Flow Restoration Toolbox

The western United States has experienced rapid population growth and all of the challenges that come with it over the past decade.  Growing environmental water demands associated with population growth and shifting economies have increased pressure on existing agricultural water users.  Market-based water transactions have emerged as tools to restore environmental flows while supporting traditional communities.  These transactions range from small-scale, partial season management agreements to large-scale, permanent water conservation projects.   The patchwork of legal, social, and economic frameworks spread across the region both allow for and limit the suitability of temporary and permanent water transactions

Temporary transactions provide the flexibility necessary to restore flows in areas with active agricultural communities.  Leases legally protect environmental flows against withdrawals by downstream users.  Split season leases legally protect environmental flows during part of the year and allow for irrigation during the rest of the year.  Management agreements, another type of temporary transaction, restore environmental flows through contractual arrangements. These three approaches restore environmental flows while allowing for long-term agricultural production.  Their relatively low costs make them well suited to testing the complex legal, administrative and management issues that accompany environmental flow transactions.

Permanent transactions provide long-term ecological benefits.  Water right purchases typically move water rights from agricultural to environmental uses.   They restore base flow during the irrigation season.  Purchasing storage water rights provides the additional flexibility necessary to address specific environmental flow needs.

These purchases permanently move water away from agriculture, a trend that sometimes leads to perceived conflict and decreased future restoration opportunities.  To avoid these perceived conflicts, restoration partners apply tools that improve irrigation efficiency while legally protecting environmental flows.  Reducing conveyance losses and increasing on-farm efficiencies can, under the appropriate legal framework, restore base flows during the irrigation season.  Additional approaches to environmental flow restoration focus on changing the source of irrigation water.  Moving a diversion downstream, moving a diversion from a headwater stream to a receiving stream, and moving from a surface water diversion to a groundwater diversion may legally protect base flows between the original point of diversion and the new point of diversion.

The transaction types identified here typify projects completed by agencies and organizations across the western United States.  Each transaction type may not be suitable to meet environmental flow goals or legally, socially and economically feasible in all locations.  They demonstrate the range of environmental flow transactions possible under existing water laws.