DESIGN OF POLDER SYSTEM AS FLOOD CONTROLLING OF CILIWUNG RIVER IN GUNUNG SAHARI JAKARTA

• Main Author: HIKMAHWATY SUTRISNO - NIM : 15814022, RASTY
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/30234
• Institution: Institut Teknologi Bandung

<p align="justify">Flood is a common water-related disaster that happen in Indonesia, especially in Jakarta. The change of land use at the upstream of Ciliwung River is one of many factors that cause flood in Jakarta. Besides, the people at the upstream and downstream area of Ciliwung River like to put away the trash into the river. The combination of those factors and the fact that Jakarta's topography is low, convinces that Jakarta is vulnerable towards flood. For example, the flood at Gunung Sahari with the height of flood is about 30 to 50 cm which had disrupted the traffic. Besides, Ciliwung River flows through some important building in Jakarta, like Istana Merdeka, Monumen Nasional, and Jakarta's Town Hall, so the flood caused by Ciliwung River at Gunung Sahari should be mitigated. <br /> <br /> <br /> The effort that could be done to overcome the flood caused by Ciliwung River at Gunung Sahari is designing the polder system. By the polder system, the flow from Ciliwung's upstream is not allowed to flow through Gunung Sahari but directed to Banjir Kanal Barat. Therefore, the Manggarai Sluice is opened just in case of extreme flood. The area of polder system in Gunung Sahari is 10 km2. River normalization should be become a part of the design of polder system. The purpose of normalization is to function the Ciliwung River as the long storage for holding flow at the Ciliwung's downstream. The sluice at the downstream should be closed to prevent the intrution of sea water. The water in the channel is pumped directly to the sea. To decrease the water level with the 50 years return period, it needs 9 main pumps and 4 additional pumps with the maximum capacity 90 m3/s. The volume of water that is pumped is 4074 million m3. <br /> <br /> <br /> At existing condition, the elevation of water level is +1.02 meter, meanwhile the highest levee elevation is +0.23 meter. After the river normalization and the polder system applied, the elevation of water level is become +0.18 meter. Therefore, the application of polder system and river normalization can decrease the water level in channel so it will not overflow. The cost that needed for the effort is Rp227,068,103,000.<p align="justify"> <br />