0.009 0.002 0.005 0.013 0.020 0.010 0.007

NO3, mg/L 1.92 2.0 1.52 2.02 1.85 1.92 1.29 1.36 1.55 1.15 Oil products, mg/L 0.03 0.07 0.04 0.05 0.05 0.06 0.02 0.018 0.02 0.01 Phenols, mg/L 0.006 0.003 0.006 0.006 0.007 0.004 0.002 0.001 0.005 0.004 DDT ND ND ND ND

Notes: “--“ indicates no information available. ND = Not Detected (below detection limit of the test) a/ Percent saturation dissolved oxygen computed for pure water at sea level from nomograph in Wetzel (1983).

Page 12 of 26

Table 7: Selected Water Quality Data for Kura River at Mingechevir Town below Mingechevir Reservoir. (Summarized from Mammadov, 2002)

Date (day / month / year) Parameter 4/2/91 3/4/91 11/6/91 2/8/91 10/8/91 4/12/91 23/3/00 8/6/00 9/8/00 16/10/00 Temperature, ºC 13.2 9.2 19.2 24.2 16 12 8.4 16.8 22.4 19.2 Susp. Solids, mg/L 364 412 92 23 106 154 27 43 93 7.3 pH 7.8 8.1 8.5 8.3 8.2 8.1 7.9 8.1 8.2 8.6 Dissolved Oxygen, mg/L 10.0 10.3 8.8 7.9 8.0 10.3 9.7 8.2 7.9 8.2

O2 Percent Saturation a/ 96% 90% 95% 80% 82% 96% 82% 84% 90% 88% BOD -5, mg/L 1.2 1.6 1.5 2.0 1.7 0.7 1.4 1.6 1.5 1.7 TDS (sum of ions), mg/L 532 593 520 539 525 493 445 398 455 425

PO4 , mg/L 0.117 0.038 0.095 0.096 0.075 0.076 0.005 0.018 0.011 0.013

NO2, mg/L 0.006 0.007 0.016 0.003 0.002 0.003 0.010 0.010 0.030 0.023

NO3, mg/L 1.49 1.51 1.32 2.21 1.36 1.31 1.4 1.62 1.79 2.22 Oil products, mg/L 0.33 0.07 0.19 0.12 0.08 0.06 0.03 0.05 0.09 0.05 Phenols, mg/L 0.006 0.009 0.009 0.009 0.010 0.005 0.004 0.006 0. 005 0.008 DDT ------ND ND ND ND

Notes: “--“ indicates no information available, ND = Not Detected by the test a/ Percent saturation dissolved oxygen computed for pure water at sea level from nomograph in Wetzel (1983).

Page 13 of 26 According to the Caspian Ecological Programme (1998), within the Kura River the oxygen regime is generally satisfactory at about 82 -100 per cent of saturation, and BOD-5 is also low typically about 2 to 2.5 mg/L. These conclusions are consistent with the limited available data and observations made during this reconnaissance study.

In systems with high levels of algal growth such as the Kura River (but not the Alazani River due to its high sediment load), dissolved oxygen levels can vary considerably from day to night. During the daytime either suspended algae or aquatic grasses produce oxygen by photosynthesis, creating high or even super-saturated levels of oxygen in the water. At night algae and other organisms utilize the dissolved oxygen, resulting in depressed oxygen levels (and in extreme cases, fish kills) in the hours before sunrise. For aquatic organisms in these environments, the most critical period for survival is nighttime when dissolved oxygen levels become depressed. No data on the diurnal variation in dissolved oxygen were reported, and all the water quality samples are expected to represent daytime conditions. Thus, nighttime dissolved oxygen levels in the Kura River may be significantly lower than indicated by the available data.

5.2. Reservoirs and Water Quality

The lack of functional wastewater treatment plants in Georgia results in a significant discharge of municipal wastewater into the Kura River, producing contaminants which are carried into the reservoirs in Azerbaijan. The travel time from Tbilisi to Shamkir reservoir is about 2 days. However, due to the dramatic decline in industrial activity in Georgia, at this point industrial wastes appear not be an important component of the wasteload discharged into the Kura River and its tributaries.

The Kura River reservoirs, when full, have a nominal hydraulic detention time of about 1.5 years. When the active storage is empty, the dead storage of these reservoirs still provides a detention period on the order of 9 months. As a result, Shamkir and Mingechevir Reservoirs will act as very efficient traps for sediment, for contaminants associated with sediment, and for organic materials which degrade over time. The reservoirs may also be effective nutrient traps to the extent that nutrients are incorporated into algal biomass which then settles to the bottom of the reservoir to become trapped as sediment. Conditions observed during the visit suggested that this process may be active, since the water in Shamkir Reservoir was green with algal growth, whereas at Mingechevir Reservoir the water was much clearer and without visible evidence of algae, suggesting a reduction in nutrient concentrations moving in the downstream direction. Nevertheless, in the Kura River a short distance below Mingechevir dam, there was vigorous growth of aquatic grasses, all covered with epiphytic algal growth. This suggests that nutrient levels remain high in the water released by the dam, despite any nutrient trapping by the reservoirs.

Page 14 of 26 5.3. Water Quality and Reservoir Stratification

The water in lakes and reservoirs tends to stratify. Water in the upper layer is heated by the sun and the deeper waters remain cold. Because cold water has a greater density than warm water, the result is to create two separate bodies of water of different densities in the reservoir, separated by a density interface which inhibits vertical mixing. Because the upper and lower waters do not mix, the transfer of oxygen from the surface into the lower water is inhibited. If there is a significant organic load in the water, all the oxygen in the lower water can be consumed producing an anaerobic bottom layer. Also, both the temperature and quality of the water released downstream of the reservoir will depend on the depth from which the water is released.

Suspended sediment also increases the density of a water body, and sediment-laden water will plunge to the bottom as soon as it enters a reservoir. This plunging flow can run along the bottom or the reservoir, depositing sediment, while the surface waters remain clear. In some cases the submerged turbidity current can run along the entire length of the reservoir and be released by low level outlets at the dam. The general behavior of a turbidity current in a reservoir is illustrated in Figure 20.

Chemical parameters from a single vertical sample (Vertical No. 3, May 1960) were reported for Mingechevir Reservoir by Mammadov (2002) and showed strong temperature stratification, but dissolved oxygen was not reported. Profiles for 1962, 1965 and 1969 showed strong stratification in summer months due to warming of the surface waters, with the thermocline located at a depth of about 15 to 20 meters. Stratification starts in May and ends in November, with surface temperatures approaching 25º C in July and August as compared to bottom waters in the vicinity of 10º C.

Since its construction in 1983, inflowing suspended sediments have been trapped in Shamkir Reservoir, upstream of Mingechevir. Thus, suspended sediment is today probably not a major factor influencing stratification in Mingechevir reservoir except in Alazani River inflow. However, turbid density currents from the Kura River may be important in the Shamkir Reservoir.

Detention periods will be much less in the case of hydraulic short-circuiting, as can occur when density currents enter the reservoir and are discharged through low level outlets at the turbines. However, given the presence of multiple reservoirs along the river, there is probably little opportunity for hydraulic short-circuiting to rapidly pass inflow from upstream of Shamkir Reservoir to downstream of Mingechevir and Varvara Reservoirs.

Page 15 of 26 6. SEDIMENTS AND SUSTAINABLE USE

6.1. Sedimentation and Reservoir Life

Like other engineering structures, dams can be rehabilitated or reconstructed when they age. However, construction of a dam interrupts the flow of sediment along the river course. Sediment eroded from the watershed and carried downstream by the river will be deposited within the reservoir until it is filled. Erosion and deposition are large-scale geologic processes, and it is rarely economically or environmentally feasible to remove the large volumes of sediment which accumulate in reservoirs. For this reason the useful life of reservoirs is determined primarily by the accumulation of sediment, and not physical aging of the dam itself.

Most reservoirs experience difficulties in meeting their design needs when half of their capacity has been lost to sedimentation. Mingechevir Reservoir is somewhat unusual in that the dead storage pool consists of 48 per cent of the total original storage volume, and it might be argued that more than half of its capacity must be lost prior to the onset of serious problems. However, sediments do not collect in reservoirs uniformly from the bottom-up, and a significant part of the active pool will be sedimented along with the dead pool, especially in the upstream end of the reservoir.

6.2. Reservoir Bathymetric Data

The rate of sediment accumulation in a reservoir is monitored over time by successive bathymetric measurements which determine the decline in reservoir capacity. The observed rate of decline in capacity can be projected into the future to estimate when sedimentation will become a serious problem. Bathymetric monitoring will also determine the rate of capacity loss in different zones of the reservoir, and can provide data for calibration of mathematical models used to predict future sedimentation. The rate of sediment accumulation as determined by bathymetric data can also be used to estimate the sediment yield from the watershed.

No bathymetric data are reported to be available for any of the reservoirs along the Kura River. Thus, there is no direct measurement of sedimentation processes within these reservoirs.

6.3. Bed Material Sediment Data

Bed material is the coarse sediment which is found on the bed of the river. When flow rates increase, the bed material is mobilized and transported by rolling or bouncing along the bottom. In sand-bed rivers having high velocities, a portion of the sand load can be carried in suspension. The bed material frequently consists of only a small percentage (e.g. <10%) of the total sediment load transported by a river, but in some situations (sand bed and mountain streams) it may represent over half of the total load.

There are no measurements of bed material sediment load for rivers tributary to the Kura River reservoirs. Furthermore, measurement of bed material load in this environment is not practical

Page 16 of 26 due to the large size of the rivers and the large size of the material (gravels and cobbles). At best, bed material load can only be estimated by computation. Observations suggest that the bed material load is perhaps on the order of 5 per cent of the total sediment load entering the Kura reservoirs.

6.4. Sediment Trap Efficiency

Not all of the sediment entering a reservoir is trapped. As a first estimate, trap efficiency may be computed by the Brune curve as shown in Figure 21 which is based on the ratio of reservoir capacity to total annual inflow (capacity:inflow ratio). The capacity:inflow ratio and resulting trap efficiency for each reservoir is computed in Table 8. Essentially all of the inflow from the Kura River is trapped in Shamkir Reservoir, and prior to the construction of Shamkir and Enikend, Mingechevir Reservoir was trapping essentially all of the sediment entering that reservoir.

Table 8: Computation of Capacity:Inflow Ratio and Trap Efficiency. Parameter Mingechevir Enikend Shamkir Capacity, km3 16.6 0.158 2.677 Inflow, km3 11.9 a/ 8.2 a/ 8.2 a/ Capacity:Inflow ratio 1.39 0.02 0.33 Trap efficiency (from Figure 21) 0.98 0.59 0.95 a/ From Table 4. b/ Kura River discharge at Khuluf, Table 4.

6.5. Suspended Sediment Data

Prior to construction of the upstream reservoirs, Shamkir and Enikend, Mammadov (2002) computed the rate of storage loss in Mingechevir Reservoir at 36 Mm3/year as shown in Figure 22 based on suspended sediment measurements in the principal tributaries, estimated sediment contributions from ungaged areas, plus the contribution from bank erosion around the perimeter of the reservoir, which will gradually decline over time. Details on the methodology were not available.

A separate dataset for suspended sediment discharge compiled by Mammadov (2002) are available for the two major and two minor tributaries for the years following 1970. Data from all four tributaries are available for: 1971, 1977, 1978, 1980, 1981 and 1982. These data were used to compute the mean annual load and percent of gauged load for each station, as summarized in Table 9. The mean concentration was computed for each gage from the entire available dataset and is also shown in the table. The suspended sediment concentrations in the Iori and Gangachay Rivers are quite low by comparison. It is not known to what extent this may be created by under-sampling these smaller rivers, which will have peak discharges and sediment concentrations of much shorter durations (and therefore more difficult to sample) as compared to the larger rivers.

Page 17 of 26 Table 9: Suspended Sediment Inflow at Gauge Stations Above Mingechevir Reservoir. Gauge Station Mean Annual Load Percent of Ga uged Mean Concentration (Mt/yr) Load (mg/L) Kura at Khuluf 9.28 62.7 1,440 Alazani at Ayrichay 5.45 36.8 1,827 Iori at Kesamen 0.05 0.3 207 Gangachay at Zurnabad 0.02 0.2 165 Totals 14.80 100.0 Notes: Mean annual load and percent computed by data from years 1971, 1977, 1978, 1980, 1981 and 1982, which are the only years for which data are available for all gage stations. Mean concentrations are computed from all years of data, except that years following closure of Shamkir dam are excluded from the Kura at Khuluf dataset. Source: Computed from discharge and mean annual load data compiled by Mammadov, 2002.

The Kura River is the largest sediment source. Although there are only six years of sediment load data from all four gage stations, data from the Kura are available for a period of eleven years prior to closure of Shamkir Reservoir above the gage station, and 19 years of data are available for the Alazani. These data are summarized in Table 10. An additional 6 per cent is added to account for bed material load plus the contribution of Iori and Gangachay Rivers, to obtain an adjusted total inflow tributary to Shamkir and Mingechevir dams. The inflow to Enikend is taken as equal to Shamkir because they are very close to each other.

Table 10: Sediment Loads Tributary to Mingechevir and Shamkir Reservoirs. Mean Annual Load Tributary to Mean Annual Load Tributary to Gauge Station Mingechevir Shamkir Kura at Khuluf a/ 12.4 12.4 Alazani at Ayrichay b/ 6.54 n/a Gauged Total 18.94 12.4

Adjusted Total Load, Mt/yr 20.08 13.1 Rate of Sedimentation Mm3/yr 20.08 13.1 a/ Period 1971-1978, 1980-1982, as compiled by Mammadov, 2002. b/ Period 1971, 1973-1990, as compiled by Mammadov, 2002. For the Kura reservoirs, sediment deposits probably have a bulk density on the order of 1.0 ton/m3 of sediment deposit. For this bulk density, the annual rate of volume loss is computed in the last row of Table 10. The tabulated rate for Mingechevir is about 55 per cent of the sedimentation rate of 36.24 Mm3/yr at Mingechevir estimated by Mammadov for the period 1953-1970.

6.6. Trends in Suspended Sediment Yield

Data on annual suspended sediment load for the Kura River at Tbilisi from 1928 to 1990 are presented in Figure 23, showing a trend of declining sediment yield. This trend could reflect long- term changes in land use and agricultural practices within the Kura watershed. No information is

Page 18 of 26 available on possible changes in the sampling methodology which could have contributed to this apparent trend. Data from the Alazani River are also plotted for a shorter time period in Figure 24, but no trend is evident.

6.7. Reservoir Half-Life

Reservoir half-life, the time required for half of the reservoir volume to be lost to sedimentation, is computed for three reservoirs by the method described here. There were insufficient data to estimate the rate of storage loss at the small Varvara Reservoir downstream of Mingechevir Reservoir.

Storage loss was computed on an annual basis by applying the Brune curve to each of the three reservoirs to estimate annual sediment trap efficiency. Inflowing sediment was assumed to be constant as presented in Table 10. Shamkir and Enikend Reservoirs were assigned the same sediment yield as they are located very close to one another. The results of the computations are summarized in Figure 24 and Figure 25. To summarize, the three reservoirs evaluated are expected to have lost half of their total capacity in the years given below: Shamkir 2100 Enikend 2107 Mingechevir 2500

Based on the available data and analysis, both Shamkir and Enikend Reservoirs will begin to encounter potentially serious sedimentation problems approximately 100 years in the future, and both will be fully sedimented around year 2200. At that time the sedimentation rate at Mingechevir will increase substantially, because Shamkir Reservoir will no longer be acting as an efficient sediment trap. Mingechevir Reservoir will be 50 per cent sedimented around year 2500.

Page 19 of 26 7. APPENDICES

Appendix A...... List of Figures

Appendix B...... Sediment Discharge at Hydrological Stations in Georgia

Appendix C...... Drainage Area of the Tributaries to the Mingechevir Reservoir

Appendix D...... Abbreviations

Appendix E ...... References

Page 20 of 26 APPENDIX A LIST OF FIGURES

Figure 1: Location of the Kura River Basin.

Figure 2: The Kura River reservoirs in Azerbaijan.

Figure 3: Satellite image of the Kura River reservoirs.

Figure 4: Mean monthly rainfall at three stations upstream of the Mingechevir Reservoir

Figure 5: Daily rainfall for one year at the Bolnisi Meteorological Station.

Figure 6: Long-term annual rainfall data from Akhaltsikhe, Georgia.

Figure 7: M assive gullying at elevations between about 1,500 and 1,900 m along the Aragvi River between Mleta and Gudauri, Georgia. Figure 8: Gully ing immediately downstream of a culvert, where flow has become concentrated. near Algeti, Georgia south of Rustavi. Figure 9: Sediment yields from gauge stations within the Kura River Basin in Georgia upstream of Mingechevir Reservoir. Figure 10: View looking upstream along Kischay River at Saki, Azerbaijan at a tributary to the Ayrichay River which discharges to the Alizani River above Mingechevir Reservoir. Figure 11: View looking upstream along a tributary to Ayrichay River in Azerbaijan showing massive recent bank erosion. Figure 12: Use of long downslope furrows instead of ploughing for soil conservation, enhanced moisture retention, and erosion control. Figure 13: Salinity-impaired soils within the irrigation area of Mingechevir Reservoir in Azerbaijan.

Figure 14: Ten years of monthly discharge data for Kura and Alazani Rivers showing the high degree of seasonality in their flows. Figure 15: Average annual water levels in Mingechevir Reservoir on the Baltic datum.

Figure 16: Original (1953) elevation-volume curve for Mingechevir Reservoir.

Figure 17: Daily streamflow data above and below the reservoirs on the Kura River showing the impact of reservoirs on streamflow. Figure 18: Discharge along Kura River at Yevlakh Station below Mingechevir dam showing a decline of river flow below the dam in recent years. Figure 19: Reported annual deliveries to irrigation canals from Mingechevir Reservoir showing recent increase in irrigation deliveries to the canals. Figure 20: Generalized behavior of turbid density current in a reservoir.

Figure 21: Brune curve for estimating the sediment trap ping efficiency of normally impounded reservoirs based on capacity:inflow ratio. Figure 22: Annual storage loss at Mingechevir Reservoir prior to construction of Shamkir and Enikend Reservoirs upstream. Figure 23: Sediment yield from gauge stations in Kura River Basin, Georgia.

Figure 24: Variation in annual rate of storage loss computed for the three Kura River reservoirs in Azerbaijan. Figure 25: Projected storage loss for the three reservoirs on Kura River in Azerbaijan without any sediment control measures

DMingechevirReportAppendices APPENDIX B

Sediment Discharge at Hydrological Stations in Georgia 1986 1987 1988 1989 1990 Sta. Mean Flow Sed. Load Mean Sed. Load Mean Sed. Load Mean Sed. Load Mean Sed. Load No. Station Name (m3/s) (103 t) Flow (103 t) Flow (103 t) Flow (103 t) Flow (103 t) (m3/s) (m3/s) (m3/s) (m3/s)

41 Mtkvari (Kura)-Khertvisi 31.0 44 46.2 570 44.5 60 28.3 24 34.4 110 42 Mtkvari (Kura)-Minadze 55.0 60 80.7 1000 86.1 350 55.2 50 66.7 66 43 Mtkvari (Kura)-Likani 80.0 950 144 2700 140 660 89.5 140 101 180 44 Mtkvari (Kuera)-Grakali 110 310 199 4400 200 3100 134 1500 155 2300 45 Mtkvari (Kura)-Tbilisi 154 2900 290 7900 259 9800 189 4100 190 2300 47 Paravani-Khertvisi 17.1 10 23.5 220 21.9 38 13.4 9.1 19.0 27 48 Portskhovistskali-Skhvilisi 22.0 440 28.0 980 39.2 850 34.7 140 30.4 210 51 Mejuda-Gori 6.77 95 10.3 1000 11.5 510 8.15 160 7.76 85 52 Ksani-Korinta 8.11 69 12.4 190 10.5 110 7.09 60 8.07 63 54 Tetri Aragvi-Pasanauri 10.5 200 15.3 1400 14.6 380 13.9 130 11.6 54 55 Shavi Aragvi-Shesartavtan 6.71 41 12.4 280 10.5 220 7.34 69 8.59 47 56 Pshavi Aragvi-Magaroskari 18.4 220 29.8 600 22.9 410 18.5 220 22.6 350 57 Ktsia-Khrami-Edikilisa 8.62 38 10.6 63 13.4 44 7.57 6.0 10.3 35 59 Ktsia-Khrami-Tciteli Khidi 52.5 180 40.5 60 104 270 48.0 47 51.0 41 63 Iori-Lelovani 8.68 49 14.4 170 14.3 150 8.69 47 11.1 35 64 Alazani-Birkiani 9.69 32 14.2 110 12.5 200 9.53 9.8 15.3 54 66 Alazani-Chiaura 50.0 570 67.3 1000 75.5 1100 35.6 120 83.9 1100 68 Stori-Lechuri 6.69 41 9.18 54 9.02 98 6.23 35 8.68 30 69 Intsoba-Sabue 1.63 3.5 2.19 32 2.09 12 0.88 2.3 2.25 10 Note: 1) Data provided by the State Department of Hydrometeorology of Georgia on October 9, 2002. APPENDIX C

Drainage Area of the Tributaries to the Mingechevir Reservoir No. Name of the Station River Basin Drainage area Elevation (sq km) (meters) 41 Mtkvari (Kura)-Khertvisi Mtkvari 4,980 1,123 42 Mtkvari (Kura)-Minadze Mtkvari 8,010 941 43 Mtkvari (Kura)-Likani Mtkvari 10,500 793 44 Mtkvari (Kuera)-Grakali Mtkvari 16,700 555 45 Mtkvari (Kura)-Tbilisi Mtkvari 21,100 390 47 Paravani-Khertvisi Mtkvari 2,350 1,121 48 Portskhovistskali-Skhvilisi Mtkvari 1,730 965 51 Mejuda-Gori Mtkvari 650 591 52 Ksani-Korinta Mtkvari 461 908 54 Tetri Aragvi-Pasanauri Aragvi 335 1,047 55 Shavi Aragvi-Shesartavtan Aragvi 235 1,069 56 Pshavi Aragvi-Magaroskari Aragvi 736 920 57 Ktsia-Khrami-Edikilisa Mtkvari 544 1,516 59 Ktsia-Khrami-Tciteli Khidi Mtkvari 8,260 263 63 Iori-Lelovani Mingechevir Reservoir 494 1,065 64 Alazani-Birkiani Mingechevir Reservoir 282 758 66 Alazani-Chiaura Mingechevir Reservoir 4,530 201 68 Stori-Lechuri Alazani 203 543 69 Intsoba-Sabue Alazani 41.4 613 Notes: 1) The elevation is based on the Baltic System. 2) Data provided by the State Department of Hydrometeorology of Georgia on October 9, 2002 APPENDIX D

Abbreviations

BOD5 5-day biochemical oxygen demand C degrees Celsius cm centimeter (10-2 m) g gram km kilometer (103 m) L liter m meter M million or “mega” (106) mg milligram (10-3 g) Mm3 million cubic meters mm millimeter (10-3 m) Mm3/yr million cubic meters per year Mt/yr million metric tons per year MW mega watt

O2 oxygen s second t metric ton (1,000 kg = 106 g) TDS Total Dissolved Solids W Watt yr year % percent (parts per hundred)

APPENDIX E

References

Caspian Environmental Programme. December 1999. “Caspian Sea Monthly Water Balance Studies.” Caspian Center for Water Level Fluctuations. Almaty. Caspian Ecological Programme. 1998. “National Report for Caspian Environmental Programme: Azerbaijan.” Baku. The Cousteau Society. 1998. “The Caspian Sea: Expedition Report May -August 1998.” UNSECO. Mammadov, Magbet. 2002. “Information on the Mingechevir Reservoir Sedimentation Conditions.” Report prepared for DAI/USAID, Baku, Azerbaijan. Wetzel, Robert G. 1983. Limnology. Saunders College Publishing, New York.

14 Paliashvili Street, Tblisi 380079 Georgia AUA Center Building; 9 Alex Manukian Street, Suite 207; Yerevan 375070 Armenia Caspian Business Center; 40 Jafar Jabbari Street, Suite 604; Baku 370000 Azerbaijan ______

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