Estimation of Agricultural Blue and Green Water Use in Upper Manair Catchment, Andhra Pradesh

An accurate assessment of agricultural blue and green water use is a key to estimate agricultural water demand and to understand human’s interference with the ecosystems. Ground water is the primary source for irrigation in Upper Manair catchment, Andhra Pradesh. Due to continuous over-pumping, groundwater resources have been greatly depleted. It is extremely important for a sustainable agricultural water management to explicitly estimate the groundwater consumption for agriculture. Crop water requirements (CWR) of various crops in a catchment are computed using CROPWAT software. The seasonal ETc values for rabi crops were 430 mm, 365 mm and 222.5 mm for paddy, sunflower and maize, respectively, and for kharif crops were 525 mm, 261 mm, 1041 mm and 535 mm for paddy, maize, sugar cane and cotton respectively. However, the amount of ground water applied (MCM) for rice (Kharif), cotton, sugarcane, sunflower, double crop rice and double crop maize are 340.11, 57.94, 114.29, 18.0, 186.75 and 175.43 respectively. The total amount of ground water applied for different agricultural crops is 421.92 MCM more than the required amount of water which leads to depletion of ground water. Hence, immediate measures are required to reduce the blue and green water loss by developing efficient irrigation practices for sustainable ground water resources.