Elevenmile Reservoir
Park County, ColoradoView mapDirections
Colorado WQCD publishes the water-quality measurements for Elevenmile Reservoir. Here is what has been measured.
- Mesotrophic
- 112 ft max depth
- Public access
- Limited data
Elevenmile Reservoir in Park County, Colorado has water-quality measurements published by Colorado WQCD, shown here as reported. Water clarity: 13.1 ft visibility. Phosphorus: 33 µg/L. Chlorophyll-a (algae): 5.5 µg/L.
Elevenmile Reservoir is a mesotrophic lake in Park County, Colorado with an estimated average depth of about 112 feet. Limited fish-species data available. Public access is available with 3 public boat landings. Compared to the 1 other monitored lakes in Park County, Elevenmile Reservoir ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, CDPHE, last sampled 2021-09-23. Methodology: how these readings are compared.
What Elevenmile Reservoir is good for
From access and monitoring records, not editorial picks.
- Clear water13.1 ft of visibility
- Boat launch3 documented ramps
- Camping2 public campgrounds nearby
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Elevenmile Reservoir is safe to swim in today is a call for the Water Quality Control Division of the Colorado Department of Public Health and Environment and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Elevenmile Reservoir
These are the measurements Colorado WQCD publishes for Elevenmile Reservoir, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 13.1 ft. Phosphorus 33 µg/L. Chlorophyll-a 5.5 µg/L. TSI 47.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 13.1ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 33µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 5.5µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 47 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Elevenmile Reservoir
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~112 ft est.
Public access
Yes
Listed by Colorado WQCD
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Colorado has not published bathymetry for Elevenmile Reservoir.
Lake Size & Watershed
Watershed (drainage) area
970 sq mi
HydroLAKES / HydroSHEDS
Surface area
3,054 acres
HydroLAKES / HydroSHEDS
Shoreline
19.3 mi
HydroLAKES / HydroSHEDS
Elevation
8,576 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- Eleven Mile State ParkPublic
- Eleven Mile State ParkPublic
- Eleven Mile State ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Public campgrounds near Elevenmile Reservoir
- Spillway Campground4.5 kmReserve
- Cove4.9 km
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Stays via Stay22
Stays near Elevenmile Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Elevenmile Reservoir in Park County, Colorado — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Elevenmile Reservoir are listed below.
Top-rated places to stay near Elevenmile Reservoir
Prices for Oct 23–25, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a trip? Cabins and lodging at Elevenmile Reservoir → · more Colorado lake trips
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Fishing Elevenmile Reservoir
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Frequently asked questions about Elevenmile Reservoir
Where is Elevenmile Reservoir?
- Elevenmile Reservoir is a lake in Park County, Colorado. Its water-quality measurements are published by Colorado WQCD and shown on this page as reported.
What is the water quality of Elevenmile Reservoir?
- Elevenmile Reservoir in Park County, Colorado has water-quality measurements published by Colorado WQCD, shown here as reported. Water clarity: 13.1 ft visibility. Phosphorus: 33 µg/L. Chlorophyll-a (algae): 5.5 µg/L.
Is Elevenmile Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Elevenmile Reservoir?
- No published bathymetric survey covers Elevenmile Reservoir, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 112 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Are there boat ramps on Elevenmile Reservoir?
- Elevenmile Reservoir has 3 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Eleven Mile State Park, Eleven Mile State Park, Eleven Mile State Park. Public access is listed as yes.
Can I fish at Elevenmile Reservoir?
- Elevenmile Reservoir has 3 documented boat landings in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Colorado's fish and wildlife agency, so check its current regulations before you go.
Are there campgrounds on Elevenmile Reservoir?
- Elevenmile Reservoir has 2 public campgrounds from USGS The National Map within 5 km, including Spillway Campground, Cove. This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
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Where this data comes from
16 measurements from 2 monitoring stations, 2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Colorado Dept. of Public Health & Environment-WQCD
21COL001_WQX16 samples · 2021
Analytical methods
- Secchi disk depth measurement
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Nitrogen in Water by Pyrolysis Detection
Monitoring station identifiers (2)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory
Public campgrounds from USGS The National Map Structures, within about 3 miles