Much of Chiddingly Parish lies within the catchment of the Bull River, one of the main tributaries to the Cuckmere River. Due to its underlying sandstone and clay geology, river levels in the Bull can rise rapidly during heavy rainfall events, contributing to flooding downstream in Hellingly and Hailsham. This page provides information about Greening Chiddingly projects funded by the Lund Trust that are using natural flood management approaches to slow the flow of floodwater into the Bull River and create new wetland habitats. 

Two of our projects involve the installation of what are called 'leaky woody dam' structures across gullies and waterways. Leaky woody dams are, in their simplest form, felled trees that are laid across a watercourse and held in place by natural anchors. They are called 'leaky' because they don't simply dam the river but allow water to slowly trickle through. In time, the low dams trap sediment and pond back the stream water. In this way, the passage of water is slowed and flood peaks reduced during periods of heavy rainfall. The areas immediately upstream and adjacent to each dam develop into new wetland habitats, providing spawning grounds for insects and increasing the length of the breeding season for amphibians.

Natural flood management at Burchetts Farm, Whitesmith

The natural flood management project at Burchetts Farm involved the installation of four leaky woody dams across a small tributary stream that feeds into the Bull River just south of Hale Farm. This is the same stream that forms the natural boundary between Chiddingly and Muddles Green further east. The positions of the leaky woody dams are labelled 1 to 4 on the image below. The project also included the creation of two scrapes. These are shallow pits dug into the floodplain (labelled A and B) that hold water when the river floods and will, in time, develop into new wetland habitats. Although only installed in September 2025, the dams are already ponding back water and slowing the flow during flood events. 

Plan of the natural flood management scheme at Burchetts Farm, showing the locations of leaky woody dams and scrapes along the river. Image: © Dean Morrison.

Overview of one of the leaky woody dams showing how the structure is anchored into the floodplain. Image: © Dean Morrison.

Close-up of a leaky woody dam, showing the dam construction in greater detail. Image: © Dean Morrison.

Angled view of the same leaky woody dam, with the gaps between the tree trunks that make up the structure visible. Image: © Dean Morrison.

A leaky woody dam in action, ponding back floodwater upstream (i.e. to the right) of the dam. Image: © Dean Morrison.

Natural flood management at Peke's Farm, Muddles Green

The photos below show the construction in 2024 of nine leaky woody dams in a shallow wooded gully on Peke's Farm. This gully feeds directly into the main Bull River immediately east of Peke's House. The leaky woody dams are in a very different setting to those at Burchetts Farm. The key difference is that the dams have been installed across a shallow gully rather than a flowing stream. This requires lower, single trunk, structures and creates a stepped sequence of shallow pond and wetland habitats rather than deeper ponds and inundated floodplain areas.

Lowering a tree trunk into place to create a leaky woody dam structure on Peke's Farm. Note the use of local trees to create the dam. Image: © Dean Morrison.

Trimming stakes to support a leaky woody dam structure across a boggy gully bottom on Peke's Farm. Image: © Neil Burfield.

Water beginning to pond upstream of a recently installed leaky woody dam on Peke's Farm. Image: © Neil Burfield.

Water starting to pond upstream of a leaky woody dam on Peke's Farm, creating new habitat for amphibians. Image: © Neil Burfield.