The StAR project (Slaugham to Ardingly Restoration) was focused on the upper River Ouse and Shell Brook. Both areas were classified as ecologically poor, due to the modified and degraded character of sections of the river channel, particularly between Slaugham and Ardingly, where the Ouse is deep and straightened. The project was delivered between spring 2019 and winter 2022 with with the following aims.
- Investigate the high levels of phosphate and fine sediment present in the water and design and install mitigation measures to trap silt and reduce nutrient inputs to the water environment.
- Enhance in-channel and bank-side habitat, including the installation of gravel to provide spawning grounds for trout and other fish species, creation of berms to improve sinuosity, and the placement of large woody debris to increase flow diversity and provide a rich environment for invertebrates and other freshwater species.
- Improve fish passage at two barriers within the sub-catchment at Ardingly and Slaugham.
- Map the extent and implement control measures for invasive non-native invasive species within the river corridor.
Funding for this project came through a Water Environment Grant from the European Agricultural Fund for Rural Development and is supported by South East Water and the Esmeé Fairbairn Foundation.
Ardingly Fish Pass
The weir at Ardingly is used to gauge river flows and is an important piece of flood defence infrastructure. Improving multi-species fish passage at this location would open 5km of main river at the top of the catchment. A solution has been sought at this location for nearly ten years so we are delighted to have installed a series of baffles to enable movement without interfering with the gauging function of the structure. This design creates a series of small jumps for fish species (less than 200mm) before reaching a more technical series of baffles enabling passage up the sloping face of the weir.
Sediment Control
Walkover surveys of the project area were undertaken and results combined with South East Water “Woodland Pathway Management” reports to identify four priority areas for the control of sediment. Four locations were highlighted as potentially effective silt traps but required de-silting. Silt was removed from these areas and placed on farmland away from the river leaving large areas to effectively collect sediment and prevent nutrients from entering the water.
Staplefield Fish Pass
A bridge culvert at Staplefield was causing blockage to fish passage due to a large concrete slab which has minimal depth of water across it. By fixing a notched baffle to the concrete apron and increasing downstream water levels through the placement of large rocks we were able to increase depth across the concrete and provide multi-species access through the bridge. This has opened 4.5km of river to fish species and when combined with Ardingly Fish pass has mitigated fish pass barriers in the entire main river section of the sub-catchment.
Habitat Enhancements
A 2km section of the River Ouse has been enhanced, adding habitat which complements the increased fish passage through the provision of shelter for juveniles and spawning grounds for adult fish. Berms have been built to increase sinuosity in this straightened section of river and bank erosion has been reduced through woody debris to the banks. Diseased trees (alder and ash) have been removed providing dappled light to the once fully shaded channel which will encourage macrophyte growth within the channel margins.
The Ouse & Adur Rivers Trust
OART is a membership based organisation dedicated to the environmental protection and enhancement of the Sussex River Ouse and Adur including their tributaries, estuaries and still waters.
The Ouse & Adur Rivers Trust (OART) is a registered charity (No: 1082447) formed in 2011 from the amalgamation of two long-standing local organisations, the River Adur Conservation Society and Sussex Ouse Conservation Society.
Contact us at info@oart.org.uk