1 / 16

Nile Hydrology

Nile Hydrology. 1.096 Preliminary Research Anthony Makana Paris 2.19.04. General Facts. Length: 6700 km Total Catchment Area: 3 million km2 Average Runoff – 30 mm Major contributors of total flow – East African lake region, Ethiopian Highlands

parry
Download Presentation

Nile Hydrology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Nile Hydrology 1.096 Preliminary Research Anthony Makana Paris 2.19.04

  2. General Facts • Length: 6700 km • Total Catchment Area: 3 million km2 • Average Runoff – 30 mm • Major contributors of total flow – East African lake region, Ethiopian Highlands • Main Tributaries – White Nile, Blue Nile and Main Nile • Wide band of Latitude – 4oS to 32oN

  3. Flow Patterns • White Nile & Atbara Seasonal • July – Oct. peak • White Nile fairly constant

  4. Flow Patterns • Seasonal Contributions

  5. Sectional View

  6. Elevations

  7. The Lake Victoria Basin • Inflows • Rainfall – 1151 mm, 122 km3/yr • Tributary – 276 mm, 22.4 km3/yr • Evaporation – 1116 mm, 107 km3/yr • Outflow – 311 mm, 39.8 km3/yr • Characteristics • Provides a relatively steady baseflow.

  8. The East African Lakes below Lake Victoria • Lakes -- Albert, Kyoga, Edward • Inflows • Rainfall – 10.3 km3/yr • Tributary – 10.6 km3/yr • Evaporation – 16.3 km3/yr • Outflow – 45 km3/yr • Characteristics • Outflow contribution to Nile dominated by lake Victoria. • Dramatic variation in flow level historically

  9. The Bahr el Jebel & the Sudd • Rainfall – 871 mm • Evaporation – 2150 mm • Characteristics • Most complex of the Nile reaches due to having many seasonal inflows. • Permanent swamp land, seasonal flood plains that are inundated • High levels of evaporation and transpiration from vegetation (ex papyrus). • Little seasonal variation with annual outflow about half the inflow. • Jonglei Canal • Reduce evaporation losses in Sudd

  10. The Bahr el Ghaal Basin • Characteristics • Ouflow to the White Nile is almost negligible (~3%) • Upper basins have relatively high rainfall, but the river flows spills over into flood plains resulting in almost total lost to evaporation. • Sediment loads of these rivers if greater than lake-fed Bahr el Jebel • Higher potential for alluvial channels.

  11. The Sobat Basin & Machar Marshes • Characteristics • The regime of Sobat and its tributaries is complex. • Most of the runoff develops in the mountains and foothills of Ethiopia. • Pibor drains a wide area of plains, but only contributes significantly in times of high rainfall. • Provides about half of the flow for the White Nile. • Relatively same outflow as the Sudd. • Relatively little is known about he hydrology of the basin area, due to the river straddling the border of Sudan and Ethiopia. • The system is reasonably self-contained with water stored in the channel and flood plain during high flow periods, returning to the channel when the flow recedes, losses to evaporation and soil moisture recharge.

  12. The White Nile below Malakal • Characteristics • Drops 13 m over 840 km • Tributary inflows are sporadic and small • Flood plain storage results in delay of outflow and increased loss to evaporation. • The Jebel Aulia dam further raised upstream river levels after June 1937 • Irrigation and evaporation have led to increased losses. • Outflow is delayed to supplement the Blue Nile in low flow season due to the dam • Sudd provides the baseflow component • Sobat basin contributes the seasonal component

  13. The Blue Nile and its Tributaries • Characteristics • Provides the greater part of flow of the Main Nile (~60%) • Limited information is known about its hydrology, especially in its upper basin within Ethiopia • Geography • Begins in Ethiopian Plateau • Elevations of 2000-3000 m, peaks of 4000m • Very broken and hilly, grassy uplands, swamp valleys, and scattered trees. • Deep ravines and canyons (~1300m at places) • Lake Tana • 1800m • Surface Area – 3000 km2 • Blue Nile leaves and travels through series of cataracts. • Travels through the Sudan Plains • Slopes westwardly from about 700 m • Covered with Savannah or thorn scrub

  14. The Blue Nile and its Tributaries • Major Tributaries • Below reservoir • Rahad • Dinder • Similar basins to lower Blue Nile, highly seasonal • Above reservoir • Dabus – wetland area of 900 km2 • Didessa – smaller swamps • Drains southwestern & humid portion of the Ethiopian basin, contributes significantly to total flow • Reservoir Storing • Roseires Dam (2.4 km2) • Sennar Dam (0.5 km2) • Largest Sediment load (especially during the flood season) • ~140- million tonnes per year

  15. The Atbara & Main Nile to Wadi Halfa • Convergence of White Nile and Blue @ Khartoum • Atbara • Only major tributary after Khartoum • Most seasonal of all tributaries • Drains northern Ethiopia (68,800 km2) and mountains north of Lake Tana (31,400 km2) • Topography • Sabaloka gorge 80 m north of Kartoum • Arid plain dotted with low hills and rock outcrops

  16. The Main Nile in Egypt • Characteristics • Major issues are storage and water use • No flows are generated below the Atbara confluence • Aswan High Dam • Storage of flood water • 1/3 lost to reservoir evaporation • Allows increased water availability for irrigation & hydroelectric • Annual release decreased, but provides a steady yield downstream.

More Related