1. Benefits & Problems of management schemes

2. BenefitsRiver Basin Management The US Bureau for Reclamation’s network of dams and reservoirs has helped to regulate the Colorado river’s flow and so reduce the flood-risk. Flood control

3. BenefitsRiver Basin Management Area under irrigation has increased since RBM initiated in the 1930’s. Agriculture now an important economic sector e.g. high value citrus crop in the Imperial Valley, California, which is now that largest area of irrigated land in USA. Agriculture

4. BenefitsRiver Basin Management Dams and reservoirs allowed development of (HEP). Hoover Dam powers 500,000 homes and produces same electricity as 6 million barrels of more expensive oil. Sale of clean, renewable cheap electricity offset RBM costs. Cheap electricity attracted industry to south-west. Dam construction leads to infrastructural improvements in roads, in order to actually build the structure. Power

5. BenefitsRiver Basin Management Energy-hungry industries benefit from cheap electricity e.g. aluminium, steel, copper, cement works in S. California. Industry

6. BenefitsRiver Basin Management Pre–RBM 266 tonnes of sediment flowed through Grand Canyon per minute, raising river levels and increasing flood- risk. Dams trap sediment. Glen Canyon Dam traps 75% of sediment flowing into Lake Mead. Sediment control

7. BenefitsRiver Basin Management Warm climate and rapid population growth increase demand for reliable water supply for domestic use and “luxuries” i.e. lawn irrigation and swimming pools. Municipal water supply

8. BenefitsRiver Basin Management RBM developed water-based recreation in a desert climate i.e. fishing, boating swimming on Lake Mead which has 6 marinas and attracts >10 million visitors every year. This boosted the area’s tourist economy e.g. London Bridge at Lake Havasu and the Hoover Dam itself attracts >7 million tourists p.a. Recreation

9. BenefitsRiver Basin Management Reservoirs are water fowl sanctuaries e.g. snow goose, blue heron. Lake Mead has over 250 species of water bird. Wildlife

10. BenefitsRiver Basin Management More people can now be supported in the region. They are attracted by jobs in growing industries and an increased food supply, coupled with the attractive climate. This benefits the region as there will be more consumers of local services and more local tax payers – both of these are beneficial to the economy. Population

11. ProblemsRiver Basin Management Colorado Delta has become a salt desert and bird life has disappeared. Rainbow Bridge is dissolving due to high water levels in Lake Powell for HEP. Dams and reservoirs destroy habitats. Environmental damage

12. ProblemsRiver Basin Management High evaporation rates and seepage means huge amounts of water loss p.a. 25% of the Colorado’s water is lost through evaporation. Siltation reduces reservoir storage capacity. Pollution is also added to the river because of the increased industry/farming in the area now. Water loss

13. ProblemsRiver Basin Management 45% of irrigated land in Colorado Basin is used for low-value, surplus crops (alfalfa). Irrigation consumes 90% of all available water. Heavily subsidised irrigation water means that farmers have no incentive to irrigate more efficiently and save water. Water waste

14. ProblemsRiver Basin Management Increasing reliance on groundwater is decreasing water table levels and causing subsidence. Groundwater overdraft

15. ProblemsRiver Basin Management Increasing reliance on groundwater is decreasing water table levels and causing subsidence. Groundwater overdraft Photograph of Las Vegas Valley Water district Well No. 5 showing well-head protrusion caused by subsidence. Photo by John W. Bell, 1989.

16. ProblemsRiver Basin Management The cost of building one of these multi-purpose water management schemes is huge, and could involve large debt being taken on. Cost

17. ProblemsRiver Basin Management The resettling of people involved in clearing areas to be ready for the construction of dams and reservoirs can cause families to move away from their home areas. This can also cost a lot in compensation payments. Resettlement of population

18. ProblemsRiver Basin Management In the 1980’s a $245 million desalination plant was built in Yuma in order to make the water that is left in the Colorado by that point usable. Water quality

19. River Basin ManagementExam style questions For your chosen River Basin Management Scheme describe and account for the Benefits and Adverse consequences of the scheme. You should refer to Social, Economic, Environmental and Political Consequences. (17 marks)

20. River Basin ManagementExam style answer In the case of the Colorado Water Basin Management Scheme there have been many advantages and disadvantages. As far as social advantages are concerned the scheme has provided water for huge numbers of people. Water is supplied to Los Angeles, and also to the cities of Tucson, San Diego and Phoenix; this water allows people to have swimming pools, pleasant neighborhoods with lakes, golf courses etc thus ensuring that the quality of life for people in desert areas is high. The scheme also allows for the opportunity for recreation, for example around Lake Mead there are facilities for fishing, boating, camping and caravanning. Lake Mead itself has 6 marinas. More electricity is now available from the power stations built at the dams and as a result air conditioning systems are widespread. In the Colorado Basin there are no significant social dis-advantages except that cities have expanded to such an extent that new highways are having to be built to cope with the increase in traffic and as a result people are losing their homes to allow for the building of these roads. There is also such a demand for water that there will soon be problems in providing enough water for cities like Phoenix. Dams have provided water for irrigation and as a result farming has benefited greatly. In the Colorado Basin crops like Alfalfa and Citrus fruits are grown and the Imperial Valley is one of the largest irrigated areas in the USA. Jobs have been created because of the availability of HEP especially in the High Tech Industries in Tucson and Phoenix. These are all economic advantages. There are several economic disadvantages. Firstly the cost of providing this water and power; the initial cost of building the dams and maintaining them is very high and 45 of the farm crops which are grown are surplus. Environmental advantages include the creation of new bird and waterfowl sanctuaries thanks to the creation of artificial lakes like Lake Mead. However many people feel that the natural wildscape of the Colorado has been destroyed. Many animals and birdlife have lost their natural habitats. Further environmental disadvantages include the increased the increased salinity of the water, which is increased when water is stored in reservoirs and evaporation is increased. This problem if very obvious where the Colorado enters Mexico. Other environmental problems are the silting up of the reservoirs and increased loss due to evaporation. Political difficulties occur as a result of the fact that in the case of the Colorado a number of different states are involved and also Mexico. It took years for agreement to be reached on sharing costs and allocation of water. There continue to be problems and disagreements with smaller states feeling that California gets more than its fair share of water.

21. Social Variable rainfall and high temp. canals for towns and cities i.e. Colorado Aqueduct to L.A. allows golf courses, parks etc Leisure activities, lake mead had 6 million visitors Migration to new areas previously uninhabitable i.e Phoenix

22. Social problems Increasing house prices Urban sprawl Relocation of people i,.e Cocpah tribe on Delta in Mexico Loss of Native American lands in the Colorado desert Loss of land under lakes Disruption of communications

23. ECONOMIC Hydroelectricity means cheap modern industry Increased employment Farmers have nine times more irrigation allowing citrus crops to be grown Recreation attracts millions of visitors Hoover dam has 700000 visitors annually

24. Problems Millions of cubic metres lost though evaporation Silting Salination Quality of water 300 million desalination plant needed in Yuma Huge cost of repaying huge capital costs

25. ProblemsRiver Basin Management · Cross-border issues arise if upper basin states affect quality/ quantity of water available to lower basin states e.g. Mexico suffers from inconsistent, saline, polluted flows from Colorado. Politics

26. ProblemsRiver Basin ManagementPolitics/Env In the case of the Colorado Water Basin Management Scheme there have been many advantages and disadvantages. As far as social advantages are concerned the scheme has provided water for huge numbers of people. Water is supplied to Los Angeles, and also to the cities of Tucson, San Diego and Phoenix; this water allows people to have swimming pools, pleasant neighborhoods with lakes, golf courses etc thus ensuring that the quality of life for people in desert areas is high. The scheme also allows for the opportunity for recreation, for example around Lake Mead there are facilities for fishing, boating, camping and caravanning. Lake Mead itself has 6 marinas. More electricity is now available from the power stations built at the dams and as a result air conditioning systems are widespread. In the Colorado Basin there are no significant social dis-advantages except that cities have expanded to such an extent that new highways are having to be built to cope with the increase in traffic and as a result people are losing their homes to allow for the building of these roads. There is also such a demand for water that there will soon be problems in providing enough water for cities like Phoenix. Dams have provided water for irrigation and as a result farming has benefited greatly. In the Colorado Basin crops like Alfalfa and Citrus fruits are grown and the Imperial Valley is one of the largest irrigated areas in the USA. Jobs have been created because of the availability of HEP especially in the High Tech Industries in Tucson and Phoenix. These are all economic advantages. There are several economic disadvantages. Firstly the cost of providing this water and power; the initial cost of building the dams and maintaining them is very high and 45 of the farm crops which are grown are surplus. Environmental advantages include the creation of new bird and waterfowl sanctuaries thanks to the creation of artificial lakes like Lake Mead. However many people feel that the natural wildscape of the Colorado has been destroyed. Many animals and birdlife have lost their natural habitats. Further environmental disadvantages include the increased the increased salinity of the water, which is increased when water is stored in reservoirs and evaporation is increased. This problem if very obvious where the Colorado enters Mexico. Other environmental problems are the silting up of the reservoirs and increased loss due to evaporation. Political difficulties occur as a result of the fact that in the case of the Colorado a number of different states are involved and also Mexico. It took years for agreement to be reached on sharing costs and allocation of water. There continue to be problems and disagreements with smaller states feeling that California gets more than its fair share of water.