river basin management Flashcards
(3 cards)
explain why there is a need for water management
COLORADO RIVER:
1st) Population increase - so additional clean water needed for domestic use (40m people) in named cities (e.g. Las Vegas)
2nd) Agriculture - irrigation would allow the growth of crops during dry months => increasing yield for exports (70% use for the Colorado)
3rd) Hyrdo-electric power - enough to power 5 million homes from the Colorado (45% from the Hoover Dam)
4th) Flood control - dams prevent flooding further downstream => allows for more development to occur.
5th) Recreation - $25b industry (e.g. rafting, fishing, golf) with 15 million people/ per year. Lake Mead is a major tourist attraction.
6th) Conservation - reservoirs produce habitat for migrating birds, endangered fish, elk, bears and mountain lions.
7th) Industry - provides all year round navigation, supports fracking and hi-tech manufacturing industry in sun-belt cities like Phoenix.
8th) Climate irregularities - low rainfall/ semi desert => summer droughts and high temperatures => high evaporation rates
9th) To mitigate climate change - temperature rising by 2C across the south-west => droughts and evaporation increased.
explain the benefits and consequences of the hoover dam
1st: social +) less flooding and more reliable freshwater supply in desert cities (Phoenix), => a higher qaulity of life (e.g. pools)
2nd: social -) people displaced due to reservoirs (St Thomas) and native American burial sites submerged..
3rd) … political disagreements over the allocation of water supplies between US states and Mexico.
4th: Economic) irrigation supports arable/livestock farming, HEP provides cheap/renewable electricity to power nearly 2 million homes…
5th) …. supports hi-tech industry in sunbelt cities like Tucson, tourism in Las Vegas => multiplier effect as population grows.
6th: Economic -ve) dam maintenance cost (turbine replacement); water treatment costs due to mineral content…
7th) … fertlisers (fertile lack of deposit) and soil salinisation costs farmers $2b /per year. Mexican fishing communities abandoned.
8th: Environmental +ve) reservoirs produce habitats (e.g. Blue Heron), tourist revenue => conservation and HEP => less fossil fuel use
9th: Environmental -ve) less wetland at mouth and riverside habitats have less flooding => fewer beavers…
dams block block fish migration and encourage invasive species (e.g. tamarisk)
explain the factors when choosing a dam site
Colorado river
1st) Physical - narrow valley dammed as more efficient due to lack of materials required, meaning less project cost..
2nd)….. and they also produce a lake with less surface area meaning less water lost due to evaporation.
3rd) Impermeable rock will reduce water loss from reservoir via percolation.
4th) High drainage density means (low rainfaill) ensures water recieved from the reservour => avoids transfers from elsewhere.
5th) Human -
