Zach Mendenhall Dam Reservoir Report

Last Updated: December 9, 2025

Zach Mendenhall Dam is a private dam located in Chariton, Iowa, and serves multiple purposes including grade stabilization, recreation, and water supply.


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Summary

This earth dam, completed in 2017, stands at a height of 26 feet and spans 441 feet in length. It has a storage capacity of 61 acre-feet and covers a surface area of 4 acres, serving a drainage area of 0.22 square miles.

Managed by the USDA NRCS, Zach Mendenhall Dam is regulated by the Iowa DNR and undergoes regular inspections to ensure its safety and functionality. With a low hazard potential and a moderate risk assessment rating, the dam plays a crucial role in managing water resources in the area. Even though the dam is not rated for its condition, it continues to provide essential services while meeting regulatory guidelines.

Located on a tributary to the Chariton River, Zach Mendenhall Dam has an uncontrolled spillway with a width of 20 feet. Despite not having outlet gates, the dam effectively stabilizes the surrounding area and contributes to water supply needs. With its strategic design and multiple benefits, this dam is a significant asset for water resource and climate enthusiasts in the region.

Year Completed

2017

Dam Length

441

Dam Height

26

River Or Stream

Trib to Chariton River

Primary Dam Type

Earth

Surface Area

4

Drainage Area

0.22

Nid Storage

61

Outlet Gates

None

Hazard Potential

Low

Foundations

Soil

Nid Height

26
       
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.