Boulder - South dam
Boulder - South
Boulder - South is a vital water resource infrastructure located in Boulder, Colorado, designed for water supply purposes including irrigation, recreation, and water supply. This earth dam, completed in 1955, stands at a height of 45 feet and has a maximum storage capacity of 17,700 acre-feet. The dam encompasses a surface area of 684 acres and serves a drainage area of 14 square miles, with a spillway width of 1644 feet for uncontrolled discharge during high water events.
Managed by the local government, Boulder - South is regulated by the Colorado Division of Water Resources, with state permitting, inspection, and enforcement in place to ensure its proper functioning and safety. Despite being categorized as having a high hazard potential, the dam's condition assessment as of November 2020 was deemed satisfactory, with a moderate risk rating. Emergency action plans are in place, and regular inspections are conducted to uphold its integrity and mitigate any potential risks associated with its operation.
Located along Little Dry Creek, Boulder - South plays a crucial role in the water management infrastructure of the region, providing essential water supply services to the community while also offering recreational opportunities. With its strategic location and significant storage capacity, this dam serves as a key component in ensuring water resource sustainability and climate resilience in the Boulder area.
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 Boulder - South -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Boulder Cr At North 75th St Nr Boulder | 37 cfs | → |
| Left Hand Creek Near Boulder | 36 cfs | → |
| Left Hand Creek At Hover Road Near Longmont | 1 cfs | → |
| Fourmile Creek At Orodell | 2 cfs | → |
| Boulder Creek Near Orodell | 63 cfs | → |
| St. Vrain Creek At Lyons | 89 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Boulder - South.
Boat launches
- Lagerman Trail Boulder County
- Miramonte Road Boulder County
- Standley Lake Trail Westminster
- Ralston Creek Trail Arvada
- West 69th Avenue 4700, Westminster
- Brighton
Campgrounds
- Boulder County Fairground
- Camp Patiya
- Meadow Park
- Union Reservoir
- St. Vrain State Park
- Glacier View Ranch
Fishing spots
- Boulder Reservoir
- Coot Lake
- Walden Ponds - Ricky Weiser Wetland
- Sawhill Ponds #5
- Walden Ponds - Bass Pond
- Walden Ponds
Track Boulder - South 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 Boulder - South
Where does the data for Boulder - South 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 Boulder - South.