Polaris

Polaris is an earth dam located in Laramie County, Wyoming, built in 1909. It carries a Significant hazard potential classification and has a poor condition assessment.

About Polaris

The primary purpose of Polaris is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Terry Grazing Association (private). It impounds the Lone Tree Creek Offstream near Timnath, Colorado.

The dam stands 51 feet tall and stretches 1,071 feet across, creates a reservoir covering 57 acres, has a maximum storage capacity of 687 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1909, the structure is over a century old.

This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. The most recent inspection on record was 05/10/2022.

At 51 feet, this dam is taller than 93% of dams nationwide.

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Significant HazardPoor ConditionEmergency Action Plan: Not Required

Location

StateWyoming
CountyLaramie
Nearest CityTimnath, Colorado
River/StreamLone Tree Creek Offstream
Coordinates41.02790, -104.89000

Physical Characteristics

Dam TypeEarth
NID Height51 ft
Dam Height41 ft
Dam Length1,071 ft
Year Completed1909 (117 years old)

Storage & Hydraulics

NID Storage687 acre-ft
Max Storage687 acre-ft
Normal Storage608 acre-ft
Surface Area57 acres
Drainage Area2 sq mi
Spillway TypeNone

Ownership & Safety

PurposeIrrigation
OwnerTERRY GRAZING ASSOCIATION
Owner TypePrivate
Hazard ClassificationSignificant
Condition AssessmentPoor
Last Inspection05/10/2022
Emergency Action PlanNot Required

Identifiers

NID IDWY00047
Federal IDWY00047
More InfoState Dam Safety Program

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