Great Ruaha river model: a study of flood behavior in the river system
| dc.contributor.author | Isaac, Asamoah | |
| dc.date.accessioned | 2019-09-25T07:19:34Z | |
| dc.date.accessioned | 2020-01-07T14:41:33Z | |
| dc.date.available | 2019-09-25T07:19:34Z | |
| dc.date.available | 2020-01-07T14:41:33Z | |
| dc.date.issued | 1997 | |
| dc.description | Available in print form | en_US |
| dc.description.abstract | The objectives of this study have been to direct flooding water upstream of Great Ruaha River to Mtera reservoir and investigate the effect of creating poundage of flooding water upstream of the river on the inflow to the Mtera reservoir as well as changes in storage in Utengule swamp. A model was developed for the Great Ruaha river basin. The model examines the effect of building buffer reservoir on the main Great Ruaha River on the inflow to Mtera reservoir. The model also can be used to assess the changes in storage in Utengule swamp pre and post impoundment. The model consists of two sub-models, namely, a flood routing component which uses the Multiple Input Linear Model to route the flow from the upstream of the river through Utengule swamp to the Msembe and a Water balance component which has been developed to carry out the water balance of the Utengule swamp. Using seven years for calibration out of a total ten years of daily mean discharges at thirteen stations, the Multiple Input Linear Model was applied to route the flow from upstream stations through Mkupule to Msembe. Non-parametric form of the model is calibrated by least squares, in design mode only (without updating), and the resulting model variances are obtained, using the last three years of data for verification (ie. model validation). Considering the hypothetical reservoir on the Great Ruaha river upstream, the daily mean discharge data for the period of 1979-1988 have been used to simulate the flow from the main Great Ruaha river upstream before and after regulation. The excess water is stored taking into consideration the potential evaporation and the stored water is released to supplement the flow during periods of low flow. The outflow from this hypothetical reservoir with the other lumped input was routed to Mtera reservoir. At each operational policy, the average daily inflow to Msembe was estimated. The water balance component of the model has been used to estimate the changes in storage in the swamp at before and after impoundment of Great Ruaha flow. The evaporation component of the water balance was estimated by using the modified Complementary Relationship Evaporation Model (Morton's model). The present study has proved that the Multiple Input Linear Model is suitable for the Great Ruaha river basin when seasonal effects are removed. The model has revealed that creating poundage of flooding water on Great Ruaha river upstream of the Utengule swamp can regulate the outflow from Station 1KA59, Msembe. Hence, the inflow to the Mtera reservoir can be increased during low flow periods, since the outflow from 1KA59, Msembe, contributes the highest flow into Mtera reservoir as compare to the flows from Little Ruaha river and River Kisigo. Though there will be increase in flow at 1KA59 if the Great Ruaha river is regulated, the increment will be significantly small because the average daily flow of Great Ruaha river at 1KA8A is about 17.1 cumecs whilst the other inflows is about 67.7 m3/s. The model has also shown that there is significant reduction in change in storage in the Utengule swamp when the Great Ruaha flow is regulated during high. | en_US |
| dc.identifier.citation | Isaac, A. (1997) Great Ruaha river model: a study of flood behavior in the river system, Masters’ dissertation, University of Dar es Salaam. Available at (http://41.86.178.3/internetserver3.1.2/detail.aspx) | en_US |
| dc.identifier.uri | http://localhost:8080/xmlui/handle/123456789/449 | |
| dc.language.iso | en | en_US |
| dc.publisher | University of Dar es Salaam | en_US |
| dc.subject | Floods | en_US |
| dc.subject | Ruaha river | en_US |
| dc.subject | Ruaha | en_US |
| dc.subject | Tanzania (district) | en_US |
| dc.title | Great Ruaha river model: a study of flood behavior in the river system | en_US |
| dc.type | Thesis | en_US |