Skerne wetlands former fish farm (Credit Jon Traill)
The crystal clear project has been estabished for a year - here Living Landscape manager Jon Traill overviews the projects activity so far.
Over the first year we have focussed attention on getting one of Yorkshire Wildlife Trust's newest land acquisitions into improved management. In 2012 the Trust purchased a fish farm site on the lower reaches of the West Beck chalk stream, consisting of a complex of 60 ponds and around 2km of chalk stream covering a 70 acre site. The intention is to turn this former commercial fish farm site into a mosaic wetland consisting of reed-bed, open water, wet grassland, wet woodland and fen alongside work to enhance and restore the degraded sections of chalk stream. The site was re-named Skerne Wetlands (formerly known as Humberside Fisheries) and is roughly split 1/3 on the western side of the West Beck and 2/3 on the eastern side.
The grant awarded by WREN in 2013 has enabled us to begin this exciting work programme and the last year has seen detailed designs and plans drawn up and work started on the area known as the Western Wetlands. The previous 18 months were spent observing the site and getting a better understanding of the complex and highly engineered fish farm infrastructure (sluices, weirs, gates, pumps, ditches and ponds) as well as beginning to realise the huge potential the site has in terms of wildlife.
In the autumn of 2014 work begun to re-work an area ready for planting, to create the wet woodland with alder, willow and aspen in the wetter areas and oak, hawthorn, guelder rose and field maple on the higher drier edges of the area. A large area of reed-bed and fen will also be created with small open water pools interspersed between the reeds. Target water levels will be controlled using sluices to aim to create the ideal conditions for 3 rare wetland plants – greater water parsnip, marsh pea and lesser tussock sedge.
As well as working to restore and create new habitats on the Trust owned land, a major part of our work is being done on other peoples land, working in partnership with them. We identified numerous stretches of chalk stream where restoration work could be undertaken through site visits and discussions with the Environment Agency (EA) and Natural England (NE) as well as through being directly involved in a major piece of work to create a restoration strategy for the River Hull Headwaters chalk streams; a joint initiative headed up by EA and NE.
Through this collaborative approach and working closely with landowners, farmers, river keepers and fly fishing clubs the work programme for the three years was drawn up which enabled us to secure the funding from WREN.
Work has been done at 3 non-Trust sites in 2014: Eastburn and Elmswell Beck – both at the very top of the catchment with springs rising in both streams and West Beck at the Bottoms and Snakeholm.
Work was undertaken on an over-straightened and poor habitat quality stretch of the Eastburn Beck, covering approximately 800m with the aim to create a more diverse flow within the channel using tried and tested green engineering techniques. Two backwaters were also created to provide dual effect – creation of areas for silt deposition and sheltered habitat for young fish and other wildlife. The techniques employed included installation of large woody debris to create flow deflectors and coarse woody debris to provide bank protection and underwater habitat for fish and invertebrates. The materials for this work are largely found on site through crown reduction of over-mature willows which has multiple benefits in that the tree is rejuvenated, increased light levels occur on the stream leading to improved wetland plant growth and the materials are not transported long distances to get to the site. Pool and riffle (beds of gravel in shallower water) creation was also undertaken to provide areas of deeper water aligned with cleaner silt free gravel beds needed for brown trout to spawn (lay their eggs).
Phase two works will be undertaken in autumn/winter 2014-2015 to create further in stream habitat improvements.
Work was carried out to restore the lake habitat at the head of the stream with bank repair to ensure erosion was minimised along with repair and refurbishment of a fish pass to enable brown trout to gain access to the lake. The lake has numerous springs rising in its bed and in years with very low rainfall the lake can dry up completely. A sluice combined with a pool and traverse fish pass ensures that when the lake is full water can be retained as long as possible and the fish pass allows fish to move in and out of the lake habitat as and when conditions are suitable.
Work was also started to restore a 250m section of headwater stream which was overgrown with wetland plants and had little in the way of habitat diversity. A low and high flow channel was created with the low flow channel cleaned of weed to open up the gravel habitats. When the springs rise and more water flows the low flow channel simply fills up and spills out into the wider high flow channel which still retains marginal and aquatic vegetation.
Where bank stabilisation is needed on both these areas, coir logs were installed. These are made of coir coconut fibre (a by-product from the coconut harvest in India) compressed into a 3 metre long, 40cm wide ‘sausage’ shape and held in place by jute netting. These logs are fixed along the bank edge using wooden stakes and re-inforce the bank to prevent erosion. They are bio-degradable and eventually rot down, by which time the bankside plants have established and roots hold the bank together.
West Beck – The Bottoms and Snakeholm
Along the section of West Beck known as The Bottoms, the stream is over-wide with sluggish shallow flows which has led to lots of silt deposition on the chalk gravels in the bed of the stream. This in turn reduces habitat for invertebrates, changes the plant growth and leads to a loss of fish habitat. Work has been carried out using logs to create flow deflectors to break up the uniform flow of water as well as narrowing the river through the creation of what are known as ‘D’ shaped low flow berms.
The berms are created using the coir logs to install a new bank profile, with backfill material taken out of the stream bed and this then covered over with coir matting to prevent it washing away in higher flows. The material taken out of the stream bed is dug out in areas where we want to create new pool and riffle habitats. The other added benefit of using this technique is the material taken from the river already has a dormant seed source within it, meaning that the new berm self-seeds with aquatic and marginal plants already growing in this location.
At Snakeholm, which is approximately 2km downstream of the Bottoms the YWT owns two fields known as Snakeholm Pastures, which sit alongside the West Beck and a smaller tributary chalk stream known as Wanlass drain. We have created new backwater habitat linked to the Wanlass drain which will act as a silt trap as well as providing extra wetland habitat adjacent to the streams. Work has also been carried out on the opposite side of the West Beck from the YWT nature reserve to crown reduce over-mature willows. Some of the wood gained from this work was used to install flow deflectors in appropriate locations along a 400m section of the West Beck.
Survey and Monitoring
Underpinning much of the practical work is the need for an understanding of what will the benefits be. To gauge this, knowledge of the habitats and more importantly the species utilising these habitats is needed. A programme of formal and informal surveys helps us to build a picture of what is currently active and what could be helped to colonise or thrive.
Moth trapping survey effort has been carried out at Skerne Wetlands, water vole survey signs recorded along several sections of the West Beck, a growing list of bird species being built up and a full day of expert survey effort provided by the Yorkshire Naturalist Union (YNU) at Skerne Wetlands to give us some base-line information on a wide range of species.
More technical survey and monitoring is also needed to inform decision making and allow us to understand if the work done in stream is having the desired effect. Examples include dip-well monitoring carried out to look at ground and surface water levels at Skerne wetlands to help with future plans and electro-fishing surveys that have been done at several project sites to monitor fish activity to enable assessment of the habitat improvements.
The range and scope of species that will benefit is far too long to list here, but some of the key species include the following:
Partnership Working & Volunteering
A massively important part of our work is creating partnerships and working collectively with others. The project funded by WREN would not have been possible without buy in and support to help create the programme which we submitted to WREN as a funding bid. Key partners in this process have been Natural England, Environment Agency and East Yorkshire Rivers Trust who not only helped identify and work to create the programme, but have also put financial contributions into the overall budget plan. They continue to support and assist and are actively helping to deliver elements of the project.
The second and equally important partners are the landowners, farmers and tenants who allow us to work with them on their land to improve our wildlife habitats. Without their buy-in and support we would not be able to link up sites to create the Living Landscape stepping stones through the headwaters of the River Hull.
A huge amount of the work we undertake is labour intensive and extra pairs of hands over and above staff and partners is essential if we are to deliver our work. Volunteers who come along in all weathers to different sites to carry out a range of tasks are massively important to us and their support is immensely appreciated. A fledgling River Hull volunteer group has emerged with over 15 regular attendees all getting stuck in. Tasks have ranged from pulling out old redundant netting from the fish ponds at Skerne through to coppicing willows and helping to install some of the in-stream structures used in our river restoration work.
A massive thank you to all who have helped so far with our Crystal Clear vision to restore the River Hull chalk streams.