Normalised difference water index based water surface area delineation and assessment

In the present paper, the geospatial technology has been extensively used to map and assess the changes of water surface area of Tighra dam situated near Gwalior city of Madhya Pradesh.. The change of water surfaces area has been examined for last one decade period. The LANDSAT digital satellite data from different sensors for the year 2004, 2009 and 2014 have been used for the present study. All the satellite data used are of the month June of respective years. The Normalised Difference Water Index (NDWI) was derived by using the NIR and SWIR-1 band. The NDWI along with the SWIR-2 band has been used to delineate the water surface area. In order to delineate the water surface, a threshold NDWI value has been assigned to separate it from other classes. The possible causes for the changes in the water surface area over the said years have been discussed. The climatic conditions particularly the rainfall over the study period has been studied and correlated with the fluctuation of the water surface area of the dam It has been concluded that the changes in open water features of the area is related to climate change and other societal development activities. However, it is observed that the resolution of the images is one of the constraints, and high-resolution image can provide more accurate and precise result.