Thompson Dam Reservoir Report
Nearby: Sievers Dam Schultz Dam
Last Updated: December 13, 2025
Thompson Dam, located in Avoca, Iowa, was completed in 1974 and is primarily used for fire protection, stock, and small fish pond purposes.
°F
°F
mph
Wind
%
Humidity
Summary
This earth dam has a height of 26 feet, a length of 478 feet, and a storage capacity of 140 acre-feet. Situated on the TR-East Br West Nisanabota river, the dam is owned and regulated by a private entity but falls under the jurisdiction of the Iowa Department of Natural Resources.
The dam, designed by USDA NRCS, has a low hazard potential and a moderate risk assessment rating. While it has not been inspected since 1978, it is deemed to be in good condition. The dam does not have any associated structures or outlet gates, and its spillway type is uncontrolled. Despite its age, Thompson Dam continues to serve its intended purposes effectively and contributes to the water resource management in Shelby County, Iowa.
Water resource and climate enthusiasts will appreciate Thompson Dam for its role in providing essential services such as fire protection and stock pond storage. With its location in a rural area and limited drainage area, the dam serves as a valuable asset for local water management. The dam's design by the Natural Resources Conservation Service underscores a commitment to sustainable water infrastructure, while its oversight by the Iowa DNR ensures compliance with state regulations. Thompson Dam stands as a testament to effective dam engineering and maintenance practices, contributing to the resilience of water resources in the region.
Year Completed |
1974 |
Dam Length |
478 |
Dam Height |
26 |
River Or Stream |
TR-EAST BR WEST NISANABOTA |
Primary Dam Type |
Earth |
Surface Area |
2.5 |
Drainage Area |
0.25 |
Nid Storage |
140 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
26 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
West Nishnabotna River At Hancock
|
154cfs |
East Nishnabotna River Near Atlantic
|
143cfs |
Boyer River At Logan
|
417cfs |
East Nishnabotna River At Red Oak
|
270cfs |
Missouri River At Omaha
|
17700cfs |
Soldier River At Pisgah
|
112cfs |
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.
Nishna Bend Rec Area
Pottawattamie County Fairgrounds
Prairie Rose State Park West Campground
Prairie Rose State Park East Campground
Prairie Rose State Park
Botna Bend County Park
Thompson Dam