Upper Chinns dam
Upper Chinns
Upper Chinns, also known as Sherwin Lake, is a private dam located in Idaho Springs, Colorado. Built in 1937, this earth dam stands at a height of 22 feet and serves primarily for irrigation purposes. With a storage capacity of 138 acre-feet, it covers a surface area of 7 acres and has a drainage area of 1 square mile.
Managed by the Colorado Division of Water Resources, Upper Chinns has a low hazard potential and is in fair condition as of the last inspection in July 2017. Despite its modest size, the dam plays a crucial role in supporting agricultural activities in the region and also offers recreational opportunities for the local community. With a maximum discharge capacity of 882 cubic feet per second and an uncontrolled spillway, Upper Chinns continues to be a vital water resource in the area.
Situated along the Fall River-TR, Upper Chinns serves as a testament to the importance of proper water management and infrastructure maintenance in the face of changing climate conditions. With its moderate risk assessment rating and state-regulated status, this dam highlights the ongoing efforts to ensure the safety and effectiveness of water storage systems in the region. For water resource and climate enthusiasts, Upper Chinns offers a fascinating case study in the intersection of human interventions and natural systems.
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 Upper Chinns -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Fraser River At Upper Sta | 25 cfs | → |
| Berthoud Pass Ditch At Berthoud Pass | 0 cfs | → |
| West Fork Clear Creek Abv Mouth Nr Empire | 55 cfs | → |
| Clear Creek Abv West Fork Clear Creek Nr Empire Co | 78 cfs | → |
| Clear Creek Near Lawson | 128 cfs | → |
| Moffat Water Tunnel At East Portal | 249 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Upper Chinns.
Boat launches
- Miramonte Road Boulder County
- Fairway Drive Evergreen
- Cr 6 Grand County
- Ralston Creek Trail Arvada
- Willow Creek Boating Site
- Us 34 Grand County
Campgrounds
- Robbers Roost
- Robbers Roost Campground
- Empire City Rv Parking
- Midland Group Campground
- Jim Creek Campground
- Mizpah
Fishing spots
Paddle runs
- Upper South Boulder Creek
- Upper Clear Creek
- Lower Snake
- Silverthorne Town Run
- Upper Blue (Blue River Cg To Columbine Landing)
More reservoirs
Track Upper Chinns 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 Upper Chinns
Where does the data for Upper Chinns 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 Upper Chinns.