ANALISIS KEANDALAN TAMPUNGAN WADUK BENDUNGAN TUGU KABUPATEN TRENGGALEK

The establishment of Tugu Dam is expected to fulfill irrigation and domestic water needs in a focused area. In estimating water availability, the researcher uses simulation method of F.J. Mock debit. The calculation involves the data of rainfall for 29 years, from 1987 to 2015 which is converted to debit data of river flow in the period of 10 days. This calculation applies F.J Mock method. The calibrated parameters are Soil Moisture Content (SMC), Initial Groundwater Storage (IGWS), infiltration coefficient, and factors of land flow recession. The calibration result of F.J. Mock parameters are MSE 0.293, RMSE 0.542, and determination coefficient of 1. The need of water irrigation based on varied planting patterns with padi-padi-palawija, padi-padi-padi, and palawija-palawija-palawija. The needs of consumption waters are calculated based on projected population for domestic needs and also for non-domestic needs such as worship place, market, school, public facilities, and goverment office to achieve the real field result. The result of reliability of reservoir capacity using simulation method is 96.20 percent for outflow debit and padi-padi-palawija pattern; padi-padi-padi pattern is 88.20 percent, and palawija-palawija-palawija pattern is 99.80 percent