Parnell Creek Subwatershed Site 21-2 Reservoir Report
Last Updated: December 15, 2025
Located in Smithland, Iowa, the Parnell Creek Subwatershed Site 21-2 is a vital water resource managed by the local government with regulatory oversight from the Iowa Department of Natural Resources.
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Summary
Built in 1967 by the USDA NRCS, this earth dam serves multiple purposes including fire protection, stock watering, and flood risk reduction for the TR-Parnell Creek. With a dam height of 31 feet and a storage capacity of 72 acre-feet, the site covers a surface area of 3.5 acres and drains a 0.5 square mile watershed.
Despite being classified as low hazard potential, the site has a moderate risk assessment level. While the dam's condition is currently not rated, regular inspections, enforcement, and emergency preparedness are in place to ensure public safety and environmental protection. The dam features an uncontrolled spillway and has not been modified since its construction. With its strategic location and multiple functionalities, the Parnell Creek Subwatershed Site 21-2 plays a crucial role in water management and conservation efforts in Woodbury County, Iowa.
Year Completed |
1967 |
Dam Length |
408 |
Dam Height |
31 |
River Or Stream |
TR-PARNELL CREEK |
Primary Dam Type |
Earth |
Surface Area |
3.5 |
Drainage Area |
0.5 |
Nid Storage |
72 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
31 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Maple River At Mapleton
|
323cfs |
West Fork Ditch At Hornick
|
80cfs |
Little Sioux River At Correctionville
|
327cfs |
Little Sioux River Near Turin
|
1040cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
Missouri River At Decatur
|
14800cfs |
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.
Parnell Creek Subwatershed Site 21-2