Island Lake
Delta County, Colorado161 acresView mapDirections
Nutrients and algae sit mid-range for this region.
↓ down from A at the last regrade
- Oligotrophic
- #1 of 4 in the county
- 21 ft max depth
- Limited data
Island Lake in Delta County, Colorado has a water quality grade of C (Fair). Water clarity: 16.7 ft visibility. Phosphorus: 34 µg/L. Chlorophyll-a (algae): 1.1 µg/L. Surface area: 161 acres.
- Clarity
- 16.7 ft
- Max depth
- ~21 ft est.
- Area
- 161 acres
- Type
- Oligotrophic
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Watch Island Lake’s letter
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Island Lake is a 161-acre cold, clear oligotrophic lake in Delta County, Colorado with an estimated average depth of about 21 feet. Water quality is graded C based on 3 sampling years through 2022. Compared to the 3 other monitored lakes in Delta County, Island Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, CDPHE, last sampled 2022-09-14. Grade methodology: LakeQuality methodology.
What Island Lake is good for
From access and monitoring records, not editorial picks.
- Clear water16.7 ft of visibility
- Camping4 public campgrounds nearby
Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The C is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: C (Fair)
Crystal clear, you can see 16.7 ft down. Phosphorus 34 µg/L. Chlorophyll-a 1.1 µg/L. TSI 41. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 16.7 ft | Not graded |
| Phosphorus | 34 µg/L | Fair |
| Chlorophyll-a (Algae) | 1.1 µg/L | Good |
| Trophic State Index (TSI) | 41 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~21 ft est. |
| Surface Area | 161 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 Island Lake.
Lake Size & Watershed
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 Island Lake
- Little Bear0.4 km
- Island Lake1.1 km
- Cobbett1.2 km
- Ward Lake1.8 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
Fishing Island Lake
Reservoir Info (USACE NID)
Island Lake is a man-made reservoir impounded by the Island Lake (completed 1954), built primarily for irrigation on the Ward Creek-Tr; earth-type dam, 23 ft tall and 620 ft long.
- Surface area
- 161 ac
- Normal storage
- 1,432 ac-ft
- Max storage
- 2,355 ac-ft
- Drainage area
- 2 sq mi
- Hazard class
- Significant
- Owner
- SURFACE CREEK DITCH & RESERVOIR CO. (WAIBEL, KEITH
All listed purposes: Irrigation;Recreation.
Source: USACE National Inventory of Dams, NID ID CO00577 · Operator website
County Ranking
Ranked #1 of 4 lakes in Delta County
Nearby Lakes in Delta County
Frequently asked questions about Island Lake
Where is Island Lake?
- Island Lake is a lake in Delta County, Colorado. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Island Lake?
- Island Lake in Delta County, Colorado has a water quality grade of C (Fair). Water clarity: 16.7 ft visibility. Phosphorus: 34 µg/L. Chlorophyll-a (algae): 1.1 µg/L. Surface area: 161 acres.
Is Island Lake safe to swim in?
- The C is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
How deep is Island Lake?
- No published bathymetric survey covers Island Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 21 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 161 acres.
Are there campgrounds on Island Lake?
- Island Lake has 4 public campgrounds from USGS The National Map within 5 km, including Little Bear, Island Lake, Cobbett, Ward Lake. 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 Island Lake across LakeQuality
Species activity outlook by water temperature and season
Where to stay at Colorado's top lakes, each with its grade
Low nutrients, clear water. The letter is not a swimming clearance.
Colorado's cleanest and most-polluted lakes, ranked
Planning a trip around Black Canyon Of The Gunnison?
Island Lake is about 35 miles from Black Canyon Of The Gunnison 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 Black Canyon Of The Gunnison →More Colorado Lake Rankings
Other Grade C Lakes in Colorado
Oligotrophic Lakes in Colorado
Where this data comes from
18 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_WQX18 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)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated 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