Pony Creek - Upper Reservoir Report

Last Updated: December 5, 2025

Pony Creek - Upper is a vital water supply resource located in Coos, Oregon, owned by the local government and regulated by the Oregon Water Resources Department.


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Summary

This earth dam, completed in 2001, stands at a height of 77 feet and serves the primary purpose of water supply. With a maximum storage capacity of 1680 acre-feet and a normal storage capacity of 6245 acre-feet, Pony Creek - Upper plays a crucial role in meeting the water needs of the surrounding area.

The dam has a high hazard potential but is currently in satisfactory condition, as assessed during the last inspection in November 2020. The structure features a slide (sluice gate) outlet gate and spans a length of 380 feet, with a drainage area of 2.88 square miles. Despite its critical function, the dam has not undergone significant modifications in recent years, and there is no designated emergency action plan in place.

Given its importance for water supply and potential hazards, ongoing monitoring and maintenance of Pony Creek - Upper are essential to ensure continued safety and functionality. The dam's location on Pony Creek and its impact on the surrounding environment highlight the significance of sustainable water resource management in the face of changing climate patterns and increasing water demands.

Year Completed

2001

Dam Length

380

Dam Height

77

River Or Stream

PONY CREEK

Primary Dam Type

Earth

Surface Area

273

Hydraulic Height

37

Drainage Area

2.88

Nid Storage

6245

Structural Height

51

Outlet Gates

Slide (sluice gate)

Hazard Potential

High

Nid Height

77
       
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.