01 · The problem
What is happening
The Phoenix area draws water from the Colorado River via the Central Arizona Project, from the Salt and Verde rivers, and from groundwater. A multi-decade drought and overallocation on the Colorado River lowered Lake Mead, leading the US Bureau of Reclamation to declare shortage conditions and reduce Arizona's allocation. Arizona's 1980 Groundwater Management Act requires new developments in active management areas to demonstrate an assured water supply.
High severity. Serious, widespread effects requiring sustained action. Severity is descriptive editorial metadata summarising documented effects. It is not a measured index or a score.
02 · Causes
Why it is happening
- 01
Long-term drought
Reduced snowpack and runoff in the Colorado River basin.
- 02
Overallocation
Legal allocations exceed the river's reliable flow.
- 03
Population growth
Rising demand in a fast-growing region.
03 · Impacts
Who and what it affects
- 01
Reduced supply
Shortage declarations cut Colorado River deliveries, especially to agriculture.
- 02
Limits on development
Groundwater modelling has constrained some new subdivisions.
04 · Solutions
Documented approaches
Assured water supply rules
Requirements that new development demonstrate long-term supply.
Expected effectAligns growth with available water.
Water recycling and banking
Recycled wastewater and underground storage of surplus water.
Expected effectBuilds reserves for dry years.
Conservation
Landscape conversion, efficient fixtures and pricing.
Expected effectReduces per-capita use.
05 · Key indicators
What can be measured
No reliable quantitative indicator is included for this issue. TerraLens shows figures only where a credible source supports them — consult the sources below for current data.
06 · Sources
Where this comes from
- [1]Lower Colorado Basin RegionU.S. Bureau of Reclamationusbr.gov(opens in a new tab)
- [2]Arizona Department of Water ResourcesState of Arizonaazwater.gov(opens in a new tab)
Links open the publishing organisation's site. Some point to the publisher's main page, where the named report or dataset can be found.