Last week Josh Robins and I travelled down south to take a look at the site visit locations for the 2017 Annual Conference. It was my first trip out of the office since starting with the RRC so I was excited to see some river restoration in action!
Josh and I met Pete King, a freelance Project Officer at the Ouse & Adur Rivers Trust (OART), and Ian Dennis, a Principal Environmental Scientist at Royal HaskoningDHV, and we headed to the Knepp Castle river restoration site as they both worked on this project. Royal HaskoningDHV were commissioned in 2009 by the Environment Agency to produce renaturalisation designs for the 2.5km reach of the River Adur which runs through the Knepp Castle Estate, to compliment the concurrent Knepp Wildland Project that the landowner had already been implementing since 2001 (and still is - find out more in the Wildland Project section here). This reach had been intensely modified by human activity for over two hundred years and had been canalised since the 1800s, leaving an over-widened, over-deepened, uniform channel cut off from its floodplain with little in-channel or riparian habitat.
Using a partnership approach Royal HaskoningDHV worked closely with the Environment Agency, Natural England, Sussex Wildlife Trust and the Knepp Castle Estate (plus advice and guidance from the RRC) and the project was successfully completed in 2013. Works included:
- Channel remeandered through old course (approximated using LiDAR) reconnecting river to floodplain
- Removal of two redundant in-channel structures
- Introduction of large wood in-channel to increase flow and habitat diversity and protect river banks
- Floodplain scrape, pond and backwater creation to maximise floodplain connectivity
The project was a finalist in the 2015 UK River Prize for its innovative and novel approach to landscape-scale restoration and its aim to restore the full range of hydrological processes. Find out more here and watch a summary video here.
Pete then showed us another restoration project near Twineham along the River Adur and a smaller tributary, the Herrings Stream. Works here included:
- Removal of four weirs, two on the River Adur and two on the Herrings Stream resulting in 4.8km of previously inaccessible river becoming passable and reducing the water level to reveal gravel substrate
- Creation of five backwater habitats to provide refuge areas
- Planting of 5000 trees along river banks and linking smaller areas of trees together into blocks to provide shade for fish and riparian animals, cool channel temperature, slow the flow over the floodplain and trap runoff from surrounding land, reducing input of potential pollutants
- Berm creation to introduce sinuosity into a straightened channel and create habitat while providing fishing platforms for local angling clubs
The OART worked closely with the landowner, the local community and any interested groups making this project an excellent example of the benefits of community involvement and the consequent cost savings. The backwater and berm creation aspects were undertaken by volunteers from the OART, the Environment Agency and Sussex Piscatorial Society and the tree planting was undertaken by OART volunteers, members of the Environment Agency Fisheries and Biodiversity team, the landowner and some helpers from his farm – a real community effort! The project was a finalist in the Wild Trout Trust Conservation Awards in 2016 due to the length of river made accessible to multiple fish species. To find out more about the work of OART click here.
Make sure to book your place at the 2017 Annual Conference to see these exciting projects yourself.
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