Henrys Fork Basin Study

The Bureau of Reclamation and the State of Idaho, in collaboration with a stakeholder working group, conducted a Basin Study for the Henrys Fork River basin. The overall purpose of the Basin Study was to assess current and future water supply and demand in the Henrys Fork Basin and adjacent areas that receive water from the basin, and to identify a range of potential strategies to address any projected imbalances. It also assisted the State and local planning efforts by exploring potential action alternatives for (1) meeting the complex water supply and management challenges in the basin, (2) meeting the goals of the Eastern Snake Plain Aquifer (ESPA) Comprehensive Aquifer Management Plan (CAMP) and Idaho State Water Plan, and (3) identifying risks posed to water supply by climate change and opportunities to mitigate that risk through developing water supplies, improving water management, and sustaining or improving environmental quality and ecological resiliency.

The study area is upstream of the Henrys Fork River’s confluence with the Snake River and includes the North Fork of the Upper Snake River, Fall River, and Teton River watersheds. It is also situated above part of the ESPA.

The study identified opportunities for development of water supplies (i.e., above-ground storage, aquifer storage) and improvement of water management (i.e., conservation measures, optimization of resources) while sustaining environmental quality. Alternatives were developed in accordance with the managed aquifer recharge program of the Idaho Water Resource Board and the goals of the ESPA CAMP, and in consideration of the environmental impacts to the entire Snake River basin.

Federal water development projects on the Snake River above Milner Dam near Burley, Idaho provide full or supplemental water supply to more than one million acres of irrigated land. Over 1.4 million acres are irrigated by privately developed irrigation systems from natural flows in the Snake River and its tributaries or groundwater from the ESPA.

The alternatives formulated during the Basin Study were evaluated and compared to understand how they met the Basin Study objectives. The comparison considered four key parameters traditionally used by Reclamation when examining alternatives for fatal flaws: 1) effectiveness of an alternative to enhance water reliability; 2) costs; 3) environmental effects; and 4) local acceptance by stakeholders. The key parameters were based on how well an alternative meets the stated objectives of the Basin Study which are to reduce risks to water supply from climate change through improved water supply and improved water management and to sustain or improve environmental quality and ecological resiliency in the Henrys Fork River basin.

The analysis of water supply and storage alternatives involved identification and evaluation of watershed hydrology and potential onstream and offstream storage sites. The focus will be on the availability, characterization, and quantification of the natural hydrology of the basin, including:

  • seasonal volume of runoff and stored water available;
  • surface water/groundwater interactions;
  • irrigated agricultural areas;
  • instream and offstream water uses;
  • irrigation water distribution facilities and their operation; and
  • the current characteristics and quality of riparian habitat.

With the completion of the Henrys Fork Basin Study, it can be used to assist future planning efforts and to provide specialized information that can be used for future decision-making processes at the state and local levels.

Reclamation's Basin Study Program >>
Meeting Notes and Handouts >>
Reference Documents >>
Status Reports >>
Technical Series Reports >>

Henrys Fork Special Study Documents
06/2015 Basin Studies Provide Options for Communities to Meet Future Water Needs in the Western United States HTML
06/2015 Henrys Fork Basin Study Final Report HTML
07/2013 Henrys Fork Basin Study Interim Report HTML
04/2012 List of Reconnaissance Alternatives PDF 81 kb
04/2010 Framework for a Special Study on Water Supply on the Henrys Fork of the Snake River Basin PDF 221 kb
04/2010 Location Map PDF 488 kb
04/2010 General Reference Map PDF 396 kb
News Releases
02/05/2013 Henrys Fork Basin Special Study Interim Report Outlines Proposed Alternatives for Idaho's Water Needs HTML


Jessica Peters
CPN Region Basin Studies Coordinator

Bureau of Reclamation
Columbia–Pacific Northwest Region
1150 N. Curtis Road
Boise, ID 83706

Last Updated: 10/4/23