Summary
It is a gravity dam standing at 7 feet high and 220 feet long, with a storage capacity of 75 acre-feet and a normal storage of 49 acre-feet. Located on the Rock River in Lyon County, this dam is state-regulated by the Iowa Department of Natural Resources, ensuring proper permitting, inspection, and enforcement measures are in place.
The dam's primary purpose is water supply, supporting the surrounding community with its storage capacity and surface area of 10 acres. Though categorized as low hazard potential with a moderate risk assessment, its condition has not been rated since its last inspection in 1989. Despite its age, the Rock Rapids Milldam continues to play a vital role in water resource management and climate resilience efforts in the area, with the state ensuring regulatory oversight to safeguard its operations and structural integrity for years to come.
With a state-regulated status and low hazard potential, the Rock Rapids Milldam stands as a testament to effective water management practices in Iowa. Its historical significance and role in water supply underscore the importance of maintaining and monitoring such structures to ensure their continued functionality and safety. As climate change impacts water resources, the presence of well-regulated dams like Rock Rapids Milldam becomes increasingly crucial for sustainable water supply and management in the region, making it a notable site for water resource and climate enthusiasts to study and appreciate.
Year Completed |
1931 |
Dam Length |
220 |
Dam Height |
7 |
River Or Stream |
ROCK RIVER |
Primary Dam Type |
Gravity |
Surface Area |
10 |
Drainage Area |
777 |
Nid Storage |
75 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
7 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
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.
Rock Rapids Milldam