Chiawana Richland Ranch Dam Reservoir Report

Last Updated: December 14, 2025

Chiawana Richland Ranch Dam, located in Richland, Washington, is a state-owned structure primarily used for irrigation purposes along the Yakima River.


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Summary

Completed in 1998, this earth dam stands at a hydraulic height of 20 feet and a structural height of 12.82 feet, with a length of 825 feet and a storage capacity of 44 acre-feet. The dam's normal storage level is 31.4 acre-feet, covering a surface area of 3.2 acres and draining an area of 0.08 square miles.

Managed by the Washington Department of Ecology, Chiawana Richland Ranch Dam has a high hazard potential but is currently in satisfactory condition, with the last inspection conducted in April 2019. While there are no associated structures or spillways, the dam is subject to state regulation, permitting, inspection, and enforcement. Situated in Congressional District 04, the dam plays a crucial role in providing water resources for irrigation in the region, highlighting the intersection of water management and climate resilience in the area.

As a key component of the water infrastructure in Benton County, Chiawana Richland Ranch Dam serves as a vital resource for agricultural activities in the region. With its strategic location offstream from the Yakima River, the dam exemplifies the importance of sustainable water management practices in mitigating the impacts of climate change on water resources. Its construction and operation are closely monitored to ensure the safety and reliability of the irrigation system, underscoring the intricate relationship between water resource management and climate adaptation efforts in the face of evolving environmental challenges.

Year Completed

1998

Dam Length

825

River Or Stream

Offstream - Yakima R

Primary Dam Type

Earth

Surface Area

3.2

Hydraulic Height

20

Drainage Area

0.08

Nid Storage

44

Structural Height

12.82

Hazard Potential

High

Foundations

Soil

Nid Height

20
       
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.