Bowman Arch Reservoir Report

Last Updated: December 5, 2025

Bowman Arch, located in California's Nevada County, is a stunning arch dam constructed in 1927 for irrigation purposes.


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Summary

With a height of 105 feet and a storage capacity of 68,500 acre-feet, this dam plays a crucial role in water management in the region. The dam also serves multiple purposes including hydroelectric power generation, recreation, and water supply, highlighting its importance in the local ecosystem.

Managed by the Federal Energy Regulatory Commission, Bowman Arch has a spillway width of 114 feet and a maximum discharge of 19,500 cubic feet per second. The dam's hazard potential is classified as high, emphasizing the need for regular inspections and maintenance to ensure its safety and integrity. With a history dating back almost a century, Bowman Arch stands as a testament to engineering excellence and the importance of water resource management in mitigating climate challenges and supporting sustainable development in the region.

As a multi-purpose structure with a very high risk assessment rating, Bowman Arch embodies the intricate balance between water resource utilization and environmental conservation. Its association with controlled spillways and radial outlet gates underscores the technological sophistication of the dam. With a primary focus on irrigation, the dam continues to play a vital role in supporting agriculture and water supply needs in the area. For water resource and climate enthusiasts, Bowman Arch serves as a remarkable example of sustainable infrastructure that adapts to changing environmental conditions while meeting the diverse needs of the community.

Year Completed

1927

Dam Length

567

Dam Height

105

River Or Stream

Canyon Creek

Primary Dam Type

Arch

Surface Area

810

Hydraulic Height

105

Drainage Area

29

Nid Storage

68500

Structural Height

109

Outlet Gates

Tainter (radial) - 7

Hazard Potential

High

Foundations

Rock

Nid Height

109
       
Seasonal Comparison

Weather Forecast

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.