Zenishek Dam Reservoir Report

Last Updated: December 5, 2025

Zenishek Dam, located in Johnson County, Iowa, was completed in 1979 by the USDA NRCS and serves multiple purposes including fire protection, stock watering, and small fish pond management.


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Summary

The earth dam stands at a height of 25 feet and spans 550 feet in length, with a storage capacity of 114 acre-feet. Situated on the TR-Cedar River, the dam is regulated by the Iowa DNR and is inspected, permitted, and enforced by state authorities.

With a low hazard potential and a moderate risk assessment, Zenishek Dam is a key infrastructure for water resource management in the area. The dam's spillway type is uncontrolled, and it has not been modified since its completion. While the condition assessment is currently not rated, the dam is considered to meet guidelines for emergency action plans. As a private-owned structure, the dam plays a crucial role in maintaining water resources and mitigating risks associated with flooding and water scarcity in the region.

Enthusiasts of water resources and climate will find Zenishek Dam to be a fascinating case study in sustainable water management. This earth dam, designed by the USDA NRCS, provides essential services for fire protection and agricultural activities while also serving as a habitat for small fish. With its low hazard potential and moderate risk assessment, the dam represents a balance between water resource utilization and environmental conservation. As a regulated structure in Iowa, Zenishek Dam showcases the importance of state oversight in ensuring the safety and functionality of critical water infrastructure.

Year Completed

1979

Dam Length

550

Dam Height

25

River Or Stream

TR-CEDAR RIVER

Primary Dam Type

Earth

Surface Area

8.8

Drainage Area

0.16

Nid Storage

114

Hazard Potential

Low

Foundations

Soil

Nid Height

25
       
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.