Arrowwood Lake Dam Reservoir Report
Last Updated: December 21, 2025
Arrowwood Lake Dam, located in St.
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Summary
Clair County, Illinois, stands as a testament to innovative engineering and environmental stewardship. Completed in 2001, this private-owned dam primarily serves the purpose of recreation, offering a serene oasis for water resource and climate enthusiasts to enjoy. Designed by THOVENOT, WADE & MOERCHEN, this earth dam spans 900 feet in length and reaches a height of 28 feet, with a storage capacity of 297 acre-feet.
Despite its low hazard potential, Arrowwood Lake Dam is regulated and inspected by the Illinois Department of Natural Resources, ensuring the safety and integrity of the structure. With a spillway width of 54 feet and the ability to discharge up to 1930 cubic feet per second, the dam minimizes potential risks while maximizing the recreational benefits for the surrounding community. Although the condition assessment is currently marked as "Not Available," the dam's risk assessment is rated as moderate, highlighting the importance of ongoing monitoring and management measures.
As a vital component of the local ecosystem, Arrowwood Lake Dam not only provides recreational opportunities but also serves as a critical water resource for the region. With its strategic location on the West Fork of Richland Creek, this dam plays a crucial role in maintaining water levels and supporting the surrounding wildlife. As water resource and climate enthusiasts continue to appreciate the beauty and functionality of Arrowwood Lake Dam, it serves as a reminder of the intersection between human ingenuity and environmental conservation in the face of changing climate conditions.
Year Completed |
2001 |
Dam Length |
900 |
Dam Height |
28 |
River Or Stream |
TRIB WEST FORK RICHLAND CR |
Primary Dam Type |
Earth |
Surface Area |
17 |
Drainage Area |
0.15 |
Nid Storage |
297 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
28 |
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.
Arrowwood Lake Dam