Mid-Trench Lake
Klamath County, OregonView mapDirections
Oregon DEQ publishes the water-quality measurements for Mid-Trench Lake. Here is what has been measured.
- Hypereutrophic
- Impaired · Algal growth
Mid-Trench Lake in Klamath County, Oregon has water-quality measurements published by Oregon DEQ, shown here as reported. Phosphorus: 240 µg/L. Chlorophyll-a (algae): 80.6 µg/L.
Mid-Trench Lake is a highly nutrient-loaded hypereutrophic lake in Klamath County, Oregon. Overall water quality is improving over recent sampling years. Compared to the 16 other monitored lakes in Klamath County, Mid-Trench Lake ranks #11 for water quality.
Source: EPA Water Quality Portal sampling records, Oregon DEQ, last sampled 2023-09-25. Methodology: how these readings are compared.
Swimming conditions
Readings onlyRecreation use not supported
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. Mid-Trench Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, mercury, oxygen depletion (low DO), pH / acidity, sediment / turbidity, temperature. Check local advisories before you swim.
Whether Mid-Trench Lake is safe to swim in today is a call for the Oregon Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Mid-Trench Lake
These are the measurements Oregon DEQ publishes for Mid-Trench Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 240 µg/L. Chlorophyll-a 80.6 µg/L. TSI 78.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 240µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 80.6µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 78 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Mid-Trench Lake
Answers come straight from the public measurements and survey records on this page.
Stays via Stay22
Stays near Mid-Trench Lake
Compare lakeside cabins, hotels, and vacation rentals near Mid-Trench Lake in Klamath County, Oregon — 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 readings cover nutrients and algae, not lodging. Cabins and rentals around Mid-Trench Lake are listed below.
Top-rated places to stay near Mid-Trench Lake
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Fishing Mid-Trench Lake
Water Quality Trend: Improving
Based on 4 years of monitoring (2020–2023).
Phosphorus
Improving-22 µg/L/yr4 years
Chlorophyll-a
Improving-27.81 µg/L/yr4 years
EPA Impairment Status
Mid-Trench Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Drinking water, Aquatic life, Fish consumption, Recreation, Other.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit OR_LK_1801020303_05_100375 · Official waterbody report
Nearby Lakes in Klamath County
Frequently asked questions about Mid-Trench Lake
Where is Mid-Trench Lake?
- Mid-Trench Lake is a lake in Klamath County, Oregon. Its water-quality measurements are published by Oregon DEQ and shown on this page as reported.
What is the water quality of Mid-Trench Lake?
- Mid-Trench Lake in Klamath County, Oregon has water-quality measurements published by Oregon DEQ, shown here as reported. Phosphorus: 240 µg/L. Chlorophyll-a (algae): 80.6 µg/L.
Is Mid-Trench Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Mid-Trench Lake is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, mercury, oxygen depletion (low DO), pH / acidity, sediment / turbidity, temperature. Check local advisories before you swim.
Explore Mid-Trench Lake across LakeQuality
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Where this data comes from
83 measurements from 1 monitoring station, 2020–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- USGS Oregon Water Science Center
USGS-OR83 samples · 2020–2023
Analytical methods
- Nutrients, wu, WCA,persulfate,CF
- Chlorophyll a, phytoplankton
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