Horseshoe Reservoir
Huerfano County, Colorado172 acresView mapDirections
Colorado WQCD publishes the water-quality measurements for Horseshoe Reservoir. Here is what has been measured.
- Impaired · Mercury
- 13 ft max depth
- Public access
- Limited data
Horseshoe Reservoir in Huerfano County, Colorado has water-quality measurements published by Colorado WQCD, shown here as reported. Water clarity: 3.9 ft visibility. Phosphorus: 12 µg/L. Chlorophyll-a (algae): 4.8 µg/L. Surface area: 172 acres.
Horseshoe Reservoir is a 172-acre lake in Huerfano County, Colorado with an estimated average depth of about 13 feet. Limited fish-species data available. Public access is available with 2 public boat landings.
Source: EPA Water Quality Portal sampling records, CDPHE, last sampled 2023-07-25. Methodology: how these readings are compared.
What Horseshoe Reservoir is good for
From access and monitoring records, not editorial picks.
- Boat launch2 documented ramps
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Horseshoe Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, metals (other than mercury), temperature. Check local advisories before you swim.
Whether Horseshoe Reservoir 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 Horseshoe Reservoir
These are the measurements Colorado WQCD publishes for Horseshoe Reservoir, 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 3.9 ft. Phosphorus 12 µg/L. Chlorophyll-a 4.8 µg/L. TSI 48.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3.9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 12µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 4.8µg/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. | 48 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Horseshoe Reservoir
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~13 ft est.
Surface area
172 acres
Public access
Yes
Listed by Colorado WQCD
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Colorado has not published bathymetry for Horseshoe Reservoir.
Lake Size & Watershed
Watershed (drainage) area
2 sq mi
HydroLAKES / HydroSHEDS
Shoreline
2 mi
HydroLAKES / HydroSHEDS
Elevation
6,437 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
- Lathrop State ParkPublic
- Lathrop State ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
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Fishing Horseshoe Reservoir
Reservoir Info (USACE NID)
Horseshoe Reservoir is a man-made reservoir impounded by the Horseshoe Lake (completed 1961), built primarily for recreation on the Cucharas River-Os; earth-type dam, 27 ft tall and 4,180 ft long.
- Surface area
- 172 ac
- Normal storage
- 2,760 ac-ft
- Max storage
- 3,750 ac-ft
- Drainage area
- 0 sq mi
- Hazard class
- High
- Owner
- COLORADO PARKS AND WILDLIFE (TAYLOR, MARGARET)
All listed purposes: Recreation;Fish and Wildlife Pond.
Source: USACE National Inventory of Dams, NID ID CO00498 · Operator website
EPA Impairment Status
Horseshoe Reservoir 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, Aquatic life.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit COARMA26_B · Official waterbody report
Nearby Lakes in Huerfano County
Frequently asked questions about Horseshoe Reservoir
Where is Horseshoe Reservoir?
- Horseshoe Reservoir is a lake in Huerfano County, Colorado. Its water-quality measurements are published by Colorado WQCD and shown on this page as reported.
What is the water quality of Horseshoe Reservoir?
- Horseshoe Reservoir in Huerfano County, Colorado has water-quality measurements published by Colorado WQCD, shown here as reported. Water clarity: 3.9 ft visibility. Phosphorus: 12 µg/L. Chlorophyll-a (algae): 4.8 µg/L. Surface area: 172 acres.
Is Horseshoe Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Horseshoe Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, metals (other than mercury), temperature. Check local advisories before you swim.
How deep is Horseshoe Reservoir?
- No published bathymetric survey covers Horseshoe Reservoir, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 13 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 172 acres.
Are there boat ramps on Horseshoe Reservoir?
- Horseshoe Reservoir has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Lathrop State Park, Lathrop State Park. Public access is listed as yes.
Can I fish at Horseshoe Reservoir?
- Horseshoe Reservoir has 2 documented boat landings in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Colorado's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
6 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_WQX6 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)
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)
Named boat-access points from the USGS National Boat Ramps inventory