Ninth Street dam
Ninth Street
Ninth Street Dam in Alpena, Michigan, is a historic gravity dam completed in 1910 primarily for hydroelectric power generation and recreation purposes. The dam stands at 24 feet in height and spans 503 feet in length, with a storage capacity of 6,000 acre-feet and a drainage area of 1,275 square miles. Situated on the Thunder Bay River, the dam's uncontrolled spillway has a width of 84 feet and can discharge up to 20,600 cubic feet per second.
Managed by the Federal Energy Regulatory Commission, Ninth Street Dam has a high hazard potential due to its age and condition, with a moderate risk assessment rating. Despite its critical importance for water resource management and energy production in the region, the dam's condition assessment is currently listed as "Not Available". Emergency action plans are in place, with the last revision in December 2020, to ensure a prompt response in case of any unforeseen events.
As a key infrastructure for both water resource management and energy production, Ninth Street Dam plays a vital role in the local community. With its historical significance and ongoing operational challenges, maintaining the dam's safety and functionality is crucial for ensuring the sustainable management of the Thunder Bay River watershed and the continued provision of hydroelectric power to the region.
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 Ninth Street -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Thunder Bay River At Herron Road Near Bolton | 1,280 cfs | → |
| Au Sable River Near Mc Kinley | 1,880 cfs | → |
| Au Sable River Near Curtisville | 1,760 cfs | → |
| Au Sable River Near Au Sable | 2,030 cfs | → |
| Au Sable River At Mio | 1,450 cfs | → |
| Au Sable River Near Red Oak | 1,470 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Ninth Street .
Boat launches
- Hinks Park Road Alpena Township
- Rockport Dock Boat Launch
- Long Lake -W, 5200 Acres, Presque Isle County
- Potawatomi Loop Alcona Township
- Lake Esau, 275 Acres, Presque Isle County
- Pine Street Presque Isle Township
Campgrounds
- Ossineke State Forest Campground
- Ess Lake State Forest Campground
- Jewell Lake Campground
- Mccollum Lake State Forest Campground
Fishing spots
Track Ninth Street 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 Ninth Street
Where does the data for Ninth Street 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 High 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 Ninth Street .