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GIS in watershed management

By Akummeren
Watershed represents a segment of the landscape with a common hydrological boundary within which the biotic community is inextricably linked. It is a convenient unit of landscape to study and evaluate the physical parameters vis-à-vis resource utilization and development. Sustainable development through watershed management has become a thrust area in both developed and developing nations. The term watershed refers to the geographic boundaries of a particular water body, its ecosystem and the land that drains to it.   

A watershed also includes groundwater aquifers that discharge to and receive discharge from streams, wetlands, ponds, and lakes. The goal of watershed management is to plan and work towards an environmentally and economically healthy watershed for the benefit of the biotic community. Watershed management essentially relates to soil and water conservation in the watershed, which means proper use of land and the protection of land against all form of deterioration. The range of issues relevant to watershed management includes environmental issues: Crop and livestock production, social and cultural concern and infrastructure planning. For optimum utilization of natural resources in an area, the integrated watershed development approach is considered to be the most ideal as it helps in maintaining the ecological balance.            

In recent years there has been a growing and intense global interest in the environmental health of the earth. Exploitations of earth's resources through the human civilization, particularity after the industrial era, have put adverse impact on the lithosphere, hydrosphere and the biosphere. It is often felt that there is a need for continuous evaluation and appraisal of the environment in terms of the physical parameters of the earth system vis-à-vis the ecosystem.            

Watershed development has been conceived basically as a strategy for protecting the livelihood of the people inhabiting the fragile ecosystem experiencing soil erosion and moisture stress. The aim of watershed management has been to ensure the availability of drinking water, fuel wood and fodder and raise the income and employment for farmers and landless labourers through improvements in agricultural production and productivity. In this regard, Geographical Information System (GIS) holds great promise with a provision to handle spatial and temporal data and aid as an integrative planning too for watershed management.            

A Geographic Information System (GIS) is a system designed to capture, store, manipulate, analyze, manage and present all types of geographically referenced data. In the simplest terms, GIS is the merging of cartography, statistical analysis and database technology. GIS technology can be used for scientific investigations, resource management, and development planning. For example, a GIS might allow emergency planners to easily calculate emergency response times in the event of a natural disaster, or a GIS might be used to find wetlands that need protection from pollution. GIS improves calculations for watershed characteristics, flow statistics, debris flow probability etc. the recent technologies like Remote Sensing and GIS helps us by giving a quicker and cost effective analysis for various applications with accuracy for planning. It also gives a better perspective for understanding the problems and therefore helps planners evolve a better solution for sustainable development. With the advancement of computers and availability of large volumes of digital data, GIS application in watershed management has changed from operational support to prescriptive modeling and tactical or strategic decision support system.            

In order to keep in pace with the modern technologies, the Land Resources Department of Nagaland has set up a GIS cell for Integrated Watershed Management Programme. The main aim of setting up this cell is to have its own state-of-art of technology for micro-watershed level planning. The Cell has generated various Geo datasets for planning at micro-watershed level. The output includes information about characteristics of the watershed in the form of maps, statistics, synthetic indexes and charts. This characteristic includes watershed morphology such as elevation, slope and aspect; watershed drainage (drainage density and hierarchical stream classification) and other thematic relevant aspects such as land use, DEM, physiography, soil. These maps are prepared from various sources such as satellite data P6 LISS IV MX, Aster data, GSI maps and SoL toposheets; all these layers are integrated in GIS platform from which the action plan map is derived.  

From the final output of these themes generated; recharge wells, percolation tank, check dams are recommended for each micro-watershed area. To increases the ground water recharge and vegetative cover to control soil erosion various action plans like construction of recharge structures afforestation etc has been proposed. The information generated from such works can be applied by decision makers and planners for sustainable development of any given watershed area. The Cell has also prepared micro-watershed map with coding for the entire state of Nagaland.    June 2011
Akummeren is based in Kohima, Nagaland.