Herwig Pond dam
Herwig Pond
Herwig Pond, located in Grasston, Minnesota, is a privately owned earth dam constructed in 1967 by the USDA NRCS. 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.
Plan around the weather
Same NOAA / yr.no feed Snoflo's iOS app uses. Watch the precipitation column on the meteogram -- rain on the basin upstream typically lifts inflow 24-72 hours later.
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind. Each cell is colour-coded relative to the column min/max.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day temperature & precipitation
Daily temperatures, snow, and rain projected over the next two weeks.
Nearby streamflow gauges
USGS streamgauges around Herwig Pond -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Snake River Near Pine City | 1,090 cfs | → |
| Kettle River Below Sandstone | 520 cfs | → |
| Rum River Near St. Francis | 494 cfs | → |
| Elk River Near Big Lake | 181 cfs | → |
| St. Croix River At St. Croix Falls | 4,110 cfs | → |
| Mississippi River At Anoka | 6,480 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Herwig Pond.
Boat launches
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Campgrounds
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Fishing spots
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River runs
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About Herwig Pond
Where does the data for Herwig Pond come from?
Structural and regulatory data come from the U.S. Army Corps of Engineers' National Inventory of Dams (NID). Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.
How often is the report updated?
NID structural data refreshes annually as the Corps publishes updated assessments. The weather forecast refreshes throughout the day.
What does the Low hazard rating mean?
The Corps of Engineers' hazard potential classification grades probable consequences if the dam fails: High = probable loss of human life; Significant = no probable loss of human life but possible economic loss / environmental damage; Low = no probable loss of human life, only minor economic / environmental losses. See the Dam Data Reference card below for the full definitions.
What's "% of normal"?
The current storage value compared to the historical average storage on this calendar day. 100% = right on average; values above 100% mean above-normal storage (wet year); values below mean below-normal (dry year or drought).
Can I get alerts when storage crosses a threshold?
Yes -- alerts are managed in the Snoflo iOS app. Favorite this dam, set a threshold, and you'll get a push the moment conditions cross.
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.
- 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.
- 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.
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, environmental 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.