Big Meadows Reservoir
Mineral County, Colorado115 acresView mapDirections
Nutrients and algae run above the regional average.
↓ down from C at the last regrade
- Eutrophic
- #1 of 1 in the county
- 19 ft max depth
- Public access
- Limited data
Big Meadows Reservoir in Mineral County, Colorado has a water quality grade of D (Nutrient-rich). Water clarity: 7.2 ft visibility. Phosphorus: 29.5 µg/L. Chlorophyll-a (algae): 7.1 µg/L. Surface area: 115 acres.
- Clarity
- 7.2 ft
- Max depth
- ~19 ft est.
- Area
- 115 acres
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- Yes
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Big Meadows Reservoir is a 115-acre productive, nutrient-rich eutrophic lake in Mineral County, Colorado with an estimated average depth of about 19 feet. Water quality is graded D based on 3 sampling years through 2023. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, CDPHE, last sampled 2023-07-26. Grade methodology: LakeQuality methodology.
What Big Meadows Reservoir is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Camping1 public campground 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 D is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: D (Nutrient-rich)
Moderate clarity, visible to about 7.2 ft. Phosphorus 29.5 µg/L. Chlorophyll-a 7.1 µg/L. TSI 50. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.2 ft | Not graded |
| Phosphorus | 29.5 µg/L | Fair |
| Chlorophyll-a (Algae) | 7.1 µg/L | Poor |
| Trophic State Index (TSI) | 50 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~19 ft est. |
| Surface Area | 115 acres |
| Public Access | Yes |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Colorado has not published bathymetry for Big Meadows Reservoir.
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
- Big Meadows Reservoir State Wildlife AreaPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Public campgrounds near Big Meadows Reservoir
- Big Meadows0.6 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 Big Meadows Reservoir
Water Quality Trend: ↑ Improving
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +1.1 m/yr | 2 |
| Phosphorus | ↑ Improving | -37.5 µg/L/yr | 2 |
| Chlorophyll-a | ↑ Improving | -17.9 µg/L/yr | 2 |
Reservoir Info (USACE NID)
Big Meadows Reservoir is a man-made reservoir impounded by the Big Meadows - North Dike (completed 1968), built primarily for recreation on the S. Fork Rio Grande; earth-type dam, 15 ft tall and 300 ft long.
- Surface area
- 115 ac
- Normal storage
- 2,436 ac-ft
- Max storage
- 3,356 ac-ft
- Drainage area
- 17 sq mi
- Hazard class
- High
- Owner
- COLORADO PARKS AND WILDLIFE
All listed purposes: Recreation;Fish and Wildlife Pond.
Source: USACE National Inventory of Dams, NID ID CO02869 · Operator website · Matched by proximity (0.18 km)
County Ranking
Ranked #1 of 1 lakes in Mineral County
Nearby Lakes in Mineral County
Frequently asked questions about Big Meadows Reservoir
Where is Big Meadows Reservoir?
- Big Meadows Reservoir is a lake in Mineral County, Colorado. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Big Meadows Reservoir?
- Big Meadows Reservoir in Mineral County, Colorado has a water quality grade of D (Nutrient-rich). Water clarity: 7.2 ft visibility. Phosphorus: 29.5 µg/L. Chlorophyll-a (algae): 7.1 µg/L. Surface area: 115 acres.
Is Big Meadows Reservoir safe to swim in?
- The D is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
How deep is Big Meadows Reservoir?
- No published bathymetric survey covers Big Meadows Reservoir, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 19 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 115 acres.
Are there boat ramps on Big Meadows Reservoir?
- Big Meadows Reservoir has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Big Meadows Reservoir State Wildlife Area. Public access is listed as yes.
Are there campgrounds on Big Meadows Reservoir?
- Big Meadows Reservoir has 1 public campground from USGS The National Map within 5 km, including Big Meadows. 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 Big Meadows Reservoir across LakeQuality
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Where this data comes from
18 measurements from 2 monitoring stations, 2022–2023. 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 · 2022–2023
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)
Named boat-access points from the USGS National Boat Ramps inventory
Public campgrounds from USGS The National Map Structures, within about 3 miles