Optimasi pemanfaatan air tanah untuk irigasi di kabupaten wajo, provinsi Sulawesi Selatan, Indonesia (the optimism of ground water utilization for irrigation IN WA]O DISTRICT, SOUTH SULAWESI PROVINCE OF INDONESIA)

Abstract

The ground water in Siwa-Pompanua basin of Wajo Regency has a coverage area of 93,900 ha and a potential debit of 379 millions m3/yr. The ground water has been utilized since 1995 to irrigate rice fields managed by farmers themselves. Without well understanding and proper management of the ground water it is easy to witness that many problems have been accumulated. This study aims for optimizing the utilization of ground water for irrigating the rice fields with taking into account socio-economical and environmental aspects. Herewith, mathematical models were developed based on the water flow equations, crop water requirement and combined with socio-economical analysis and preventing degradation of the aquifers. The water flow model was compared to measured data and resulted in a good conformity. Based on the daily water requirement of46 mt/ha and with preventing excessive drawdown, the optimum discharge of each well differs with the others. It's values are between 279 m3jd and 1,268 m-/d and the command areas range from 10 ha to 28 ha, respectively. A neighboring well should be in the radius of about 479 m away. In the average,farmers would gain an extra income if they manage the ground water in this sustainable way.