Pleasant Valley No. 12 Reservoir Report

Last Updated: December 5, 2025

Pleasant Valley No.


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Summary

12, also known as Lucas Detention, is a private earth dam located in Winona, Minnesota. Constructed in 1968 by the USDA NRCS, this dam serves as a crucial flood risk reduction structure along the Pleasant Valley CR-TR. With a height of 30 feet and a length of 440 feet, Pleasant Valley No. 12 has a storage capacity of 30 acre-feet and a drainage area of 0.41 square miles.

Managed by the Minnesota Department of Natural Resources, this dam is regulated, permitted, inspected, and enforced by state authorities to ensure its structural integrity and functionality. The dam's hazard potential is considered significant, with a fair condition assessment as of April 2015. The last inspection date was in May 2019, with inspections conducted every four years to monitor its performance and safety. Despite its moderate risk level, Pleasant Valley No. 12 continues to play a vital role in protecting the surrounding area from potential flooding events.

Water resource and climate enthusiasts will appreciate the strategic location and design of Pleasant Valley No. 12, which showcases effective flood risk reduction measures in a high-risk area. With its uncontrolled spillway and buttress core type, this dam exemplifies efficient engineering practices to manage water flow and prevent potential disasters. As a significant structure in the St. Paul District, Pleasant Valley No. 12 stands as a testament to the collaboration between private owners, state agencies, and federal designers in safeguarding communities and ecosystems against the impacts of extreme weather events.

Year Completed

1968

Dam Length

440

Dam Height

30

River Or Stream

PLEASANT VALLEY CR-TR

Primary Dam Type

Earth

Drainage Area

0.41

Nid Storage

30

Structural Height

35

Outlet Gates

Uncontrolled

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

35
       
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.