Rahmah Dara Lufira, Suwanto Marsudi, Lily Montarcih Limantara, Rendy Khoirul Ilham
Declining potential of water resources and the highly increased exploration of water resources along with highly increased needs in society demand the analysis of water balance of the Gandong Watershed in Magetan Regency. Analysis results showed that surface water availability that comes from discharges, springs, and drilled wells is 35.144 m3/s in the dry season, 48.050 m3/s in the low season, 59.833 m3/s in the normal season, and 78.163 m3/s in the peak season. The availability of subsurface water is 163.650 m3/s. The surface water requirement of Gandong Watershed is 183.580 m3/s with 55 irrigation areas, and the subsurface water requirement is 118.990 m3/s. The highest surface water deficit is in the Jejeruk Irrigation Area, with 13.680 m3/s or only 1.23% of the needs met in December (dry season), and the highest surplus is in the Gemblung Irrigation Area, with 10.430 m3/s or 100% of the needs fulfilled in February (peak season). Water balance evaluated by the Water Evaluation and Planning (WEAP) Software showed only 10 irrigation areas met 100% of the demand. Subsurface water balance is at a surplus condition from January to December. Land water balance is at a deficit condition from May to December. © Published under licence by IOP Publishing Ltd.
Water Resources Engineering Department, Faculty of Engineering, Universitas Brawijaya, Jl. Mayjen Haryono 167, Malang, 65145, Indonesia