Left Hand Park Reservoir Report

Last Updated: December 4, 2025

Left Hand Park, located in Boulder, Colorado, along Left Hand Creek, is a privately owned irrigation dam constructed in 1966 by the USDA NRCS.


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Summary

The dam stands at 65 feet tall, with a hydraulic height of 50 feet and a length of 1325 feet, providing a storage capacity of 2075 acre-feet. The primary purpose of the dam is for irrigation, with additional uses including fire protection, stock watering, and small fish pond support.

The dam is classified as having a high hazard potential, although its condition was assessed as satisfactory during the last inspection in October 2020. It is regulated by the Colorado Department of Water Resources, with permitting, inspection, and enforcement activities overseen by state agencies. Left Hand Park Dam poses a moderate risk level, with emergency action plans in place to address any potential safety concerns.

Left Hand Park Dam is a significant water resource infrastructure in the area, serving multiple purposes while also posing potential risks that are actively managed. Its location along Left Hand Creek and its role in irrigation highlight its importance in the local water supply system. Climate and water resource enthusiasts can appreciate the engineering behind the dam's design and operations, as well as the ongoing efforts to ensure its safe and efficient functioning within the regulatory framework.

Year Completed

1966

Dam Length

1325

Dam Height

50

River Or Stream

LEFT HAND CREEK

Primary Dam Type

Earth

Surface Area

98

Hydraulic Height

50

Drainage Area

1

Nid Storage

2075

Structural Height

65

Hazard Potential

High

Nid Height

65
       
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.