Sewage Lagoon Reservoir Report

Last Updated: December 16, 2025

Sewage Lagoon, located in Sweetwater, Wyoming, is a privately owned water resource structure designed by George C.


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Summary

Toland in 1976. This Earth dam stands at a height of 12 feet with a hydraulic height of 9 feet, serving a primary purpose other than flood control. With a storage capacity of 148 acre-feet, this lagoon covers an area of 18 acres and has a low hazard potential as assessed in 2019.

Despite being state regulated and permitted by the Wyoming SEO, Sewage Lagoon has a fair condition assessment and a high risk assessment due to its location in a high-risk area. The structure lacks a spillway and outlet gates, with no associated locks or drainage area. The last inspection in 2019 revealed no major issues, but the risk management measures and emergency action plan status remain unclear. Sewage Lagoon presents a unique challenge for water resource and climate enthusiasts, highlighting the importance of infrastructure maintenance and risk mitigation in managing wastewater systems.

Year Completed

1976

Dam Length

3900

Dam Height

12

River Or Stream

NONE

Primary Dam Type

Earth

Surface Area

18

Hydraulic Height

9

Nid Storage

148

Structural Height

12

Outlet Gates

None

Hazard Potential

Low

Foundations

Soil

Nid Height

12
       
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.