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.