Rio Vista Reservoir Report

Last Updated: December 13, 2025

Rio Vista, a private water resource located in Payette River, Idaho, is a significant recreational site built in 1971 with a dam height of 20.3 meters and a storage capacity of 41 million cubic meters.


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Summary

Managed by the Idaho Department of Water Resources, this earth dam serves as a popular spot for outdoor enthusiasts seeking activities like fishing and boating on the Hyde Creek and Salmon River. Despite being labeled as having a "significant" hazard potential, the dam's fair condition assessment and controlled spillway with a width of 8 meters ensure safety measures are in place.

With a drainage area of 0.3 square kilometers and a maximum discharge capacity of 118 cubic meters per second, Rio Vista offers an expansive surface area of 11 hectares for recreational use. The dam's structural integrity is regularly inspected, with the last assessment conducted in September 2020. Managed for recreation purposes and with a very high risk assessment rating, Rio Vista remains a vital water resource in Valley County, providing both enjoyment and essential water management functions for the region. As the climate changes and water resources become increasingly important, the sustainable management of sites like Rio Vista will be crucial for ensuring continued access to clean water and recreational opportunities.

Year Completed

1971

Dam Length

700

Dam Height

20.3

River Or Stream

HYDE CREEK SALMON RIVER

Surface Area

11

Hydraulic Height

12.7

Drainage Area

0.3

Nid Storage

41

Outlet Gates

Slide (sluice gate)

Hazard Potential

Significant

Foundations

Rock, Soil

Nid Height

20
       
Seasonal Comparison

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Dam Data Reference

Condition Assessment

Satisfactory
No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.

Hazard Potential Classification

High
Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.