Nyumba ya Mungu reservoir system simulation by using HEC-resSim model in Pangani river basin in Tanzania.

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University of Dar es Salaam
The focus of this Research was to study the water balance in the NyM reservoir. Different models were used, Rainfall run-off model (GFFS) were used to fill missing data during analysis period. The effective inflows to the NyM reservoir were determined using HEC-ResSim model and the reservoir water balance model (NWBM) was developed to check the total water losses in the system. Further analysis was done to investigate the water loss through irrigation abstractions in Kikuletwa and Ruvu reaches before it enters the NyM reservoir. The loss was estimated to be 27% of the total inflows at the gauging station. Reservoir evaporation was estimated using pan evaporation data collected from NyM meteorological station. Effective inflows determined were the mandatory data to the reservoir system simulations for power production. HEC ResSim model were used to simulate the system, where the simulated releases were used to determine the power production at NYM hydro power plant. The first simulated alternative favored storage conservation in the reservoir. The power achieved in this alternative was 7% above the TANESCO production (41.6GWh/yr). The Second simulated alternative was to maximize power production at NyM hydro power plant. This alternative yielded 13% above TANESCO production. Despite of high energy attainable in maximization option, the reservoir water trend were viewed to draw down drastically. Study also investigated the extent of impact brought about by the abstracted water. If Irrigation abstractions were restricted from the two reaches then Power production would increase by 11.5GWh. This increment is about 24% above the production when abstraction is entertained in Ruvu and Kikuletwa reaches.
Available in printed form, East Africana Collection, Dr. Wilbert Chagula Library, Class mark (THS EAF TC167.N3)
Resevoirs, Man-made lakes, Nyumba ya Mungu, Water balance (hydrology), Tanzania
Ng’ondya, R.(2006) Nyumba ya Mungu reservoir system simulation by using HEC-resSim model in Pangani river basin in Tanzania. Master dissertation, University of Dar es Salaam. Dar es Salaam.