ESTIMATION OF CROPWATER REQUIREMENT FOR KOLAR TALUK SUBWATERSHED
Mohammed Badiuddin Parvez, Chalapathi k, Dr.M.Inayathulla, Nanjundi prabhu
Watershed management, Evapotranspiration amd Water balance comoponents
The water balanced of a place, whether it be an agriculturals field, watershed, or continent, can be determineds by calculatings the input, output, and storage changes of waterd at the Earth's surface. The major input of water is fromd precipitation and output is evapotranspiration. The water balance is intended for use as a screeningd tool to further evaluates water resources allocations withina the watershed and to identify water balancee components that may require furtherd analysis during the next levels of watersheds planning. The study area chosen for the present study area is Doddavalabhi sub watershed which falls in Kolar taluk of Kolar district. The study areas geographically lies between 760 8’ 0” E and 760 23’ 0” E longitudef and 120 20’ 0” N and 120 28’ 0” N latitudes with an area 15.20 sq.km. For the determination of crop water requirement for Kolar major crops considered are ragi and groundnut with the crop period of 120 days and 140 days respectively. The year and monthly wise potential evapotranspiration and actual evapotranspiration is calculated by using penman method, blaney-criddle method, pan evaporation and radiation methods. The year wise potential evapotranspiration calculated by Blaney-criddle is maximum 645.66 mm during 2014, in this year monthly PET is maximum in july month ie 150.4mm. The year wise potential evapotranspiration calculated by Pan evaporation is maximum 236.43 mm during 2014, in this year monthly PET is maximum in july month ie 56.67mm. The Year wise actual evapotranspiration is also maximum during 2014 for both ragi and groundnut. Hence Blaney criddle method is best suitable since it provides the most satisfactory results compared to other methods because This methodd is suggested for areas wherea available climatic data cover air temperature data only.