Understanding the data

The data on this portal has been provided so that river users can be better informed on local river water quality. However, it does not guarantee the safety of any river site. All potential river users should make their own safety assessment including risks other than poor water quality such as underwater obstructions, water temperature and speed.

Similarly, measuring river health is complicated and caution should be taken to not over-generalise based on the data in this portal. Rivers are very complex systems and, just like human health, there are many parameters that we can potentially measure.

In the UK, the quality of our water environment is assessed following the Water Environment Regulations (2017, also called the Water Framework Direcrtive or WFD). This approach aims for good status for all surface waters (rivers, lakes, estuaries and coasts) and groundwater.

We have included some variables, like phosphate, ammonia and dissolved oxygen that are legislated under the WFD. Wherever possible, we have provided thresholds based on this legislation. However, a WFD assessment of a river includes many other variables not included in the portal, such as invertebrate and fish populations, how artificially modified a river has been and the concentrations of certain chemicals.

There are also other variables not measured by the WFD at all, such as pharmaceuticals and microplastics, which may be significant for some rivers.

Similarly, a more accurate picture of river health is gained from comparing long term averages with the thresholds than comparing a single reading.

UKCEH Land Cover Maps 2021	Classified satellite images of the UK land surface from 2021.
EA ecological status of waterbodies for 2022	The Rivers Trust State of Our Rivers Report describes the current ecological health of the rivers in your local area.
Thames Water investment plans storm discharge sites	Regularly updated information about investments in your local area.
EA river Thames conditions	The current conditions affecting boaters on the River Thames and what the warnings mean.
Canal and River Trust: Water level and strong stream warnings	These are warnings about conditions that may affect navigation, such as varying water levels and faster flows.
Oxford University Rowing Clubs status flags	The colour of the OURCs status flags represents restrictions on the number and minimum level of experience of crews permitted to embark.