Task Force

S.O.C.S. runs a group of volunteers that we call “The Task Force”.

The Task Force objective is to maintain and improve the habitats of our river and its many tributaries. Not just for our satisfaction, but for the benefit of future generations, and of course the ecology of the river system.

Due to man's influence many of our rivers and streams have suffered degradation . All of the watercourses that make up the Sussex Ouse catchment have been modified to some degree for development, milling and agriculture. The need for water for human consumption, industry and agriculture has resulted in damaging abstraction from the river and the aquifers of the South Downs , the source of many of the Ouse chalk streams. The resultant low flows are often inadequate to dilute treated sewage causing further ecological damage. Some of this degradation can be reversed by the restoration work planned by the S.O.C.S. Task Force.

All of the work carried out by the Task Force is in accordance with current conservation practices, as laid down in our

Introducing Woody Debris

Bank stabilisation and channel modification to combat erosion

This is a particular problem with some of the Ouse tributaries. Here in the South East this is exacerbated by the sudden influx of rainwater from the increase in impervious surfaces such as roads and roofs as a result of over-development. Insensitive farming practices such as ploughing up close to the margins of streams compounds the problem. Unfenced pastures allowing ingress of cattle also has a deleterious effect.

To protect banks against erosion, Large Woody Debris (LWD) or willow bundles can be securely pinned against the bank to deflect the flow. Once installed this encourages the growth of vegetation, further stabilising the bank and providing cover for fish and other animals.

In-stream enhancements like channel narrowing and the creation of riffles and pools can be also be achieved using locally sourced materials like LWD. Constructing deflectors and groynes to locally concentrate flow is beneficial to scour away sediment.

Modification of existing in-stream structures to facilitate fish migration

Man made obstructions such as weirs and sluices are a formidable barrier to the migration of fish, particularly sea trout trying to reach their spawning grounds. Many of the fish passes associated with these structures on the Ouse are inadequate or of poor design and need attending to.

By simple modification to some of the smaller structures, the task force hope to extend sea trout access to new spawning grounds in the headwaters of selected tributaries. Carefully planned modifications may consist of cutting slots in weir crests, effectively lowering the height for ascending fish and the construction of small fish passes to bypass weirs.

Loosening of compacted gravels to facilitate salmonid spawning

This is an annual task undertaken at selected sites each autumn. Volunteers rake stream bed gravel to loosen it and wash out the silt.

Sea trout rely on the existence of certain grades of stream bed gravel where they can excavate a nest, termed a redd, in which to deposit their eggs. Whilst suitable gravel does exist in many stretches of the tributary streams, most is in poor condition. Low water velocity during the summer months has resulted in silt deposits, causing concretion of the gravels.

We have found a significant increase in the number of redds in the treated areas

Aquatic Planting

Another aspect of our work involves repopulating the waterways with indigenous water plants. In the past, a culture of persistent dredging to facilitate land drainage has left many sections denuded of plant life. We have been successful in restoring plants particularly to the River Uck and Bevern Stream