]> 2026-04-14T19:27:40+00:00 Case study:Twineham Weir Removal & In-channel Enhancements 500 en Approved 3.8 2 - 5 m 0.01 - 0.1 8.2 5 - 10 m Weir removal Creation of backwaters Habitat restoration Creation of berms Gravel augmentation Adding sinuosity Enhancing flow diversity Ouse and Adur Rivers Trust Environment Agency Rampion Offshore Wind Ltd Sussex Piscatorial Society Great Britain Defra WFD funded Rampion Offshore Wind Ltd OART Yes No Yes false P1070619.JPG P1070905.JPG Twineham TG After.jpg Rakes.jpg Penstock.jpg P1080577.JPG Wineham Penstock .jpg P1090525.JPG P1100549.JPG 20150819 130702.jpg P1100428.JPG Twineham Tilting Gate Pre-Removal Twineham Tilting Gate Immediate Post Removal Twineham Tilting Gate 12 months on Rakes Barn Weir Pre Project (Half Boards Removed) Twineham Penstock Pre Project Twineham Penstock Post Project Wineham Weir with Half the Boards Removed Upstream Wineham Weir Pre-Project One of Five Fish Refuges Created Berm Construction Volunteers Help With Erosion Control No Gareth Williams 10 - 50 k€ Environment Agency Environment Agency Ouse & Adur Rivers Trust Landowner A number of valuable lessons have been learnt through the process of this project, one of the most important being that previous lessons learnt were implemented into this scheme, cutting down on the time it takes to develop and deliver projects. In addition the following form the additional lessons learnt from this project. * It is not always necessary to engineer river restoration project or provide detailed construction designs, especially in the case of demolition of weir structures in areas of no perceived flood risk. * Building relationships can lead to cost effective methods of undertaking a variety of river enhancement work, however, all partners must be willing to think a little “outside the box” when discussing delivery options. * Angling club concerns remain centered around access to the river when water levels are reduced, the creation of berms which slope into the water not only constrict the channel and create flow diversity but also provide year round access to the water irrespective of the water levels. 50.9632263,-0.21077939999998 Oartpk Peter Ouse and Adur Rivers Trust King 1 - 10 m³/s Weir removal, Creation of backwaters, Habitat restoration, Creation of berms, Gravel augmentation,,Tree planting,,Adding sinuosity, Enhancing flow diversity, ,,Volunteer engagement, Peter King 10 - 50 k€ Ouse & Adur Rivers Trust Prior to the weir removal fish surveys were conducted by the Environment Agency with the next surveys due in 2016. We continue to liaise with the angling clubs who have kept catch records at this site for a number of years. Currently we are seeing the expected dip in overall biomass of fish through this section as the resident Carp disperse away from the now flowing river and the overall species composition changes. We expect to see more natural, sustainable populations of river species develop over the coming years. The backwater habitats were immediately effective with over 300 fry counted in a single refuge within days of completion and larger individuals recorded during over-winter peak flows resting in the still waters these refuge areas have created. In addition to the changes in fish species composition we have also recorded two kingfishers on site, the first time they have been observed here for over a decade. Through a separate project OART have been supporting the landowner in a programme of mink trapping which has not only captured 26 mink in its first year (in 2km of river) but has also recorded Polecat (known to have re-colonised Sussex approximately 8 years ago) and seen the number of wading and river birds rapidly increase. We continue with our regime of fixed point photography to monitor change in bank profiles and the rate of vegetation establishment. Gareth Peter Robert Williams King Worsley 22074 Environment Agency, Rampion Offshore Wind Ltd, Sussex Piscatorial Society Berm Construction to Create Sinuosity Robert Worsley Landowner 2015-09-15Z 2457280.5 Berms at Twineham.JPG 2013-11-04Z 2456600.5 Complete The Twineham Weir Removal and In-Channel Enhancement project has seen multiple benefits delivered to the upper Adur in West Sussex which has, over many years, been dredged and straightened with numerous impoundments present along its course. In 2014 the Ouse & Adur Rivers Trust (OART) led a project in collaboration with the Environment Agency to remove four weirs on the River Adur and Herrings Stream tributary. Due to the restricted availability of funding a novel approach was taken which saw OART employ the landowner as principle contractor to undertake the work resulting in a cost saving of over £160,000 and enabling work to be undertaken during suitable weather windows without incurring increased costs. The removal of these obstructions has restored river continuity, instigated a more natural dynamic flow regime and removed barriers to fish passage opening up 4.8km of unrestricted river. Rather than developing a programme of in-channel enhancements prior to removing the weir structures, the partnership decided it would be better to wait to see how the site developed for six months to ensure that any further works were necessary and would be located in appropriate sections of the river. Throughout this period, along with fixed point photography to monitor changes to bank profiles, the local angling clubs were consulted to ensure their requirements were considered within the framework of the enhancement programme. It was clear from an early stage that the main constraint on anglers as a result of this project was reduced water levels limiting access to the river. To fund the proposed in-channel works the local Environment Agency team negotiated a £15k contribution from Rampion Offshore Wind LTD, a joint venture between EON and the green investment bank, to enhance the upper Adur through the sections impacted by these weir removals on the Herrings Stream and River Adur. A number of previously unknown features had been uncovered through the reduced water levels and a number of the enhancements expected to be necessary could now be removed from the list. The project partnership, in consultation with the Wild Trout Trust, angling clubs and the landowner developed a programme of enhancements which has seen a dozen features created along 2.8km of channel combined with extensive tree planting on the banks and surrounding floodplain to provide natural recharge of woody debris to the channel. Again this work was undertaken by the landowner and his team, building on the relationships developed during the weir removals and allowing limited funding to maximise benefits. A number of volunteers, including members of the angling club, assisted in the creation of the in-channel features as well as providing essential manpower to plant a trees along the river bank and surrounding floodplain. The overall outcomes of this project are; * Four weirs removed from the upper Adur, including the priority structure listed in the South East River Basin Management Plan for this catchment. * Five backwaters have been dug to provide shelter for small fish in times of flood and warm conditions in the shallow backwaters will provide an ideal nursery for fish, invertebrates and amphibians. * Six berms have been installed along a 1km straight section of river which has narrowed the channel, sped up flows and increased morphological diversity which will in turn improve the ecology. * 10 tonnes of gravel placed in two sections of river to improve spawning opportunities for fish, habitat for invertebrates and replacing gravel lost over the centuries due to dredging of the river. * 800 trees have been planted to provide shading, bank stabilisation and additional wildlife benefits such as habitat linkage. Twineham Weir Removal & In-channel Enhancements twineham weir removal & in-channel enhancements http://www.oart.org.uk/our-work/projects/restoration-projects/twineham-project No 4800 Adur and Ouse South East Tree planting Adur (East) adur (east) Twineham twineham Volunteer engagement Sea trout (Salmo trutta) kingfisher (Alcedo atthis) Peter King 2000 Ouse & Adur Rivers Trust 10 - 100 km² 42 Less than 100 m Adur (East) GB107041012180 Environmental flows and water resources Fisheries Habitat and biodiversity 180000 100 - 500 k€ GB107041012180 & GB107041012150 Adur (East) & Herrings Stream Peter King 158000 Ouse & Adur Rivers Trust 2015-09-15Z 2457280.5 2014-08-04Z 2456873.5 2016-01-19T13:36:55Z 2457407.0673032 2017-06-06T12:25:32Z 2457911.0177315 Twineham Weir Removal & In-channel Enhancements 500 1 plainlist 5 [[Category:Case study]] [[Project title::!Twineham Weir Removal & In-channel Enhancements]] [[Subcatchment title::Adur (East)]] Twineham Weir Removal & In-channel Enhancements# QUERYd80710563396d26f129b2dfa69c3cdec