Frankfurth Marsh Reservoir Report

Last Updated: December 5, 2025

Frankfurth Marsh, located in Dodge County, Wisconsin, is a captivating part of the larger Horicon Marsh ecosystem.


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Summary

Owned and regulated by the Wisconsin Department of Natural Resources, this Federal fish and wildlife pond serves as a crucial habitat for a variety of species. Completed in 1994, the Earth dam stands at 7 feet tall, with a storage capacity of 2900 acre-feet and a surface area of 435 acres.

With a low hazard potential and a very high risk assessment rating, Frankfurth Marsh is closely monitored and inspected every 10 years. The controlled spillway design ensures proper water management, with a maximum discharge capacity of 81 cubic feet per second. Despite being not rated for condition assessment, the marsh continues to fulfill its primary purpose as a valuable fish and wildlife pond.

The marsh's location on the Rock River, under the jurisdiction of the Rock Island District, and its proximity to HORICON make it a key component of the region's water resource management. As climate change continues to impact water availability and quality, Frankfurth Marsh's conservation efforts play a vital role in maintaining a healthy ecosystem for future generations of water resource and climate enthusiasts.

Year Completed

1994

Dam Length

6828

Dam Height

7

River Or Stream

ROCK R

Primary Dam Type

Earth

Surface Area

435

Hydraulic Height

4

Drainage Area

3.7

Nid Storage

2900

Structural Height

7

Hazard Potential

Low

Nid Height

7
       
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.