Advisory Visit 25 th September Rivers Greta & Derwent, Cumbria. On Behalf of Keswick & District Angling Association

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1 Advisory Visit 25 th September 2007 Rivers Greta & Derwent, Cumbria On Behalf of Keswick & District Angling Association

2 1.0 Introduction (Advisory Visit) This report is the output of a site visit undertaken by Simon Johnson of the Wild Trout Trust on the Rivers Greta and Derwent, Near Keswick, Cumbria. Comments in this report are based on observations on the day of the site visit and discussions with Mr David Calvert (Keswick DAA) and Mr Keith Kendal (Environment Agency) and a representative from Natural England. Normal convention is applied throughout the report with respect to bank identification, i.e., the banks are designated left hand bank (LHB) or right hand bank (RHB) whilst looking downstream. Visual assessment of in-channel habitat was difficult due to river levels being 3ft above normal. 2.0 Fishery Background Keswick Angling Association has approximately 100 members paying 50 per year. The Association controls various beats on the main River Derwent, its tributaries and Derwent Water. The rivers have the reputation of being fine brown trout, sea trout and salmon fisheries. However in recent years there has been a concern within the Association regarding the apparent decline of catches of wild fish. Currently the club stocks with around 350 domesticated diploid brown trout. Members are allowed to kill four fish per day, however catch and release and the use of barbless hooks is encouraged. The AV focused on two beats one on the Greta and one on the main Derwent itself (see location maps in Section 3.0) comprising approximately 2km of single and double bank fishing. The Environment Agency undertake fisheries surveys within the Derwent catchment. However data on trout are limited as sampling effort has been mainly targeted at monitoring salmon populations. Both beats visits fall within the boundaries of the Derwent and Bassenthwaite Lake Special Area of Conservation (SAC). On the Derwent the primary features of conservation interest are sea, river and brook lamprey, Atlantic Salmon and Otter. The Association would like to sustainably develop its fisheries to maximise gains to local biodiversity.

3 3.0 Habitat Overview River Greta Greta Site Visit Due to high river levels on the day of the visit an assessment of in-stream habitat proved to be very difficult. The top of the beat has been extensively engineered to allow the construction of the railway to Keswick in the 1800 s. Although the railway is now a footpath its legacy still remains in the form of straightened channel containing very little in the way of in-stream features such as boulders and Large Woody Debris. Large Woody Debris (LWD) is a general term referring to all wood naturally occurring in streams including branches, stumps and logs. The presence of LWD has been shown to be extremely important in several respects including increases in mean flow, depths and localised scouring velocities, and development of high in-channel physical habitat diversity. LWD can have significant benefits to the control of run-off at the catchment scale. Woody Debris helps regulate the energy of running water by decreasing the velocity. Thus the travel time of water across the catchment is increased. Almost all LWD in streams is derived from trees located within the riparian corridor. Streams with adequate LWD tend to have greater habitat diversity, a natural meandering shape and greater resistance to

4 high water events. Therefore LWD is an essential component of a healthy stream s ecology and is beneficial by maintaining the diversity of biological communities and physical habitat. Traditionally many land managers and riparian owners have treated LWD in streams as a nuisance and have removed it, often with uncertain consequences. This is often unnecessary and perhaps harmful to high quality streams such as the Greta and Derwent. Stream clearance can reduce the amount of organic material necessary to support the aquatic food web, remove vital instream habitats that fish will utilise for shelter and spawning and reduce the level of erosion resistance provided against high flows. In addition LWD improves the stream structure by enhancing the substrate and diverting the stream current in such a way that pools and riffles are likely to develop. A stream with a heterogeneous substrate and pools and riffles is ideal for benthic (bottom dwelling) organisms as well as for fish species like wild trout. There appears to be an ongoing programme of removal of LWD either during annual KAA working parties and / or Environment Agency routine maintenance operations. Along the railway reach riparian tree growth is dominated by mature Sycamores. The tree cover is mainly high canopy, with very little in the way of understory cover in the form of boughs, branches and bushes. The latter type of habitat provides useful overhead cover for all three life stages of trout (fry, parr, adult) and is a source of terrestrial invertebrates. Due to low light penetration through the high canopy there is little in the way of vegetative bankside cover in the form of shrubs, tall herbs and grasses.

5 Removal of LWD reduces the availability of valuable cover for wild trout (Greta) Light penetration of through the high canopy has allowed the colonisation of grasses and low level bush growth which provides useful overhead cover.

6 Below is an example of LWD that has been left in the channel on a stream in North Wales, which has created pool and riffle habitat. Downstream of the railway viaduct the river regains more natural and meandering characteristics. Habitat improves considerably with the presence of in-stream boulders which provide good cover for salmon and trout parr. Land use adjacent to the river is a mixture of grazing and broadleaved woodland. The grazed areas are fenced but there is very little in the way of cover in the form of tall herbs, grasses and shrubs. The River Naddle enters the Greta at this point and is thought to be an important spawning stream for both salmon and trout. Two other streams entering the Greta, the Brundleholme Beck and the Glendettria Beck, are also potentially important for the same reasons as the Naddle. However time constraints meant that an inspection of these two becks was not possible. There have been fencing projects on both becks mainly to improve salmon habitat. There are opportunities for further fencing works at the top of both becks which could be particularly beneficial to trout in terms of spawning and nursery habitat. (Pers Comm, Keith Kendal, EA) On the day of the visit bank repair works (using blockstone) were being undertaken to address an erosion problem on the RHB. This was caused by wind-blown trees falling into the main channel with their rootwads still attached. This has allowed the river to erode freshly exposed and unstable banks. A programme of regular coppicing may have alleviated

7 this problem by allowing understory vegetation to naturally strengthen the banks. Bank engineering works on the RHB (note introduced artificial revetment, blockstone in the background and removed natural revetment, rootwads in the foreground) At bottom end of the reach there were some considerable erosion problems on the LHB again possibly caused by unmanaged mature trees toppling into the main channel.

8 Erosion on LHB 4.0 Habitat Overview River Derwent (Between Derwent Water & Bassenthwaite Lake) Derwent Site Visit

9 In many places this section of river is suffering from severe erosion problems caused by grazing pressure (the reach is not fenced). River banks are constantly on the move: it is a natural part of the river processes of erosion and deposition. The banks of the River Derwent are composed of soft sands, soils and gravels, all highly erodable materials. The roots of bank vegetation bind the soil together, making it more resistant to the powerful erosion forces of the river. Livestock overgrazing can result in a loss of river bank vegetation which accelerates river bank erosion. This is a double whammy for not only is valuable land lost, but spawning gravels can also become choked with sediment, which has a devastating effect on the biodiversity of the river and the ability of trout to spawn. Along the reach there are various erosion nick points caused by mature trees that have toppled into the main channel, leaving an area of exposed bank. In spate conditions, flows can erode the banks behind neighbouring riparian trees causing further bank loss problems. Example of heavy erosion of LHB. Note trees indicating original line of bank and no riparian vegetation.

10 Nick point note further erosion problems are starting to occur behind alders immediately downstream. (lifting rootwad) KAA have expressed concern regarding the widespread planting of willows to combat erosion due to loss of fishing access. Natural England have put proposals forward to protect the toe of the bank (the most vulnerable bit) using log revetments. In the section 5.0 other potential prescriptions will be suggested. 5.0 Recommendations It is a legal requirement that all the works to the river require written Environment Agency consent prior to undertaking any works, either inchannel or within 8 metres of the bank. Local EA Fisheries and Development Control and Natural England staff should be contacted at the earliest opportunity to discuss any recommendations arising from this report that the Association may wish to pursue. 5.1 Large Woody Debris The importance of LWD to wild trout cannot be overstated KAA should adopt a policy of leaving LWD in river unless it is causing significant problems. As a guide the following simple check list has been developed by the West Country Rivers Trust:

11 1. Is Is the the debris debris fixed, fixed, if if yes yes then then continue continue to to 2, 2, if if not not continue continue to to Is the debris causing excess erosion by redirecting the current into a vulnerable bank? If yes then go to 5 if not then go to Would fish be able to migrate past it (take into account high river flows). If yes got to 4, if no go to Retain the woody debris in the river. 5. Extract the debris. Note: If the debris dam needs to be removed but there is still a significant amount of the root system attached to the bank then it is recommended that the stump be retained for its wildlife habitat value and its stabilising effect on the bank In the short-term the KAA should introduce LWD. A little-and-often programme needs to be adopted with regard to tree management on the fishery to achieve a good balance of LWD, light and shade. Willows can be trained to hang over the channel by nicking the trunks and pushing them over. A sensitive programme of coppicing should be undertaken on a five to seven year rotation. This will create low-level aerial cover and allow light into the channel to promote in-stream and riparian plant cover. A tree management plan should be developed that would facilitate the natural introduction of LWD which should be combined with the above checklist. Arisings from tree work could be used to install LWD. It is recommended to introduce upstream facing submerged log deflectors (single or paired) to create localised scour pools in the margins and mid-channel. LWD will need to be securely keyed into the bank and possibly the riverbed using posts or rebar and wire to avoid problems of washout. Another option would be to hinge trees, leaving them still connected to stumps, again for added security these can be secured to the bed of the river using posts and wire.

12 Example of naturally hinged LWD on River Derwent (Co Durham) KAA should avoid the temptation to remove too much tree cover from the banks. Canopy growth can provide a valuable temperature refuge, something that may become more important as summer temperatures increase due the predicted effects of climate change. Before tree works are undertaken it is recommended that protected species surveys are carried out. These surveys should assess impacts of any proposed tree management on breeding birds, otters, water voles and bats. EA Biodiversity Team officers will be able to advise on this. The correct placement of LWD will help to sort gravels by creating scour pools and gravel mounds suitable for both salmon and trout spawning. Fallen timber can be used to create flow deflectors. Deflectors need to be; 1) keyed into the bank to avoid localised erosion and; 2) staked and wired to the bed of the river to avoid being washed-away. As a very rough guide deflectors should be set upstream at approximately 30 degrees to the bank with a length of between 40-50% of channel width, or staked in mid channel as paired submerged upstream facing logs. Deflectors keyed in from the bank should be set just at summer water level. Scour pools have been shown to be very important habitat for juvenile and adult life stages of brown trout. This approach is particularly useful where there are problems with the ingress of fine silt into spawning gravels.

13 Introduction of LWD into the main river Derwent could be technically challenging due to high energy flow conditions in the main river. It is recommended that an assessment of the various tributaries within the catchment is undertaken. It is these becks that are likely to be of high importance as a spawning and nursery resource for wild trout. With very little effort LWD can be introduced to these streams to create scour pools, riffles, bankside cover and sediment traps. A recent site visit to Wales on the Afon Ceri, a tributary of the Teifi, found some very good examples of naturally occurring LWD. In both these examples we can see the scouring and gravel sorting actions LWD performs in high flows. It is planned to introduce LWD to these streams to facilitate greater wild trout production in the Summer of 2008 under the Wild Trout Wales Initiative.

14 Bank protection and Cover Sorting Spawning Gravels Scouring Pools Some of the functions and benefits of LWD

15 Gravel riffle suffering from siltation on the Afon Ceri in Wales. Hinging LWD into the channel

16 A Hinged and stable LWD dam that is scouring a pool and creating a clean gravel riffle in the headwaters of a large catchment. 5.2 Erosion Control There are many options for erosion control however the KAA should consider options that also deliver gains to the fishery and local biodiversity. Riverbanks can be re-profiled, seeded and planted with appropriate vegetation and the bank toe (bit next to the water) can be faced off with willow withies to protect it from erosion. 'Green' willow withies are woven through 'green' willow stakes, which continue to grow, putting out root systems and binding the soil together. This will allow over-hanging, fringing vegetation to develop that is important habitat for fry and parr. The use of willow withies and willow stakes has proved to be less costly and more effective than 'hard' forms of river engineering. It is also sustainable and has far less environmental impact than the alternatives as seen on the Greta.

17 Use of willow withies, re-profiling and planting (Copyright Eden Rivers Trust) From Managing River Habitats for Fisheries Scottish Environmental Protection Agency Where the river runs through grazing pastures (sheep, cattle, horses) it is recommended that a fence is installed. Unhindered access by stock to the river is causing some major bank side poaching and erosion, which is leading to the loss of valuable vegetated margins. Although it is suggested that a buffer strip of at least 5 metres be created, a fence nearer than this to the river will still have a beneficial effect.

18 Example of a hypothetical tree management & fencing scheme The fence line should be placed well back from the bank in a straight line to avoid trash getting caught on wires (causing blow-out ) during peak flows. Stock drinking points should be sited in order to reduce the risk of debris accumulating on it during flood events. An alternative option might be to install pasture pumps. These operate to lift water from the river or an adjacent sump area to the stock. A more innovative technique could be to use Tree Kickers in the areas worst affected by erosion. The toe of the bank and the bank itself all require protection. It is suggested that tree-kickers are considered as an innovative technique that could be deployed in this section. Tree kickers are hardwood logs which are used to deflect stream flow away from an unstable bank area. One or more logs are anchored to the streambank and placed at an angle to kick stream flow away from the bank and towards the middle of the stream. Brush is tied between the log and the bank to prevent scour erosion. Tree kickers are most often used to correct bank undercutting especially where the crest of the cut is 1.5m or more above normal water levels. A kicker deflects the concentration of stream energy away from the bank. In addition, kickers help to re-build the bank by providing an area for sediments to deposit and provide underwater structure for fish and aquatic insects.

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20 Kickers need to be securely anchored to the streambank. Anchoring it to two live anchor-trees on the bank is best. If no anchor trees are available consideration should be given to installing a deadman anchor. The same angle is used for placing the kicker log. A T-shaped trench will need to be excavated and the kicker will need to be cabled to a large telephone pole or log placed in the crossbar of the T In conjunction with kickers the problems of slope stability need also to be addressed. This can be undertaken by re-profiling the sheer cliff faces back to a slope of around Coupled with this it is strongly recommended that the re-profiled slope be stabilised with the sowing of grass seed conservation mix and/or planting of whips (alder / willow). The bank work should be undertaken as early as possible to allow roots to establish and stabilise banks before the winter spate season. An alternative and potentially less expensive approach (machinery / spoil disposal) to re-profiling may be the stabilisation of the banks using an evergreen revetment such as pines, firs or recycled Christmas trees. The more limbs and fine branches a tree has the more it will continue to slow the streams current after the needles are gone, allowing sediments to accumulate within the anchored trees. Anchoring trees to the streambank in a manner that will resist the force of the water is imperative. In order to protect the area of active erosion an evergreen revetment needs to

21 extend beyond the area of exposed soils on the riverbank. The trees need to be fixed to log revetment which has been pinned at the toe of the bank. Logs need to be 3m by m diameter secured with two pins (2 m of iron rod, 2 cm diam); each tree nailed to log in at least two places Start downstream of the exposed soil anchoring each tree in place with the butt end of the trunk pointing upstream. Work upstream laying each tree so that it overlaps the previously laid tree by 50% until the revetment extends beyond the exposed soils. The first row of trees needs to be placed so that tree crown (the widest part of the tree) rests on the toe of the bank slope.

22 7.0 Making it all happen! This report makes a series of recommendations that will improve biodiversity and the status of the wild trout populations in the Derwent and Greta. Physical enhancement works could be kick-started with the assistance of a WTT Practical Visit (PV). PV s typically comprise a 1-3 day visit where an approved WTT Wet- Work experts will complete a demonstration plot on the site to be restored. This will enable project leaders and teams to obtain on the ground training regarding the appropriate use of conservation techniques and materials, including Health & Safety equipment and requirements. This will then give projects the strongest possible start leading to successful completion of aims and objectives. The WTT can fund the cost of labour (two-man team) and materials (max 1800). Recipients will be expected to cover travel and accommodation expenses of the WTT team. The use of specialist plant will be by separate negotiation. WTT wet-work experts will demonstrate one or more of the following techniques that are appropriate to the site. Tree management (coppice, pollard, sky-lighting) Tree Planting Fencing (Installation & Repair) Stream Narrowing (Faggots, Coir Rolls, Spilling) Flow Deflectors Introduction of spawning substrate Gravel Jetting Introduction / Management of Woody Debris Recipient clubs will be expected to cover travel and accommodation expenses of the Wet-work team. The use of specialist plant will be by separate negotiation. Further assistance with project funding can be provided through the WTT s Rods for Conservation Scheme. The WTT will donate a Sage or Hardy rod for the club to raffle to raise funds for habitat conservation work. Clubs typically raise from these initiatives. Sage is particularly keen to work with clubs in upper reaches of rivers that are important for spawning fish.

23 Note: Recipients should have received a WTT AV and have obtained the appropriate consents from the relevant authorities, prior to arrangements being made to undertake the PV. WTT can advise on this. Applications for all the above and the Rods for Conservation initiative should be made via projects@wildtrout.org Lastly, the Association should discuss this report with local EA Fisheries Officers. EA and WTT will be able to provide further technical advice and possibly assistance through the National Advisory Visit Project. The Association is reminded that all works within rivers and within 8m of the bank will require written permission from Environment Agency and Natural England Disclaimer This report is produced for guidance only and should not be used as a substitute for full professional advice. Accordingly, no liability or responsibility for any loss or damage can be accepted by the Wild Trout Trust as a result of any other person, company or organisation acting, or refraining from acting, upon comments made in this report.