Marian Lake Dam Reservoir Report
Nearby: Moorman Park Dam East Lake Centre Dam
Last Updated: December 19, 2025
Marian Lake Dam in Quincy, Illinois, is a privately owned earth dam primarily used for recreation purposes.
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Summary
With a height of 26 feet and a length of 330 feet, the dam holds a storage capacity of 65 acre-feet and covers a surface area of 4.2 acres. It is located on the Trib Cedar Creek and falls under the jurisdiction of the Illinois Department of Natural Resources.
Despite its recreational purpose, Marian Lake Dam poses a high hazard potential, with a moderate risk assessment rating. While the condition assessment is not available, the dam is subject to regular state inspection, enforcement, and permitting. The dam features an uncontrolled spillway type and has not been modified in recent years.
Water resource and climate enthusiasts may find Marian Lake Dam intriguing due to its unique design and significant storage capacity, providing a recreational oasis in the Adams County area. However, the high hazard potential and moderate risk assessment underscore the importance of proper maintenance and monitoring to ensure the safety of the dam and surrounding community. The involvement of the Illinois Department of Natural Resources in regulating and inspecting the dam adds an additional layer of oversight to its operations.
Dam Length |
330 |
Dam Height |
26 |
River Or Stream |
TRIB CEDAR CREEK |
Primary Dam Type |
Earth |
Surface Area |
4.2 |
Drainage Area |
0.1 |
Nid Storage |
65 |
Hazard Potential |
High |
Foundations |
Unlisted/Unknown |
Nid Height |
26 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
North River At Palmyra
|
15cfs |
South Fabius River Near Taylor
|
12cfs |
Bear Creek Near Marcelline
|
5cfs |
Wyaconda River Above Canton
|
13cfs |
Bear Creek At Hannibal
|
2cfs |
Salt River Near New London
|
82cfs |
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.
Marian Lake Dam