Pat Mayse Reservoir
Lamar County, Texas5,993 acresView mapDirections
TCEQ publishes the water-quality measurements for Pat Mayse Reservoir. Here is what has been measured.
- Eutrophic
- Impaired · Algal growth
- Public access
- Limited data
Pat Mayse Reservoir in Lamar County, Texas has water-quality measurements published by TCEQ, shown here as reported. Water clarity: 3.9 ft visibility. Phosphorus: 30 µg/L. Chlorophyll-a (algae): 21.8 µg/L. Surface area: 5993 acres.
Pat Mayse Reservoir is a 5,993-acre productive, nutrient-rich eutrophic lake in Lamar County, Texas. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 4 public boat landings. Compared to the 2 other monitored lakes in Lamar County, Pat Mayse Reservoir ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, TCEQ, last sampled 2025-09-10. Methodology: how these readings are compared.
What Pat Mayse Reservoir is good for
From access and monitoring records, not editorial picks.
- Boat launch4 documented ramps
- Camping1 public campground nearby
- Big water5,993 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. Pat Mayse Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth. Check local advisories before you swim.
Whether Pat Mayse Reservoir is safe to swim in today is a call for the Texas Commission on Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Pat Mayse Reservoir
These are the measurements TCEQ publishes for Pat Mayse 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 30 µg/L. Chlorophyll-a 21.8 µg/L. TSI 57.
| 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 | 30µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 21.8µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 57 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Pat Mayse Reservoir
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
5,993 acres
Public access
Yes
Listed by TCEQ
No bathymetric survey has been published for Pat Mayse Reservoir, so its depth is not documented here.
Recreation & Access
- FM 197 BridgePublic
- Pat Mayse East Recreation Area (East)Public
- Sanders Cove (North)Public
- Sanders Cove (South)Public
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Public campgrounds near Pat Mayse Reservoir
- Sanders Cove2.8 kmReserve
Nearest public campgrounds in the USGS National Map inventory, within about 3 miles. An empty list means USGS records no campground that close, which is not the same as camping being unavailable. Where the source gives an official reservation link, it is used; the cabin and hotel search does not cover campsites. More camping lakes
Stays via Stay22
Stays near Pat Mayse Reservoir
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Fishing Pat Mayse Reservoir
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Stable6 years
Phosphorus
Improving-3 µg/L/yr5 years
Chlorophyll-a
Improving-1.02 µg/L/yr5 years
Reservoir Info (USACE NID)
Pat Mayse Reservoir is a man-made reservoir impounded by the Pat Mayse Dam (completed 1967), built primarily for flood risk reduction on the Sanders Creek; earth-type dam, 96 ft tall and 7,080 ft long.
- Surface area
- 5,993 ac
- Normal storage
- 189,100 ac-ft
- Max storage
- 457,800 ac-ft
- Drainage area
- 175 sq mi
- Hazard class
- High
- Owner
- USACE - Tulsa District
All listed purposes: Flood Risk Reduction;Recreation;Water Supply.
Source: USACE National Inventory of Dams, NID ID TX04359 · Operator website
EPA Impairment Status
Pat Mayse 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: Other.
Source: EPA ATTAINS assessment unit TX-0209_01 · Official waterbody report
Nearby Lakes in Lamar County
Frequently asked questions about Pat Mayse Reservoir
Where is Pat Mayse Reservoir?
- Pat Mayse Reservoir is a lake in Lamar County, Texas. Its water-quality measurements are published by TCEQ and shown on this page as reported.
What is the water quality of Pat Mayse Reservoir?
- Pat Mayse Reservoir in Lamar County, Texas has water-quality measurements published by TCEQ, shown here as reported. Water clarity: 3.9 ft visibility. Phosphorus: 30 µg/L. Chlorophyll-a (algae): 21.8 µg/L. Surface area: 5993 acres.
Is Pat Mayse Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Pat Mayse Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth. Check local advisories before you swim.
Are there boat ramps on Pat Mayse Reservoir?
- Pat Mayse Reservoir has 4 documented boat landings in the USGS National Boat Ramps inventory. Named access points include FM 197 Bridge, Pat Mayse East Recreation Area (East), Sanders Cove (North), Sanders Cove (South). Public access is listed as yes.
Can I fish at Pat Mayse Reservoir?
- Pat Mayse Reservoir has 4 documented boat landings in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Texas's fish and wildlife agency, so check its current regulations before you go.
Are there campgrounds on Pat Mayse Reservoir?
- Pat Mayse Reservoir has 1 public campground from USGS The National Map within 5 km, including Sanders Cove. This is a location join, not a booking. Cabins and hotels are listed separately; campsite reservations use the official link when the source provides one.
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Where this data comes from
56 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Texas Commission on Environmental Quality
TCEQMAIN56 samples · 2020–2025
Monitoring station identifiers (1)
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
Named boat-access points from the USGS National Boat Ramps inventory
Public campgrounds from USGS The National Map Structures, within about 3 miles