Oaknoll Dam Reservoir Report

Last Updated: December 6, 2025

Oaknoll Dam, also known as Davis Dam, is a private-owned structure located in Johnson County, Iowa, specifically in the city of Iowa City.


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Summary

Completed in 1994, this earth dam stands at a height of 25 feet and has a length of 545 feet. Its primary purpose is designated for fire protection, stock, or a small fish pond, with a normal storage capacity of 43 acre-feet and a maximum storage of 95 acre-feet.

Managed by the Iowa Department of Natural Resources, Oaknoll Dam is situated along the TR-Iowa River, with a drainage area of 0.12 square miles. Despite its satisfactory condition assessment as of July 2020, the dam poses a high hazard potential and is subject to biennial inspections to ensure its structural integrity and safety. While an uncontrolled spillway is present with a width of 2 feet, there are no outlet gates or associated structures linked to the dam.

Although Oaknoll Dam presents a moderate risk level, its strategic location and purpose make it a vital resource for fire protection and recreational activities in the region. With ongoing monitoring and maintenance efforts, the dam continues to serve its intended functions while remaining a focal point for water resource and climate enthusiasts interested in the management of dams and reservoirs.

Year Completed

1994

Dam Length

545

Dam Height

25

River Or Stream

TR- IOWA RIVER

Primary Dam Type

Earth

Surface Area

5.9

Drainage Area

0.12

Nid Storage

95

Hazard Potential

High

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.