Marys Lake Dike No. 1 dam
Marys Lake Dike No. 1
Marys Lake Dike No. 1 is a federally-owned structure located in Larimer, Colorado, near the city of Estes Park. Built in 1948 by the Bureau of Reclamation, this earth dam stands at a height of 29 feet and spans 820 feet in length. Its primary purpose is for hydroelectric use, with a storage capacity of 1,149 acre-feet and a normal storage level of 927 acre-feet.
The dam sits on the Fish Creek Tributary and is regulated by the Colorado Department of Water Resources. With a high hazard potential and risk assessment rating of 2, Marys Lake Dike No. 1 undergoes regular state inspections and enforcement to ensure its structural integrity and safety. Although no spillway is present, the dam's construction on rock foundations and use of arch core types contribute to its stability.
Water resource and climate enthusiasts fascinated by hydroelectric infrastructure will appreciate the historical significance and engineering details of Marys Lake Dike No. 1. Its critical role in water management and energy production underscores the importance of maintaining and monitoring such structures in the face of changing climatic conditions and evolving regulatory requirements.
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 Marys Lake Dike No. 1 -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| St. Vrain Creek At Lyons | 135 cfs | → |
| Grand Lake Outlet Blw Chipmunk Ln At Grand Lk | 212 cfs | → |
| Colorado R Below Baker Gulch | 121 cfs | → |
| South St. Vrain Creek Near Ward | 39 cfs | → |
| Grand River Ditch At La Poudre Pass | 60 cfs | → |
| Colorado River Bl Shadow Mountain Reservoir | 22 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Marys Lake Dike No. 1.
Boat launches
- Boat Launch Grand Lake
- Hilltop Boating Site
- Grand County
- Us 34 Grand County
- Cr 6 Grand County
- Boat Ramp Larimer County
Fishing spots
Paddle runs
- Begins 0.5 Miles Upstream From End Of Fern Lake Road To Eastern Boundary Of Rocky Mountain National Park
- Begins 0.5 Miles Upstream From End Of County Hwy 115 To Eastern Boundary Of Rocky Mountain National Park
- Gnar Section
- Main Section
- Headwaters To Ends 0.5 Miles Upstream From End Of County Hwy 115
- Nsv
Track Marys Lake Dike No. 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 Marys Lake Dike No. 1
Where does the data for Marys Lake Dike No. 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 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 Marys Lake Dike No. 1.