Cottonwood Lake Reservoir Report

Last Updated: December 13, 2025

Cottonwood Lake, located in Smoot, Wyoming, is a stunning reservoir that serves as a popular recreational spot for water resource and climate enthusiasts.


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Summary

Managed by the Forest Service, this Earth-type dam was completed in 1925 and boasts a height of 10 feet, a length of 90 feet, and a storage capacity of 240 acre-feet. The lake covers a surface area of 45 acres and is fed by Cottonwood Creek, offering visitors a picturesque setting for activities such as fishing, boating, and birdwatching.

Despite its low hazard potential, Cottonwood Lake underwent modifications in 2015 to enhance its hydraulic capabilities. With uncontrolled spillways and outlet gates, the dam is equipped to handle a maximum discharge of 1 cubic foot per second. The reservoir's risk assessment categorizes it as moderate, emphasizing the importance of regular inspections to ensure its structural integrity. While the condition assessment is currently marked as "Not Rated," ongoing management measures are in place to maintain the lake's safety and functionality for all who enjoy its natural beauty and recreational opportunities.

Years Modified

2015 - Hydraulic

Year Completed

1925

Dam Length

90

Dam Height

7

River Or Stream

COTTONWOOD CREEK

Primary Dam Type

Earth

Surface Area

45

Hydraulic Height

5

Drainage Area

7

Nid Storage

240

Structural Height

10

Outlet Gates

Uncontrolled

Hazard Potential

Low

Foundations

Unlisted/Unknown

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.