BANGER WATERSHED MANAGEMENT IN SEMARANG CITY

Floods that occur on the north coast of Central Java in general are caused by high rainfall, where water flows from upstream to downstream carrying soil grain and rubbish in the form of used bottles, plastic, tree branches and others so that the presence of waste will disrupt and inhibit the flow rate of water. Government efforts to deal with flooding in the city of Semarang by optimizing the retention pool in the city of Semarang for example retention ponds in Tawang, Muktiharjo, Tanah Mas and Banger, these pools are used to collect water and later the water will be discharged using a pump to the river then to the sea, if there is a tide or tidal flood that inundates the streets and houses, the pump is turned on. Meanwhile, if the water recedes and does not inundate residential areas, the pump is turned off. The purpose of this study is to formulate a correlation between pumps and retention ponds, while flood control uses a 50 year return count Banger watershed flood control uses a 3 m deep pond pool volume of 406,000 m 3 . The pump is set to start at 2.5 meters of water depth, and shut down at a depth of 0.5 meters.