The Steyning Downland has its own chalk stream which emerges from a series of springs in the wooded valley at the base of the Rifle Range. The stream supports a series of ‘online’ ponds. These were dug artificially, it is believed, to create a steady flow of water for the watermills downstream. For more detail on the history of the stream, please read this report (with thanks to Alec Harden).
In more recent times the ponds had fallen into disrepair, being deeply shaded and invaded by trees. The SDS Pond Group was set up to explore the options for their future management. The Group is made up of local people and ecologists with interests in the beauty, wildlife, recreational value and history of these special habitats.
The team’s goals were shaped by the aims of the SDS; to conserve its wildlife, enhance its landscape, and enable the local community, especially young people, to enjoy and better understand the area. It is known that this special section of the SDS has been enjoyed by many people for its tranquil and enchanting atmosphere since at least Victorian times.
The Pond Group sought the views of visitors, and gathered relevant technical information (including surveys of plants, reptiles and freshwater invertebrates, and historical and engineering data). For more information, please read Sally Clifton’s Aquatic Macroinvertebrate Survey here.
The plan has been to adopt a step-by-step approach, clearing some of the trees, allowing more light to reach the pond and reducing leaf-fall. It is hoped this will increase the diversity of aquatic plant and animal life without loosing the specialists that thrive in shaded conditions. In landscape terms, more of the upstream end of the pond is now visible. This has added interest to views from all around it, and so enhanced the very special ‘feel’ of the area.
The brick dam at the Upper Pond has added its own complications to the interesting challenge of balancing the needs of conservation and amenity value to people. The risks to be considered in doing anything around dams have added a sobering background to this exciting process, and much valuable advice has been provided by a variety of engineering specialists.
The brick dam has an overflow pipe which was cleared to restore flow through it, as originally designed, and to reduce erosion around the ‘wing wall’ next to it. This work was also carried out (after taking appropriate technical advice) by enthusiastic volunteers.
This artificial dam is one of three which create the ‘online’ ponds on this section of stream; it is understood their original purpose was to control water supply to the mill below.
Ecologically the most important part of the system is the spring-fed, heavily shaded, chalk stream (or ‘ghyll’) flowing through a steep-sided wooded ravine above the main pond. This type of chalk stream has only recently been appreciated as a habitat type distinct from the lowland, mostly unshaded, ‘Wind in the Willows’ kind of chalk stream with which we associate elusive trout and billowing beds of water crowfoot. Not much is known yet about the conservation needs of these chalk ghylls, so this area will remain untouched until these are better understood.
Future planned work includes stopping up a sink hole which has appeared in the Upper Pond floor, using special ‘puddling clay’. This promises to be an enjoyable, if rather muddy summer undertaking for the Conservation Volunteers.
To find out more, or to get involved in the pond group, please e-mail us.