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RBM

RBM. What do I need to know?. 1. Describe & Explain The Distribution Of River Basins & Rivers In The USA. 2. Explain Water Supply Issues For A River Basin In North America & Why A Management Scheme Was Needed. 3. Explain The Physical & Human Factors Involved

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RBM

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  1. RBM What do I need to know?

  2. 1 Describe & Explain The Distribution Of River Basins & Rivers In The USA 2 Explain Water Supply Issues For A River Basin In North America & Why A Management Scheme Was Needed 3 Explain The Physical & Human Factors Involved In Choosing A Site For Dams/Reservoirs 4 Explain Impact Of Management Schemes On The Hydrological Cycle Of Your Chosen River Basin 5 Describe & explain the social, economic & environmental effects of the water control project and assess its impact in these terms Explain The Political Problems Resulting From The Management Schemes On Your Chosen River Basin And Discuss How Political Issues May Hinder Such Projects 6

  3. 1 Describe & Explain The Distribution Of River Basins & Rivers In The USA

  4. There are no major rivers in the North Due to the Desert Conditions. • The Nile Flows Northward from it’s source in the wetter Ethiopian mountains and Lake Victoria. • Main Rivers flow east or west apart from Nile that flows North • Nile flows into the Mediterranean. Other rivers flow into Atlantic apart from Zambezi and Limpopo which flow East to the Indian Ocean. • The Niger, Volta and Benue are influenced by the seasonal rainfall of the ITCZ.

  5. Mackenzie River flows North to the Arctic Ocean and is fed by spring snow melt. • Rocky Mountains form major watershed. • Columbia and Colorado drain West to Pacific. Mississippi flows South to Gulf of Mexico • The St Lawrence flows East from the Great Lakes into the Atlantic. There are a greater number of rivers flowing to the Eastern part of the USA as it receives more precipitation. This is because wet air is driven into the Gulf of Mexico by North East Trade Winds • Remember that these winds also drive the canaries current to the Equator and the Northern equatorial current to the Caribbean (Gulf Of Mexico).

  6. For North American river basins: • description should include reference to general patterns/numbers of rivers, and should refer to the directions of flow • explanation should refer to the fact that drainage basins are determined by the location of the main continental watersheds and that major rivers rise in the main mountain ranges that have greater precipitation, eg the Rockies and Appalachians in North America.

  7. Patterns within North America could distinguish between: • west flowing rivers are fed from the western side of the continental divide. Rivers like the Columbia-Snake and the Colorado flow west in to the Pacific Ocean • north-flowing rivers drain to the Arctic Ocean or to Hudson Bay and are fed from the Canadian Shield • the St Lawrence system is fed from the Great Lakes areas and flows east to the Atlantic Ocean • most of south-eastern USA is dominated by the Mississippi and its tributaries which are fed from the Rockies in the west and the Appalachians in the east and flow to the Gulf of Mexico.

  8. Source of most major rivers is in the Himalayas. • Rivers mainly flow North to Arctic Ocean or South to Pacific / Indian Ocean

  9. Explain Water Supply Issues For A River Basin In North America & Why A Management Scheme Was Needed 2

  10. Domestic use in cities Drinking, swimming pools, bathing Increased food supply required for expanding cities Provide electricity to nearby cities Sustainable management Of all river users Rivers prone to flooding In south USA due to trop storms Population Irrigation for farming Flooding Pollution H.E.P e.g Colorado River Drought Industry A need for RBM Precipitation in Upper Basin Tourism Distribute to other drier areas Monsoon Seasons Navigation Lake Mead is a major Tourist attraction: Fishing, Water sports, relaxing Ships and trade Store water run off In wet season High temperatures resulting in evaporation in dry season

  11. When answering this question use the mind map as a structure. You also need to consider all the information they give you in maps/diagrams and charts. This will give you clues about what you should focus on and the points you should expand to gain more marks

  12. 3 Explain The Physical & Human Factors Involved In Choosing A Site For Dams/Reservoirs

  13. • solid foundations for dams • consideration of earthquake and underground movements •cost of compensating farmers and home owners • impact on communications. • narrow cross-section to reduce dam length • large, deep valley to flood behind dam • impact on hydrological cycle. • cost of construction • proximity of urban areas for water and electricity • proximity of agricultural areas for irrigation • cost of displacing people • impermeable rock beneath reservoir • sufficient water supply from catchment area • low evaporation rates, due to small surface area of reservoir Use these factors to complete the dam diagram

  14. 4 Explain Impact Of Management Schemes On The Hydrological Cycle Of Your Chosen River Basin

  15. Impact Of Management Schemes On The Hydrological Cycle Of Your Chosen River Basin Evapo-transpiration Evaporation Considerations Groundwater Discharge Reduced Discharge Controlled

  16. Hydrological Cycle Hydrological Cycle • Storing large amounts of water will effect the hydrological cycle as infiltration will increase, evaporation will increase and surface run off will be decreased.

  17. Hydrological Cycle Infiltration • Large areas of water such as Lake Mead over porous sandstone increase infiltration rates. • Red Desert and Grey-Brown Podzol soil allow infiltration so have decreased water available for surface run off.

  18. Evaporation • Lake Mead has a surface area of 157,900 sq miles. • Summer temperatures over 30 degrees. • Huge surface area in hot climate increases evaporation rates. • High evaporation results in 2 million cubic metres being lost from Lakes Powell and Mead.

  19. Water table • The Colorado can no longer meet the growing demand and water is drawn from underground sources. • In some areas the water table is being lowered by over use of ground water.

  20. Evapotranspiration • Increased irrigation has led to more vegetation. • Evapotranspiration has increased and therefore decreased the surface run off.

  21. 5 Describe & explain the social, economic & environmental effects of the water control project and assess its impact in these terms

  22. Use the sample answer given to you to complete the social/economic/environmental circles exercise

  23. Explain The Political Problems Resulting From The Management Schemes On Your Chosen River Basin And Discuss How Political Issues May Hinder Such Projects 6

  24. Mark the sample answer given to you. There should be more than 10 marks to be awarded.

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