Did the Dalton Mill fire pollute the river worth?

​River Worth Friends were very concerned that the fire at Dalton Mill may have led to pollution of the river. You will remember that there were about six tenders pumping water from the river to fight the fire, much of that water will have run off, probably into the river, carrying pollutants from the burning mill. We thought that the contaminated runoff may have affected the river fauna.

​A good way to check the health of a river is to take a kick sample, this involves standing in the river holding a net down stream from you and kicking up the rocks and stones on the riverbed to dislodge any little river bugs (invertebrates) that might be underneath, then identifying and counting the different species. These bugs are rather like the proverbial canary in the coalmine, they tell us when pollution is or has occurred,  a sudden drop in numbers indicates a problem.

​To check the health of the river following the fire we recently did a kick sample below the bridge by the mill. We were very relieved to find that there was a good population of invertebrates showing, indicating that the river has not been unduly affected. Here are the figures from the recent sample with some from a sample last autumn for comparison.......

Caseless caddis.

​Last year           20
​Last week          10

Flat bodied stone clinger (Heptogeniidae)

Last year        20
Last week        40

Mayfly (Ephemeridae).

​
​Last year           0
Last week         3

Olives (Baetidae)

Last year       100
Last week        40

Fresh water shrimp (Gammarus).

Last year        0
This year        4

Blue winged olive (Ephemerellidae).

Last year       10
​Last week        3

Stonefly.

​Last year       30
​Last week        6

The figures do show a slight drop in population but this is not significant.
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Nationwide a group of local volunteers regularly sample sites on their local rivers as part of the Riverfly Partnership with the Environment agency. They are an important part of the agency's pollution monitoring. For a couple of years RWF have sampled at a number of sites on the Worth and North beck on an informal basis but recently two sites, one on North Beck and one below Woodhouse bridge, have been registered with the Riverfly Partnership. We are looking for volunteers to sample at these sites.

Stonefly nymph from North Beck.

​On Saturday 2nd April  at 10.00 am by the river at Aireworth Grove there is an opportunity to find out more about river flies on the Worth as we are encouraging people to get in the river with a net and get kicking to see what turns up, we will have experts on hand to help identify the invertebrates. It will be a great opportunity to find out more about the life in our wonderful river, so if you want to find out more please come along. Bring the children as well as kick sampling is almost as much fun a pond dipping!
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Spot the bugs in just part of this sample tray from North beck.