Grassy Trail Reservoir Report

Last Updated: December 5, 2025

Grassy Trail is a privately owned dam located in Carbon County, Utah, specifically in East Carbon City.


°F

°F

mph

Wind

%

Humidity

Summary

It was completed in 1952 and serves the primary purpose of providing water supply. The dam, which is classified as an Earth dam type, stands at a structural height of 89 feet, with a hydraulic height of 81 feet. It has a storage capacity of 1,156 acre-feet and is situated on the Whitmore Canyon Creek, within the Omaha District of the US Army Corps of Engineers.

The dam is considered to have a high hazard potential, but its condition was assessed as fair as of January 2006. Regular inspections are conducted, with the last one taking place in September 2020. The Utah Division of Water Rights regulates and inspects the dam, ensuring that it meets state safety standards. Although the dam has not undergone significant modifications in recent years, it remains a critical water infrastructure in the region, supporting the local water supply needs and contributing to the management of the surrounding drainage area.

Water resource and climate enthusiasts will find Grassy Trail to be an essential component of the water supply infrastructure in Carbon County, Utah. Its presence on the Whitmore Canyon Creek showcases the importance of dams in managing water resources in arid regions. The dam's storage capacity, inspection frequency, and regulatory oversight by the Utah Division of Water Rights highlight its significance in ensuring the safety and reliability of water supply for the residents of East Carbon City and beyond.

Year Completed

1952

Dam Length

600

River Or Stream

WHITMORE CANYON CREEK

Primary Dam Type

Earth

Hydraulic Height

81

Drainage Area

19

Nid Storage

1156

Structural Height

89

Hazard Potential

High

Nid Height

89
       
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.