A MANNINGTREE environmental charity has revealed that the River Stour has lower than expected water quality following its volunteer-led water sampling sessions.

On the last Wednesday of the month, members of PACE (Practical Actions for Climate and the Environment) Manningtree, conducts river quality checks to assess the river’s biodiversity.

John Hall, chairman, said the Environment Agency trains 150 volunteer groups across the country,  including PACE Manningtree, to take samples.

John said that unlike other readings of the river using machines that could miss sewage pollution by the timings of the results, sampling animals sensitive to oxygen provides a much greater time range – weeks not days or hours.

Harwich and Manningtree Standard: Kick - John Hall doing some kick-sampling in the River Stour Kick - John Hall doing some kick-sampling in the River Stour (Image: Newsquest)

John added that though there could be a continuous recorder – which would do updates every 10 minutes – this would cost about £28,000 and that for the five sites viewed by the volunteer on one stretch of one river, that it would cost about £140,000. 

John said the river “canaries” are a part of a well-researched method called ‘Riverfly’ where a score of 0 is given when no relevant, or oxygen-sensitive, animals have survived and a maximum of 16 is given for good water quality.

In the last annual report from July last year, the ARMI Riverfly Total Scores were low for both the Dedham sites, which are situated above and below the Dedham Sewage Works.

Harwich and Manningtree Standard: Variety - Pointed at is the the nymphs of Burrowing Mayflies which typically fly out of the river in May hence their name and below are two freshwater shrimpsVariety - Pointed at is the the nymphs of Burrowing Mayflies which typically fly out of the river in May hence their name and below are two freshwater shrimps (Image: Newsquest)

As the score is low above the sewage works, before any sewage is entered into the river, the report says there appears to be a “chronic” problem.

In general, the score at the River Stour at Dedham is the worst with scores of 1 to 3 for most of the year, only improving to a score of 7 in early spring.

All scores are entered onto a website so the EA can investigate, which happened after a very low score at the River Stour at Langham in the past year.

Harwich and Manningtree Standard: Community - (Left to right) Steve Marr, Iris Marr, Tom Hancock, Philip Bohannan, John Hall, Caroline Hall, and Trudi Needham (behind)Community - (Left to right) Steve Marr, Iris Marr, Tom Hancock, Philip Bohannan, John Hall, Caroline Hall, and Trudi Needham (behind) (Image: Newsquest)

Scores of 8 and 5 were recorded at both the river Stour sites on January, 31 and John said that without the ongoing pollution “it would be at least a 10” for both areas.

He added: “The river is not as clean as it should be”.

For more information about PACE Manningtree and to join the team doing practical river actions visit here.