Grindstone River Reservoir Report

Last Updated: December 5, 2025

The Grindstone River, also known as Hinckley, is a state-owned water resource situated in Pine, Minnesota.


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Summary

This river is regulated by the Minnesota Department of Natural Resources, with permitting, inspection, and enforcement processes in place to ensure its proper management. The primary purpose of the Grindstone River is for recreation, offering opportunities for outdoor activities and enjoyment for enthusiasts and nature lovers.

The Grindstone River features a gravity dam of 18 feet in height, providing a storage capacity of 428 acre-feet and a maximum discharge of 1500 cubic feet per second. Despite its significant hazard potential and poor condition assessment, the river continues to attract visitors for its scenic beauty and recreational opportunities. With a moderate risk level associated with the dam, there is a need for ongoing risk management measures to maintain the safety and integrity of the structure.

Overall, the Grindstone River serves as a valuable water resource in Minnesota, offering both recreational and environmental benefits. As climate and water resource enthusiasts explore this area, it is important to be aware of the regulatory measures in place and the potential risks associated with the dam structure. By understanding and respecting these factors, visitors can continue to enjoy the beauty and diversity that the Grindstone River has to offer.

Year Completed

1955

Dam Length

58

Dam Height

18

River Or Stream

GRINDSTONE RIVER

Primary Dam Type

Gravity

Surface Area

20

Hydraulic Height

10

Drainage Area

95

Nid Storage

428

Structural Height

23

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

23
       
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.