Highland Mary dam
Highland Mary
Highland Mary, located in San Juan, Colorado, is a privately owned masonry dam built in 1903 for water supply purposes along Cunningham Creek. With a height of 27 feet, the dam boasts a storage capacity of 722 acre-feet and a normal storage of 168 acre-feet, serving the surrounding area with its 48-acre surface area. Despite its low hazard potential, the dam's condition assessment in 2018 was deemed unsatisfactory, highlighting the need for maintenance and potential risk management measures.
Owned and regulated by private entities, Highland Mary falls under the jurisdiction of the Colorado Department of Water Resources for permitting, inspection, and enforcement. The dam has no spillway and a low hazard potential, but its risk assessment is rated as high (2), signaling the importance of implementing effective emergency action plans and risk management strategies. The last inspection in 2018 identified unsatisfactory conditions, indicating the need for closer monitoring and maintenance efforts to ensure the safety and reliability of the structure for the community's water supply.
Highland Mary, with its historic significance and crucial role in water supply, stands as a reminder of the intricate balance between human infrastructure and natural resources. As climate change impacts water resources, the maintenance and management of dams like Highland Mary become increasingly vital in ensuring water security for communities. With its unique features and challenges, the dam serves as a focal point for water resource and climate enthusiasts seeking to understand the intersection of infrastructure, regulation, and environmental stewardship in the face of a changing climate.
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 Highland Mary -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Animas River At Howardsville | 226 cfs | → |
| Animas River Below Silverton | 590 cfs | → |
| Animas River At Silverton | 306 cfs | → |
| Mineral Creek At Silverton | 205 cfs | → |
| Cement Creek At Silverton | 53 cfs | → |
| Rio Grande At Thirtymile Bridge | 719 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Highland Mary.
Boat launches
- Cr 10 Hinsdale County
- Cr 11 Hinsdale County
- Rito Hondo Reservoir Boating Site
- Deep Creek
- Cr 243 La Plata County
- Devil's Creek Bridge Boat Ramp
Campgrounds
- Cunnigham Gulch Recreation Site
- Molas Lake Campground
- Molas Lake Public Park
- Little Molas Lake Campground
- Kendall Campground
- Animas Forks Camp
Fishing spots
- Andrews Lake Swa
- North Fork Animas River
- Sheep Corrals Fishing Site
- Haviland Lake
- Road Canyon Dam Fishing Site
- Continental Reservoir
Track Highland Mary 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 Highland Mary
Where does the data for Highland Mary 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 Highland Mary.