Richard Hanrahan Dam Reservoir Report

Last Updated: December 10, 2025

Located in Carlisle, Iowa, the Richard Hanrahan Dam is a recently completed earth dam designed by the USDA NRCS for grade stabilization along a tributary to Badger Creek.


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Summary

Completed in 2018, this private-owned dam serves multiple purposes including grade stabilization, recreation, and water supply. With a height of 29 feet and a length of 280 feet, the dam has a storage capacity of 30 acre-feet and a surface area of 1.2 acres.

The dam's spillway type is uncontrolled with a width of 48 feet, capable of handling a maximum discharge of 456 cubic feet per second. Despite being classified as having a low hazard potential, the dam is subject to moderate risk and is not currently rated for condition assessment. While no emergency action plan has been prepared or updated for the dam, it meets regulatory guidelines and has been inspected for safety and operation by state authorities. As an integral part of the local water resource infrastructure, the Richard Hanrahan Dam plays a crucial role in maintaining water quality and availability in the region.

Water resource and climate enthusiasts will find the Richard Hanrahan Dam a fascinating example of modern dam engineering for sustainable water management. From its design by the USDA NRCS to its multiple purposes of grade stabilization, recreation, and water supply, this earth dam showcases the importance of strategic infrastructure development in safeguarding natural resources. With its recent completion in 2018 and a storage capacity of 30 acre-feet, the dam contributes significantly to water conservation efforts in the area, serving as both a practical solution for environmental challenges and a recreational asset for the community.

Year Completed

2018

Dam Length

280

Dam Height

29

River Or Stream

Trib to Badger Creek

Primary Dam Type

Earth

Surface Area

1.2

Drainage Area

0.21

Nid Storage

30

Outlet Gates

None

Hazard Potential

Low

Foundations

Soil

Nid Height

29
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.