Ecology and Geomorphology

Key terrestrial and aquatic flora and fauna species in the Shepley Mill study area include:

  • Kingfisher (Alcedo atthis);

  • Common pipistrelle (Pipistrellus pipistrellus);

  • Soprano pipistrelle bat (Pipistrellus pygmaeus);

  • Daubenton’s Bat (Myotis daubentoniid);

  • Japanese Knotweed (Fallopia japonica);

  • Giant Hogweed (Heracleum mantegazzianum);

  • Cherry Laurel (Prunus laurocerasus);

  • Snowberry (Symphoricarpos albus);

  • Floating Pennywort (Hydrocotyle ranunculoides);

  • Bullhead (Cottus gobio);

  • Brown/Sea Trout (Salmo trutta);

  • European eels (Anguilla anguilla);

  • Mirror carp (Cyprinus carpio);

  • Pike (Esox lucius);

  • Various caddisflies species (up to 18 species found in Wildness Island).

Although fish, such as brown trout may spawn within local reaches of the River Wandle, Shepley Mill is providing a significant barrier preventing all fish species using good quality habitat upstream of the Shepley Mill. There is anecdotal evidence, the actual brown trout population above Shepley Mill are hatchery reared fish.

The aquatic survey undertaken in October 2021 of the Carshalton and Croydon branches of the River Wandle identified low habitat diversity, with few habitat features in common with a natural channel, and a range of bank and channel modifications. The macrophyte species were restricted, and although the survey was out of season, the Environment Agency survey data nearby and previous macrophyte surveys support these findings.

Sedimentation is large issue within the Carshalton and Croydon branches of the River Wandle, with silt deposition evident including a shelf of silt deposited in the channel. Sediment deposition, impoundment and/or barrier movement restrictions are likely to be the influencing factors impacting the aquatic ecology within the river, in particular the macrophytes and fish.

A summary of the fluvial geomorphology of the Shepley Mill study area is provided below:

Water Framework Directive