Lake Isabel
Custer County, Colorado35 acresView mapDirections
Colorado WQCD publishes the water-quality measurements for Lake Isabel. Here is what has been measured.
- 12 ft max depth
- Limited data
Lake Isabel in Custer County, Colorado has water-quality measurements published by Colorado WQCD, shown here as reported. Water clarity: 5.9 ft visibility. Phosphorus: 232 µg/L. Chlorophyll-a (algae): 0.8 µg/L. Surface area: 35 acres.
Lake Isabel is a 35-acre lake in Custer County, Colorado with an estimated average depth of about 12 feet.
Source: EPA Water Quality Portal sampling records, CDPHE, last sampled 2022-07-13. Methodology: how these readings are compared.
Lake Isabel covers about 35 acres in Custer County. For a place on the water, look through cabin and lake-house rentals near Lake Isabel on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
What Lake Isabel is good for
From access and monitoring records, not editorial picks.
- Camping11 public campgrounds nearby
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Lake Isabel 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 Lake Isabel
These are the measurements Colorado WQCD publishes for Lake Isabel, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 5.9 ft. Phosphorus 232 µg/L. Chlorophyll-a 0.8 µg/L. TSI 54.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5.9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 232µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 0.8µg/L | Measured, not scored The green pigment in algae — a direct measure of how much algae is in the water. |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 54 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Lake Isabel
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~12 ft est.
Surface area
35 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 Lake Isabel.
Lake Size & Watershed
Watershed (drainage) area
19 sq mi
HydroLAKES / HydroSHEDS
Shoreline
1.1 mi
HydroLAKES / HydroSHEDS
Elevation
8,497 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 Lake Isabel
- Southside0.4 km
- Lake Isabel Cabin0.5 kmReserve
- Southside Campground - Lake Isabel0.5 kmReserve
- La Vista Campground - Lake Isabel0.6 kmReserve
- La Vista0.7 km
- St Charles Campground - Lake Isabel1.2 kmReserve
- St. Charles1.5 km
- Ponderosa1.9 km
- Spruce2.2 km
- Ponderosa Group - Lake Isabel2.3 kmReserve
- Spruce Group - Lake Isabel2.3 kmReserve
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 Lake Isabel
Compare lakeside cabins, hotels, and vacation rentals near Lake Isabel in Custer 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.
Top-rated places to stay near Lake Isabel
Prices for Oct 23–25, 4 adults. Change dates on the map below.
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Fishing Lake Isabel
Reservoir Info (USACE NID)
Lake Isabel is a man-made reservoir impounded by the Lake Isabel (completed 1937), built primarily for recreation on the St Charles River; earth-type dam, 98 ft tall and 680 ft long.
- Surface area
- 35 ac
- Normal storage
- 1,037 ac-ft
- Max storage
- 1,320 ac-ft
- Drainage area
- 18 sq mi
- Hazard class
- High
- Owner
- USDA FS
Source: USACE National Inventory of Dams, NID ID CO00494 · Operator website
Nearby Lakes in Custer County
Frequently asked questions about Lake Isabel
Where is Lake Isabel?
- Lake Isabel is a lake in Custer County, Colorado. Its water-quality measurements are published by Colorado WQCD and shown on this page as reported.
What is the water quality of Lake Isabel?
- Lake Isabel in Custer County, Colorado has water-quality measurements published by Colorado WQCD, shown here as reported. Water clarity: 5.9 ft visibility. Phosphorus: 232 µg/L. Chlorophyll-a (algae): 0.8 µg/L. Surface area: 35 acres.
Is Lake Isabel safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Lake Isabel?
- No published bathymetric survey covers Lake Isabel, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 12 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 35 acres.
Are there campgrounds on Lake Isabel?
- Lake Isabel has 11 public campgrounds from USGS The National Map within 5 km, including Southside, Lake Isabel Cabin, Southside Campground - Lake Isabel, La Vista Campground - Lake Isabel. 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 Lake Isabel across LakeQuality
Planning a trip around Great Sand Dunes?
Lake Isabel is about 32 miles from Great Sand Dunes National Park & Preserve. 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 Great Sand Dunes →More lakes in Colorado
Other Lakes in Colorado
Eutrophic Lakes in Colorado
Where this data comes from
6 measurements from 2 monitoring stations, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Colorado Dept. of Public Health & Environment-WQCD
21COL001_WQX6 samples · 2022
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)
Public campgrounds from USGS The National Map Structures, within about 3 miles