Socio-Economic Characteristics of Groundwater Users of Irrigation in High and Low Recharge areas of the Pulangui River Basin, Cotabato Province, Philippines

A study on the socio-economic characteristics of groundwater users for irrigation was performed in selected shallow aquifers in Pulangui River Basin, Cotabato Province. Using Water Table Fluctuation Method of groundwater recharge estimation, the sample study area was arbitrarily zonified into high and low recharge areas. Using survey data, the study revealed that at an average duration of pumping of 81.49 hrs ha-1 and 129.60 hrs ha-1 during wet season cropping in high and low recharge areas, the corresponding volume of groundwater extraction for irrigating rice is 2,324.57 m3 ha-1 and 2,816.98 m3 ha-1. While on the dry season cropping, at an average duration of pumping of 175.91 hrs ha-1 and 269.18 hrs ha-1 during dry season cropping in high and low recharge areas, the corresponding volume of groundwater extraction for irrigating rice is 5,004.97 m3 ha-1 and 6,451 m3 ha-1, respectively. Likewise, using survey data the mean rice yield function was estimated with the cost of pumping, which represents well depth and water availability, used as water supply proxy variable input into the stochastic production function. The net benefit for both wet and dry season cropping in both recharge areas was estimated using actual yield and the estimated mean yield function. The significant higher difference in gross margin (Php 7,323 ha-1) attained by farmers in high recharge areas in dry season cropping is probably due to higher water levels in turn more water availability than in low recharge areas.