EVALUASI PERUBAHAN KEBUTUHAN AIR IRIGASI D.I. BILI-BILI AKIBAT PERLUASAN PERMUKIMAN KOTA MAKASSAR DAN KABUPATEN GOWA

Abstract

Bili-Bili’s irrigation area with the service plan area 3.505 Ha include the partial of Makassar city and Gowa regencyexperience the decrease of service area due to the expansion of resident area. To optimize utilization of irrigation water,study about the modification of service area and irrigation water is needed.The analysis of irrigation water necessity isdone by calculate the influence factor, include the necessity of water in land preparation, water consumptive used,percolation and seepage, replacement of layering water, effective rainfall and the most importance is the service area.Irrigation water necessity in Bili–Bili’s irrigation Area 1.15 lt/s/ha. Irrigation area in Bili – Bili’s Irrigation Areaexperience the decrease every year. Until 2017, the area decrease up to 130 ha from the first plan or service area become3.375 Ha, this is directly proportionate with the water irrigation necessity, current irrigation water necessity up to3874,70 lt/s, decrease up to 3,71% from the first plan or equivalent with 149,37lt/s.