Lawson Subwatershed Site 3-1 Reservoir Report
Last Updated: December 14, 2025
Lawson Subwatershed Site 3-1, located in Monona, Iowa, is a key water resource managed by the Natural Resources Conservation Service.
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Summary
This earth dam, completed in 1968, serves multiple purposes including fire protection, stock watering, and small fish pond management. With a maximum storage capacity of 61 acre-feet and a drainage area of 0.55 square miles, this dam plays a crucial role in flood risk reduction and water conservation in the region.
Situated on the TR-Maple River, Lawson Subwatershed Site 3-1 has a low hazard potential and is currently rated as "Not Rated" in terms of condition assessment. Despite its structural integrity, the dam has a moderate risk level of 3, prompting the need for ongoing risk management measures. The site's emergency action plan (EAP) status, inundation maps, and risk assessment guidelines are currently not available, highlighting the importance of further evaluation and preparedness to ensure the safety and resilience of this vital water resource in the face of changing climate conditions. With its strategic location and significance for the local community, Lawson Subwatershed Site 3-1 serves as a valuable asset for water resource and climate enthusiasts seeking to understand the intricate balance between water management, infrastructure development, and environmental stewardship.
Year Completed |
1968 |
Dam Length |
556 |
Dam Height |
30 |
River Or Stream |
TR-MAPLE RIVER |
Primary Dam Type |
Earth |
Surface Area |
2.8 |
Drainage Area |
0.55 |
Nid Storage |
61 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
30 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Maple River At Mapleton
|
323cfs |
Little Sioux River Near Turin
|
1040cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
West Fork Ditch At Hornick
|
80cfs |
Missouri River At Decatur
|
14900cfs |
Soldier River At Pisgah
|
112cfs |
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.
Lawson Subwatershed Site 3-1