Twain Harte Reservoir Report

Last Updated: December 5, 2025

Twain Harte, a private water resource structure located in Mono Vista, California, stands as a vital entity for water supply in the area.


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Summary

This multi-arch dam, completed in 1928, boasts a height of 36 feet and a storage capacity of 143 acre-feet. The dam serves not only for water supply but also for recreational purposes, highlighting its role in the community's livelihood and enjoyment.

Managed by the California Department of Water Resources (DWR) and regulated for safety, Twain Harte's dam stands as a symbol of water resource management in the region. With a significant hazard potential but a satisfactory condition assessment, the dam is crucial for ensuring water security while mitigating potential risks. The last inspection in September 2020 affirmed its operational integrity, demonstrating its reliability in safeguarding the surrounding environment.

With a drainage area of 1.04 square miles and a spillway type yet to be specified, Twain Harte's dam remains a focal point for water enthusiasts and climate advocates alike. Its historical significance, combined with its modern-day functionality, underscores the importance of sustainable water management practices in the face of changing climate conditions. As a key element in the local water infrastructure, Twain Harte's dam continues to play a crucial role in ensuring water security and environmental resilience in the region.

Year Completed

1928

Dam Length

325

Dam Height

36

River Or Stream

unnamed creek

Primary Dam Type

Multi-Arch

Surface Area

12

Hydraulic Height

36

Drainage Area

1.04

Nid Storage

143

Hazard Potential

Significant

Nid Height

36
       
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.