Trinidad Reservoir
Las Animas County, Colorado1,442 acresView mapDirections
Colorado WQCD publishes the water-quality measurements for Trinidad Reservoir. Here is what has been measured.
- Oligotrophic
- Impaired · Mercury
- 123 ft max depth
- Public access
- Limited data
Trinidad Reservoir in Las Animas County, Colorado has water-quality measurements published by Colorado WQCD, shown here as reported. Water clarity: 6.6 ft visibility. Phosphorus: 46 µg/L. Chlorophyll-a (algae): 1.1 µg/L. Surface area: 1442 acres.
Trinidad Reservoir is a 1,442-acre cold, clear oligotrophic lake in Las Animas County, Colorado with an estimated average depth of about 123 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 2024-09-11. Methodology: how these readings are compared.
What Trinidad Reservoir is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Big water1,442 acres
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Trinidad Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, metals (other than mercury), oxygen depletion (low DO). Check local advisories before you swim.
Whether Trinidad 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 Trinidad Reservoir
These are the measurements Colorado WQCD publishes for Trinidad 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 6.6 ft. Phosphorus 46 µg/L. Chlorophyll-a 1.1 µg/L. TSI 47.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 6.6ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 46µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 1.1µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 47 | Oligotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Low nutrients, clear water. No reading is a swimming clearance.
Ask about Trinidad Reservoir
Answers come straight from the public measurements and survey records on this page.
→ Trinidad Reservoir water level: the live USGS gauge reading
Lake Details
Max depth
~123 ft est.
Surface area
1,442 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 Trinidad Reservoir.
Lake Size & Watershed
Watershed (drainage) area
669 sq mi
HydroLAKES / HydroSHEDS
Shoreline
10.1 mi
HydroLAKES / HydroSHEDS
Elevation
6,234 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
- Trinidad Lake 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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Stays near Trinidad Reservoir
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Fishing Trinidad Reservoir
Reservoir Info (USACE NID)
Trinidad Reservoir is a man-made reservoir impounded by the Trinidad Dam (completed 1976), built primarily for flood risk reduction on the Purgatoire River; earth-type dam, 203 ft tall and 6,610 ft long.
- Surface area
- 1,442 ac
- Normal storage
- 71,779 ac-ft
- Max storage
- 164,930 ac-ft
- Drainage area
- 671 sq mi
- Hazard class
- High
- Owner
- USACE - Albuquerque District
All listed purposes: Flood Risk Reduction;Other;Irrigation;Recreation.
Source: USACE National Inventory of Dams, NID ID CO00050 · Operator website
EPA Impairment Status
Trinidad 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 COARLA15_B · Official waterbody report
Nearby Lakes in Las Animas County
Frequently asked questions about Trinidad Reservoir
Where is Trinidad Reservoir?
- Trinidad Reservoir is a lake in Las Animas County, Colorado. Its water-quality measurements are published by Colorado WQCD and shown on this page as reported.
What is the water quality of Trinidad Reservoir?
- Trinidad Reservoir in Las Animas County, Colorado has water-quality measurements published by Colorado WQCD, shown here as reported. Water clarity: 6.6 ft visibility. Phosphorus: 46 µg/L. Chlorophyll-a (algae): 1.1 µg/L. Surface area: 1442 acres.
Is Trinidad Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Trinidad Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, metals (other than mercury), oxygen depletion (low DO). Check local advisories before you swim.
How deep is Trinidad Reservoir?
- No published bathymetric survey covers Trinidad Reservoir, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 123 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 1442 acres.
Are there boat ramps on Trinidad Reservoir?
- Trinidad Reservoir has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Trinidad Lake State Park. Public access is listed as yes.
Can I fish at Trinidad Reservoir?
- Trinidad Reservoir has 1 documented boat landing 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.
Explore Trinidad Reservoir across LakeQuality
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Where this data comes from
24 measurements from 4 monitoring stations, 2022–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Colorado Dept. of Public Health & Environment-WQCD
21COL001_WQX24 samples · 2022–2024
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 (4)
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