Petro No. 1 Dam Reservoir Report

Last Updated: December 14, 2025

Located in Natrona County, Wyoming, the Petro No.


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Summary

1 Dam stands as a crucial water resource managed by the Bureau of Land Management. Constructed in 1999, this gravity dam serves a primary purpose beyond just water retention. With a structural height of 27 feet and a hydraulic height of 20 feet, Petro No. 1 Dam holds a storage capacity of 57.04 acre-feet, making it a key component in water management for the surrounding area.

Rising on the unnamed draw, this dam covers a surface area of 3.9 acres and has a drainage area of 0.19 square miles. The dam's spillway type is uncontrolled, with a width of 1 foot, and it has a low hazard potential with a fair condition assessment. Despite its moderate risk rating, Petro No. 1 Dam has undergone regular inspections, with the last one conducted in July 2017. With its strategic location and significant role in water storage, Petro No. 1 Dam remains a vital asset in ensuring water security and climate resilience in the region.

Managed by the Bureau of Land Management, Petro No. 1 Dam plays a crucial role in water management for the city of Midwest and the surrounding areas. With its fair condition assessment and low hazard potential, this gravity dam continues to support various purposes beyond water retention. As climate change impacts water resources, Petro No. 1 Dam stands as a reliable structure in maintaining water security and adapting to evolving environmental conditions.

Year Completed

1999

Dam Length

314

River Or Stream

UNAMED DRAW

Primary Dam Type

Gravity

Surface Area

3.9

Hydraulic Height

20

Drainage Area

0.19

Nid Storage

57.04

Structural Height

27

Outlet Gates

None

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

27
       
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.