<p>Dam is a reservoir that is needed to save water so that it can be used at the time needed both for irrigation, hydropower, and tourism. One of the Functional Dam in Indonesia is the Sangiran Dam. Sangiran Dam is located in Sumber Bening Village, Bringin District, Ngawi Regency, East Java Province. The Sangiran Dam is equipped with an overflow ogee crest type overflow building with side channels. Sangiran Dam gate type is slide gate with automatic operation using electric generator. The reservoir, which was operated starting in 2000, is designed to meet the needs of a plantation area of 1535 ha. However, in the operation that is needed in meeting the needs of irrigation air needs to be done in research the current operating patterns of the operating patterns that have been designed at the time of the reservoir design to compile an operating pattern that can meet water needs, at this time, looking for a relation between the elevation of reservoir water levels with an outflow discharge coming out of the reservoir. Based on the results of the analysis conducted on the current operating patterns are not in accordance with the pattern of initial design operations with an average deviation of 51.78% per year. This research is being carried out to analyze the optimal operating patterns of the Sangiran Dam and / or possible operating patterns in meeting water needs in the following years.</p>

Abstract The stability of riverbed became an important part in the river. Basically, the stability would be maintained if the grains of sediment was not moving (transported). Riverbeds that were disrupted because of carried details (degradation) or stacked granules (aggradation) in certain parts of the river caused the structure to be damaged. Degradation and aggradation along the river road at a certain time would be figured out in this study, so that it could assist in making treatment recommendations layer riverbed. The case study was conducted on Dengkeng River along the 8 km segment Karangjoho-Jetis which was a fixed flow (quasi-steady) sub critical Froude number <0.6. Bottom sediment sample material with a grain diameter variation D35, D50, D65, and d90 in grain size analysis was used for the calculation. The process of degradation and aggradation riverbed sediment discharge was known by calculation using the method of Meyer-Petter & Muller. Parabolic model analysis with the help of MS Excel was used to calculate the degradation and aggradation happened. At the time of running, graph illustrating the comparison between degradation and aggrades with a segment length of the river at a certain time was seen. The graph showed the longer segment of the river, degradation and aggradation would less.