The waterways in the Parish are all tributaries of the Ouse. These streams spring from the Downs and are considered chalk streams for the initial part of their passage (thus Plumpton Stream is considered as a chalk stream from its source by Plumpton Place until it joins the Mill Stream at Old Mill). Such streams should have a very rich invertebrate fauna. At various points they become more clay streams, also with important wildlife features. Sea trout spawn in some of the streams and bullheads (Miller’s thumbs) are numerous. The latter fish is declining throughout its range in Europe and has been listed on Annex II of the EU Habitats Directive in an attempt to improve its conservation. The streams and their surroundings attract a variety of birds, including kingfishers, and insects, including dragonflies and damselflies.