Fluctuation Effect of Reservoir Water Level on the Seepage of Earth-Fill Dam

Lots of dam failures are the result uncontrolled seepage. The collapse Situ Gintung Dam in Tangerang, Banten-Indonesia 2009 due to heavy rains caused structure collapse. This is increased pore water pressure landfill. To anticipate seepage, it necessary monitor based on behavior changes rainfall and reservoir levels. Seepage within body often monitored using instrumentation tools such as standpipe piezometer (standpipe piezometer) or electric piezometer. But cannot work properly because clogged, so condition Other instrumentations V-Notch also used measure seepage discharge. study aims determine level by its effect earth-fill Type dam. By knowing phenomenon relationship between infiltration rainfall, will obtain information that endangers which affect downstream. In this study, a case Selorejo was taken has large enough capacity about 31 million m3 included Brantas River Basin. results showed 5 piezometers devices were damaged (SL 1, SL 2, 4, 6, 7) where they could not read phreatic properly, 2 less sensitive reading fluctuations namely 10 11 R2 values 29.78% 39.4%, respectively. While maximum discharge recorded at 1474 liters/minute, still below critical 1630 liters/minute allowed for dam, but needs be concern, especially from toe drain left side C-area leakage support pedestal contributes larger than other observation points.