Lock dam
Lock
Lock is a historic hydroelectric dam located on the Allagash Stream in Maine. Built in 1875, this timber crib dam stands at a height of 15 feet and has a storage capacity of 105,200 acre-feet. With a primary purpose of flood risk reduction and hydroelectric power generation, Lock plays a crucial role in the water resource management of the region.
State regulated and inspected, Lock is classified as having a low hazard potential. Despite not being rated for its condition assessment, the dam is maintained regularly with inspections every 12 years. With its strategic location and design, Lock serves as a key infrastructure for water resource management and climate resilience in Piscataquis County, Maine.
As one of the few timber crib dams still in operation today, Lock represents a piece of history in water resource engineering. With its proximity to the New England District and Congressional District 02, Lock continues to play a significant role in the local ecosystem and economy. Enthusiasts of water resources and climate resilience will find Lock to be a captivating example of sustainable infrastructure in the face of changing environmental conditions.
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.
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 Lock -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| St. John River At Ninemile Bridge | 2,000 cfs | → |
| Seboeis River Near Shin Pond | 430 cfs | → |
| North Branch Penobscot River Nr Pittston Farm | 327 cfs | → |
| Big Black River Near Depot Mtn | 190 cfs | → |
| Aroostook River Near Masardis | 1,780 cfs | → |
| East Branch Penobscot River At Grindstone | 2,930 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Lock.
Boat launches
Campgrounds
- Little Coffeelos Tentsite
- North Branch Bunkhouse
- N.W. Cove Tentsite
- Pine Point Tentsite
- Sandy Point
- Second Lake Tentsite
Paddle runs
- Headwaters To Confluence With Penobscot River, East Branch
- Grand Lake Matagamon To Bowlin Camps
- Golden Road Bridge (Approx. 2 Miles Below Lobster Stream) To Confluence With Pine Stream
- Headwaters To Confluence With Penobscot River, East Branch
- The North Branch Headwater From Canal Cut Approximately 1.25 Miles Upstream Of Big Bog To Pittston Farm
- Lobster Lake To Confluence With West Branch
More reservoirs
Track Lock in the Snoflo app
Save this dam as a favorite and get the local NOAA / yr.no forecast plus regional flow context wherever you are.
About Lock
Where does the data for Lock 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 above 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.
Other water bodies near here
Snoflo-tracked reservoirs and dams within driving distance of Lock.