Knoll Reservoir Report

Last Updated: December 5, 2025

Knoll is a state-regulated dam located in Coconino, Arizona, near the city of Winslow.


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Summary

Built in 1963, this Earth dam stands at a height of 58 feet and serves primarily as a Fish and Wildlife Pond, with additional purposes including recreation. The dam has a storage capacity of 1,774 acre-feet and covers a surface area of 77 acres, drawing water from the East Leonard Canyon Creek.

Managed by the Arizona Department of Water Resources, Knoll has a low hazard potential and a moderate risk assessment rating. The dam has not been rated for its condition, with the last inspection taking place in May 2012. It is equipped with an uncontrolled spillway with a width of 40 feet and a maximum discharge capacity of 875 cubic feet per second. While there are no locks associated with the dam, it is crucial for the conservation of fish and wildlife in the area.

Water resource and climate enthusiasts will find Knoll to be an intriguing structure due to its role in supporting local ecosystems and recreational activities. With its picturesque location in the Coconino County, this dam serves as a vital water source for the region while also providing a habitat for various species. The management and maintenance of Knoll by the Arizona Department of Water Resources ensure its continued functionality and safety for the community and the environment.

Year Completed

1963

Dam Length

500

Dam Height

58

River Or Stream

EAST LEONARD CANYON CREEK

Primary Dam Type

Earth

Surface Area

77

Hydraulic Height

58

Drainage Area

4

Nid Storage

1774

Structural Height

63

Hazard Potential

Low

Foundations

Rock, Soil

Nid Height

63
       
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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.