Robert Coyier Reservoir Report
Nearby: Eldon Rule Ludden Lake
Last Updated: December 12, 2025
Robert Coyier is a privately owned earth dam located in Mifflin, Wisconsin, along the TR Pecatonica River.
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Summary
Completed in 1974, this dam serves primarily for fire protection and as a stock or small fish pond. With a height of 24 feet and a hydraulic height of 15 feet, it has a storage capacity of 107 acre-feet and a drainage area of 0.2 square miles. The dam has a low hazard potential and is currently in fair condition as of the last assessment in May 2020.
Despite being privately owned, Robert Coyier is regulated by the Wisconsin Department of Natural Resources, which oversees its permitting, inspection, and enforcement. The dam has a moderate risk assessment rating of 3, indicating a level of risk that requires attention but is not immediately threatening. The dam's spillway is uncontrolled, and it has a maximum discharge capacity of 40 cubic feet per second. The last inspection of the dam was conducted in August 2010, with an inspection frequency of every 10 years.
For water resource and climate enthusiasts, Robert Coyier presents an interesting case study of a privately owned dam in rural Wisconsin. Its location along the TR Pecatonica River and its primary purposes of fire protection and stock or small fish pond highlight the diverse roles that dams play in water management. With its fair condition and moderate risk assessment, it serves as a reminder of the importance of regular inspections and maintenance to ensure the safety and reliability of such structures in the face of changing climate conditions.
Year Completed |
1974 |
Dam Length |
395 |
Dam Height |
24 |
River Or Stream |
TR PECATONICA |
Primary Dam Type |
Earth |
Surface Area |
3 |
Hydraulic Height |
15 |
Drainage Area |
0.2 |
Nid Storage |
107 |
Structural Height |
24 |
Hazard Potential |
Low |
Nid Height |
24 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Pecatonica River At Darlington
|
218cfs |
Platte River Near Rockville
|
85cfs |
Wisconsin River At Muscoda
|
5850cfs |
East Br Pecatonica River Near Blanchardville
|
162cfs |
Grant River At Burton
|
345cfs |
Sinsinawa River Near Menominee
|
19cfs |
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 |
|---|---|---|
Blackhawk Lake Rec Area - Highland
|
||
Moundview Park
|
||
Moundsview Park
|
Robert Coyier