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Geoinformatics In Water Resource Management At Micro Watershed Level; Dangra A Case, West Bengal

World Water Congress 2015 Edinburgh Scotland
10. Management of water resources
Author(s): Kartic Bera
Jatisankar Bandyopadhyay
Presented by Kartic Bera
In Collaboration with:
Dr. Jatisankar Bandyoapadhyay
Department of Remote Sensing & GIS
Vidyasagar University, Midnapore, West Bengal, India

Keyword(s): Sub-theme 10: Management of water resources,
Article: Oral:


This study was undertaken for Dangra sub-watershed and its Micro-watersheds located respectively in Bankura and Puruliya district of West Bengal state in India. The Sub-watershed is located in between 2301400" and 23032'30" North latitudes and 8604230" and 8605500" East longitudes on the globe. The area of Dangra sub-watershed is 210.16 km2 and its elevation varies between 120 m and 300 m above mean sea level (msl). The area enjoys subtropical humid climatic condition with high intensity of rainfall during monsoon period (May to October). The watershed lies on the SOI toposheet number: 73/I-11, I-14, I-15, and I-16 (1:50000 scale), which was used to delineate sub-watershed boundary and topographic parameters. The sub-watershed got its origin over the Chhotanagpur Plateau region thus has developed mostly non perennial rivers. This study sought to provide a protocol for defining sustainable watershed management. This aim was realized through some objectives i) Drainage morphometric characters at micro watershed level. ii) Calibration and validation of a deterministic SCS-CN and SYI model in simulation of runoff and sediment yield response from the study area. iii) Appropriate distribution of water to socially and economically backward classes of people can be provided in times of need. Primarily, water resource management is to be carried out on micro-watershed wise. Being a distinct hydrological unit, integration of both surface and sub-surface water availability to be tuned with land use practices as well as socio-economic considerations. In this respect, water may be considered as an economic resource and may not be perceived as a free and indefinite supply -- emphasis should be given on social awareness programmers. Due to unavailability of hydrologic data, a logical alternative is to estimate the hydrologic characteristics of a watershed by using morphometric parameters. These parameters can be accurately estimated in GIS environment. One of the most widely used techniques for estimating direct runoff depths from storm rainfall is the United States Department of Agriculture (USDA) Soil Conservation Service's (SCS) Curve Number (CN) method (USDA, 1985). The quantitative assessment of soil erosion is a basic aspect of watershed management and therefore, using SYI model one can predict the rate of soil loss by using some empirical formulae. And special emphasis on demographic aspect for best management practices on concerned areas and assessment of BMP implementation effectiveness on water amiability improvement through monitoring strategies. Analytic Hierarchy Process (AHP) based Multi-criteria evaluation of each micro-watershed is used for assessing final action plan. The study used different data in different source i.e Survey of India toposheets, satellite image (NRSC), DEM (GLCF) soil information (NBSS & LUP) demographic record (Census report) and village boundary etc. The dataset uses various image processing and GIS software's like ERDAS/ IMAGINE--9.2, Arc GIS-9.3, PCI-Geomatica-9.1 and ENVI-4.7. The Analytical Hierarchy Process (AHP) is not as unequivocal as current 'AHP standard practice' suggests. By contrast, AHP can contribute to the multiple criteria for procedural justice, which may explain AHP's continuing and growing popularity. By AHP comparing five (Scarcity zone, Morphometric, Run-off volume, Sediment Yield Index, Socio- economic condition) parameters based compound parameter value is calculated for evaluation of each micro- watershed wise final priority classes. The three classes are-1 High 2 Moderate and 3Low. Maximum micro- watershed (25) falls under first class except 4 micro-watersheds. And only one micro- watershed is in 2nd class (2A2C8C6d) and 3 micro-watersheds under low priority class (2A2C8C4b, 2A2C8C6b and 2A2C8C6c). One of the management processes relates to the construction of reservoir / dam, nala bund, contour bund, percolation tank and pond. This construction should be based on the suitability of site, physical and geomorphic parameters and special consideration like societal perspectives. Nala bund, small reservoir, reservoirs are suggested (Figure: 2) for temporary storage for adequate safe dirking water facilities to domestic use and life saving irrigation purpose of the rural areas. But one thing is very important that harvesting of run-off at a micro-level for storage and recycling is necessary for better utilization of rainfall, control of erosion and providing life saving irrigation to crops during dry spells in the monsoon season and also for growing a second crop in Rabi season in many parts of the area. Rainwater harvesting is suggested for challenging water scarcity for the entire area. Water is renewable natural resources, however availability is influenced by the physical and anthrop factors. Water resources management / development require a comprehensive evaluation of both surface water and ground water conditions of an area on micro watershed basis with regional perspective. Water resources development needs very careful analysis of the upper catchments to the lower stretch of a watershed otherwise scattered local level surface/ ground water management in the upstream is likely to affect negatively the recharge in the downstream of a river. It is observed form the study that the study areas only major sources of all purpose use is rainfall. Due to vigorous monsoon and non Perennial River therefore villager's alleys suffer. Side by side watersheds where as no roof top harvesting is suggested, due to short period of rainy secession, so surface sub-surface water storage is only responsible for human use. The high runoff sub watersheds, soil erosion rate is very low here due to hard rock. To prevent soil erosion the appropriate conservation techniques are to be adopted in the study area. The study area under plateau topography hence the agriculture activities are major source of economy for the villagers. For development of cultivation, necessary to increase water availability/ develop irrigation system at list side select for reservoir or nala bund for live saving agriculture purpose. This approach can be further enriched by incorporating other socio-economic and environmental variable to obtain the optimum result.

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