Runoff potential estimation of Anjana Khadi Watershed using SWAT model in the part of lower Tapi Basin, West India

Abstract

Anjana Khadi watershed is situated at downstream of Ukai dam, covers 836 km2 area and consists of 25 micro-watersheds. Water drain from the Anjana Khadi to Tapi River is one of the responsible factors for flooding at Surat city. Present work is focused on flooding potentiality of Anjana Khadi micro-watersheds using the soil and water assessment tools (SWAT). IRS P6 LISS III and Shuttle Radar Topography Mission (SRTM) C band radar data is used for preparation of various input file like land use/land cover, slope, drainage and watershed boundaries in GIS environment. SWAT model is used to simulate the runoff for the monsoon of 2006. Daily, weekly, monthly and annual runoffs are estimated for each micro-watershed. The results obtained show that WS-22 micro-watershed has maximum flood potential while WS-25 as least. In addition, runoff classification map is prepared based on per unit area runoff (PUAR) and for that 25 micro-watersheds are categorized into three runoff classes viz. low (<1 m3/s), moderate (1–6 m3/s) and high (>6 m3/s). The analyzed map shows that WS-10, 19, 20, 21, 22 and 23 are fall in the high runoff category. With this, to prevent the flooding suitable remedial measures are also suggested.