Initial findings show town's waterways are healthy

Mayfly nymph

Mayfly nymph - Credit: Ed Dolphin

Ed Dolphin writes for the Herald on behalf of the Sid Valley Biodiversity Group

The River Sid is healthy, that is the initial finding of a survey being run by volunteers from the Sid Valley Biodiversity Group.

Our river is one of the many plus points to living in Sidmouth. There are delightful riverside walks with the chance of seeing otters, kingfishers, and dippers. Dogs and children love splashing about in the shallow areas in The Byes. Perhaps less obvious to many people, the river makes a major contribution to the biodiversity of the valley.

As part of their project mapping the valley’s nature, a group of volunteer citizen scientists has been recording the water quality all year, and they have begun sampling what is actually living in the river because that gives very good evidence for the cleanliness of the water. This is a serious business but involves the fun activity of kick sampling. The volunteers don their wellies and stand in the river with a net in the water. They walk backwards upstream kicking their heels into the stones and gravel. The small animals that live in the gravel are disturbed and washed into the net so that they can be identified.

In a 2014 survey by the SVA, the invertebrate population indicated The Sid was free from major pollution. Children from St John’s School found the same thing when they kick sampled with the Science Festival in 2018. One thing that the 2014 survey did highlight was that the Woolbrook supported hardly any invertebrates, perhaps because of pollution from road runoff. We are pleased to report that the Woolbrook seems to have recovered.

When volunteers kick sampled in the Woolbrook recently, there was plenty of life hiding in the gravel. There were lots and lots of the freshwater shrimp Gammarus. Gliding smoothly across the bottom of the inspection dish there were tiny water snails and planarians, a type of primitive flatworm. Most significantly, there were also mayfly and caddisfly nymphs, these are only found in relatively unpolluted water.

The Biodiversity Group volunteers will be splashing about in other parts of our river system soon and a full report will appear at the end of the year.

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