Marys Lake Reservoir Report

Last Updated: December 5, 2025

Marys Lake is located in Estes Park, Colorado, and was named after the wife of an early settler in the area.


°F

°F

mph

Wind

%

Humidity

Summary

The lake is fed by snowmelt and runoff from the surrounding mountains, and is part of the Big Thompson River watershed. The lake is approximately 15 acres in size and has a maximum depth of 30 feet. The surrounding area is known for its recreational activities, including fishing, boating, and hiking. The lake is also used for irrigation purposes by local agricultural communities. During the winter months, the snowpack that accumulates in the surrounding mountains provides a critical source of surface flow to the lake and the surrounding areas. Marys Lake is an important part of the region's hydrology and plays a vital role in supporting both agricultural and recreational activities in the area.

Reservoir Details

Storage 24hr Change -0.81%
Percent of Normal 100%
Minimum 16.0 acre-ft
2011-12-02
Maximum 1,060.0 acre-ft
1999-11-12
Average 684 acre-ft
Nid_Height 35
Hydraulic_Height 25
Primary_Dam_Type Earth
Year_Completed 1949
Dam_Height 35
Structural_Height 35
River_Or_Stream FISH CREEK TR, BIG THOMPSON RIVER
Surface_Area 40
Hazard_Potential High
Nid_Storage 1149
Dam_Length 950
       
Seasonal Comparison
Storage Levels
Storage Levels
Pool Elevation Levels

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.