Dutch Hollow Subwatershed Site 1a-1 Reservoir Report
Last Updated: December 15, 2025
Dutch Hollow Subwatershed Site 1a-1, located in Woodbury County, Iowa, is a local government-owned earth dam completed in 1991 by the USDA NRCS.
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Summary
The dam, designed for fire protection, stock, and small fish pond purposes, stands at a height of 41 feet and spans a length of 655 feet. With a storage capacity of 216 acre-feet and a surface area of 6.9 acres, this structure plays a crucial role in flood risk reduction within the TR-Koker Creek watershed.
Managed by the Iowa DNR, this dam is classified as low hazard potential with a moderate risk assessment rating. While the condition assessment is yet to be rated, the structure is regularly inspected and maintained by state regulatory agencies to ensure its effectiveness in emergency situations. Despite its uncontrolled spillway type and lack of outlet gates, Dutch Hollow Subwatershed Site 1a-1 serves as a vital resource for water storage and management in the region, supporting local ecosystems and mitigating potential flooding risks.
As a focal point for water resource and climate enthusiasts, this site showcases the collaborative efforts between local government and federal agencies to enhance water infrastructure and protect surrounding communities. With its strategic location in the Rock Island District and close proximity to the city of Danbury, Dutch Hollow Subwatershed Site 1a-1 exemplifies the importance of sustainable water management practices in promoting resilience against changing environmental conditions.
Year Completed |
1991 |
Dam Length |
655 |
Dam Height |
41 |
River Or Stream |
TR- KOKER CREEK |
Primary Dam Type |
Earth |
Surface Area |
6.9 |
Drainage Area |
0.54 |
Nid Storage |
216 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
41 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Maple River At Mapleton
|
323cfs |
Little Sioux River At Correctionville
|
327cfs |
West Fork Ditch At Hornick
|
80cfs |
Little Sioux River Near Turin
|
1040cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
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.
Dutch Hollow Subwatershed Site 1a-1