J-J No. 3 Reservoir Report

Last Updated: December 5, 2025

J-J No.


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Summary

3, also known as Pocket Lake, is a privately owned rockfill dam located in Sublette, Wyoming. Built in 1927, this dam serves primarily for irrigation purposes, with a storage capacity of 101 acre-feet and a normal storage of 64 acre-feet. The dam stands at 9 feet high and spans 262 feet in length, with a spillway width of 0 feet.

Despite being classified as having a low hazard potential, J-J No. 3 is considered to have a high risk due to its condition assessment being rated as fair. The dam is inspected every 5 years, with the last inspection conducted in August 2020. While there are no associated structures with this dam, it is regulated by the State of Wyoming and has state jurisdiction, permitting, inspection, and enforcement in place.

Water resource and climate enthusiasts will find J-J No. 3 an intriguing structure due to its historical significance, unique design, and the role it plays in supporting irrigation in the region. With its location on Pocket Creek and the potential risks associated with its condition, this dam serves as a reminder of the importance of proper maintenance and management of water resources for sustainable use in the face of changing climate conditions.

Year Completed

1927

Dam Length

262

Dam Height

9

River Or Stream

POCKET CREEK

Primary Dam Type

Rockfill

Surface Area

8

Hydraulic Height

5

Nid Storage

101

Structural Height

9

Outlet Gates

Other Controlled - 1

Hazard Potential

Low

Foundations

Soil

Nid Height

9
       
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.