Herwig Pond Reservoir Report
Nearby: Albert Lake Fish Lake
Last Updated: December 5, 2025
Herwig Pond, located in Grasston, Minnesota, is a privately owned earth dam constructed in 1967 by the USDA NRCS.
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Summary
The dam, standing at 16 feet high and spanning 560 feet in length, serves various purposes, primarily as a water resource management structure for the Spring Brook river. It has a storage capacity of 50 acre-feet, with a normal storage level of 12 acre-feet and a surface area of 7 acres.
This low hazard potential dam has been deemed to be in satisfactory condition as of the last inspection in October 2016. The structure is regulated by the Minnesota Department of Natural Resources - Ecological and Water Resources division, with state permitting, inspection, and enforcement in place. Despite the moderate risk assessment score of 3, the dam has not required any significant risk management measures or emergency action planning as of the most recent data update in May 2021.
Overall, Herwig Pond serves as a vital component of water resource management in Kanabec County, Minnesota, providing flood control and water storage capabilities for the surrounding area. Enthusiasts of water resources and climate will find interest in the dam's design and construction details, as well as its role in maintaining water quality and quantity in the region.
Year Completed |
1967 |
Dam Length |
560 |
Dam Height |
16 |
River Or Stream |
SPRING BROOK |
Primary Dam Type |
Earth |
Surface Area |
7 |
Drainage Area |
0.7 |
Nid Storage |
50 |
Structural Height |
16 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
16 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Snake River Near Pine City
|
127cfs |
Kettle River Below Sandstone
|
170cfs |
Rum River Near St. Francis
|
209cfs |
Elk River Near Big Lake
|
274cfs |
St. Croix River At St. Croix Falls
|
1470cfs |
Mississippi River At Anoka
|
2940cfs |
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Herwig Pond