Review of the design of the lower Kihansi hydropower project

In Tanzania, hydropower faces three major challenges which are environment, economical and frequently change of Government polices. It is believed that power production at Kihansi dam is limited due to less availability of water. This study crosschecks whether the design flow for LKHP as determined by the consultant, Norplan was realistic. The objective of the study was achieved by establishing the rating curves at IKB28 and NC3 gauging stations (dam is between these stations) by using logarithmic method. These curves were tested for absence of bias and goodness of fit. The results of analysis at IKB28 and NC3 stations show that the rating curves of 1974- 1983 and 1993-2001 respectively are sufficient. Comparison of flows at IKB28 and NC3 Stations shows average correlation of 0.58 on daily basis . The areal rainfall within the catchment was calculate between 1995 and 2005. Areal rainfall was extended backwards to 1942 by regression equation by making use of the data from the neighboring station outside the catchment. The extended rainfall was then used to forecast flow backward from 1942 to 1973 by using LPM, whose parameters were obtained during the calibration of the model for the period between 1974 and 1990(R^2 =64.66).The model was verified for the period from 1991 to 1998 (R^2=65.48). The simulated flows at IKB28 were used to represent the dam site flow by area method and were compared to the norplan dam flows between 1992 and 1987. Results show that norplan dam site underestimated the flows (16.581m^3/s) compared to the simulated flows in this study at the dam site (18.289m^3/s). The study conclude that, hydro power problem may be due to other reasons as described previously which also need to be investigated