Land Resource and Hydrological Inventory of Chenduru Sub-watershed for Watershed Planning and Development Koppal Taluk, Koppal District, Karnataka (AESR 3.0)

Abstract

The average annual rainfall of 581 mm in the Chenduru sub-watershed as recorded from the Manglur station data by KSNDMC. 66 percent, 17 percent and 17 percent of the annual rainfall occurs during kharif, rabi and summer seasons respectively and exhibited a higher temporal variability. The evapotranspiration estimation tool developed indicates that the watershed water balance is in deficit .The cropping & irrigation choices are not appropriate and need to be altered to shift the deficit water balance. The estimated runoff available to use is 4 mm for an average annual rainfall of 660 mm (2009-2017). The utilizable groundwater is 31 mm (70% of 44 mm recharge estimated). This means the total available water resource combining the soil moisture store for kharif & rabi (204 mm) and utilizable runoff plus recharge is 239 (=204+4+31) The average actual evapotranspiration estimated in the watershed based on the current land use and irrigation practices for the kharif and rabi seasons is 559 mm. Hence the amount of water use for kharif and rabi seasons may be estimated as 699 mm (i.e 125% of AET). This demand for the two seasons is higher by 460 mm, i.e. (699-239). The AET in June-Sept months is 88% of rainfall. Hence, there is a slightly less opportunity to harvest the excess water through watershed management practices for utilizing during rabi season. The total number of wells present in Chenduru Sub-watershed as per LRI data is 15 (13- Borewells 2-Open wells). The groundwater level was found from the data obtained from KSNDMC for the nearest station Irakalgad. Deepest level was found in 2017.