MODELLING OF POTENTIAL RECHARGE ZONE USING GEOGRAPHICAL INFORMATION SYSTEM BASED ON INDONESIA REGULATION AND WATER BALANCE MODEL

Abstract

Recharge zone is an important aspect for sustainable water resources management. Recharge are difficult to measure directly and the field-based methods are time consuming, expensive, and require large number of skilled manpower. Application of remote sensing and geographical information system (GIS) has wide application and good result in delineating recharge zone and various other fields. The present study aim to delineating potential recharge zone using GIS based on Indonesia Regulation with comparison of water balance modelling (NRECA and FJ Mock) in Cisadane watershed Indonesia. Water balance model is used for generating rainfall data into monthly discharge (base flow and direct runoff) with validation of 3 discharge station (Genteng, Batubeulah and Serpong) as representative of upstream, middle and downstream of Cisadane watershed. Rainfall is a dynamic and sensitive factor for generating potential recharge zone, there is a significant changing of potential recharge zone between using 3 parameters and 4 parameters, potential recharge zone can increase or decrease based on annual rainfall. The accuracy of NRECA and FJ Mock model and result fairly good validation with acceptable NSE (0.52-0.61) and R values (0.76-0.87). Potential recharge zone map using 4 parameters (land use, slope, soil and rainfall) is suitable with the results of baseflow percentage of NRECA and FJ Mock model. Cisadane watershed is dominated by medium (33.62%) to high potential recharge (55.49%)