Matt Warner Reservoir E
Uintah County, UtahView mapDirections
Nutrients and algae run above the regional average.
↓ down from C at the last regrade
- Eutrophic
- Impaired · Algal growth
- #13 of 14 in the county
Matt Warner Reservoir E in Uintah County, Utah has a water quality grade of D (Nutrient-rich). Water clarity: 6.2 ft visibility. Phosphorus: 72 µg/L. Chlorophyll-a (algae): 15.2 µg/L.
- Clarity
- 6.2 ft
- Type
- Eutrophic
- Phosphorus
- 72 µg/L
- Chlorophyll-a
- 15.2 µg/L
- Trend
- → Stable
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Stays near Matt Warner Reservoir E
Compare lakeside cabins, hotels, and vacation rentals near Matt Warner Reservoir E in Uintah County, Utah — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Matt Warner Reservoir E are listed below.
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Watch Matt Warner Reservoir E’s letter
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Matt Warner Reservoir E is a productive, nutrient-rich eutrophic lake in Uintah County, Utah. Water quality is graded D based on 2 sampling years through 2024. Phosphorus level is declining over recent sampling years. Compared to the 13 other monitored lakes in Uintah County, Matt Warner Reservoir E ranks #13 for water quality.
Source: EPA Water Quality Portal sampling records, Utah DWQ, last sampled 2024-09-30. Grade methodology: LakeQuality methodology.
Swimming Safety
Grade onlyAlgae risk
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 D is nutrients and algae, not a swimming clearance. Matt Warner Reservoir E is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, nutrients (phosphorus, nitrogen), oxygen depletion (low DO), pH / acidity, temperature. Check local advisories before you swim.
Water Quality Grade: D (Nutrient-rich)
Murky, only visible to about 6.2 ft. Phosphorus 72 µg/L. Chlorophyll-a 15.2 µg/L. TSI 58. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6.2 ft | Not graded |
| Phosphorus | 72 µg/L | Fair |
| Chlorophyll-a (Algae) | 15.2 µg/L | Poor |
| Trophic State Index (TSI) | 58 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Fishing Matt Warner Reservoir E
Water Quality Trend: → Stable
Based on 11 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.035 m/yr | 11 |
| Phosphorus | ↓ Declining | +3.7 µg/L/yr | 5 |
| Chlorophyll-a | ↑ Improving | -6.06 µg/L/yr | 7 |
Reservoir Info (USACE NID)
Matt Warner Reservoir E is a man-made reservoir impounded by the Warner (Matt) (completed 1938), built primarily for irrigation on the Pot Creek; earth-type dam, 38 ft tall and 297 ft long.
- Normal storage
- 3,947 ac-ft
- Max storage
- 6,729 ac-ft
- Drainage area
- 32 sq mi
- Hazard class
- Significant
- Owner
- DIVISION OF WILDLIFE RESOURCES
Source: USACE National Inventory of Dams, NID ID UT00314 · Operator website · Matched by proximity (0.92 km)
EPA Impairment Status
Matt Warner Reservoir E is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit UT-L-14040106-033_00 · Official waterbody report · Matched by proximity (0.64 km)
County Ranking
Ranked #13 of 14 lakes in Uintah County
Nearby Lakes With Higher Grades
Matt Warner Reservoir E holds Grade D. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Uintah County
Frequently asked questions about Matt Warner Reservoir E
Where is Matt Warner Reservoir E?
- Matt Warner Reservoir E is a lake in Uintah County, Utah. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Matt Warner Reservoir E?
- Matt Warner Reservoir E in Uintah County, Utah has a water quality grade of D (Nutrient-rich). Water clarity: 6.2 ft visibility. Phosphorus: 72 µg/L. Chlorophyll-a (algae): 15.2 µg/L.
Is Matt Warner Reservoir E safe to swim in?
- The D is nutrients and algae, not a swimming clearance. Matt Warner Reservoir E is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, nutrients (phosphorus, nitrogen), oxygen depletion (low DO), pH / acidity, temperature. Check local advisories before you swim.
Explore Matt Warner Reservoir E across LakeQuality
Planning a trip around Dinosaur?
Matt Warner Reservoir E is about 26 miles from Dinosaur National Monument. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.
Best time to visit Dinosaur →More Utah Lake Rankings
Other Grade D Lakes in Utah
Eutrophic Lakes in Utah
Where this data comes from
79 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Utah Department Of Environmental Quality
UTAHDWQ_WQX79 samples · 2020–2024
Analytical methods
- Field Measurements
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (1)
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