Woods Hollow Subwatershed Sta 40+42 Reservoir Report
Last Updated: December 14, 2025
The Woods Hollow Subwatershed Sta 40+42 in Monona County, Iowa is a vital earth dam structure completed in 1960 by the USDA NRCS, with a primary purpose of fire protection, stock, or small fish pond.
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Summary
The dam stands at a height of 35 feet and has a length of 880 feet, providing a storage capacity of 45 acre-feet and serving a drainage area of 0.58 square miles along the TR-Beaver Creek. Despite being classified as having a low hazard potential, the dam is regulated and inspected by the Iowa DNR, ensuring that it meets state permitting and enforcement standards.
Located in Little Sioux, Iowa, the Woods Hollow Subwatershed Sta 40+42 dam plays a critical role in flood risk reduction for the surrounding area, along with its primary purposes of fire protection and water storage. With a moderate risk assessment rating of 3, the dam is monitored for any potential issues that may arise, although its condition assessment is currently listed as not rated. As a structure owned and operated by the local government, the dam is a key asset in managing water resources and climate challenges in the region, highlighting the importance of infrastructure for sustainable water management practices.
Year Completed |
1960 |
Dam Length |
880 |
Dam Height |
35 |
River Or Stream |
TR-BEAVER CREEK |
Primary Dam Type |
Earth |
Surface Area |
2 |
Drainage Area |
0.58 |
Nid Storage |
45 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
35 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Little Sioux River Near Turin
|
1040cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
Soldier River At Pisgah
|
112cfs |
Maple River At Mapleton
|
323cfs |
Missouri River At Decatur
|
14900cfs |
West Fork Ditch At Hornick
|
80cfs |
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.
Woods Hollow Subwatershed Sta 40+42