WATER SOURCES MODELS AND OPTIMAL MANAGEMENT OF JATIGEDE RESERVOIR IN ORDER TO FULFILL RAW WATER REQUIREMENTS FOR METROPOLITAN REGIONAL SPAM CIREBON RAYA, WEST JAVA

• Main Author: Jayanti, Merri
• Format: Dissertations
• Language: Indonesia
• Subjects: Teknik saniter dan perkotaan; teknik perlindungan lingkungan
• Online Access: https://digilib.itb.ac.id/gdl/view/66173
• Institution: Institut Teknologi Bandung

Jatigede Reservoir is one of the largest reservoirs in Indonesia, which located in Sumedang Regency, West Java. The reservoir in capacity of 979.5 million m3 of water was built for meeting irrigation water needs (90,000 ha), raw water supply of 3.5 m3/second (Cirebon City, Cirebon Regency, Sumedang Regency, Indramayu, and Majalengka) and hydropower (110 MW). The purpose of this study was to develop a conceptual optimal reservoir management by examining changes in the hydrological regime and the most representative water source model to obtain optimal gains in the Jatigede reservoir operational pattern in the context of raw water sustainability for the development of the Metropolitan Regional SPAM Cirebon Raya, West Java. The results showed that there had been a change in the hydrological regime in the Cimanuk, Jatigede watershed with changes in the rain and discharge parameters. The research area was proven to be a Monsoon area, with a water availability index of 0.8 and an average rainfall of 12452 mm/year, with a change in discharge that occurs is 0.041 m3/year, with a temperature change rate of 0.074°C per year. The high variability of discharge and rainfall in the study area poses a major challenge in managing water resources. Based on the simulation and comparison of the water source model in estimating a flow rate to achieve the optimal reservoir conceptual, the largest correlation was obtained in the Continuous-Correlation model with the value of r being 0.93 and the next sequence is the Discrete Markov model, ARIMA model, NRECA model, and lastly is the FJ Mock model. The selected and most representative water source model in this study could be used as the basis for modeling water sources in optimal reservoir management. The results of the optimal management simulation of the Jatigede reservoir with variations in the input discharge of the ARIMA model, the Discrete Markov 3 (three) class model, the Discrete Markov 5 (five) class model, the Continuous-Correlation model produces the correlation value between the guideline and the actual path approaching number one, namely successively -respectively of 0.889; 0.915; 0.929; and 0.940 and the correlation value between the forecast discharge and the actual discharge is 0.776, respectively; 0.793; 0.917; and 0.922. It has shown that the optimal management simulation with the Continuous-Correlation model could better anticipate the effect of discharge extremities in the Jatigede reservoir compared to other simulation models. In the optimal reservoir management simulation, the Continuous-Correlation model iv reservoir trajectory results in the actual path correlation value against the guideline path which is closest to the value of '1' compared to other models. The development of the optimal model of Jatigede reservoir management resulted in a conceptual model of reservoir management in the Monsoon area with discharge release according to the reservoir's utility function for irrigation and drinking water. The results of a series of analyzes in this study showed the dependable flow of the Jatigede reservoir in the 10-year and 20-year dry return periods, respectively, at 30.978 m3/second and 22.587 m3/second. In addition, there is an increase in water potential after the Jatigede reservoir. This is evidenced by the increase in the mainstay discharge after the Jatigede reservoir of 38.005 m3/second compared to before the reservoir which was only 6.133 m3/second. In this case, the Jatigede reservoir is reliable to be used as a source of raw water for drinking water and is able to meet the needs of the planned SPAM raw water intake both in the first stage of SPAM development (1.5 m3/second) and second stage (2 m3/second). The initial goal of the construction of the Jatigede Reservoir was only to meet the water needs for irrigation and hydropower, but there was no intake for raw water sources. Therefore, the location of the raw water intake (intake) is planned to be located in the Jatigede reservoir, with an intake location elevation (230 masl) and a planned IPA location (99 masl) in Parakan Kondang Hamlet, Jatigede District. So that the flow of water from the intake to the WTP is expected to be carried out by utilizing the gravity system. With the alternative treatment with appropriate technological responses and distribution systems by prioritizing the gravity system, it is expected to improve service strategies based on competitive water prices in accordance with the integrated and sustainable SPAM concept, especially in the Monsoon climate zone with raw water sources from reservoirs.