Knob Lake Dam Reservoir Report

Last Updated: December 5, 2025

Knob Lake Dam, also known as Knob Lake Sawmill Hollow Dam, is a state-owned structure located in Jackson, Indiana.


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Summary

Built in 1940, this earth dam stands at a height of 27 feet and spans 420 feet in length. Its primary purpose is for recreation, providing a serene environment for water resource and climate enthusiasts to enjoy. The dam holds a maximum storage capacity of 131 acre-feet and covers a surface area of 6.49 acres.

Managed by the Indiana Department of Natural Resources, Knob Lake Dam is regulated, inspected, and enforced by the state regulatory agency. With a high hazard potential and fair condition assessment, the dam has a moderate risk level. The spillway, with a width of 64 feet, is uncontrolled, while the outlet gates are other controlled. Despite its age, the dam continues to serve its purpose effectively, offering a picturesque setting for outdoor activities and relaxation.

The dam is situated on an unnamed tributary of Pond Creek, contributing to a drainage area of 0.28 square miles. With a maximum discharge of 371 cubic feet per second, Knob Lake Dam plays a vital role in managing water flow in the area. As a popular destination for recreation, the dam attracts visitors seeking to appreciate the beauty of nature while also serving as an essential infrastructure for water resource management in Indiana.

Year Completed

1940

Dam Length

420

Dam Height

27

River Or Stream

UNNAMED TRIBUTARY POND CREEK

Primary Dam Type

Earth

Surface Area

6.49

Hydraulic Height

27

Drainage Area

0.28

Nid Storage

131

Structural Height

27

Outlet Gates

Other Controlled

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

27
       
Seasonal Comparison

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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.