Big Swamp Reservoir Reservoir Report

Last Updated: December 5, 2025

Big Swamp Reservoir, located in Bly, Oregon, is a privately owned water resource that serves primarily for irrigation purposes.


°F

°F

mph

Wind

%

Humidity

Summary

Built in 1908, this earth dam structure stands at a height of 10 feet and has a storage capacity of 350 acre-feet. The reservoir covers an area of 37.1 acres and is fed by Cold Spring Creek, with a drainage area of 0.44 square miles.

Managed by the Oregon Water Resources Department, Big Swamp Reservoir is subject to state regulations, permitting, inspection, and enforcement to ensure its safety and efficient operation. The dam's hazard potential is classified as low, and its condition assessment is currently listed as 'Not Rated'. The outlet gates consist of a slide (sluice gate) mechanism for water release.

With its scenic location amidst nature, Big Swamp Reservoir provides a vital water source for agricultural activities in the region while also contributing to the local ecosystem. Enthusiasts of water resources and climate will find this reservoir an interesting case study of sustainable water management and the importance of maintaining infrastructure for irrigation purposes within a changing climate.

Year Completed

1908

Dam Length

150

Dam Height

10

River Or Stream

COLD SPRING CREEK

Primary Dam Type

Earth

Surface Area

37.1

Hydraulic Height

8

Drainage Area

0.44

Nid Storage

350

Structural Height

10

Outlet Gates

Slide (sluice gate)

Hazard Potential

Low

Nid Height

10
       
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.