Shadow Mountain Lake
Grand County, Colorado1,852 acresView mapDirections
Colorado WQCD publishes the water-quality measurements for Shadow Mountain Lake. Here is what has been measured.
- Mesotrophic
- Impaired · Metals (other than mercury)
- 39 ft max depth
Shadow Mountain Lake in Grand County, Colorado has water-quality measurements published by Colorado WQCD, shown here as reported. Water clarity: 7.9 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 5.1 µg/L. Surface area: 1852 acres.
Shadow Mountain Lake is a 1,852-acre mesotrophic lake in Grand County, Colorado with an estimated average depth of about 39 feet. Water clarity is declining over recent sampling years. Compared to the 6 other monitored lakes in Grand County, Shadow Mountain Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, CDPHE, last sampled 2024-01-30. Methodology: how these readings are compared.
Shadow Mountain Lake covers about 1,900 acres in Grand County. For a place on the water, look through cabin and lake-house rentals near Shadow Mountain Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
What Shadow Mountain Lake is good for
From access and monitoring records, not editorial picks.
- Camping3 public campgrounds nearby
- Big water1,852 acres
Swimming conditions
Readings onlyElevated nutrients
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. Shadow Mountain Lake is listed impaired under Clean Water Act §303(d) (IR 5) for metals (other than mercury). Check local advisories before you swim.
Whether Shadow Mountain Lake 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 Shadow Mountain Lake
These are the measurements Colorado WQCD publishes for Shadow Mountain Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 7.9 ft. Phosphorus 20 µg/L. Chlorophyll-a 5.1 µg/L. TSI 47.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 7.9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 20µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 5.1µg/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 Shadow Mountain Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~39 ft est.
Surface area
1,852 acres
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Colorado has not published bathymetry for Shadow Mountain Lake.
Lake Size & Watershed
Watershed (drainage) area
186 sq mi
HydroLAKES / HydroSHEDS
Shoreline
9 mi
HydroLAKES / HydroSHEDS
Elevation
8,383 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
Public campgrounds near Shadow Mountain Lake
- Green Ridge1.3 km
- Cutthroat Bay Group4.0 kmReserve
- Cutthroat Bay4.0 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 Shadow Mountain Lake
Compare lakeside cabins, hotels, and vacation rentals near Shadow Mountain Lake in Grand 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 Shadow Mountain Lake are listed below.
Top-rated places to stay near Shadow Mountain Lake
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 whole trip? See where to stay at Colorado’s top lakes →
Follow Shadow Mountain Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Shadow Mountain Lake
Water quality readings over time
3 seasons of samples on record (2021–2023). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Worsening3 years
Phosphorus
Stable0 µg/L/yr3 years
Chlorophyll-a
Improving-1 µg/L/yr2 years
Reservoir Info (USACE NID)
Shadow Mountain Lake is a man-made reservoir impounded by the Shadow Mountain Dam (completed 1946), built primarily for irrigation on the Colorado River; earth-type dam, 63 ft tall and 3,077 ft long.
- Surface area
- 1,852 ac
- Normal storage
- 18,369 ac-ft
- Max storage
- 18,369 ac-ft
- Drainage area
- 184.47 sq mi
- Hazard class
- High
- Owner
- BUREAU OF RECLAMATION
Source: USACE National Inventory of Dams, NID ID CO01666 · Operator website
EPA Impairment Status
Shadow Mountain Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Drinking water.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit COUCUC12_B · Official waterbody report
Nearby Lakes in Grand County
Frequently asked questions about Shadow Mountain Lake
Where is Shadow Mountain Lake?
- Shadow Mountain Lake is a lake in Grand County, Colorado. Its water-quality measurements are published by Colorado WQCD and shown on this page as reported.
What is the water quality of Shadow Mountain Lake?
- Shadow Mountain Lake in Grand County, Colorado has water-quality measurements published by Colorado WQCD, shown here as reported. Water clarity: 7.9 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 5.1 µg/L. Surface area: 1852 acres.
Is Shadow Mountain Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Shadow Mountain Lake is listed impaired under Clean Water Act §303(d) (IR 5) for metals (other than mercury). Check local advisories before you swim.
How deep is Shadow Mountain Lake?
- No published bathymetric survey covers Shadow Mountain Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 39 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 1852 acres.
Are there campgrounds on Shadow Mountain Lake?
- Shadow Mountain Lake has 3 public campgrounds from USGS The National Map within 5 km, including Green Ridge, Cutthroat Bay Group, Cutthroat Bay. 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.
Explore Shadow Mountain Lake across LakeQuality
Planning a trip around Rocky Mountain?
Shadow Mountain Lake is about 12 miles from Rocky Mountain National Park. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.
Best time to visit Rocky Mountain →More lakes in Colorado
Other Lakes in Colorado
Mesotrophic Lakes in Colorado
Where this data comes from
980 measurements from 4 monitoring stations, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- USGS Colorado Water Science Center
USGS-CO974 samples · 2020–2024 - Colorado Dept. of Public Health & Environment-WQCD
21COL001_WQX6 samples · 2022
Analytical methods
- Secchi disk method
- Phosphorus, LL,wu,persulfate(CO)
- YSI EXO, 470/685/40,S bacillaris
- Plant pigments, sonication & 445
- YSI EXO turbidity sensor, FNU
- Secchi disk depth measurement
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Nitrogen in Water by Pyrolysis Detection
Monitoring station identifiers (4)
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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Public campgrounds from USGS The National Map Structures, within about 3 miles