Colne Mere
Herts and North London, EnglandView mapDirections
EA publishes the water-quality measurements for Colne Mere. Here is what has been measured.
- Limited data
Colne Mere in Herts and North London, England has official water-quality measurements, shown as reported. Phosphorus: 480 µg/L. Chlorophyll-a (algae): 7.9 µg/L.
How Colne Mere is classified
Colne Mere in England is published with the authority's own measurements and class. The measurements here are published by the agency that samples the lake, as reported. Sampling here has recorded phosphorus and algae (chlorophyll-a), but not water clarity.
LakeQuality publishes no grade of its own beside it. Everything below thathas been measured is reported on this page.
Monitoring: the Environment Agency (England).
Colne Mere is a lake in Herts and North London County, England.
Source: the Environment Agency (England) — not the EPA Water Quality Portal, last sampled 2021-11-24. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Colne Mere is safe to swim in today is a call for the Environment Agency (England) and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Colne Mere
These are the measurements EA publishes for Colne Mere. More on the source.
No clarity data. Phosphorus 480 µg/L. Chlorophyll-a 7.9 µg/L. TSI 72.
| 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 | 480µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 7.9µg/L | Measured, not scored The green pigment in algae — a direct measure of how much algae is in the water. |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 72 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
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Frequently asked questions about Colne Mere
Where is Colne Mere?
- Colne Mere is a lake in Herts and North London, England. This page reports official water-quality measurements, shown as reported.
What is the water quality of Colne Mere?
- Colne Mere in Herts and North London, England has official water-quality measurements, shown as reported. Phosphorus: 480 µg/L. Chlorophyll-a (algae): 7.9 µg/L.
Is Colne Mere safe to swim in?
- Colne Mere 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.
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Where this data comes from
6 measurements from 1 monitoring station, 2019–2021. Retrieved from the Environment Agency (England; not the EPA Water Quality Portal) on 2026-08-16.
Collected and reported by
- Environment Agency (England)
ea-wqa6 samples · 2019–2021
Monitoring station identifiers (1)
TH-PRTS0034
Authority classifications are shown as the authority published them. See where the data comes from and data sources.