Deep Dive
River pollution monitoring for Henley-on-Thames - Deep Dive.
Deep Dive
River pollution monitoring for Henley-on-Thames - Deep Dive.
The data is offered for those interested in gaining a better understanding of the river water quality at Henley-on-Thames. Again, your attention is drawn to the Terms and Conditions as set out on home page of this site.
The following table shows rainfall, river flow and river temperature as well as pollution data collected from various points along the river at Henley-on-Thames.
See column descriptions below.
You can also download the following table for your own analysis.
Date: Date when sample was taken.
Marsh Lock: E.Coli readings just downstream of Marsh Lock What3Words. (1)
River & Rowing: E.Coli readings just downstream of The River and Rowing Museum What3Words (1)
Henley Bridge: E.Coli readings just downstream of Henley Bridge What3Words (1)
Fawley Meadows: E.Coli readings at Fawley Meadows (2025 only) What3Words (1)
Rainfall: Rainfall event in the previous 72 Hours - Historical weather data for Henley-on-Thames, England, United Kingdom
Flow m3/sec: Thames flow rate in cubic metres per second - Hydrology Data Explorer - Reading
Water Temperature: River water temperature in degrees Celsius - River Temperature: River Thames above Shiplake Lock
Fawley Meadows (Lab) E.Coli: E.Coli readings by Latis Labs. MPN/100ml (2025 only)
Fawley Meadows (Lab) I.E.: Intestinal Enterococci (IE) readings by Latis Labs. cfu/100ml (2025 only)
River & Rowing (TW) E.Coli: E.Coli readings by Thames Water Labs, Caversham. MPN/100ml
River & Rowing (TW) I.E.: Intestinal Enterococci (IE) readings by Thames Water Labs, Caversham. MPN/100ml
Marsh Lock (TW) E.Coli: E.Coli readings by Thames Water Labs, Caversham. MPN/100ml
Marsh Lock (TW) I.E.: Intestinal Enterococci (IE) readings by Thames Water Labs, Caversham. MPN/100ml
(1): Readings are taken using a Fluidion Alert One Analyser (Laboratory assessment). Units of measurement are colony forming units of E.Coli. / 100ml. Fluidion Alert One can measure both planktonic (free-floating) and comprehensive bacteria (which are bound in aggregates, such as on faecal or sediment particles), providing more accurate risk assessments. Results are presented based on a comprehensive analysis. Typically Fluidion Alert One results are made available the day after the sample was taken.
(Lab): Lab based results tested by Latis Labs - Normec Latis Scientific (UKAS Accreditation: 2279Testing Multiple). Lab based tests generally take a few days to process, and results are made available once complete.
(TW): Readings taken by Thames Water with the following caveat - "This data should not be used to determine the safety of the river. We have been providing this data for public information only and no specific reliance should be put on it unless explicitly agreed by Thames Water. Due to the lab analysis required to process the samples the data will always be retrospective".
E. Coli: E. Coli are a group of organisms found in the intestines of animals and humans and survive for a while in the environment when excreted. Many types of E. Coli are not harmful but some such as E. Coli 0157, can directly cause illness. The presence of the bacteria indicates that human or animal faeces may be present in bathing water and could contain other potentially harmful organisms that could cause illness. Occasionally, usually during heavy rainfall, soil containing E. Coli bacteria is washed into rivers, streams, lakes, or groundwater, leading to bathing waters, and if found, E. Coli bacteria indicate that harmful bugs could be present .
Intestinal Enterococci (IE): Intestinal Enterococci are found in the intestines of animals and humans although some types are environmental in origin. The presence of the bacteria indicates that human or animal faeces may be present in bathing water alongside other potentially harmful organisms that could cause illness.
MPN/100 ml: Most probable number per 100 ml. The results for E. coli & Intestinal Enterococci may be reported as either CFU or MPN, depending on the analytical method used.
For an insite into Fluidion Alert One technology and results, see 2024 Olympics - Seine Water Quality.
Environment Agency Bathing water quality glossary