Sandy Lock And Dam
Sandy Lock And Dam
Sandy Lock and Dam, located in Libby, Minnesota, is a crucial federal structure managed by the US Army Corps of Engineers. Built in 1895 on the Sandy River, this Earth-type dam serves multiple purposes such as flood risk reduction, navigation, and water supply. With a height of 14 feet and a length of 109 feet, the dam holds a normal storage capacity of 38,000 acre-feet in the Sandy Lake Reservoir.
Despite being classified as a low hazard potential structure, Sandy Lock and Dam is subject to various flood risks that the USACE actively manages. By continuously monitoring the dam's condition, prioritizing risk-reducing activities, and collaborating with local emergency managers, the USACE ensures the safety and functionality of the structure. Additionally, the USACE regularly updates the emergency action plan and conducts maintenance to mitigate potential issues and maintain the dam's structural integrity.
As water resource and climate enthusiasts, understanding the risk management measures employed at Sandy Lock and Dam provides valuable insight into the complexities of maintaining and safeguarding critical infrastructure. By staying informed about the dam's operations and potential risks, enthusiasts can contribute to efforts aimed at protecting communities and ecosystems in the face of changing climatic conditions and severe weather events.
Inside the reservoir
The real shoreline of this water body, with a depth model scaled so the basin holds exactly its recorded storage. Drag to orbit, scroll to zoom, and use the slider to drain and refill it. Click anywhere on the basin for the modelled depth there.
NID normal pool storage (38000 AF) over this shoreline implies a 14 ft basin, deeper than the 14 ft dam. Depth capped to the dam; storage shown is modelled, not NID.
How this is built. The shoreline is the National Hydrography
Dataset polygon for this water body (“Aitkin Lake”),
matched to the dam by proximity and confirmed by comparing its area with the
National Inventory of Dams surface area (agreement 0.777×).
Depth is modelled, not surveyed: the basin is shaped by distance from
shore — deep in open water, shallow in the bays — and scaled so its
volume equals the recorded storage. No national bathymetric survey exists for
US reservoirs. Treat the shoreline, area and volume as measured, and the depth
distribution as an informed approximation.
Above normal pool, water is shown rising within the normal-pool
shoreline. Where it would actually spread depends on the surrounding
terrain, which is not modelled here — a reservoir in a steep canyon barely
widens, one on flat ground can spread a long way. This is a depth and volume
figure, not an inundation map. Official inundation mapping for a dam
comes from its Emergency Action Plan.
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 Sandy Lock And Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Mississippi River At Aitkin | 487 cfs | → |
| Mississippi River At Grand Rapids | 344 cfs | → |
| Prairie River Near Taconite | 39 cfs | → |
| St. Louis River At Scanlon | 427 cfs | → |
| Mississippi River At Brainerd | 616 cfs | → |
| Kettle River Below Sandstone | 79 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Sandy Lock And Dam.
Boat launches
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Campgrounds
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Fishing spots
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River runs
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About Sandy Lock And Dam
Where does the data for Sandy Lock And Dam 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.
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