Colorado Integrated River Management

• Colorado River = 2330 km long and flows through a basin of 637,000 km²
• 97% of basin in USA and 3% in Mexico
• Source: rocky mountains ; flows through semi-arid areas of Colorado plateau and has its mouth at the Gulf of California in Mexico
• Precipitation in the basin varies but has recently been drought prone due to climate change
• Other challenges e.g increased urbanisation, population increase and agricultural needs for irrigation water
• Even in 1920s it was recognised that growing western states needed water, especially in South California which has no major river to use
• In 1922, US Congress passed the Colorado Compact - an agreement between seven Western States (Arizona, New Mexico, Utah, Wyoming, Nevada, Colorado and California) on how much water they would be allocated from the river.
• The compact stated that Arizona could have up to 2.8 million acre feet per year, with other states having smaller amounts based on their populations
• 1944: further agreements and compacts to define priorities and a water treaty with Mexico to allocate water to the country
• 1956: a comprehensive development plan was developed to cover river regulation, HEP production, water rights and irrigation
• Now: 29 dams and numerous diversion projects
• Sometimes there has not been enough water to meet all allocations which led to disputes that still exist today
• All of 21st century has seen discussions for solutions but no new agreement has been reached
• 1990: lower basin US states used their full allocation for the first time making the issue worse but with drier conditions and reservoir levels falling there is not enough water to meet demand
• Environmental protection laws can complicate management e.g Grand Canyon Protection Act 1992

  E.G: Nevada tried negotiating for extra water allocation especially for Las Vegas. California introduced irrigation restrictions and is investigating desalination.
• 1996: Arizona established a Water Banking Authority with the aim of using its water share efficiently and storing surpluses in aquifers within the state (creating a water bank)