Why was it dammed? How has it affected the lives of the local people?

Now using the atlas- complete your map following the instructions on the side

 Much of the area the river runs through is desert and area twice as big as the UK  Early settlers dammed the river to provide water to local cities and towns- much of this comes from the snowmelt in the Rocky Mountains  It also regulated the flow of the river to ensure a constant supply of water to cities such as Las Vegas and Phoenix  25 million people in the SW rely on this supply

In Boulder Canyon Lake Mead and Lake Powell are two largest man made lakes in the USA

 Using the sheet you have be given colour in the bubbles to show the effects of the dam in the following categories  Social  Economic  Environmental  Political

 400,000 ha of land is irrigated for farming (most of it in California’s Imperial Valley)  Lake Mead and Lake Powell are major tourist centres  Lake Powell offers sailing, power boating, water skiing and fishing and attracts over 2 million visitors a year The photo above was taken on July 26 th 2007, 7 th year of drought, lake level dropped more than 100 ft- lowest level since the late 1960’s.

Annual rainfall of 50mm 90% of water from Lake Mead Much of the water is lavish and wasteful- lawns, parks, golf courses and swimming pools are seen as essential and can only be maintained by irrigation Major tourist destination- over 37 million visitors a year Water is becoming increasingly scarce

 ‘Grass for Cash’- the city pays householders $1 for every square foot of lawn they remove  They hope they will replace them with Cacti and other desert plants  Pumping water from aquifers (permeable rocks underground) or oases- but what are the issues with this?

 This is north of Las Vegas  The oases in the desert such as Ash Meadows are rich in wildlife- 239 species of bird, 27 mammals, 20 reptiles, 5 amphibians and 7 fish  25 of which are nowhere else in the world  These are protected as national wildlife refuges

 The Las Vegas Water Authority wants to pump around 2 million cubic metres of groundwater each year from the aquifer  It will lower the water table  Springs will dry up  The unique environment will be destroyed

 How will Las Vegas meet the demands of its growing population and tourism industry?  How important is the natural environment compared to urban lifestyles and jobs?