Coal Ridge Waste Dam #1 dam
Coal Ridge Waste Dam #1
Coal Ridge Waste Dam #1, also known as Sand Hill Lake, is a privately owned structure located in Weld County, Colorado, near the city of Platteville. Built in 1954 for irrigation purposes, this earth dam stands at a height of 31 feet and has a hydraulic height of 25 feet. The dam has a storage capacity of 1189 acre-feet, with a normal storage of 591 acre-feet and a surface area of 81 acres.
With a significant hazard potential and a satisfactory condition assessment as of July 2020, Coal Ridge Waste Dam #1 is regulated by the Colorado Department of Water Resources. The dam has an uncontrolled spillway with a width of 242 feet and a maximum discharge rate of 9290 cubic feet per second. The structure has been modified in 2001 for hydraulic purposes, and regular inspections are conducted, with the last one taking place in July 2020.
For water resource and climate enthusiasts, Coal Ridge Waste Dam #1 presents an interesting case study of a private irrigation dam in Colorado. Its location near the South Platte River and its association with recreational activities make it a vital part of the local water management infrastructure. With a moderate risk assessment and a history of satisfactory condition, this dam serves as a reminder of the importance of maintaining and monitoring such structures to ensure the safety of both the surrounding community and the environment.
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 Coal Ridge Waste Dam #1 -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| South Platte River At Fort Lupton | 238 cfs | → |
| Big Dry Creek At Mouth Near Fort Lupton | 24 cfs | → |
| St Vrain Cr Blw Boulder Cr At Hwy 119 Nr Longmont | 82 cfs | → |
| Boulder Creek At Mouth | 46 cfs | → |
| St. Vrain Creek Below Longmont | -999,999 cfs | → |
| St. Vrain Creek At Mouth | 158 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Coal Ridge Waste Dam #1.
Boat launches
- Brighton
- Adams County
- Lagerman Trail Boulder County
- Standley Lake Trail Westminster
- West 69th Avenue 4700, Westminster
- Ralston Creek Trail Arvada
Campgrounds
- St. Vrain State Park
- Union Reservoir
- Boulder County Fairground
- Missile Site Park
- Standley Lake
- Tipi Village
Fishing spots
- Milavec Reservoir
- Brighton City Park Lake
- St. Vrain State Park (Barbour Ponds)
- Ken Mitchell Park Pond
- Union Reservoir
- Hudson Fishing Pond
Track Coal Ridge Waste Dam #1 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 Coal Ridge Waste Dam #1
Where does the data for Coal Ridge Waste Dam #1 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 Significant 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 Coal Ridge Waste Dam #1.