Falxa No. 1 Reservoir Report

Last Updated: December 9, 2025

Falxa No.


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Summary

1 is a privately owned earth dam located in Johnson County, Wyoming, specifically in the city of Arvada. Built in 1958, this dam serves multiple purposes including fire protection, stock watering, and creating a small fish pond. With a height of 25 feet and a length of 255 feet, it has a storage capacity of 73 acre-feet and covers a surface area of 6 acres.

Despite its low hazard potential, Falxa No. 1 is currently in poor condition, as indicated by a recent inspection in August 2021. Its spillway type is uncontrolled, with a width of 40 feet, and it lacks outlet gates. The dam is regulated by the Wyoming State Engineer's Office and undergoes regular inspections every 5 years. While the risk assessment deems it to have a moderate risk level, there is no emergency action plan in place, raising concerns for potential safety issues in the event of a dam failure. For water resource and climate enthusiasts, monitoring the condition and maintenance of Falxa No. 1 is vital to ensure the safety and sustainability of this important water resource infrastructure.

Year Completed

1958

Dam Length

255

Dam Height

25

River Or Stream

PHILLIPS DRAW

Primary Dam Type

Earth

Surface Area

6

Hydraulic Height

20

Nid Storage

73

Structural Height

25

Outlet Gates

None

Hazard Potential

Low

Foundations

Soil

Nid Height

25
       
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.