Excerpts from email exchange with Dr. Roger Tall, on behalf of the HOA, requesting information from Cynthia Bridge-Clark, representing the Idaho Department of Water Resources:
[Cynthia Bridge-Clark:] I received your inquiry about the status of the Island Park Reservoir Enlargement Project (Project) and understand you would like to pass this information along to others. The following is an update on the project status and responses to your specific questions.
Project Background:
Under the direction of Idaho’s Governor and Legislature, the IWRB pursues opportunities to increase water supply statewide, and supports projects that help address regional water supply needs and promote water supply resiliency. These include new surface water storage projects, ground recharge, cloud seeding, demand reduction, and financing improvements to existing water projects.
The Island Park Reservoir enlargement concept was identified by the U.S. Bureau of Reclamation (Reclamation) and stakeholders in the Henry’s Fork Basin Study (Basin Study) as a new surface storage alternative that could provide additional water supply to help meet demand regionally in the Henry’s Fork Basin and Eastern Snake Plain. The Basin Study provided a high-level inventory or evaluation of a number of potential water storage sites and other water management options in the Henry’s Fork basin. The raise of the Island Park Reservoir was identified as an option to secure additional storage with minimal modifications to the existing dam and appurtenant structures. Specifically, the concept involved utilizing storage space secured under a permanent flowage easement which conveyed control of relevant property to Reclamation for reservoir operations and periodic inundation (flowage or flood easement) to increase the normal operating reservoir water surface elevation of 6303 feet by as much as four feet to a potential full pool elevation of 6307 feet. Conversion of the existing flood easements around the reservoir to active storage would result in an estimated 26,000 to 35,000 acre-feet of additional storage space, and minimize the impacts and costs generally associated with the construction of a new dam.
Land assessment:
The alternatives developed in the Basin Study were evaluated at a conceptual level, recognizing that additional data collection, feasibility-level analysis, and environmental compliance studies would be required for further project development. Given the limited level of analysis of the reservoir inundation area in the Basin Study, the IWRB, in consultation with Reclamation, determined there was a need to further analyze of potential effects to land and infrastructure surrounding the reservoir prior to initiating a comprehensive feasibility study or Environmental Impact Study. The IWRB commissioned an evaluation of potential effects to residential property, utilities, septic systems, and other infrastructure resulting from an increased full-pool elevation (land assessment study). Detailed elevation data for the reservoir was not available during the Basin Study; therefore LIDAR and orthoimagery was collected to provide high resolution elevation data and corresponding imagery for use in the Land Assessment Study. This data is publicly available for other purposes.
The study included evaluation of a variety of available data, development of base mapping (including field reconnaissance for mapping accuracy), water surface rise simulations, and preparation of a Land Assessment Report. While the study did not include field verification or survey of infrastructure, basements, or septic systems, it provided a summary of the relative scale of potential effects for a raise in the water surface elevation from 6303 feet to 6307 feet (1-foot increments). The results of the study are published on the IWRB’s webpage (https://idwr.idaho.gov/IWRB/projects/island-park/).
Flowage or flood easements:
As documented in the Land Assessment Study, the permanent flowage easement conveyed control of relevant property to Reclamation related to reservoir operations and periodic inundation of the described lands. Based upon information provided by Reclamation, it was determined that much of the property that may be affected by an increase in full pool elevation are encumbered by Reclamation flowage easements, though some expansion of the flowage easements in limited areas around the reservoir would be required to accommodate a rise in water surface elevation. The study did not analyze the flowage easements and recommended further clarification by Reclamation as it is important to understand the easement authorities within the areas of potential inundation, particularly in areas in which private residences were constructed. The study also noted the benefit of working with local jurisdictions to preclude further infringement on existing flowage easements.
As proposed in the Basin Study, the Island Park Reservoir Enlargement concept envisioned conversion of existing reservoir space secured under Reclamation’s flood easements for appropriation of water supply for regional benefits. To complete the IWRB’s understanding of the viability of this opportunity, the IWRB is coordinating with Reclamation, with legal support from the Attorney General’s Office, to clarify federal flowage and flood easement authorizations, the areas encumbered, and impacts of encroachment on the easement to potential new water storage for regional benefits.
Questions: [questions were sent by Dr. Tall, the responses are from Cynthia Bridge-Clark]
- Has the Attorney General’s office rendered an opinion regarding shoreline easements for Welling, Bills Island, Silverhawk, Centennial Shores, and McRae Ranch?
The Attorney General’s office is providing legal to support the IWRB in its coordination with Reclamation. It has not completed its review as it has been supporting current priority IWRB projects and initiatives.
- Is raising the Island Park Reservoir still being studied?
The IWRB has not initiated any additional studies of the Project.
- Is there a public or Zoom meeting scheduled this summer to report/discuss raising the reservoir?
Due to other priority projects, the IWRB is not currently scheduled to discuss the Island Park Reservoir project. However, upon completion of the legal review of the flowage easements, the IWRB will convene a meeting open to the public.
- Does the IDWR have an environmental impact study and a DEQ opinion regarding changes in water quality from raising the reservoir?
The IWRB and Reclamation have not initiated the environmental compliance studies or other feasibility studies necessary to move forward with a change in reservoir operations or an increase in the normal operating pool of the reservoir.
- Is the IWRB aware that hundreds of concerned citizens have sent letters to Governor Little in opposition to raising the reservoir, asking him to stop the study?
The IWRB is aware of and appreciates the concerns of the property owners as well as interest expressed by stakeholders in support of the project for its potential benefit to water quality, temperature, and water supply.
I hope this helps address some of your immediate questions. We will notify you and other stakeholders who have expressed interest in the project when additional information is available.