Analysis of Precipitation, Runoff and Tides of Water Level in Lebak Swamp Ogan Keramasan

Problems encountered in the production of rice in swamp land, namely the existence of climate change, the el Nio (drought) and la Nina (flooded), so that during the dry season drought, it is because the floodgates unused in the drain water. When it is rainy season, the water exceeded the sluice. This leads to stagnant water, water level further high then the water fluctuations cannot be controlled. And also water management system of macro and micro poorly, channels were damaged and less irrigation planning. These issues can reduce the productivity of rice and led to the failure of agriculture in lebak swamp. Thus, this study aims to clarify he relationship between rainfall, runoff, tidal rivers and water level in the lebak swamp especially in Ogan Keramasan. The method used was observation, experiment and inventory data. This study was conducted at Ogan Keramasan, Ogan Ilir District in March 2014 to October 2014. The conclusions obtained were 1) the trend of rainfall more fluctuative than the trend of evapotranspiration. Beside that, evaporanspiration value was higher than rainfall. This often causes dry conditions during drought. The value of evapotranspiration is not affected by rainfall, but affected by the area of land cover, 2) the water level is strongly influenced by rainfall, tides river and runoff. Thus, a mathematical model of the relationship between rainfall, runoff and tides water level is required.