Conchas Reservoir
San Miguel County, New Mexico2,694 acresView mapDirections
Clarity, phosphorus, and algae all sit in the cleanest band for this region.
- Mesotrophic
- Impaired · Mercury
- #2 of 2 in the county
- Public access
- Limited data
Conchas Reservoir in San Miguel County, New Mexico has a water quality grade of A (Excellent). Water clarity: 8.9 ft visibility. Chlorophyll-a (algae): 2.2 µg/L. Surface area: 2694 acres.
- Clarity
- 8.9 ft
- Area
- 2,694 acres
- Type
- Mesotrophic
- Chlorophyll-a
- 2.2 µg/L
- Trend
- ↓ Declining
- Public access
- Yes
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Watch Conchas Reservoir’s letter
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Conchas Reservoir is a 2,694-acre mesotrophic lake in San Miguel County, New Mexico. Water quality is graded A based on 1 sampling years through 2016. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 3 public boat landings. Compared to the 1 other monitored lakes in San Miguel County, Conchas Reservoir ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, NMED, last sampled 2016-09-28. Grade methodology: LakeQuality methodology.
What Conchas Reservoir is good for
From access and monitoring records, not editorial picks.
- Boat launch3 documented ramps
- Big water2,694 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 A is nutrients and algae, not a swimming clearance. Conchas Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, pCBs. Check local advisories before you swim.
Water Quality Grade: A (Excellent)
Moderate clarity, visible to about 8.9 ft. Chlorophyll-a 2.2 µg/L. TSI 42. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8.9 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | 2.2 µg/L | Good |
| Trophic State Index (TSI) | 42 | Mesotrophic |
Moderate nutrients, good water quality
Current Conditions
USGS snapshot Sep 7, 2026, 3:00 PM from gauge 07223500 (CONCHAS LAKE AT CONCHAS DAM N. MEX.). Station page ↗ — a live reading replaces this snapshot when the gauge responds. Missing live data is not an all-clear.
→ Conchas Reservoir water level: the live USGS gauge reading
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 2,694 acres |
| Public Access | Yes |
No bathymetric survey has been published for Conchas Reservoir, so its depth is not documented here.
Recreation & Access
- Conchas Lake State Park - Southside Recreation AreaPublic
- Conchas Lake State Park - NorthPublic
- Cove CampgroundPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Conchas Reservoir
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.18 m/yr | 2 |
Reservoir Info (USACE NID)
Conchas Reservoir is a man-made reservoir impounded by the Conchas Dam (completed 1940), built primarily for flood risk reduction on the Canadian River/Conchas River; gravity-type dam, 235 ft tall and 19,500 ft long.
- Surface area
- 2,694 ac
- Normal storage
- 61,532 ac-ft
- Max storage
- 709,119 ac-ft
- Drainage area
- 7,409 sq mi
- Hazard class
- High
- Owner
- USACE - Albuquerque District
All listed purposes: Flood Risk Reduction;Recreation.
Source: USACE National Inventory of Dams, NID ID NM00006 · Operator website
EPA Impairment Status
Conchas Reservoir is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit NM-2304_00 · Official waterbody report
County Ranking
Ranked #2 of 2 lakes in San Miguel County
Nearby Lakes in San Miguel County
Frequently asked questions about Conchas Reservoir
Where is Conchas Reservoir?
- Conchas Reservoir is a lake in San Miguel County, New Mexico. LakeQuality grades it A for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Conchas Reservoir?
- Conchas Reservoir in San Miguel County, New Mexico has a water quality grade of A (Excellent). Water clarity: 8.9 ft visibility. Chlorophyll-a (algae): 2.2 µg/L. Surface area: 2694 acres.
Is Conchas Reservoir safe to swim in?
- The A is nutrients and algae, not a swimming clearance. Conchas Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, pCBs. Check local advisories before you swim.
What is the water level at Conchas Reservoir?
- The USGS snapshot on this page for Conchas Reservoir is 178.64 ft of gage height, recorded Sep 7, 2026, 3:00 PM at gauge 07223500. Current Conditions hydrates a live NWIS reading from that same station when the gauge responds. A missed live fetch is not an all-clear.
Are there boat ramps on Conchas Reservoir?
- Conchas Reservoir has 3 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Conchas Lake State Park - Southside Recreation Area, Conchas Lake State Park - North, Cove Campground. Public access is listed as yes.
Explore Conchas Reservoir across LakeQuality
Depth, room, public access, and the state wake-sport rules
Species activity outlook by water temperature and season
Where to stay at New Mexico's top lakes, each with its grade
Moderate nutrients, good water quality
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Where this data comes from
14 measurements from 2 monitoring stations, 2014–2016. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- NM Environmental Dept./SWQB
21NMEX_WQX14 samples · 2014–2016
Analytical methods
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
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
Named boat-access points from the USGS National Boat Ramps inventory