Rock Creek Dam Reservoir Report
Nearby: Keenen Dam Oakland Acres Dam
Last Updated: December 14, 2025
Rock Creek Dam, located in Lynnville, Iowa, is a state-regulated structure designed by Bauer Engineering Inc.
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Summary
The dam, situated on Rock Creek, serves primarily for recreational purposes and boasts an earth dam type with a height of 33 feet and a length of 1500 feet. With a storage capacity of 13,700 acre-feet and a surface area of 640 acres, Rock Creek Dam provides essential water resources for the surrounding area while offering recreational opportunities for visitors.
Despite its significant hazard potential, Rock Creek Dam has been assessed as satisfactory in condition as of May 2016. The dam features an uncontrolled spillway type with a width of 200 feet, ensuring efficient water release during periods of high flow. Managed by the Iowa Department of Natural Resources, the dam undergoes regular inspections every five years to uphold safety standards and mitigate potential risks. With a moderate risk assessment rating, Rock Creek Dam remains a crucial infrastructure for water resource management and climate resilience in Jasper County.
In the event of an emergency, the dam's emergency action plan (EAP) status and preparedness remain unspecified, highlighting the importance of ongoing risk management measures. With no associated federal agency involvement, Rock Creek Dam showcases the state's commitment to regulating and maintaining essential water infrastructure for both recreational and environmental purposes. As a key component of the local watershed, Rock Creek Dam stands as a testament to effective water resource management in Iowa's diverse landscape.
Dam Length |
1500 |
Dam Height |
33 |
River Or Stream |
ROCK CREEK |
Primary Dam Type |
Earth |
Surface Area |
640 |
Drainage Area |
41.4 |
Nid Storage |
13700 |
Hazard Potential |
Significant |
Foundations |
Soil |
Nid Height |
33 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Timber Creek Near Marshalltown
|
37cfs |
South Skunk River At Colfax
|
211cfs |
Richland Creek Near Haven
|
12cfs |
Iowa River At Marshalltown
|
1040cfs |
Indian Creek Near Mingo
|
79cfs |
Walnut Creek Near Hartwick
|
13cfs |
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.
Area Campgrounds
| Location | Reservations | Toilets |
|---|---|---|
Rock Creek State Park
|
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Kellogg RV Park
|
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Mariposa Co Park
|
Rock Creek Dam