Gatfield No 1 Reservoir Report
Last Updated: December 19, 2025
Gatfield No 1, also known as Gatfield Lower Dam, is a privately owned structure located in Gem County, Idaho.
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Summary
Completed in 1938, this earth dam stands at a height of 16.2 feet and has a hydraulic height of 13.3 feet. It serves as a crucial resource for water management in the area, with a normal storage capacity of 14 acre-feet and a drainage area of 0.5 square miles, primarily impacting Rock Creek and the Payette River.
Despite its age, Gatfield No 1 has been consistently regulated and inspected by the Idaho Department of Water Resources, ensuring its structural integrity and safety. The dam has a fair condition assessment and is classified as having a significant hazard potential, with a moderate risk level. With a spillway width of 9 feet and a maximum discharge capacity of 26 cubic feet per second, the dam plays a vital role in flood control and water storage in the region, contributing to the overall water resource management efforts.
As a key component of the water infrastructure in the area, Gatfield No 1 continues to be an important structure for water resource enthusiasts and climate advocates alike. Its history, design, and impact on the surrounding environment make it a fascinating subject for those interested in the intersection of water management, engineering, and environmental sustainability. The ongoing maintenance and regulatory oversight of Gatfield No 1 reflect a commitment to preserving and enhancing water resources for future generations, highlighting the importance of responsible stewardship of our natural resources.
Year Completed |
1938 |
Dam Length |
400 |
Dam Height |
16.2 |
River Or Stream |
ROCK CREEK PAYETTE RIVER |
Surface Area |
4 |
Hydraulic Height |
13.3 |
Drainage Area |
0.5 |
Nid Storage |
14 |
Hazard Potential |
Significant |
Foundations |
Rock, Soil |
Nid Height |
16 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Payette River Nr Horseshoe Bend Id
|
2790cfs |
Payette River Nr Emmett Id
|
1660cfs |
Spring Valley Creek Nr Eagle Id
|
0cfs |
Dry Creek Nr Eagle Id
|
0cfs |
Eagle Drain At Eagle
|
7cfs |
Nf Payette River Nr Banks Id
|
638cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Gatfield No 1