Held Watershed Site E-4 Reservoir Report
Last Updated: December 13, 2025
Held Watershed Site E-4, located in Plymouth County, Iowa, is a crucial piece of infrastructure designed by the USDA NRCS for flood risk reduction along the TR-Floyd River.
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Summary
Completed in 1978, this earth dam stands at a height of 37 feet and spans 493 feet, with a storage capacity of 224 acre-feet and a surface area of 7 acres. The dam serves multiple purposes, including fire protection, stock or small fish pond maintenance, and flood risk reduction, making it a vital asset for water resource management in the area.
Managed by local government authorities and regulated by the Iowa DNR, Held Watershed Site E-4 is in satisfactory condition with a high hazard potential. Despite its age, the dam has undergone regular inspections, with the last assessment conducted in August 2020. With a moderate risk rating of 3, the site is equipped with an uncontrolled spillway and is capable of handling emergencies effectively. The surrounding community in Hinton relies on the proper functioning of this dam for protection against flooding, highlighting its importance in the region's water resource and climate resilience efforts.
As climate change continues to impact weather patterns and increase the frequency of extreme events, structures like Held Watershed Site E-4 play a crucial role in mitigating flood risks and protecting communities. With ongoing monitoring and maintenance, this earth dam will continue to serve as a key asset in safeguarding Plymouth County against the challenges posed by a changing climate. The collaboration between local government agencies and the USDA NRCS underscores the importance of proactive water resource management and the need for sustainable infrastructure solutions in the face of climate variability.
Year Completed |
1978 |
Dam Length |
493 |
Dam Height |
37 |
River Or Stream |
TR-FLOYD RIVER |
Primary Dam Type |
Earth |
Surface Area |
7 |
Drainage Area |
0.56 |
Nid Storage |
224 |
Hazard Potential |
High |
Foundations |
Soil |
Nid Height |
37 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Floyd River At James
|
187cfs |
Perry Creek Near Milnerville
|
25cfs |
Missouri River At Sioux City
|
15100cfs |
Big Sioux River At Akron
|
816cfs |
Omaha Cr At Homer
|
45cfs |
Floyd River At Alton
|
36cfs |
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.
Held Watershed Site E-4