Geography

Advantages

• Hydro electric power produced. Provides power for growing cities eg Las Vegas.
• Cheap electric for industry
• Power used to pump water over the rocky mountains to phoenix. This has lead to expansion.
• Increase in agriculture. Farmers have increased their yields.
• Transport. Provides new links between Nevada and Arizona

Disadvantages

• Desalination plant built in Mexico which was expensive.
• Crop surplus, thus affecting crop prices
• Increased traffic congestion.
• Terrorist threats.
• New expensive bridge

Advantages

• Huge artificial lakes act as sancturies for waterfowl such as pintail.
• The land was useless before.
• Clean water which is a) better for your health.

                             b) more suitable for drinking and irrigation as sediment stays on river                                  bed. 

                             c) Renewable and pollution free.

Disadvantages

• Sediment is trapped behind the dam. Requires dredging which is costly.
• Salinisation is ruining the soil.
• Natural landscape has been lost.
• Water evaporates leaving salt which means farmers have to use more fertilisers.

Advantages

• Huge artificial lake has increased tourism. 8 million visitors per year.
• Lake Mead is a popular caravan destination.
• Prevents some flooding as snow melt is controlled.
• HEP has meant cities have expanded.

Disadvantages

• Still some flooding.
• Salinity level increasing which causes problems downstream for example at the mouth of the gulf of California. The saline levels are high so mexicans can't use the water :(

• Each state requires water. In the 1922 compact 6 states signed it to share out the water. 
• California gained the most as it had the largest population.
• When the allocations of water were calculated it was based upon a rainy year so water was exaggerated.
• Some states were not left with enough water becuase the figures were wrong.

Human

• Consider the are behind the dam incase of flooding
• Consider the flooding of historical sites etc ancient burial site.
• Consider the workforce.
• Consider the distance to farms/urban areas for HEP or irrigation.

Physical

• Deep, narrow valley to reduce cost of building it. Narrow valley =smaller surface area for evaporation.
• Strong, impermeable rock such as granite.
• Not on tectonic plates.

Site

• Built around and on the crag and tail. This was a good defensive site when the castle was built as it was hard to climb and the loch also protected the castle.
• Plenty of open space for expansion over the moorland.
• Lots of hills and hollows which means there are a lot of green spaces which gives Edinburgh a nice appearance.

Situation

• Has a good central location as several main roads meet from London, Aberdeen and Glasgow.
• Good airport, railway and port for importing goods in the past.

• Around the coast a) for trade- London for trading with Europe. Glasgow with America
•                           b) for fishing and oil- Aberdeen
•                           c) ship building- Glasgow
• Near rivers for transportation of raw materials and communication.
• Access to raw materials such as coal and iron- Glasgow
• Historical/Political purposes- Edinburgh and London
• In southern areas because the land is flatter.

• Along the coast for fishing and trading- Rio de Janeiro.
• New little settlements have located along the trans Amazon highway.
• Planned cities- Brasilia
• Inland settlements developed as route centres for coffee trading.
• Near the coast because most of the land is covered with dense vegetation and has poor infrastructure.