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LakeQuality

Martin Lake

Huerfano County, Colorado190 acresView mapDirections

NR
Not rated

Not enough samples to grade — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). No letter yet. Here is what we do have.

Water temp
No reading
No gauge
Clarity
4.8 ft
Secchi · sampled 2023
Level
No reading
No gauge
Trend
No reading
Not enough history
  • 17 ft max depth
  • Public access
  • Limited data

Martin Lake in Huerfano County, Colorado is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.8 ft visibility. Phosphorus: 17 µg/L. Chlorophyll-a (algae): 6.1 µg/L. Surface area: 190 acres.

Clarity
4.8 ft
Max depth
~17 ft est.
Area
190 acres
Public access
Yes
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Watch Martin Lake’s letter

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Why Martin Lake has no grade

We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Martin Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded water clarity, phosphorus and algae (chlorophyll-a).

Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.

Sampling is run by CDPHE and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.

Martin Lake is a 190-acre lake in Huerfano County, Colorado with an estimated average depth of about 17 feet. Limited fish-species data available. Public access is available with 1 public boat landing.

Source: EPA Water Quality Portal sampling records, CDPHE, last sampled 2023-07-25. Grade methodology: LakeQuality methodology.

What Martin Lake is good for

From access and monitoring records, not editorial picks.

  • Boat launch1 documented ramp

Swimming Safety

Not rated

Limited data

The letter is not a swimming clearance. Martin Lake is listed impaired under Clean Water Act §303(d) (IR 5) for metals (other than mercury), temperature. Check local advisories before you swim.

Get alerts for Martin Lake

Water quality measurements for Martin Lake

These readings exist but are not enough for an A–F grade — see why.

Murky, only visible to about 4.8 ft. Phosphorus 17 µg/L. Chlorophyll-a 6.1 µg/L. TSI 49.

MetricValueGrade
Water Clarity (Secchi Depth)4.8 ftNot graded
Phosphorus17 µg/LNot graded
Chlorophyll-a (Algae)6.1 µg/LNot graded
Trophic State Index (TSI)49Mesotrophic

Moderate nutrients, good water quality

Lake Details

CharacteristicValue
Maximum Depth~17 ft est.
Average Depth~11 ft est.
Surface Area190 acres
Public AccessYes

Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Colorado has not published bathymetry for Martin Lake.

Lake Size & Watershed

Watershed (drainage) area
3 sq mi
Shoreline
2.1 mi
Elevation
6,404 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

1
Boat Landings
Yes
Public Access
  • Lathrop State ParkPublic

Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps

Fishing Martin Lake

Reservoir Info (USACE NID)

Martin Lake is a man-made reservoir impounded by the Martin Lake (completed 1910), built primarily for recreation on the Cucharas River-Os; earth-type dam, 29 ft tall and 1,500 ft long.

Surface area
190 ac
Normal storage
3,077 ac-ft
Max storage
4,076 ac-ft
Drainage area
2 sq mi
Hazard class
High
Owner
CITY OF WALSENBURG

All listed purposes: Recreation;Irrigation;Water Supply.

Source: USACE National Inventory of Dams, NID ID CO01327 · Operator website

EPA Impairment Status

Martin Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

Metals (other than mercury)Temperature

Source: EPA ATTAINS assessment unit COARMA26_C · Official waterbody report · Matched by proximity (0.19 km)

Graded lakes near Martin Lake

Martin Lake has no grade, but these lakes within a short drive do.

Nearby Lakes in Huerfano County

Frequently asked questions about Martin Lake

Where is Martin Lake?

Martin Lake is a lake in Huerfano County, Colorado. LakeQuality has not rated this lake (UNRATED) — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years).

What is the water quality grade for Martin Lake?

Martin Lake in Huerfano County, Colorado is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.8 ft visibility. Phosphorus: 17 µg/L. Chlorophyll-a (algae): 6.1 µg/L. Surface area: 190 acres.

Is Martin Lake safe to swim in?

The letter is not a swimming clearance. Martin Lake is listed impaired under Clean Water Act §303(d) (IR 5) for metals (other than mercury), temperature. Check local advisories before you swim.

How deep is Martin Lake?

No published bathymetric survey covers Martin Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 17 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 190 acres.

Are there boat ramps on Martin Lake?

Martin Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Lathrop State Park. Public access is listed as yes.

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-WQCD21COL001_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)

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

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