NGJI, An International Peer-Reviewed Journal NGSI-BHU, ISSN: 0027-9374/2020/1733 Vol. 66, No. 2, June 2020

Environmental Risk Assessment: A Geomorphic Investigation over the -Santiniketan-Illambazar Lateritic Patch of , , India

Vibhash C. Jha1 and Subhasis Ghosh2 1Professor of Geography, Former Vice-Chancellor, TMBU, Former Director NATMO, DST, Government of India, Visva-Bharati University, Santiniketan, West Bengal, 2Research Scholar, Department of Geography, Visva-Bharati University, Santiniketan, West Bengal, (Corresponding author's e-mail: [email protected])

Abstract A proper geomorphic study of a region can be useful in understanding past and present environmental circumstances and analyzing potential environmental risks. Careful analysis of morphodynamic processes and existing diagnostic landforms reveal several aspects about the origin, characteristics and possible pattern of morpho-climatic interactions on the landscape over temporal scale, which helps significantly in proper terrain evaluation from societal welfare and integrated management point of view, including environmental risk assessment and disaster management. This paper has made a thorough geomorphic investigation based on intensive fieldwork and multi-sourced remote sensing data to characterize the lateritic soil profile and landforms of the study area in respect to their morphology and Physico-chemical properties at the different sites of land degradation to understand the outcome of morphoclimatic interactions on the landscape over time, and to evaluate the severity of operation with pedo-geomorphic constraints in the lateritic environment for sustainable management purposes. It is found that the region is highly sensitive to weathering, mass movement and denudational activities, mainly caused by rainwater erosion which has resulted into varied landforms including well-developed rills and gullies, lateritic ridges, isolated residual hills etc and generated a unique identity to this part of the lateritic region. The study also suggested a model for the development of geomorphic landforms in a lateritic terrain based on past and present morphoclimatic interactions, nature of physiography, lithology, soil characteristics and other biotic and abiotic elements. The region is also found to be a subject to moderate to severe land degradation due to the active geomorphic processes in operation in tropical regions and inherently poor physical and chemical formation of the existing soil profile and radical conversion of land uses as observed at cadastral level leading towards irresistible desertification. Annual topsoil loss amount has been calculated using the Universal Soil Loss Equation method. Three sample Mouzas namely Ballavpur, Shyambati and Chawpahari jungle have been assessed to be having 36.98%, 71.42% and 61.73% of degraded land in respect to their total village area. Various conservative measures like stabilization of gully heads and beds through reforestation and afforestation with cutting earth plug, brush fills and check dams; improvement of the irrigation network, suitable dryland farming etc. have been recommended to arrest the desertification process. Environmental Risk Assessment: A Geomorphic Investigation ... 95 Keywords: Land degradation, desertification, environmental management, lateritic terrain, morphoclimatic interaction, environmental risk Introduction

The rapidly evolving discipline of limited to the planet earth, but it also takes a geomorphology has undergone a sea change in close look at the images of Moon, Mars and methodology and approaches to the study of other planets provided by spacecraft has landforms and related processes since 1945 created an extraterrestrial aspect to when R. E Horton introduced a quantitative geomorphology. The main aspects i.e. Static method for the analysis of morphometric Geomorphology, Dynamic Geomorphology, characteristics of a fluvial eroded landscape. Genetic Geomorphology and Environmental Although the subject matter of geomorphology Geomorphology can be studied in terms of is often commonly restricted to those Spatio-temporal concepts to understand the landforms that have developed at or above sea factors and independent variables responsible level, in reality, it includes all the aspects of the for landscape modifications and the cycle of interface between the solid earth, the process-form mechanisms existing in a region hydrosphere and the atmosphere, therefore not (Verstappen,1983). With alteration in scale only are the landforms of the continents and different problems can be identified, different their margins are of concern, but also the types of explanations become relevant and morphology of the seafloor. Today though, the dominant variables can be identified for proper scope of the subject has witnessed a gradual terrain evaluation purposes or to understand the change with the advancement of technology. morphodynamics of a certain region (Figure 1). Today the scope of the subject is not only The landform is a crucial part of the

Figure 1 - Different Aspects of Geomorphology 96 Vibhash C. Jha and Subhasis Ghosh environment and has a direct relationship with Several studies have been carried out the environmental conditions. These are not previously by different investigators regarding created instantaneously. The smallest, such as a the concepts of the origin of Indian laterites ripple mark may develop in a few minutes, but over time as discussed by Roychowdhury et al. large landforms of continental dimensions or (1965), Bhattacharya and Banerjee (1979) who even large units of continents such as mountain discussed about the regional geology and chains or extensive plains have a history of tens geomorphology of Birbhum district; or hundreds of millions of years. Geomorphic Bandopadhyay (1987) regarding the slope processes leave their distinctive imprints upon evolution and cliff-line retreat rates of the landforms and each geomorphic process western and south-western parts of Birbhum; develops its own characteristic assemblage of Das and Bandopadhyay (1996) who strictly landforms as different erosional agencies act on analyzed the process of badland development the earth's surface, thereby producing a in the lateritic region of Santiniketan, West sequence of landforms having distinctive Bengal from the physical or geomorphic point physical and chemical characteristics at the of view; Jha (1997), Jha and Kapat (2009, successive stages of their development. It is a 2011)who extensively worked on the origin fact that different processes work in different and properties of the lateritic patches of climatic regions and with climatic variations, Birbhum district, determination of risk of rill there is also variability in the nature and mode and gully erosion hazards in terms of their kind, of influences of climatic parameters (e.g. extent and degree as manifested in morphology rainfall, temperature, humidity etc.) which and morphometric characteristic of affect denudation processes such as erosion, geomorphic features in hydrogeomorphic units weathering, mass movement, run-off etc. and land-use practices within lateritic Hence, landforms also differ significantly in confinement of the basins. Besides these, many different climatic regions. These typical other pieces of research on land degradation in diagnostic landforms are one of the main tools respect to geomorphic processes, change in of climatic geomorphologists which help them land use have been conducted as done by in determining climate-landform relationships Ghosh and Bhattacharya (2012), Ghosh and in different climatic regions. Morphoclimatic Guchhait (2015), Das (2015) and others. The mechanisms in particular significantly change present study is aimed to examine the above the landscape in terms of spatial and temporal concept by investigating and characterizing the scales. The denudational processes are very lateritic soil profile and landforms of a part of crucial in this very effective regard, Birbhum district of West Bengal State, India in particularly in the tropical and subtropical respect to their morphology and Physico- regions where the landforms characteristics are chemical properties in different sites of land the best indicator in studying the rate of degradation to understand the morphoclimatic denudation. Hence, it is considered that a effect on the landscape over the years, and to proper geomorphic study of the area of interest evaluate the severity with pedo-geomorphic (AOI) may significantly help experts in constraints at the lateritic environment for understanding the past and present better crisis management. environmental status, reasons behind the Study area evolution of present landscape and finding out The Birbhum district (23° 36'N to 24° 4' any potential environmental risk it might have. 40''N, 87° 25' 30''E to 87° 39' 26'' E) lies Environmental Risk Assessment: A Geomorphic Investigation ... 97 between the western upland and the eastern pedo-geomorphic characteristics of the alluvium plain (Jha and Kapat, 2011). This degraded lateritic region. Though the Birbhum region is a part of the , which is also district is characterized by three types of known as 'Self of Lateritic Alluvium'. Three geomorphic processes, namely denudational, sample morphosites, i.e. Ballavpur and fluvial and anthropogenic mechanisms, Shyambati mouzas in Bolpur- C.D however, the sample morphosis is the result of Block, and Chowpahari Jungle situated in denudational morphoclimatic mechanisms. Illambazar C.D Block have been taken into This has resulted in the development of major consideration for collecting soil samples, and minor geomorphic features as well as Karst profiling purposes and to evaluate village level type geomorphic features (Figure 2).

Figure 2: Location and Geomorphology of the study area based on multi-temporal (monsoon, post-monsoon, pre- monsoon) satellite data of 2016 from Resourcesat-2 LISS III 98 Vibhash C. Jha and Subhasis Ghosh Data sources and methodology prepared by NRSC and downloaded from The present study has been conducted Bhuvan portal of ISRO ( https://bhuvan- mainly based on intensive fieldwork and multi- app3.nrsc.gov.in/data/download/index.php) source remote sensing data. Toposheet has been used. (73M/10) on the scale of 1:50,000 published by Results and discussion the Survey of India in 1928 and 1972; satellite Physico-Chemical Morphodynamics imageries of Resourcesat-2, LISS-III(24m) of Pieces of evidence present in the field monsoon, post-monsoon, pre-monsoon suggest that the study area is highly influenced seasons of the year2016(DOP- 14th October by weathering, mass movement, rill and gully 2016, 15 t h April 2016, 10 t h January erosion, slumping, creeping, subsidence or 2016)obtained from Bhuvan portal of ISRO lowering of relief and wind action. The (https://bhuvan-app3.nrsc.gov.in/data/ presence of laterite plays an important role in download/index.php); cadastral maps on the the evolution of geomorphic features. It scale of 1 inch to 16 miles along with field data appears that primary laterites, originally on widening trend of gullies, extent and type of formed in Santhal Parganas, were eroded and degraded land use - land cover under different re-deposited in the adjoining areas of the geomorphic characteristics; and rainfall- Birbhum District, probably in Pliocene and temperature data of 1995-2005 collected from P l e i s t o c e n e t i m e s . S u b s e q u e n t l y, Sriniketan weather station have been used for reconsolidation of the deposited lateritic the analysis. Soil profiles of three degraded material has resulted in the development of sample sites have also been studied and their only a partly mature profile. The various horizons have been differentiated based on horizons of this profile, namely pisolitic, their colour (moist), structure, texture, and iron massive, concretionary, columnar and pallid concentration. Collected soil samples from zone with kaolinitic material at the base are still these sites have been analyzed in the laboratory imperfectly developed and show a lot of to find out particle size, pH value, and organic disturbances. carbon-based saturation. USLE or Universal Based on the intensity of active Soil Loss Equation (Wischmeir, Smith, 1978) geomorphic processes, the following types of has been applied to calculate annual topsoil loss laterites are found in various stages of their based on Fournier index, the particle size of development or decay occurs in the study area. lateritic samples, guidelines of Central Soil (i) Pisolitic laterite: This type of laterite Conservation and Training Institute for occurs above massive laterite zone. It calculating the value of CP factor and other forms the surface of the highest ridges field data. The formula used for Universal Soil near Ratanpalli, Shyambati, and Loss Equation is as follows - Sriniketan area. This layer is 4.5 m to 8 A= RKLSCP m thick in Bolpur police station. The Where A= Average Annual Soil Loss; R= removal of pisolitics from the highest Rainfall Erosivity; K= Soil Erodibility; LS= part of the laterite plateaus and ridges Slope and Topography; CP= Existing Cropping is still going on under the processes of and Conservation Practices. sheet flow and sheet wash along with For elevation information, Cartosat-1 the spring and gully heads. PAN(2.5m) Stereo Data (CartoDEM- Version 3 (ii) Massive Laterites: With a thin pisolitic R1, Tile name F45D, dated 29/04/2015) layer at the top occupies the highest Environmental Risk Assessment: A Geomorphic Investigation ... 99 part of the lateritic plateaus. The It is observed that the lateritic soil profiles massive lateritic surface is found near as developed under prolonged leaching, are Sriniketan and Ratanpalli side. Breaks typically suffering from constraints of acidity, in slope in lateritic plateaus have been plenty of sesquioxides, low base saturation, noted 6 km north of Ratanpalli where deficiency of organic matters and high rate of the top surface belongs to massive water erosion. Laterite profiles are having lateritic and pisolitic and nodular varying ranges of brown colours. Texture in A laterites. horizon and the upper B horizon is coarse and (iii) C o n c r e t i o n a r y L a t e r i t e : T h e ranges between loamy sand to sandy loam with concretionary laterite develops below contents of sand between 61.19% to 85.7%, silt the massive laterite. It is exposed in the less than 10% and clay properties less than walls of gullies and springs at 10%. The lower B horizons consist huge Ballavpur. Its occurrence has been also amount of iron concretion with diameter ranges noted in places where the pisolitic and from 1 mm – 10mm, particularly at the depth of massive laterite horizons have been 40 cm – 90 cm, and more than 30% clay either removed by erosion or indicating illuviation of clay. The soil structure weathered to form nodules of various ranges from granular to apedal at the surface sizes. area and in the upper B horizons, nearly (iv) Columnar Laterite: Stalactite like structureless to subangular in B22 zone and columnar masses of laterite has been massive in the lower B horizon. Soils here are observed in vertical headwalls of found to be ranging from acidic to strongly springs. This structure seems to have acidic as evidenced by the average PH value been formed due to rapid movement of ranges between 4.12 – 5.2. Besides, a very low percolating water on the very steep magnitude of electrical conductivity indicates slopes of gully heads. no problem related to salinity. The average base (v) Reconsolidated Laterite: Occurrence saturation is found to be mostly less than 40%, of this type of laterite of Pleistocene- except in Ballavpur mouza most probably Pliocene times is noted near Ballavpur because of the existence of wetland and South lateritic patch. Thick masses of Kopai main canal (Figure 3). primary laterites removed from A chemistry testing of sample ferric

Rajmahal trap have been re-deposited laterites also shows presence of Fe3O2 ranges

in this area and developed a peculiar between 36.26% - 44.4%, SiO2 16.66% -

gully with micromorphological 17.27%, TiO2 2.90% - 7.80%, Al2O3 21.6% -

variations in the materials of the gully 33.28% and H2O 4.46% - 12.60% (Figure 4).

beds and gully valley walls. Fe3O2 Iron Oxides result from the alteration of (vi) Recent and Pleistocene Laterites: other iron minerals from a highly ferruginous Groundwater laterite in the juvenile rock there may be formed by its degradation stage of development is observed in weathered residual deposits, consisting largely laterite sheet wash re-deposited in the of ferric hydroxide mixed with clay and other Taltore wide flats and moderately well- impurities. These iron caps are common over drained parts of the wide flat bottom the outcrops of iron oxides deposits forming valleys in Amar Kutir and Surul areas the lateritic surfaces with high contents of iron of the Bolpur P.S. ores. By weathering, the oxides aggregate 100 Vibhash C. Jha and Subhasis Ghosh

Figure 3: Physical and Chemical Properties of different horizons of sample lateritic profiles at (a) Ballavpur, (b) Shyambati, (c) Chowpahari Jungle, Illambazar Source: Field data, 2018 together as nodules and layers in the residual a deeper level while the concentration clay which forms on the outcrop of the /accumulation of ferrous oxides at or near the weathered rock. It is also observed that the surfaces in the lateritic patches of the leaching of silicates is taking place in the area at Iilambazar and the Bolpur Police Stations.

Figure 4: Chemistry of some ferric laterites of the study area in percentage Source: Field data, 2018 Environmental Risk Assessment: A Geomorphic Investigation ... 101 Occurrences of two water tables (Perched denudational processes in the area have been and Permanent) contributed significantly in the operating by weathering, mass movement and operation of the denudational mechanisms and erosional processes at varied spatial and the development of resultant geomorphic temporal scales which have been lowering the features. The other processes such as strength, eroding the surface materials and infiltration, leaching and percolation also play a ultimately breaking the lateritic plateau. The vital role in denuding the region. The original role of the base level of the two trunk rivers in Surface of the Birbhum Lateritic Plateau forms breaking the initial surface in this part of the the erosion surface at a 60m-68m elevation study area is very significant in this above mean sea level. The topographical sheet denudational processes. published by the Survey of India in 1928 Stages in the break-up and retreat of the depicts that throughout the study-area this consolidated laterite of Ballavpur laterite plateau exists at this height, while the The Occurrences of two water tables in this base level of rivers in this region was between area, one situated above the massive laterite 40m-42m. The latest topographical sheet and the other above the kaolinitic horizon at the published by the survey of India in 1972 shows base of the pallid zone, has been noted. The the plateau height at 58m-65m and the river former is seasonal and later is permanent. The beds between 39.5m-41m. Based on field process of spring shaping, guided by the observation and GPS Survey in 2018 it is also permanent water table has led to break up of the noted that the upland level is between 38m- lateritic plateaus and subsequent development 19.5m particularly in the southwestern part of of wide flat bottom valleys (Figure 5). The the Birbhum District where the two trunk formation of the gully is accelerated by streams, the Ajai and the Kopai rivers play a denudational processes. vital role in denuding the region. The

Figure 5: Stages in the break-up and retreat of the consolidated laterite of Ballavpur (after Jha, 2003) 102 Vibhash C. Jha and Subhasis Ghosh Cross Profile Analysis relief and development of particular lateritic The cross profile details of the channel landforms (major and minor). The Bolpur widening and deepening for two decades have patch on the other hand is characterized by a been surveyed in 1986, 1996, 2003 and 2019. lower relief than that of Illambazar. It indicates The gully width is found to be changing at a that rate of denudational processes is higher in more or less constant rate (Table 1). The main Bolpur area due to the lateritic surface and the gully forms a super-wide to wide 'V' shaped base level of Kopai and Ajai rivers near the valley while the gully developed on the main plateau, while in the case of Illambazar the gully left bank reveals the narrow 'V' shaped to base level of Ajairiver is nearer but the Kopai 'I' shaped (gorge type) valleys (Figure 6). It has base level is quite away from the Illambazar also been noted that several rills and gullies of lateritic plateau. It may also be noted that the different shapes, sizes and depths have formed anthropogenic processes are more active in the on the flat-topped massive laterite surfaces in Bolpur patch (having urban concentration) the area within two decades. The initial laterite than the Illambazar patch (Rural background). surface has been broken up and resulted in the Diagnostic Landforms and their indications development of characteristic laterite The initial surface is characterized by the geomorphic features. The processes of flat-topped hard surface which is being broken subsidence and slumping are very much in up by the development of rills and gullies of evidence in the lateritic terrain. Two lateritic various types such as Pointed Gully Head, patches are very important in the study area for Circular Gully Head, Notched Gully Head, denudational processes. These are Illambazar Digitate Gully Head etc. The longitudinal patch and Bolpur patch. Since 1926-27, these profiles of the gully, however, show the two patches have experienced lowering of the existence of Caves, Vertical Walls, Armchair

Table 1: Shape, Size and Depth of Gullies in the Ballavpur Lateritic Patch in 1986, 1996, 2003 and 2019

Source: Field Survey Environmental Risk Assessment: A Geomorphic Investigation ... 103

Figure 6: Landscape Profiles of a part of lateritic terrain in P.S Bolpur (After Jha, 2003) heads, and inclined heads. The caves plateau (dissected by natural as well as man- particularly play a vital role in denuding the induced processes), karst type window, surface where the slumping and the subsidence stalagmite or stumps like landform, sinkholes, materials are washed out by the stream (Figure blind valleys, small waterfall features at the 6). The development of rills and gullies is gully interiors and plunge pool, rounded small initiated by the intensity of processes of vertical elevated isolated residual hills in a bunch (like a and head-ward erosion in the area. The shape basket of eggs), isolated hillocks, Interlocking and size of the gully depend upon the rate of Spur etc indicates the high intensity of morpho- downward and head-ward denudational climatic mechanisms operating over the study- processes. These processes have led to the area (Plate I). development of 'V' and 'I' shaped gullies in The intensity of rain wash action and soil Ballavpur laterite patch. The existence of creeping processes is being supported by the various diagnostic landforms such as rills and high rate of weathering in the area probably well-developed gullies, mesa and butte, since Pleistocene times. Differential Erosion is lateritic ridges affected by denudational also one of the main mechanisms which have processes of spring sapping, gullying and slope been operating in the study-area resulting in wash; Flat-topped lateritic plateau capped by such typical lateritic geomorphic features. massive lateritic terrain, valleys, dissected Eleven years (1995-2005) of rainfall- 104 Vibhash C. Jha and Subhasis Ghosh

Plate I: Some important denudational geomorphic features in the lateritic terrain temperature data also shows characteristics of significant role behind the formation of this typical semi-arid and sub-humid climatic topography. All of these observations suggest condition (average rainfall- 130.54mm, an ideal model of landform formation in a average temperature- 26.23°C) with adequate lateritic terrain induced by past and present rainfall mostly throughout the year, which morphoclimatic interactions, based on the played a very crucial role in the formation of nature of existing lithology, physiography and available landforms. Field pieces of evidence geo-materials (physical and chemical soil indicate that the slope morphology of ridges properties) and intensity of the active and rounded shaped low elevated isolated hills geomorphic processes on a regional level, in the study area is the result of weathering, rain accelerated by other biotic and abiotic elements wash action and soil creeping denudational (Figure 7). processes. It is seen that at the initial stage, the The extraction of top surface materials retreat of hill slope angle is clear and ultimately particularly from the ridges, isolated hills and the region is characterized by the wide flat- flat-bottom valleys has been taking place in the bottom surfaces. This ultimate product, the area mainly through man-induced activity. This wide flat-bottom valley is characterized by a has accelerated the denudational processes in thin layer of deposition of sands and silt. the study area. Other biotic mechanisms are Though not only the geomorphic processes but also active in the study-area resulting in the the influence of biotic elements also played a development of termite mounds, earthworm Environmental Risk Assessment: A Geomorphic Investigation ... 105

Figure 7: Model for landform evolution in the lateritic terrain mound and deforestation by man, while Pedo-Geomorphic Characteristics, Land termites quite often destroy the young Degradation, Desertification, Land Cover seedlings. The presence of quartz pebbles and and Land Use cobbles on the original surface, and later on · Ballavpur Mouza: This region is disintegrated and spread throughout the wide found to be having a total of 3.58 Sq. flat-bottom valley in the area has increased the km area with laterite exposure percentage of sandy terrain in the region. All (61.30% of its total area), out of which these observations suggest that a strong 60.31% per cent is degraded desertification process is active in this region manifested as 7.26% of degraded (Plate II). agricultural land, 23.74% of highly If the rate of denudational processes affected rill and gully induced forested and deforestation by men and termites badland, 2.79 % scrubland, 5.30% of continue in the area, the landscape degraded forest area (Reserve Forest), dynamics will certainly change both in the 7.82 % barren terrain induced by spatial and temporal scale ultimately mainly rill and sheet erosion with low affecting the landscape in this part of the relief deformity and 6.70% of badland world. with settlement cover. 106 Vibhash C. Jha and Subhasis Ghosh

Plate II: Development of sandy terrain accelerating land degradation and desertification

· Shyambati Mouza:17.85% or nearly induced erodibility in this region. 0.20 square km of its total lateritic Seven types of degraded land use/land soils cape, which happens to be widely cover of varying extent and severity have been deformed lateritic badland, is now identified over the sample regions which converted into the built-up area. indicate the significant occurrence of inherent Though, about 71.42% area of this and anthropogenic soil or land degradation in mouza is still showing characteristics the lateritic environment (Table 2). of landscape ecology as enhanced by Water Erosion is the major geomorphic the poor physical and chemical status constraint in the lateritic enclosure as profound of highly erodible laterites and urban in all the sites, but the worst impact of gullying sprawling. is remarkable in the intensely deformed · Chowpahari Jungle Mouza: As the lateritic badland in Ballavpur area with strong name indicates, it this region has a topsoil loss (30.72 t/he), well-developed rills large area of forest dominated lateritic and gullies, and severe to very severe land exposure which covers nearly 14.70 degradation status which ultimately resulted in Square Km or 84.57%, out of which pisolite-pebble-gravel assorted laterite horizon 73.99% area is found as degraded badly exposed all over the region. ones. Presence of widespread rills and Chowpahari Jungle, on the other hand, gullied terrain indicates higher water- does not show signs of having well-developed Environmental Risk Assessment: A Geomorphic Investigation ... 107 Table 2: Degraded Land cover/land use classification and their areal extension at cadastral level

gullies, relief deformations or badland chemical status and fresh growth of ramified formation although the region has higher new drainage network. topsoil loss rate (27.14 t/he). This happens Lateritic exposures of the study area are probably because of the dominance of the found to be undergoing moderate to severe forested landscape over the region. It is found degradation status. Otherwise, all villages are that 59.49% of the total village area of dominated by the least degradation. Severe to Chowpahari (roughly 10.34 Square km area) is very severe degradation prevail in 1.9 Square affected by rill and gully erosion. On the km or 32.53% of land in Ballavpur mouza, 0.62 contrary, Shyambati is found to be lying Square km or nearly 55.35 % in Shyambati area entirely on the badly deformed and degraded and 10.34 Square km or 59.49% in badland. The area affected by varying severity Chowpahari Jungle area particularly related to of degradation and pedo-geomorphic rill-gully erosion induced badland in reserve constraints in respect to average annual Top forest or moderate relief deformity in the Soil Loss (TSL), Terrain Deformations (TD) protected forest; barren lateritic or rocky and type of degrading land-uses in lateritic terrain with a least and moderate deformity in surroundings (cadastral level) has been local mining sites of lateritic wastes. described in detail in Table 3. Encroachment towards agricultural land is also The Shyambati mouza has now mostly detected in the study region. Figure 8 shows been converted into the residential area. Many comparative statistics of the area affected by hotels, homestays, restaurants have been different types of degradation in the sample spotted in this region (because of the nearness mouzas / villages. to Santiniketan, an international tourist Conclusion destination) obliterating old ephemeral This type of study is also the need of the drainage network, adversely modifying present time to create a digital database for degraded soil profile of poor physical and addressing the issues and their solutions 108 Vibhash C. Jha and Subhasis Ghosh Table 3: Severity of degradation in sample mouzas / villages

Figure 8: Percentage of the area affected by different types of degradation Environmental Risk Assessment: A Geomorphic Investigation ... 109 relating to sustainable development goals. It is Quaternary Geology and Geomorphology evident that the above investigation for the of the Ajoy-Bhagirathi Valley, Birbhum whole region witnesses serious problems of and Murshidabad District, West Bengal, land degradation and desertification, which is India, J. Earth Sci.,6(1), pp. 91-102. the function of both physical and socio- Braimoh Ademola, K, Paul Vlek, L.G., 2008, economic influences. It has also accelerated the desertification processes resulting in larger Land Use and Soil Resources, Springer. sandy terrain in the study area. Though the Dabral, Prasad, Parmendra, Baithuri, study suggests that the degradation of existing Neelakshi, Pandey, Ashish, 2008, Soil lateritic soilscape might seem irresistible, still erosion Assessment in Hilly Catchment of protective measures could be taken to North East India using USLE, GIS and minimize the rate of degradation and overall Remote Sensing, Water Resources adverse effects caused by it. Various Management, Vol. 22, No. 12, p. 1783- conservation measures have already been taken 1798. up by the government and local people overtime for which the rate of degradation is Das, K, Bandyopadhyay, S, 1996, Badland found to be minimized to some extent, but a Development in a Lateritic Terrain, substantial gap has been noticed between the National Geographer, Vol-XXXI, Nos. two participants. The priority-based action plan 1&2, PP-87-103. needs to be prepared and three major Das, R.K, 2015, Laterite and landscape approaches – vegetative, engineering and a development in Ballabpur-4, Bolpur- combination of two should be adopted Sriniketan block, Birbhum district, West- accordingly to control water erosion and to Bengal, Golden Research Thoughts, Vol.5, stabilize gully heads and beds. Stabilization of M r s L a x m i A s h o k Ya k k a l d e v i , gullies can be done by afforestation, Maharashtra. constructing earth plug, brush fills and checks dams. Irrigation network is also to be improved Grau, H, Aide, Mitchel, 2008, Globalization to increase the agricultural intensity as and land-use transition in Latin America encroachment of degradation towards adjacent ecology and society, Ecology and Society, agricultural fields has been duly noted. Land Vol. 13, No. 2. use planning on micro watershed basis along Jha V C, 2003, Land Degradation and with dryland farming which will be suitable in Desertification, Rawat Publication, Jaipur such a degraded area and is also recommended. and New Delhi, p. 405. References Jha, V C, Kapat, S, 2009, Rill and gully erosion Ajai, Arya, A.S, Dhinwa, P.S, Pathan, S.K, risk of laterite terrain in south western Ganesh Raj, K, 1990, Desertification and Birbhum district, West Bengal, India, Land Degradation Status Mapping in Sociedade & Natureza, Uberlândia, Vol. India, Current Science, Vol. 97, No. 10: 25, 21 No. 2, pp.141-158. pp. 1478-1483. Jha, V C, 2005, Denudational processes and Banerjee, P. K, 1998, Basic Research On landform characteristics in the laterites of Laterites in Tropical Countries, Birbhum district, West Bengal, India, Q u a t e r n a r y I n t e r n a t i o n a l , Transactions, Journal of the Institute of Revitalization concepts in Paleopedology, Indian Geographers, Vol.27, pp.19-29. Vol. 51-52, P. 69 – 72. Jha V C, Kapat, S, 2011, Degraded lateritic Bhattacharya, A, and Banerjee, S.N, 1979, soils cape and land uses in Birbhum 110 Vibhash C. Jha and Subhasis Ghosh district, West Bengal, India, Sociedade & Singh, Savindra, 2005, Geomorphology, Natureza,Uberlândia, Vol.23, No.3. Prayag Pustak Bhawan, Allahabad, India. Mcfarlane, M. J, 1986, Geomorphological Singh, S, Dubey, 2002, Gully erosion and analysis of laterites and its role in management, methods and applications (A prospecting geological survey of India. field Manual), New Academic Publishers, Memoirs Lateralization Processes, Vol. Delhi, pp.229-237. 120, pp. 41-50. Valentin, C, Poesen, J, Li, Yong, 2005, Gully Ollier, Cliff, Seth, Hetu, 2008, The high Erosion: Impacts, Factors and Control, Deccan duricrusts of India and their Catena, Vol. 63, pp. 132-153. significance for the laterite issue, Journal Ve r s t a p p e n , H . T h , 1 9 8 3 , A p p l i e d of Earth System Science, Springer India in Geomorphology: Geomorphological co-publication with Indian Academy of Surveys for Environmental Development, science. Vol. 117, No. 5. Elsevier Scientific Pub. Co., Amsterdam, Prescott, J. A, 2006, The Early History of The New York, pp.xii-442. Use of term Laterite, European Journal of Zhang, Y, Degroote, J, Wolter, C, Sugumaran, Soil Science, Vol. 5, pp.1-6. R, 2008, Integration of modified USLE into Roychowdhury, M. K, Venkatesh, V, GIS framework to assess soil erosion risk, Anandalwar, M. A, Paul, D. K, 1965, Land Degradation and Development, Vol. Recent Concept on Origin of Indian 20, pp. 84-91. Laterites, Proc. Nat. Inst. Sci. India, Vol.31A, No.6, pp. 547-558.