Thompson, Julian Richard;
(1995)
Hydrology, Water Management and Wetlands of the Hadejia Jama'are Basin, Northern Nigeria.
Doctoral thesis (Ph.D), UCL (University College London).
Text
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Abstract
The floodplain wetlands of the Hadejia-Jama'are Basin, Northern Nigeria are a valuable economic and environmental resource and similar hydrologically to the Inner Niger Delta and the Senegal Valley. Seasonal inundation is the key. Drought and large-scale water resource schemes upstream have reduced flood extent and thereby impacted the wetlands' many benefits. This thesis provides a hydrological assessment as a basis for management strategies to ensure the sustainable development of the basin's water resources and wetlands. Wet season surveys in 1992/3/4 show the Jama'are is responsible for the majority (around 80%) of inflow to the wetlands. Inundation from the Hadejia River and its distributaries reduces downstream discharge by on average 32.8% before the Burum Gana River. The Marma Channel normally takes 85% of the Burum Gana's flow. Measured village wells indicate equivalent groundwater recharge of 343 mm in 1992/3 and 304 mm in 1993/4. The declines in groundwater levels reported in the basin are not evident within the wetlands. The infiltration rate beneath flooded fadamas of 0.209 m month-1 was obtained with simple infiltrometers. A hydrological model of the river basin show a general decline in flood extent from over 2000 km2 being inundated in the 1960s and often less than 1000 km2 in the 1980s. The simulation of large-scale schemes shows that the basin's water resources are insufficient to meet all the demands of all the proposed schemes. Also the schemes would nearly halve flood extent and groundwater recharge. A regulated flooding regime provides assured and reliable flooding of around 1000 km2 and permits the existing extent of large-scale formal irrigation. The development of a user friendly front end for the model has enabled its use by Nigerian water managers. Daily flow analysis (only feasible for 1964-73) shows a significant division between the hydrographs upstream and downstream of a major hydrogeological divide. Two indices based on the range and temporal distribution of high flows show that in the uplands regimes are very flashy whereas further downstream, where discharges decline, hydrographs are smooth possessing a single peak which slowly moves downstream. As the ten day discharge of the Hadejia at Wudil increases beyond approximately 100 106m3 transmission losses increase systematically as a greater proportion of the wetted perimeter contacts the river banks. Daily discharge artificial flood hydrographs are developed for the basin's three largest dams. Two hydrograph types are based on mean daily discharge at nearby gauging stations. The third is a composite based on historic peak discharges and baseflow components. These hydrographs are smoothed to make their release more practicable and their volumes adjusted to conform with the envisaged regulated flooding regime. The next steps to ensure the sustainable development of the basin's water resources are enumerated.
Type: | Thesis (Doctoral) |
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Qualification: | Ph.D |
Title: | Hydrology, Water Management and Wetlands of the Hadejia Jama'are Basin, Northern Nigeria |
Open access status: | An open access version is available from UCL Discovery |
Language: | English |
Additional information: | This thesis has been digitised by ProQuest. |
UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL SLASH UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS UCL > Provost and Vice Provost Offices > UCL SLASH > Faculty of S&HS > Dept of Geography |
URI: | https://discovery.ucl.ac.uk/id/eprint/151689 |
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