Advisory Walkover Cock Beck, Wharfe Catchment November 2017

Advisory Walkover

Cock Beck, Wharfe Catchment

November 2017

Index

 Key Findings

 Introduction

Link to Google Map with images

 Catchment & Fishery Overview

 Habitat Assessment

 Recommendations

Quick Wins

Riparian Habitat

Spawning Habitat

Pollution

Fish Passage

 Making it Happen

Key Findings

 Cock Beck is severely challenged. It has been stripped of its ability to perform many natural geomorphological processes through historic dredging, in places with associated straightening or realignment. In essence, it has been converted into a drain. To reinstate this would require significant raising of the bed level throughout, to allow for better connection with the flood plain. Resource and a change in land management are likely to be prohibitive.  Water quality is an ongoing issue. No specific point sources of nutrient pollution were witnessed. Diffuse pollution of fine sediment is rife, with some clearly defined point sources identified around fords, poorly conceived field drains and/or field buffers, cattle drinks, and bank degradation due to poaching. These point sources of fines provide opportunities for quick wins through installation or reinstatement of fencing.  Daylighting some of the lower reaches and livestock exclusion around the mid reaches, both to promote better, natural riparian growth should encourage the Beck to self-heal through diversifying the bank profile and pinching the channel through instream colonisation.  Encouragement of geomorphological process by judicious installation of woody material where the channel is already trying to renaturalise will aid retention and sorting of substrate, in particular the gravels required for spawning and invertebrate habitat. Value added benefit will be realised through extending the interventions above and below those sections.  Working to maintain, enhance and extend the ‘better’ reaches of habitat will probably provide more value in the first instance by providing relatively regularly spaced island ‘refugia’ between more barren, less hospitable sections.

1.0 Introduction

This report is the output of site visits to Cock Beck, a tributary of the River Wharfe, W. Yorkshire. The visit was requested by David Morley (Fisheries Officer, Environment Agency) and Marie Taylor (Project Officer, Yorkshire Dales Rivers Trust) for the ‘Rivers in Elmet’ project. Jonny Grey of the Wild Trout Trust undertook various walkovers with David and Marie.

Normal convention is applied with respect to bank identification, i.e. left bank (LB) or right bank (RB) whilst looking downstream. Upstream and downstream references are often abbreviated to u/s and d/s, respectively, for convenience. The Ordnance Survey National Grid Reference system is used for identifying locations.

Map 1. Overview of Cock Beck catchment highlighting areas walked: black rectangle – Map 2; red rectangle – Map 3; yellow rectangle – Map 4

Map 2. Cock Beck upper section, from Throstle Nest Farm to Aberford and the A1M culvert

Map 3. Cock Beck from Lead Hall Farm to Stutton village bridge at Mill Lane

Map 4. Cock Beck from A1M culvert to Lead Hall Farm (completed later)

A map with imported photos from the walkover has been created in Google at: https://drive.google.com/open?id=1Maf9ert1G7RXiMWAOA4J2yOlYX Z3uB9I&usp=sharing

2.0 Catchment / Fishery Overview

Cock Beck is a ~40km tributary of the Lower Wharfe (Cock Beck Catchment; Environment Agency waterbody ID# GB104027063940; Maps 1-4), arising on the NE outskirts of Leeds and wending its way slowly to the tidal Wharfe just downstream of Tadcaster. The shallow valley and low-lying topography (~50m a.s.l.) reflects the underlying magnesian limestone which produces freely draining, lime-rich loamy soils ideal for arable farming.

Over two cycles of assessment for the Water Framework Directive, Cock Beck has deteriorated from Moderate to Bad Ecological Status, primarily for nutrients and water quality issues (drivers of the Rivers in Elmet project), but also for fish diversity. Quite surprisingly, Cock Beck is not designated as artificial or heavily modified despite having been straightened or realigned in many sections, and dredged in its entirety; there is barely a discernible difference in channel cross- sectional proportions, i.e. trapezoidal, for the ~22kms viewed.

Anecdotal evidence from historical angling reveals that grayling of ~1kg were caught and that the Beck provided spawning habitat for Atlantic salmon; indeed, there is a suggestion that the etymology of Cock Beck stems from male salmon. Just after the turn of the century, the EA installed several paired upstream deflectors, and introduced gravels to improve spawning habitat at Leyfield Farm. The latest EA fish data show that only trout were detected in low numbers in the vicinity of those works (u/s of Aberford), and a few salmon and small coarse species were found at Stutton, relatively close to the Wharfe confluence.

3.0 Habitat Assessment

The reporting that follows considers the Beck from the most u/s point (Throstle Nest Farm; SE 40790 35620; Fig 1) to the most d/s point (just below Stutton on the Mill Lane bridge; SE 48206 41599). The channel has been dredged to a trapezoidal shape for much of this length, over-deep and over-capacity for the majority of flows, especially as the catchment lacks gradient. As a consequence, the bed is deep with fine silt, especially where flow has been impounded by natural wood fall or artificial rock ramps serving as fords. In the upper reaches, it appears that the Beck is entirely disconnected from the flood plain. Hence, the impoundments simply build up until a spate of sufficient size ‘blows’ them out, or the EA Ops Team removes them all (as was intimated upon meeting a team during the visit).

The bed has been dug down to a clay base (probably throughout the entire length but certainly evident in the upper sections) and the Beck lacks the power even to erode down and sideways on the outside of meanders, resulting in the retention of the trapezoidal cross-section. While gravels of appropriate size for the redds of resident trout (~10- 25mm) were present in the upper reaches, they were effectively ‘welded’ to the clay bed or so clogged with silts as to be of little use for invertebrate habitat, let alone fish spawning habitat.

In terms of riparian habitat, Cock Beck is a bit of a curate’s egg. The wooded sections and wooded riparian fringe provide ample litter and woody debris but are so dense in some sections that the banks were bare of understory; this is a particular problem in the lower reaches where Himalayan balsam is present. Some fields were fenced but in general, even those were dilapidated to the extent that livestock could access the water edge and cause severe poaching and sediment ingress. Several formalised cattle drinks were observed but none were appropriately constructed and had been churned to a slurry.

Fig 1. Cock Beck at Throstle Nest Farm. The u/s & d/s sides of Parlington Lane bridge (upper & lower panel, respectively), demonstrating the impounded nature of the watercourse, generally deep, and with dubious colouration of the water. A saving grace is that the riparian vegetation in the upper sections is mostly native and dense.

Fig 2. A twin-pipe field drain to the Beck. The incision through the bank was ~2m at its deepest. Since this was adjacent to a recently ploughed, bare field on a relatively steep gradient with no bund or buffer strip in between, then it is likely to be a considerable source of soil ingress.

Fig 3. A straighter section of the Beck. From a distance, the quality of the riparian fringe might suggest that the Beck is in good shape but even from this image it is evident that the channel bed is flat and featureless with some shallow depositions of fine silt.

Fig 4. A natural log jam and accumulated leaf litter, unlikely to be an issue for fish passage as a) it will be ephemeral, and b) the water was flowing through and underneath it. Even such a structure provided little evidence of out of channel flow paths. Note that despite meandering here, the channel still retains the trapezoidal form resulting from dredging.

Fig 5. A rare example of substantial erosion on the outside of a bend, likely exacerbated here by livestock grazing right to the bank top and hence little physical matrix from the roots of a naturally diverse vegetation community to help resist erosion.

Fig 6. Image taken from d/s of the Ass Bridge (SE 40986 37429) depicting typical nature of the Beck – some narrow, native and mature riparian fringe but heavily straightened (here) between pasture and arable fields.

Fig 7. At Leyfield Farm (SE 42138 37983), there appears to be an old mill race / culverted weir (inset) which represents a considerable obstacle to free fish passage. Below, the sudden increase in gradient and energy has led to the widening of the channel (weir pool) but without much increase in depth (again probably reflecting that even here, the Beck has little erosive power downwards). A deposition bar had been colonised with aquatic plants creating a short braiding of the channel and some much needed flow variation. This was the most u/s site where fish (trout) were observed. Horses had complete access to the bank top so the riparian vegetation was not as diverse.

Fig 8. Paired, upstream deflectors installed by the EA, circa 2001, were still functioning as intended, creating a scour pool and sorting some of the substrate. Gravels contained less silt fractions compared to u/s sites, and were generally looser. Approximately 15 years after being placed instream, these structures are testament to potential for further augmentation works to increase the spatial extent of the benefits (see Recommendations).

Fig 9. Three images from a short section assumed to be within the Parlington Estate. The Beck appears to have shaken off the shackles of mismanagement and attempted to regain a more natural form through the processes of scour and deposition, yet still within the confines of the trapezoidal channel. Note the pale areas of bed in the mid and lower panels are clay substrate, not fine deposit.

Fig 10. An exceedingly generous (and welcome) buffer strip, presumably a part of the Parlington Estate (just u/s of the willow plantation at SE 42630 37852). However, the bunding resulting from dredging spoil can just be discerned along the bank top (at the trees) to the left of image (more evident at Fig 12).

Fig 11. ‘Shaggy’, trailing vegetation provides some much needed cover along the straightened sections of otherwise featureless channel. However, there was typically a strip of bare bank between the water surface and the start of any vegetative growth of ~50-60cm, presumably reflecting the depth to which the channel had been dredged into the clay and hence a lack of rooting substrate for plants to access on the steep sides. Here, that is hidden by the overhanging plants but it can be seen as a shadow behind the vegetation on the left bank (red line). Unfortunately this might suggest fluming flow below / behind the vegetation, thus reducing the refugia benefit for juvenile trout.

Fig 12. Bunding from dredging spoil along the right bank top further prevents the Beck from interacting with its flood plain.

Fig 13. Examples of straightening for conveyance and drainage. Upper: a side channel (choked with deep silt) entering the Cock Beck just u/s of Aberford. Lower: the Beck is straightened (and overwidened) on the approach to the Main Street bridge in Aberford (SE 43342 37332; Fig 14). 14

Fig 14. Upper: the u/s side of Main Street bridge, Aberford (SE 43342 37332) where the encroaching emergent vegetation clearly hints at the more natural width of the channel (here, still overly wide, shallow and with unsorted substrate). The bridge engineers were clearly well versed in future proofing! The private land at Waterside Meadows might offer a suitable site (visible from the bridge) for some enhancement. Lower: immediately d/s, it is still heavily straightened and uniform in proportions. The hard flood defences on the right bank have been augmented by re-profiling of the left bank to increase capacity (without actually using the flood plain field).

Fig 15. The box culvert carrying Cock Beck beneath the A1M (upper) and the revetment on the right bank immediately d/s of the culvert (lower), steering the Beck back to its (probable) original path prior to the construction of the motorway. Note the bank of fine sediment accumulating within the culvert (on the inside of the bend), probably restricting the aperture of the culvert by ~12-15%.

Fig 16. D/s from the motorway culvert, the channel is directed to turn several times to skirt Kingfisher Lane and the water treatment works (see Fig 17). Banks have been lined with geotextile material which is locked into position in the riparian zone by tree growth, but has failed instream in several places (see inset).

Fig 17. The entrance to the Yorkshire Water WTW; the plant is of considerable size relative to the neighbouring village. Fly-tipping and associated pollutant run-off is an issue here. Just behind the barrier to left of image is the small carrier beck picked up in Fig 19.

Fig 18. Cock Beck environs to East of A1M with detail of man-made pools and carrier beck to the north of the main channel. Arrow denotes position of Fig 17.

Fig 19. The straightened carrier beck just below Field Lane (upper) where there is negligible field boundary, and the channel is filled with silt and the brash from insensitive tree management; and (lower) just above its confluence with Cock Beck.

Fig 20. D/s of the wooded area and ponds highlighted in Fig 18, there are areas of very rough, low-lying pasture on both banks (SE 44226 37927) that could potentially be used as wetland / scrape / refugia areas for habitat and flood storage. The extracted material could be used for bunding across the valley at the d/s end.

Fig 21. Public footbridge at SE 44782 37738 where the concrete blocks of an old crossing point litter the Beck bed. Stock access is an issue on the RB. Otherwise, there is a more natural pool-riffle-glide sequence for 50-60m around this feature. The blocks could be easily repositioned as deflectors to maximise the localised benefits. Trout and evidence of otter were seen just u/s.

Fig 22. Dredged profile reverting to type, d/s of the footbridge in Fig 21 – a featureless channel with uniform silty substrate.

Fig 23. Buffer zones were considerable on both banks, exceptionally so on the LB (north bank) assumed to be part of Hayton House Farm.

Fig 24. Sections with less tree cover contained substantial growths of starwort (Callitriche spp.) hinting at potential for instream cover / habitat diversification if some of the more ‘tunnelled’, wooded reaches were subject to a judicious coppicing regime to allow dappled light to reach the bed.

Fig 25. The majority of the LB d/s to the Crooked Billet pub (assumed to be land associated with Lead Hall Farm) appeared to be fenced to protect the banks (although some will need repair in very short order) and hedges had been recently replanted. Only one or two drinking points (lower panel) would benefit from some formalisation of the banking to prevent poaching and sediment ingress. The riparian fringe without trees was dominated by nettle (Urtica dioica) implying excess nutrient supply.

Fig 26. In general, the ~700m u/s of the Crooked Billet (SE 46375 36717; associated with Lead Hall Farm) appeared to have more energy (increased gradient), with abundant riffles and deeper pools around tree roots. This appeared to be a good candidate reach for enhancement and extension of habitat features.

Fig 27. The Beck is constrained within the floodplain by the B1217 for ~700m. Of that, for ~300m the road is virtually on the top of the RB and as a consequence, the bank is walled with numerous drainage points which will introduce fines and pollutants. As a consequence of the straightened channel and hence shortened path of conveyance, the gradient is steeper, resulting in relatively continuous riffle (see Fig 29) or glide habitat.

Fig 28. SE 46758 37101: At the end of a continuous glide, the Beck shallows, widens and then is forced to the right (upper). Instream growth of water parsnip (Berula spp.; lower) has braided the channel and cleaned and sorted some of the gravels which felt loose underfoot.

Fig 29. SE 46746 37037: An example of continuous riffle (as at Fig 27) resulting from straightening and hence increasing the gradient. Some judicious instream work here (deflectors or tree hinging) could pay dividends to sort the substrate and create depth diversity through exacerbated scour & deposition.

Fig 30. The over-incision of the channel means that naturally occurring log jams (such as around the roots of trees growing alongside or in some instances within the channel; upper) do not result in out-of-bank flows. Instead the Beck remains impounded (as in the lower panel) until a spate of sufficient size blows the debris out through the channel.

Fig 31. Two contrasting processes breaking the mould of the trapezoidal channel. Upper: encroachment by emergent vegetation has led to the pinching of the channel. Lower: livestock poaching is currently introducing fine soils and potentially guttering more along the desire lines, but the actual bank profile is more natural, and has allowed a localised widening and shallowing of the channel (missing from much of the reach). If this was now protected from stock and allowed to recolonise with plants, thereby stabilising the soils, it would also provide slack-water refugia for small fish species or juveniles during spate flows.

Fig 32. SE 47013 38310: A wonderful meander bend which could do with some protection from stock on the RB. Given the low gradient along this reach, it is likely that many of these meanders have been eradicated by straightening and dredging regimes, and hence the conveyance of water will have increased markedly as hundreds of metres have been shaved off the original Beck course. Note the riffle on the exit of the meander (rhs) was one of the few sites in the lowest 7km examined that had loose gravels and a diverse assemblage of macroinvertebrates.

Fig 33. SE 47344 38349: Evidence of heavy poaching, again a double-edged sword. The introduction of fine soils is unwanted but the re-profiling of the bank line, and here, actually accentuating some braiding and narrowing of the channel is beneficial (once the stock access is restricted). Note precious little buffer has been afforded by the line of fencing. A more generous allowance will allow for better riparian development and enhanced resilience to spate flows affecting the fence.

Fig 34. Two examples of fords where the bed has been formalised with the addition of stone / hardcore to facilitate crossing. Essentially, these have created impounded sections upstream, and a brief cascade immediately downstream. None were serious obstacles to fish passage when viewed, having focussed, natural flow paths over the material. However, at summer low flows, there might be insufficient depth of water flowing over these structures. Associated issues are the bank poaching, guttering along desire lines, and introduction of fine sediments, especially evident in the lower panel.

Fig 35. Examples of fenced drinking bays. While these certainly restrict livestock access to certain sacrificial points on the river bank (while allowing protection elsewhere), they quickly become focal points for poaching. Hence, they require some hard-standing arrangement (cobbles / sleepers) as well as fencing, to ensure they do not act as gutters and point sources of sediment.

Fig 36. Examples of natural woody debris which many river restoration techniques aim to emulate. Upper: a log jammed across the Beck at an angle has caused scour and limited erosion of the RB; there is deposition occurring at the LB opposite. Lower: a whole alder tree with two main trunks has wedged with the remains of the root bole upstream, thereby creating a V-deflector which encourages deposition on the upstream side, and scour in the V downstream. Unfortunately, in both these cases, the natural processes these features are initiating are only working on deep silt depositions which is a clear indication that silt ingress and supply of a more natural, diverse substrate are major issues.

Fig 37. Some insensitive land and riparian tree clearance near to Willow House Farm (SE 47217 39587). There are narrow buffer zones but probably insufficient to prevent more soil ingress under heavy rainfall. All riparian trees have been felled on the LB.

Fig 38. Deep, impounded sections upstream from the bridge (dismantled railway) at SE 48295 40483, the embankment and footings of which are likely to have been the original cause of the wetland forming. Its extent can be determined by the stands of Phragmites and Filipendula.

Fig 39. Immediately downstream of the railway bridge (SE 48295 40483) there is a more natural section through native woodland. The extent of the gradient is short and again points to the impounding action of the bridge footings upstream as the cause. Despite the turbulent flow, there was still considerable evidence of fine silt accumulation smothering the substrate (see Fig 40).

Fig 40. Rocks from immediately up- (upper) and downstream (lower) of the impounded section described at Fig 39. Algal growth was abundant where tree canopy was reduced, hinting at excess nutrient ingress. Both sites suffered considerable accretion of fine sediment.

Fig 41. In the lower sections, upstream from Stutton, it was rare to find any substrate other than clay chips and fine silt (NB - that is not gravel in the upper panel). With little power in the trapezoidal channel, the substrate was typically uniformly distributed across the bed, exacerbating the lack of features.

Fig 42. A rare section of Beck near to Stutton Ings SSSI (wet woodland) where a 20m section of cobble and small boulder substrate associated with close proximity to the valley side (RB) and hence bedrock supply, had created a riffle. However, because the channel is over capacity, there has been no sorting of the bed material; instead it is distributed uniformly.

Fig 43. Example of the natural supply of woody debris, which again unfortunately does little to improve conditions because the channel is so over-capacity.

Fig 44. A seam of cobble substrate creates a very short and relatively shallow riffle section which, because of a reduced canopy here, has allowed submerged aquatic plants (Callitriche) to colonise and focus flow paths.

Fig 45. The lower sections (~800m upstream of Mill Lane bridge, Stutton; SE 48253 41528) have barely discernible flow and are typically heavily incised and straightened through wet woodland. While there is very little gradient anyway, the impounded nature was probably exacerbated historically by the construction of a major embankment to carry Mill Lane across the Beck. Copious natural wood fall adds to the impounded nature because the Beck bed has been lowered so far.

Fig 46. Immediately below the Mill Lane bridge (SE 48253 41528), and the sizeable embankment carrying that road across the valley, there is a short section of riffle resulting from the unnatural step in gradient. The bridge culvert represents no issue to fish passage. NB – this site (lower panel) is where the EA record salmon parr.

Fig 47. There was evidence throughout the walked reaches of historic and ongoing tree maintenance / removal. Some was clearly associated with ride creation on the bank top, especially on the shooting estate. Some was more clearly to remove perceived blockages (mid). It is hard to imagine why the saplings in the upper image were cut!

4.0 Recommendations

The dredging of Cock Beck has left it barely connected to its floodplain. In an ideal world, it should have its bed raised to restore ecosystem functioning. Cost alone would be prohibitive. There would also be considerable opinion and perception of land drainage and management to overcome.

Quick wins

 Reinstatement or installation of riparian fencing and formalising approaches to cattle drinks / fords. Especially important on the mid sections (Figs 25-36). Reduces diffuse / point source soil ingress (pollution), thereby improving water quality.  Review of tree management regime by YDRT / EA FBG and EA Ops / FCRM. Some could be left in situ or at least secured within the lower reaches. Some tunnelled sections could be ‘skylighted’ in areas to diversify canopy structure.  Potential engagement with land owners regarding perceived flood risk and better use of the flood plain (ie allowing the Beck to flood within the mid sections). Potential also for swales and bunds within the flood plain to aid natural flood management (e.g. Fig 20).  Installation of fixed woody structure (locally won or already in situ) to specifically enhance and complement natural geomorphological process. This will extend the impact on parts of the beck that are starting to renaturalise, primarily to improve habitat for invertebrates and fish spawning.

4.1 Riparian habitat

4.1.1 Fencing of field sections (with drinking access)

Within the fields that have been subject to prolonged livestock access, the bank vegetation has been reduced to a short sward monoculture of grass. Excluding the stock from the bank while retaining a couple of access points for drinking can provide numerous benefits to both the livestock (safer, formalised access; limiting disease or parasite transmission; grazing of herbage ‘through’ fence), and beck ecology and bank stability (more diverse vegetation providing multiple ecosystem services). Simply excluding livestock will allow a naturally diverse array of plants to recolonise rapidly.

Many fields contained evidence of old fence-lines that should be reinstated, preferably with a more generous buffer strip.

4.1.2 Buffer zones & tree management

There were examples of excellent (>20m) and extremely poor (absent; <0.5m) buffer zones. Engagement with the relevant landowner or tenant farmer regarding current thinking on best management practice should be addressed, especially in light of the new Farming Rules for Water coming into force in April 2018.

In general, where low tree branches and bushes currently overhang the Beck, these should be left rather than tidied back; these areas are essential for fish to hide beneath / in, and perform a useful ecosystem service in providing ‘hydraulic roughness’ to help slow flow.

There was little evidence observed during the visit for a requirement to remove large woody debris. Presumably this is ‘routinely’ undertaken by EA Ops teams in response to perceived flood risk and because it ‘has always been done’, but on what actual basis? Localised stage height may be affected by log jams but since the majority of the Beck catchment is low gradient under improved pasture, flooding (ie inundation of the floodplain) should be expected and indeed encouraged in these more enlightened times.

4.1.3 Invasive species

Himalayan balsam was the only invasive plant identified during the walkover, and that was quite extensive in distribution in the mid to lower sections, as it is throughout the Wharfe catchment. Options are relatively limited at the moment pending more trials on the use of rust as a biocontrol agent by Cabi BioScience, and the best option is a coordinated approach from the top of the catchment. However, since the majority of the Beck is not accessible to the public, it requires substantial engagement from the landowners involved.

4.2 Spawning habitat

Gravel retention for spawning habitat is an issue throughout, and especially on the straightened and impounded sections. To emulate natural pinch-points and treefall, the EA have installed paired deflectors (upstream-V) but these could be readily complemented by individual and off-set, upstream-angled stub deflectors: short (<1m), well anchored / pinned trunks of wood (<300mm diameter). The 40

purpose of such installations would be to cause small-scale, localised scour and ‘hummocking’ of the bed, thereby focussing and retaining smaller gravels in their lee (see WTT video, here: https://vimeo.com/32317564). These essentially encourage the Beck to meander within the confines of the trapezoidal channel. At higher flows, they would simply be over-topped, and thereby constitute no flood risk. The EA structures have been in situ for >15 years with little sign of degradation or adverse erosion.

Fig 48. Conceptual diagram of use of woody material as deflectors. From the top of the figure:

Upstream angled – diverts flow to the centre of the watercourse, and creates localised scour; locating deflectors on opposite banks of a straightened section, but off-set in position can create sinuosity of flow without eroding the banks.

Downstream angled – diverts flow toward the bank, increasing likelihood of erosion and can be used to increase sinuosity of the entire channel. Not recommended on Cock Beck

Paired upstream angled – focuses more flow to the centre and creates a deeper scour pool with associated ramp of sorted substrate (gravels) further downstream.

Wood of this size can also be installed under Environmental Permitting Regulations exemptions. They might also introduce an element of sinuosity to the flow under low-flow conditions (Fig 48). Angling the deflectors u/s focuses flow toward the middle of the channel (i.e. away from the bank and hence reduces erosion risk there) when they are overtopped. In terms of perceived flood risk, because these structures are relatively small (<5% of bank height) 41

and occupy <50% of the cross-sectional channel width, they are completely overtopped during high spate flow.

4.3 Pollution

Diffuse pollution from soil ingress where livestock is trampling the banks should be addressed by the measures suggested above. No specific point sources were identified. Any instances of unnaturally discoloured or foul-smelling water should be reported immediately to the Environment Agency Incident Hotline (0800 807060).

4.4 Fish passage issues

Aside from the culvert at Leyfield Farm (Fig 7), above which no fish were directly observed, there were no issues at the various bridges. Natural log jams may look like they pose issues for fish passage but they are generally not, as water is typically finding its way through (so fish will follow the flow). Even if they are an obstruction, they are ephemeral, and as a natural feature should be left to wax and wane.

The sloping culvert face was of relatively low gradient, and thus could be overcome with a simple, low-cost baffle installation to interrupt the laminar flow and create sufficient depth and slack water refugia to allow fish of varying sizes to ascend and descend more easily. This could be augmented by a pinch point on the outflow of the pool d/s to raise the water level and drown the d/s edge of the culvert.

5.0 Making it Happen

The WTT may be able to offer further assistance:

 WTT Project Proposal o Further to this report, the WTT can devise a more detailed project proposal report. This would usually detail the next steps to take and highlight specific areas for work, with the report forming part of a flood defence consent application.  WTT Practical Visit o Where recipients are in need of assistance to carry out the kind of improvements highlighted in an advisory visit report, there is the possibility of WTT staff conducting a practical visit. This would consist of 1-3 days’ work, with a WTT Conservation Officer teaming up with interested parties to demonstrate the habitat enhancement methods described above. The recipient would be asked to contribute only to reasonable travel and subsistence costs of the WTT Officer. This service is in high demand and so may not always be possible.  WTT Fundraising advice o Help and advice on how to raise funds for habitat improvement work can be found on the WTT website - www.wildtrout.org/content/project-funding

The WTT officer responsible for fundraising advice is Denise Ashton: [email protected]

In addition, the WTT website library has a wide range of free materials in video and PDF format on habitat management and improvement: http://www.wildtrout.org/content/index

6.0 Acknowledgement

The WTT would like to thank the Environment Agency for supporting the advisory and practical visit programme in England, through a partnership funded using rod licence income.

7.0 Disclaimer

This report is produced for guidance only; 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 guidance made in this report.