Lake Roslyn Reservoir Report

Last Updated: December 13, 2025

Lake Roslyn, also known as Ruby Lake, is a private water resource nestled in Jackson County, Colorado.


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Summary

Built in 1938, this earth dam stands at 35 feet tall and serves multiple purposes including irrigation and recreation. With a storage capacity of 425 acre-feet, the lake covers a surface area of 27 acres and is fed by Howdy Creek. Its significant hazard potential is managed through regular inspections, with the latest assessment in 2018 deeming its condition satisfactory.

Owned by a private entity, Lake Roslyn offers a serene escape for water and climate enthusiasts seeking outdoor activities. Its uncontrolled spillway and ample storage make it a vital resource for the region, with a maximum discharge capacity of 510 cubic feet per second. The dam's structural integrity is upheld through state-regulated inspections and enforcement, ensuring the safety of its surrounding community and downstream areas along Howdy Creek.

Visitors to Lake Roslyn can enjoy the scenic views and recreational opportunities provided by its tranquil waters. From fishing and boating to picnicking along its shores, this picturesque reservoir offers a peaceful retreat in the heart of Colorado's natural beauty. With a moderate risk assessment rating and a history dating back to the early 20th century, Lake Roslyn remains a beloved destination for nature lovers and water enthusiasts alike.

Year Completed

1938

Dam Length

880

Dam Height

35

River Or Stream

HOWDY CREEK

Primary Dam Type

Earth

Surface Area

27

Hydraulic Height

26

Drainage Area

25

Nid Storage

425

Structural Height

42

Hazard Potential

Significant

Nid Height

42
       
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.