A recent survey of the River Avon and its estuaries has found that pollution levels of water ways in Portishead and Clevedon have greatly reduced since the last survey in 2023.

The Bristol Avon RiverBlitz survey has been run by the Bristol Avon Rivers Trust (BART) for the past nine years and is conducted by volunteer citizen scientists living on and around the River Avon who upload their findings to the RiverBlitz database.

This year's edition saw 133 volunteers test 202 water samples for nitrate and phosphate levels, or nutrient pollution, the most common pollutants of rivers that enter the waterways due to run off from farming fertilisers, sewage, road surfaces, and household waste.

Included in the 202 tests were samples from Clevedon and Portishead, both of which came back cleaner than samples from last year.

Water from the River Rhyne in Portishead was tested in 2023 with results showing over 5mg/L of nitrate and 0.5mg/L of phosphate to be present, with both measurements being considered high levels of pollution.

However, the 2024 tests from the same body of water have given much more promising results, with samples from the outfall of the River Rhyne returning results of low to no nitrate and phosphate pollution.

Meanwhile in Clevedon water from the Blind Yeo, a channel off the River Kenn, was tested and although not as drastic, improvements have been made.

In 2023 the river was found to have at least 5 mg/L of nitrate and 0.2 mg/L of phosphate present, both high levels, whilst in 2024 a nearby area of the same waterway recorded 2mg/L of nitrate and 0.1 mg/L of phosphate, reductions that reclassify the river into medium levels of nutrient pollution.

The testing in 2024 also showed that 69% of the 202 samples had high nutrient loads of phosphate and nitrate while just 3.5% recorded low nutrient levels from same sample group, an improvement from 2023 when 88% of samples confirmed high pollution levels and only 1 out of 290 samples showed low levels.

However, despite the improvements BART have warned that there are still many issues with water pollution around the Avon.

The RiverBlitz events only capture the water quality during a short amount of time and so can be affected by external factors like extreme heat or heavy rainfall.

Volunteers also doesn’t test for several other factors which affect a rivers health such as bacterial pollution, chemical pollution, animal habitats, and more, meaning that there is still much more to be done to assure the safety of our waterways.

For more information about Bristol Avon Rivers Trust and their work to create a clear future for our rivers, please visit their website here.