Vernon Spring Dam Reservoir Report

Last Updated: December 5, 2025

Vernon Spring Dam, located in Howard County, Iowa, was completed in 1857 and serves as a vital water resource structure on the Turkey River.


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Summary

With a height of 8 feet and a length of 150 feet, the dam has a storage capacity of 110 acre-feet and a drainage area of 73 square miles. The spillway type is controlled, and despite its low hazard potential, the dam is classified as having a very high risk due to its age and condition assessment being not rated.

Owned by the local government and regulated by the Iowa Department of Natural Resources, Vernon Spring Dam plays a crucial role in managing water flow and storage in the area. While its primary purpose is categorized as "Other," the dam serves various purposes related to water resource management. Although not currently rated for its condition, the dam is subject to regular state inspections, with enforcement and permitting also carried out by state agencies.

For water resource and climate enthusiasts, Vernon Spring Dam presents an intriguing case study in the management of aging infrastructure and the challenges of balancing water storage and flood control. With a rich history dating back to the mid-19th century, the dam stands as a testament to the importance of maintaining and upgrading critical water resource structures to adapt to changing environmental conditions and ensure long-term sustainability.

Year Completed

1857

Dam Length

150

Dam Height

8

River Or Stream

Turkey River

Drainage Area

73

Nid Storage

110

Hazard Potential

Low

Nid Height

8
       
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.