Lawson Subwatershed Site 1-1 Reservoir Report
Last Updated: December 14, 2025
Lawson Subwatershed Site 1-1, located in Monona, Iowa, is a crucial water resource managed by the local government for multiple purposes including fire protection, stock, and small fish pond usage.
°F
°F
mph
Wind
%
Humidity
Summary
This earth dam, completed in 1968, stands at a height of 39 feet and stretches 347 feet in length, with a storage capacity of 93 acre-feet. Situated on the TR-MAPLE RIVER, this dam covers a surface area of 5.9 acres and serves a drainage area of 0.4 square miles, making it a vital component in flood risk reduction efforts in the region.
Managed by the Iowa Department of Natural Resources, Lawson Subwatershed Site 1-1 has a low hazard potential and a moderate risk assessment rating. With a spillway type of 'Uncontrolled' and a spillway width of 2 feet, this dam plays a crucial role in managing water flow in times of excess rainfall. Despite its age, the dam's condition is currently 'Not Rated', highlighting the need for regular inspections and maintenance to ensure its continued effectiveness in protecting the surrounding area from potential flooding events.
Overall, Lawson Subwatershed Site 1-1 serves as a valuable asset in water resource management and climate resilience efforts in the region. With its strategic location and multi-purpose functionality, this earth dam stands as a testament to the importance of sustainable water infrastructure in safeguarding communities and ecosystems against the impacts of a changing climate.
Year Completed |
1968 |
Dam Length |
347 |
Dam Height |
39 |
River Or Stream |
TR-MAPLE RIVER |
Primary Dam Type |
Earth |
Surface Area |
5.9 |
Drainage Area |
0.4 |
Nid Storage |
93 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
39 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Little Sioux River Near Turin
|
1040cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
Maple River At Mapleton
|
323cfs |
West Fork Ditch At Hornick
|
80cfs |
Missouri River At Decatur
|
15500cfs |
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 1-1