Longmont Wtp Forebay Embankment dam
Longmont Wtp Forebay Embankment
The Longmont Wtp Forebay Embankment, also known as the Nelson Flanders Forebay, is a crucial water resource infrastructure located in Boulder County, Colorado. Owned by the local government, this embankment serves the primary purpose of water supply and was completed in 2005 by Lyman Henn Inc. The structure is designed as an earth dam with a height of 20 feet and a hydraulic height of 19 feet, providing a storage capacity of 129 acre-feet with a maximum discharge of 369 cubic feet per second.
Situated along the St. Vrain Creek, the Longmont Wtp Forebay Embankment is state-regulated and inspected regularly by the Colorado Department of Water Resources to ensure its safety and functionality. With a moderate risk assessment rating and a high hazard potential, it is crucial for water resource and climate enthusiasts to monitor and maintain this critical infrastructure. The embankment has a satisfactory condition assessment as of June 2020, but emergency preparedness measures, such as an Emergency Action Plan, may need updating to meet current guidelines.
In the event of a breach or failure, the embankment has an uncontrolled spillway with a width of 28 feet to manage excess water flow. With its strategic location and vital role in water supply for the city of Hygiene, the Longmont Wtp Forebay Embankment serves as a significant asset in the management and distribution of water resources in 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 Longmont Wtp Forebay Embankment -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| St. Vrain Creek At Lyons | 309 cfs | → |
| Left Hand Creek Near Boulder | 47 cfs | → |
| Left Hand Creek At Hover Road Near Longmont | 1 cfs | → |
| Boulder Cr At North 75th St Nr Boulder | 119 cfs | → |
| St. Vrain Creek Below Longmont | -999,999 cfs | → |
| Boulder Creek At Mouth | 63 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Longmont Wtp Forebay Embankment.
Boat launches
- Lagerman Trail Boulder County
- Miramonte Road Boulder County
- Boat Ramp Larimer County
- Standley Lake Trail Westminster
- Ralston Creek Trail Arvada
- West 69th Avenue 4700, Westminster
Campgrounds
- Meadow Park
- Boulder County Fairground
- Carter Lake - South Side Campgrounds
- North Pine Campground
- Carter Lake - North Side Campgrounds
- Union Reservoir
Fishing spots
- Mccall Lake
- Pella Crossing
- Mcintosh Lake
- South Saint Vrain Fishing Site #2
- Golden Ponds
- Lagerman Reservoir
Track Longmont Wtp Forebay Embankment 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 Longmont Wtp Forebay Embankment
Where does the data for Longmont Wtp Forebay Embankment 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 Longmont Wtp Forebay Embankment.