Application of Remote Sensing Techniques for Water Resources Planning and Management

This paper describes the importance and capabilities of modern techniques such as remote sensing (RS) and geographic information systems (GIS) as water resource management and conservation tool. RS/GIS analysis can show where water enters a system and how it leaves through evapotranspiration and runoff. Using this information, planners can identify areas where there is potential for development of new water resources; where water can be reallocated from one use or one basin to another; and identify potential areas of water scarcity before water shortages occur. The main objective of this research is to calculate accurate crop water requirement by using RS/GIS in combination with hydraulic models. The results helped in devising guidelines, which in turn will help the policy makers to release the water supplies based on crop requirement only rather than supply based. Multi temporal satellite images were used to identify various crops and cropping pattern in the area. This study was conducted for the Pehure high level canal (PHLC) and the upper Swat canal (USC) system in the North Western Frontier Province (NWFP) of Pakistan. Crop identification at distributary level was made from multi-temporal remote sensing satellite images. Various image processing techniques such as supervised, unsupervised classification and spectral mixture analysis were used to correctly identify various types of crops in the region and ultimately accurate areas of all the classified crops was calculated from the satellite images. These calculated areas were compared with the seasonal data recorded by the irrigation department. ET was calculated using CROPWAT model at various stages of crop growth. Then water required for each individual crop was calculated. The results are very encouraging. The results of this study can be used while devising guidelines for water managers to release the canal supplies based on crop water requirement This practice will help in avoiding wastage of canal water at farm level, which can be optimally used for increasing irrigated areas and crop productivity in the area.