Wills Reservoir Report

Last Updated: December 5, 2025

Wills is a privately owned earth dam located in Jackson County, Colorado, with a primary purpose of irrigation.


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Summary

Completed in 1917, this dam stands at 13 feet high and has a length of 250 feet, providing storage for up to 60 acre-feet of water. Situated on Sixmile Creek-OS, the dam's location in Saratoga, Wyoming, makes it a pivotal resource for water management in the region.

Despite its age, Wills has a low hazard potential and is currently rated as "Not Rated" in terms of condition assessment. With a risk assessment categorizing it as high, there is a need for continued monitoring and risk management measures to ensure the safety and reliability of this crucial water resource infrastructure. The last inspection of Wills took place in August 1989, emphasizing the importance of regular assessments to safeguard against potential failures.

In light of its historical significance and continued importance for irrigation in the area, Wills serves as a reminder of the intricate balance between water resource management and climate resilience. As climate change poses new challenges for water availability and infrastructure durability, the preservation and upkeep of dams like Wills are essential for sustainable water resource management in the face of evolving environmental conditions.

Year Completed

1917

Dam Length

250

Dam Height

13

River Or Stream

SIXMILE CREEK-OS

Primary Dam Type

Earth

Surface Area

10

Hydraulic Height

13

Nid Storage

60

Structural Height

13

Hazard Potential

Low

Nid Height

13
       
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.