Twp Road 18 Reservoir Report
Nearby: Monroe 13 & Redwood Co. Monroe Twp 3
Last Updated: December 12, 2025
Twp Road 18 is a vital flood risk reduction structure located in Tracy, Minnesota, along the Cottonwood River.
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Summary
Built in 2000 by MNDOT, this earth dam stands at 23 feet tall and spans 600 feet in length. Its primary purpose is flood risk reduction, with a normal storage capacity of 1 acre-foot and a maximum discharge rate of 556 cubic feet per second. Despite its low hazard potential and satisfactory condition assessment, the dam is under state regulation by the Minnesota Department of Natural Resources, Environmental and Water Resources Division.
The dam's design features a buttress core type and an uncontrolled spillway, with an unlisted/unknown foundation. It is inspected every 8 years, with the last assessment conducted in 2016. The structure has a moderate risk assessment rating of 3, indicating a need for ongoing risk management measures. While no Emergency Action Plan (EAP) or inundation maps have been prepared, the dam's emergency contacts and risk management procedures are up to date. With its critical role in protecting the surrounding area from flooding, Twp Road 18 remains a key asset in water resource management for Lyon County.
Water resource and climate enthusiasts will appreciate the detailed information available for Twp Road 18, showcasing its importance in flood risk reduction efforts in Minnesota. The dam's location, design specifications, and regulatory oversight provide insight into the complexities of managing water infrastructure in environmentally sensitive areas. As climate change continues to impact precipitation patterns and water levels, structures like Twp Road 18 play a crucial role in safeguarding communities and ecosystems from the threat of flooding. By understanding the nuances of this dam's construction, maintenance, and risk assessment, enthusiasts can gain a deeper appreciation for the intersection of water resources and climate resilience in the region.
Year Completed |
2000 |
Dam Length |
600 |
Dam Height |
23 |
River Or Stream |
COTTONWOOD RIVER-OS |
Primary Dam Type |
Earth |
Surface Area |
1 |
Drainage Area |
5 |
Nid Storage |
88 |
Structural Height |
24 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
24 |
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.
Area Campgrounds
| Location | Reservations | Toilets |
|---|---|---|
Swift Lake Park
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Garvin CP- Lower Campground
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Garvin CP - Upper Campground
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Sundquist Park at West Lake Sarah
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Twp Road 18