D.O.E. Rocky Flats B-5 Reservoir Report

Last Updated: December 5, 2025

D.O.E.


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Summary

Rocky Flats B-5, also known as South Walnut Creek No. 5, is a federally-owned dam located in Westminster, Colorado. Built in 1979, this earth dam stands at a height of 48 feet and serves the primary purpose of flood risk reduction along the Walnut Creek. Managed by the Department of Energy, this dam has a storage capacity of 70.9 acre-feet and a normal storage level of 14.3 acre-feet, covering a surface area of 2.17 acres.

Despite its low hazard potential, D.O.E. Rocky Flats B-5 is subject to state regulations and inspections by the Colorado Division of Water Resources. With a maximum discharge capacity of 3500 cubic feet per second and an uncontrolled spillway width of 80 feet, this dam plays a crucial role in mitigating flood risks in the area. While the condition assessment of the dam is currently listed as "Not Available," its risk assessment is rated as moderate.

In the event of an emergency, the preparedness measures and risk management protocols for D.O.E. Rocky Flats B-5, as well as the existence of an Emergency Action Plan, are not currently specified in the data. However, with its strategic location and vital role in flood control, this dam remains a significant asset in the water resource management and climate resilience efforts in Jefferson County, Colorado.

Year Completed

1979

Dam Length

550

Dam Height

48

River Or Stream

WALNUT CREEK

Primary Dam Type

Earth

Surface Area

2.17

Hydraulic Height

51

Drainage Area

0.58

Nid Storage

70.9

Structural Height

57

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

57
       
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.