Roc-Mar-Ton Lake Dam Reservoir Report
Last Updated: December 26, 2025
Roc-Mar-Ton Lake Dam, also known as County Line Fishing Lake Dam, is a private-owned structure located in Madison, Indiana.
°F
°F
mph
Wind
%
Humidity
Summary
Completed in 1929, this earth dam stands at a height of 21 feet and has a length of 450 feet, creating a reservoir with a normal storage capacity of 30 acre-feet. The dam serves primarily for recreational purposes, offering an 8.07-acre surface area for activities such as fishing and boating.
Despite its recreational importance, Roc-Mar-Ton Lake Dam poses a high hazard potential with a poor condition assessment, last evaluated in 2008. The dam's spillway is of the uncontrolled type and has a width of 70 feet, allowing for a maximum discharge of 1590 cubic feet per second. The dam is regulated by the Indiana Department of Natural Resources and undergoes periodic inspections, with the last one conducted in November 2016.
With a moderate risk rating of 3, Roc-Mar-Ton Lake Dam requires attention and management to ensure the safety of the surrounding community and the preservation of the water resource. As a significant contributor to the local environment and recreation opportunities, efforts to improve the dam's condition and emergency preparedness are essential to mitigate potential risks and maintain the sustainability of this valuable asset.
Year Completed |
1929 |
Dam Length |
450 |
Dam Height |
21 |
River Or Stream |
LITTLE CREEK |
Primary Dam Type |
Earth |
Surface Area |
8.07 |
Hydraulic Height |
21 |
Drainage Area |
4.94 |
Nid Storage |
97 |
Structural Height |
21 |
Outlet Gates |
None |
Hazard Potential |
High |
Nid Height |
21 |
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.
Roc-Mar-Ton Lake Dam