Lawson Subwatershed Site 2-2 Reservoir Report
Last Updated: December 14, 2025
Lawson Subwatershed Site 2-2 is a crucial water management infrastructure located in Monona, Iowa, specifically in the city of Castana.
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Summary
Owned by the local government and regulated by the Iowa Department of Natural Resources, this site serves multiple purposes including fire protection, stock, small fish pond, and flood risk reduction. Built in 1968 by the USDA NRCS, this earth dam stands at a height of 45 feet with a length of 605 feet, providing a storage capacity of 138 acre-feet and covering a surface area of 3.7 acres.
With a low hazard potential and a moderate risk assessment rating of 3, Lawson Subwatershed Site 2-2 plays a critical role in managing water resources and mitigating potential risks in the area. Even though its condition assessment is currently not rated, this site is equipped with an uncontrolled spillway and soil foundation, ensuring its structural integrity and functionality. While there is no information available on emergency action plans or risk management measures, the site's location along the TR-Maple River underscores its importance in maintaining water quality and protecting the surrounding environment.
Overall, Lawson Subwatershed Site 2-2 exemplifies the collaborative efforts between local and federal agencies in managing water resources and enhancing climate resilience in Iowa. As a key component of the water infrastructure network in the region, this site highlights the importance of sustainable water management practices and the need for continued monitoring and maintenance to ensure its effectiveness in safeguarding the community against potential water-related risks.
Year Completed |
1968 |
Dam Length |
605 |
Dam Height |
45 |
River Or Stream |
TR-MAPLE RIVER |
Primary Dam Type |
Earth |
Surface Area |
3.7 |
Drainage Area |
1.08 |
Nid Storage |
138 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
45 |
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
|
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 2-2