Ridgway Reservoir
Ouray County, Colorado1,109 acresView mapDirections
Nutrients and algae sit mid-range for this region.
- Mesotrophic
- #1 of 1 in the county
- 130 ft max depth
- Public access
- Limited data
Ridgway Reservoir in Ouray County, Colorado has a water quality grade of C (Fair). Water clarity: 9.8 ft visibility. Phosphorus: 45 µg/L. Chlorophyll-a (algae): 2.2 µg/L. Surface area: 1109 acres.
- Clarity
- 9.8 ft
- Max depth
- ~130 ft est.
- Area
- 1,109 acres
- Type
- Mesotrophic
- Public access
- Yes
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Watch Ridgway Reservoir’s letter
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Ridgway Reservoir is a 1,109-acre mesotrophic lake in Ouray County, Colorado with an estimated average depth of about 130 feet. Water quality is graded C based on 3 sampling years through 2023. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, CDPHE, last sampled 2023-09-13. Grade methodology: LakeQuality methodology.
What Ridgway Reservoir is good for
From access and monitoring records, not editorial picks.
- Clear water9.8 ft of visibility
- Boat launch1 documented ramp
- Big water1,109 acres
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)
Moderate clarity, visible to about 9.8 ft. Phosphorus 45 µg/L. Chlorophyll-a 2.2 µg/L. TSI 47. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9.8 ft | Not graded |
| Phosphorus | 45 µg/L | Fair |
| Chlorophyll-a (Algae) | 2.2 µg/L | Good |
| Trophic State Index (TSI) | 47 | Mesotrophic |
Moderate nutrients, good water quality
→ Ridgway Reservoir water level: the live USGS gauge reading
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~130 ft est. |
| Average Depth | ~73 ft est. |
| Surface Area | 1,109 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 Ridgway 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
- Ridgway State ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Ridgway Reservoir
Reservoir Info (USACE NID)
Ridgway Reservoir is a man-made reservoir impounded by the Ridgway Dam (completed 1987), built primarily for flood risk reduction on the Umcompahgre River; earth-type dam, 330 ft tall and 2,340 ft long.
- Surface area
- 1,109 ac
- Normal storage
- 84,410 ac-ft
- Max storage
- 93,945 ac-ft
- Drainage area
- 264.58 sq mi
- Hazard class
- High
- Owner
- BUREAU OF RECLAMATION
All listed purposes: Flood Risk Reduction;Irrigation;Recreation;Water Supply.
Source: USACE National Inventory of Dams, NID ID CO02706 · Operator website
County Ranking
Ranked #1 of 1 lakes in Ouray County
Nearby Lakes in Ouray County
Frequently asked questions about Ridgway Reservoir
Where is Ridgway Reservoir?
- Ridgway Reservoir is a lake in Ouray County, Colorado. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Ridgway Reservoir?
- Ridgway Reservoir in Ouray County, Colorado has a water quality grade of C (Fair). Water clarity: 9.8 ft visibility. Phosphorus: 45 µg/L. Chlorophyll-a (algae): 2.2 µg/L. Surface area: 1109 acres.
Is Ridgway Reservoir safe to swim in?
- The C is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
How deep is Ridgway Reservoir?
- No published bathymetric survey covers Ridgway Reservoir, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 130 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 1109 acres.
Are there boat ramps on Ridgway Reservoir?
- Ridgway Reservoir has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Ridgway State Park. Public access is listed as yes.
Explore Ridgway Reservoir across LakeQuality
2 documented falls within 21.8 mi, nearest Box Canyon Falls
3 thermal springs within 22.3 mi, nearest Orvis Hot Spring
Species activity outlook by water temperature and season
Where to stay at Colorado's top lakes, each with its grade
Moderate nutrients, good water quality
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Where this data comes from
18 measurements from 2 monitoring stations, 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 · 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