Eastdale #1 Reservoir Report

Last Updated: December 7, 2025

Eastdale #1 is a privately owned irrigation dam located in Costilla, Colorado, along the Costilla Creek.


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Summary

Built in 1909, this earth dam stands at 31 feet high and spans 2175 feet in length, with a storage capacity of 5820 acre-feet. Despite its low hazard potential, the dam's condition has been assessed as unsatisfactory, with the last inspection in May 2017 revealing the need for improvements.

The dam features two slide (sluice) gates as outlet structures and an uncontrolled spillway with a width of 75 feet. With a maximum discharge capacity of 4384 cubic feet per second, Eastdale #1 serves the critical purpose of irrigation for the surrounding area. However, with a moderate risk assessment rating and a history of unsatisfactory condition, there may be challenges ahead in ensuring the dam's safety and functionality in the face of changing climate conditions and water resource management practices.

As water resource and climate enthusiasts, keeping a watchful eye on Eastdale #1's maintenance and potential upgrades will be crucial in safeguarding its role in supporting agricultural activities and water supply in the region. With a clear understanding of the dam's history, purpose, and current condition, stakeholders can work together to address any risks and ensure the resilience of this essential infrastructure for the future.

Year Completed

1909

Dam Length

2175

Dam Height

31

River Or Stream

COSTILLA CREEK-TR

Primary Dam Type

Earth

Surface Area

336

Hydraulic Height

31

Drainage Area

12

Nid Storage

5820

Structural Height

31

Outlet Gates

Slide (sluice gate) - 2

Hazard Potential

Low

Nid Height

31
       
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.