Gross Dam Reservoir Report
Last Updated: December 21, 2025
Gross Dam, located in Shelby County, Iowa, was completed in 1975 and serves multiple purposes including fire protection and small fish pond management.
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Summary
Owned privately, this earth dam stands at a height of 25 feet and stretches 580 feet in length, with a storage capacity of 43 acre-feet. The dam is regulated by the Iowa Department of Natural Resources and undergoes state inspections and enforcement to ensure its safety and compliance with regulations.
Situated on the TR-Mosquito Creek, Gross Dam poses a low hazard potential with a moderate risk assessment. Although its condition is not rated, the dam meets regulatory guidelines and its risk management measures are in place. Despite its uncontrolled spillway type, the dam's emergency action plan readiness and inundation maps preparation status remain unknown. With a surface area of 3 acres and a drainage area of 0.23 square miles, Gross Dam plays a crucial role in water resource management and climate protection in the region.
With its strategic location and design by USDA NRCS, Gross Dam not only provides essential water storage for fire protection and fish pond management but also contributes to the overall water resource management in the area. As climate change continues to impact water availability and quality, the proper maintenance and regulation of dams like Gross Dam are essential to ensure the safety and sustainability of water resources for both human and environmental needs.
Year Completed |
1975 |
Dam Length |
580 |
Dam Height |
25 |
River Or Stream |
TR-MOSQUITO CREEK |
Primary Dam Type |
Earth |
Surface Area |
3 |
Drainage Area |
0.23 |
Nid Storage |
43 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
25 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Boyer River At Logan
|
417cfs |
Soldier River At Pisgah
|
112cfs |
West Nishnabotna River At Hancock
|
154cfs |
Little Sioux River Near Turin
|
1040cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
Maple River At Mapleton
|
323cfs |
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.
Gross Dam