Environmental Issues > Water Main Page > All Water Documents

Read the Report

• Full Report (PDF)

New water management strategies are needed in the western United States. With mounting populations, over-tapped rivers, extended droughts, severely damaged aquatic ecosystems, and the likelihood of future impacts from climate change, water managers face increasing challenges in locating reliable water supplies.

Some western water managers are working to conserve and reuse water supplies. However, NRDC's research has revealed another trend. Some water managers and entrepreneurs are pursuing a growing number of proposals for long-distance water supply pipelines. Some of these projects are extremely large in scale and would stretch for hundreds of miles, raising a host of questions for water policymakers and the public.

The maps below show a number of the of the more prominent pipeline projects in the West. The first map includes existing pipelines, constructed over the past century. The second map represents proposed projects that are currently at different stages of development. These projects were selected to include the largest pipeline projects, as well as broad geographic representation.

Pipeline Projects in Operation

Most of these existing pipeline projects were built in conjunction with surface storage projects on major river systems. Those surface storage projects were expensive and often came at significant environmental cost. Nevertheless, they produced relatively reliable sources of water for pipelines and aqueducts to carry to distant users.

Projects "In the Pipeline"

Most of these proposed pipeline projects do not include new surface storage facilities. This change is, to a large extent, the result of the far less abundant water sources that these projects propose to tap into. Together, this new generation of pipeline proposals represents a significant new phase in western water policy, presenting critical issues that must be closely examined before proposed projects are pursued further.

These key issues include: 1) sustainability of water sources, including potential environmental impacts, demands of existing water users, and likely impacts from climate change; 2) conflicts regarding transbasin diversions; 3) costs and potential alternatives, including water use efficiency; 4) energy use; and 5) the role of federal agencies.

Some proposed projects could have dramatic effects on the environment, on existing water users, on water rates, and on the reliability of water supplies for the communities that would be served by them.

For example, several of these proposed pipeline projects would divert water from the Colorado River. In its Colorado River Basin Study, the Bureau of Reclamation has determined that existing demand exceeds available water supply in the Colorado River Basin, and that climate change is likely to further reduce existing supplies over time. The Bureau's findings clearly demonstrate that there is no additional water available in the Colorado River Basin, suggesting that new large pipeline projects could fail to provide reliable long-term water supplies and could threaten the water supplies of other existing users who rely on the Colorado River.

last revised 2/21/2013