Big Sandy Creek Watershed S-23 Reservoir Report
Last Updated: December 5, 2025
Big Sandy Creek Watershed S-23, also known as Lasater South, is a vital flood risk reduction structure located in Matheson, Colorado.
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Summary
Managed by the local government, this earth dam was completed in 1959 by the USDA NRCS and is regulated by the Colorado Division of Water Resources. With a height of 22 feet and a length of 1267 feet, the dam provides protection to the Big Sandy Creek-TR and has a maximum discharge capacity of 1736 cubic feet per second.
Despite its low hazard potential and satisfactory condition assessment, the Big Sandy Creek Watershed S-23 poses a high risk due to its location and purpose. With a normal storage capacity of 158 acre-feet and a drainage area of 3 square miles, the dam plays a crucial role in mitigating potential flooding events in the area. Inspected every 3 years, the dam has a needle outlet gate and a spillway width of 202 feet, ensuring efficient water release during high flow periods.
In the event of an emergency, it is essential for local authorities to have an updated Emergency Action Plan (EAP) in place to guide response efforts. While the risk management measures and inundation maps for the dam are not currently documented, the structure remains a key asset in safeguarding the surrounding community from the impacts of extreme weather events and ensuring the sustainable management of water resources in the region.
Year Completed |
1959 |
Dam Length |
1267 |
Dam Height |
22 |
River Or Stream |
BIG SANDY CREEK-TR |
Primary Dam Type |
Earth |
Surface Area |
31 |
Hydraulic Height |
20 |
Drainage Area |
3 |
Nid Storage |
313 |
Structural Height |
29 |
Outlet Gates |
Needle - 0 |
Hazard Potential |
Low |
Nid Height |
29 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Big Sandy Creek Watershed S-23