Author(s): Fajar Baskoro Wicaksono, Fransiscus Xaverius Suryadi, Arie Setiadi Moerwanto
Linked Author(s): Fajar Baskoro Wicaksono
Keywords: Urban Flood, polder system, polder components, mathematical model
Abstract: Kota Lama Semarang which is located 1. 5 km from the sea shore of Java Island, Indonesia has been part of the UNESCO heritage site tentative list because it has been maintaining the continuity of 105 European-style colonial buildings. Even though Kota Lama (26 ha) is in the list and a new drainage scheme is already applied, the flood events still occurred. The new drainage scheme for Central Semarang drainage system has been developed in 2012, all the outlets of Semarang and Baru River that are connected to the sea have been closed. However, Kota Lama drainage system is still connected to Banger River through Banger sub drainage system which the tidal fluctuation still influences Kota Lama. Kota Lama drainage canals are connected to Tawang Retention Basin with the area of about 1 ha and the capacity of 20, 000 m3. Survey and mathematical model simulation showed that the occurrence of high rainfall intensity, sediment and solid waste in drainage system, lack of capacity of working pump during flood and tidal fluctuation through Banger sub drainage system will affect the inundation problem in Kota Lama. Water level in Semarang and Baru River are also crucial for determination operations of drainage system in Kota Lama. Gravity driven polder system is the most appropriate possible solution to solve the flood problems in Kota Lama due to the constraint of land availability for open water storage. A new micro drainage scheme and some of hydraulic structures are needed to be applied and constructed due to implementation of the polder. The inside area of polder is designed with the existing pump capacity of 0. 45 m3/s. The height of the ring dike is 1. 0 m by considering the highest water level outside of the polder with 1000 years return period of rainfall, land subsidence and high tides
Year: 2017