Derwent Reservoir
Derwent Reservoir in Derbys Notts and Leics, England has official water-quality measurements, not a LakeQuality A–F grade. Phosphorus: 13.4 µg/L. Chlorophyll-a (algae): 1.7 µg/L.
Why Derwent Reservoir has no A–F grade
Derwent Reservoir in England is published with the authority's own measurements, not a LakeQuality letter. official authority class; not a LakeQuality A–F letter Sampling here has recorded phosphorus and algae (chlorophyll-a), but not water clarity.
A letter on the LakeQuality scale would be an invention, not an official class. Everything below that has been measured is still reported on this page.
Monitoring: the Environment Agency (England).
Derwent Reservoir is a lake in Derbys Notts and Leics County, England.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2026-05-19. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Derwent Reservoir
These readings exist but do not meet the evidence bar for an A–F grade — see why.
No clarity data. Phosphorus level: 13.4 µg/L. Chlorophyll-a: 1.7 µg/L. Trophic State Index: 39.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 13.4 µg/L | Not graded |
| Chlorophyll-a (Algae) | 1.7 µg/L | Not graded |
| Trophic State Index (TSI) | 39 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Derwent Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Derwent Reservoir in Derbys Notts and Leics, England — 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.
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Fishing Derwent Reservoir
Frequently asked questions about Derwent Reservoir
What is the water quality of Derwent Reservoir?
- Derwent Reservoir in Derbys Notts and Leics, England has official water-quality measurements, not a LakeQuality A–F grade. Phosphorus: 13.4 µg/L. Chlorophyll-a (algae): 1.7 µg/L.
Is Derwent Reservoir safe to swim in?
- Derwent Reservoir has official nutrient and clarity measurements, not a bacteria swim class and not a safety clearance. Algal blooms, currents, and depth are not covered. Always check local notices before swimming.
Explore Derwent Reservoir across LakeGrade
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Where this data comes from
132 measurements from 1 monitoring station, 2016–2026. Retrieved from the Environment Agency (England; not the EPA Water Quality Portal) on 2026-08-16.
Collected and reported by
- Environment Agency (England)
ea-wqa132 samples · 2016–2026
Monitoring station identifiers (1)
MD-49714220
Authority classifications are stored separately from LakeQuality A–F letters and are never blended. See methodology and data sources.
Data Sources
Water quality data from the EPA Water Quality Portal
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion
Most recent sample: 2026-05-19
Monitoring stations: 1