WATER: the Colorado River Flashcards
how does integrated drainage basin management affect the Colorado river?
a
key facts
The source is in the Rocky Mountains
flows through the semi-arid areas of the Colorado plateau
Its mouth at the Gulf of California in Mexico
97% of the basin is in the USA
3% of the basin is in Mexico
drains 7% of the USA
supplies water to 8 states
provide drinking water for over 50 million Americans
15 dams on its course
demand and climate change have depleted storage to 48%
since the 1990s, annual Colorado flow has depleted by 15%
the 11-year average temperature has increased by 2 degrees Celsius sin 1970
the Colorado River Basin has been in persistent drought since 2000
has experienced persistent drought since 2000
Integrated Drainage Basin Management Plan
agencies in California, Arizona and Nevada are working on plans to reduce their extraction
Mexico takes 10% of water flow
California takes 20% more than its allocation
Native Americans are allocated 5% but could claim more
heavy pumping of groundwater aquifers that slowly feed the river has led to reduced base flow and declining aquifers in parts of the river basin
timeline
1922: 7 states agreed to basin plan that was divided into upper and lower sections for management purposes, water was allocated by state
1944: further agreements 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 projects, water rights and irrigation
1990: the lower basin US states used their full allocations for the first time, causing drier conditions and reservoir levels to fall
1992: Grand Canyon Protection Act was established
1996: Arizona established Water Banking Authority to use its water share more efficiently and store surpluses in aquifers within the state (creating a water bank)
2007: new agreement was reached
2012: the agreement Minute 139 was signed between the USA and Mexico and gives Mexico the right to store some of its water in Lake Mead
