Re-naturalising an historically modified for brown trout and flood prevention

Ruth Craig, Project Officer, Lincolnshire Chalk Streams Project, Navigation Warehouse, Louth, Lincolnshire, LN11 0DA [email protected], www.lincswolds.org.uk/chalk-streams.

River Bain The is a mixed geology chalk stream (Biodiversity Action Plan 'priority habitat') found in Lincolnshire, rising from the chalk bed of the Area of Outstanding Natural Beauty. The bain has been classified as 'moderate status' under the Water Framework Directive but is in danger of going into 'poor status' due to sediment input. The bain rises in the village of Ludford and follows a course through agricultural land. The chalk stream is under threat from farming, sedimentation, on-line lakes, old mill impoundments, abstraction, pollution, flooding and signal crayfish.

Opportunity The Bain flows into the village of Donington-on-Bain via a straightened channel past an old mill house. Several of the old mill structures still exist in the channel and act as barriers to fish migration whilst slowing down the flow and encouraging the deposition of silt on the gravel bed. The river is also known to flood the downstream village of . In 2011 the owner of the mill offered up the opportunity to the Lincolnshire Chalk Stream Project (LCSP) to investigate what could be done to improve fish & eel passage. The LCSP commissioned APEM, via the Environment Agency (EA), to carry out a feasibility study on three suggestions made by the LCSP partners. Upon revising the report the Wild Trout Trust (WTT) offered the suggestion of re-naturalising the river channel.

Crown Copyright. All rights reserved. Lincolnshire County Council 100025370

Re-naturalising the river A specialist consultant Prof. Richard Hey from Streamwise was employed to design the location of the new channel to include pool-riffle sequences, meanders and to incorporate a 'log vane' structure to grade the river bed where the land dropped considerably for the use of weirs. The project aimed to divert the Bain from flowing down an approximately 200m straightened section towards the mill by redirecting the flow along a newly constructed channel meandering through an adjacent field extending the length of the river. This will in turn hold a greater volume of water up- stream in the system. Consideration in providing habitat for all forms and stages of aquatic and ter- restrial wildlife was included in the design. As part of the planning phase ecological consultants were employed to carry out a Habitat Survey in the area where the new channel was to be dug and to check what species of interest inhabited the current stream. The Environment Agency carried out fish and invertebrate surveys on the old stream to provide baseline monitoring data.

The project was managed by the LCSP Project Officer. The work started in mid October 2013. Prof. Richard Hey along with support from the WTT, were onsite to ensure the contractors created the channel in the way it had been designed so that all levels, riffles and log vane structures were where they should be to ensure the river flowed. The Environment Agency carried out a fish rescue from the old channel into the new before it became blocked off. Designs by Prof. R Hey Designs by AECOM Pre and Post Monitoring The Environment Agency carried out an electrofishing survey of the old channel, we are currently awaiting results of the fish species and populations that are using the new river channel. The landowner is a volunteer for the LCSP Riverfly Monitoring project actively undertaking monthly surveys to monitor the river. We are currently monitoring the re-colonisation of riverflies which in turn is helping us to monitor the water quality coming from upstream.

Fish species present in the old stream

March Riverfly monitoring results, the first for the new channel

Photograph: David Hutchinson EA

Lord Chris Smith visits the project in February 2014

Log Vanes downstream of the mill house

A partnership of: