Marys Lake Dike No. 1 Reservoir Report

Last Updated: December 4, 2025

Marys Lake Dike No.


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Summary

1 is a federally-owned structure located in Larimer, Colorado, near the city of Estes Park. Built in 1948 by the Bureau of Reclamation, this earth dam stands at a height of 29 feet and spans 820 feet in length. Its primary purpose is for hydroelectric use, with a storage capacity of 1,149 acre-feet and a normal storage level of 927 acre-feet.

The dam sits on the Fish Creek Tributary and is regulated by the Colorado Department of Water Resources. With a high hazard potential and risk assessment rating of 2, Marys Lake Dike No. 1 undergoes regular state inspections and enforcement to ensure its structural integrity and safety. Although no spillway is present, the dam's construction on rock foundations and use of arch core types contribute to its stability.

Water resource and climate enthusiasts fascinated by hydroelectric infrastructure will appreciate the historical significance and engineering details of Marys Lake Dike No. 1. Its critical role in water management and energy production underscores the importance of maintaining and monitoring such structures in the face of changing climatic conditions and evolving regulatory requirements.

Year Completed

1948

Dam Length

820

Dam Height

29

River Or Stream

FISH CREEK TR

Primary Dam Type

Earth

Surface Area

47

Hydraulic Height

19

Drainage Area

1

Nid Storage

1149

Structural Height

29

Hazard Potential

High

Foundations

Rock

Nid Height

29
       
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.