Life up in the Groynes has changed

Life up in the Groynes has changed

Chris Avery | Wednesday, 5 June 2024

It wasn’t just the shifting gravels of the Nassington Road Bridge, life up in the Groynes had changed too, I discovered this as I waded up through the length of it early in that season back in the flowing waters of the Brook. Ever since that regular canalized channel that had been treated with 8 pairs of flow deflectors over a dozen years ago, we occasionally had to replace the odd one that had drifted away, either the post losing its mooring , or the mooring itself being worried out by the flows, and a new post needed driving in. It was a constantly shifting and developing channel being nudged into a new shape.
Others, tightly bound branch faggots, had simply got squashed down, lower beneath the surface, as the new flows came up over them and eroded the bed to the rear of them while adding material to the front, creating quite a step up or step down when wading. Pressed down like this under the surface the deflection of the current in the channel was reduced as the velocity was now focused over the faggot and down scouring out the bed behind.
To these we simply added an extra faggot on the top and broke the surface of the water again diverting the energy back into the central stream.  This hollow was soon filled with silts as the water calmed and lost its energy behind the deflector again.

The silt deposited at the sides of the channel gradually found vegetation starting to establish upon it; Reed Canary Grasses and Woody Nightshade; mostly. Both species tangled and sprawled, especially after being pressed down by the summer rains, into floating matts on the gentle currents in the fringes of the main flow. These matts, then catching both fine silt sediment in the water; any woody debris; twigs; small branches; and drift wood; consolidated over time.  

The areas of this new matting that survived the winter floods, were then bolstered with a new generation of sprawling plant stems in the next season, rotting vegetation; more trapped silt; and more woody debris. Thickening and toughening this cruston the surface to the extent that eventually, after a few years of it developing, it would take your weight, and you could, somewhat gingerly, cross it, feeling a spongy give with each footstep.

Out by the old high river banks it became more solid and dependable, and later trees like scrubby Willows, Elders and Hazels became established, occasionally aided with some gorilla planting, adding to the roots holding these forming soils and stabilizing this new ground. These new waterside banks within the existing high banks, I’d like to say ‘encroaching’ but it’s not the right word, it has negative connotations; they were narrowing the flows, but this seemed to balance with the extra depth of water that was created between them. And, the energy now in that current.  

It would look to some, viewed from above like we were choking up the stream. We were simply taking up the slack areas, but still the waters flowed deep under the edges of theseshelf like matts of a yard or so, and created a whole new environment and shelter underneath this new cover..

The faster summer flows in mid stream, checked and halted the progress of the vegetation out beyond the fringes, the higher winter flows pushed them back further, folding them back and consolidated them over time. In places now they have covered over the old flow deflectors on one side, and the current has cut in deeper across the other bank as a curve is created and the Brook gains a natural meander within the high bunded banks. All this is good as long as the new central deeper meandering channel is functioning. Resulting in clear aerated water flowing through Ranunculus beds and over new forming beds of gravel riffles, following the occasional deep pool now formed, and the trapped silt at the edges has wild flowers; grasses; and marsh irises; along the banksides, ecologically it created a diverse and varied habitat, supporting the life cycles of a wide variety of species.


Viewing it from a practical level, purely looking at the Brook as a water course, a drain taking the water that crosses the farm lands while catching extra run off. How have the Grounds affected the efficiency of the drainage.?

When looking down from the banks, the stream is now thinner within the banks, a new svelte and  slimline Brook showing off some terrific new curves!

That water surface being maybe only a third of its original width in places. Somewhat counter intuitively when viewed from here, it is still flowing the same height in relation to the banks. It looks like less water from above, although summer holding capacity is largely the same and the flow rate is now varied, from slow pools to fast racing riffles of broken water.The volume of the water carried has been maintained becausethe deflectors have carved out deeper channels in the bed,sorting the silt to the sides or away down-stream. While heavier new materials, the grit small boulders and precious gravels have remained around the mid-stream and started to gather in beds that one day may become deep enough pockets to be Trout Redds.

Before the Groynes were put in this  stretch of stream was consistently less than knee deep in its entire length, it now varies from ankle deep occasionally to shoulder deep. Most of it is now being crotch deep water. (For an admittedly small bloke!)


In the winter floods, the holding capacity of the bunded  banks has now increased for the farmer whose vulnerable crops are planted on either bank, because of this extra depth of stream base.  Crucially, due to the meandering nature of the flows, the resistance of new vegetation; and the eddying effects of the pool and riffle sequence below; the speed of the flow carrying this huge amount of flood water, satisfyingly, is at roughly the same pace as it is when measured in normal levels.

Carrying less violence and chances of eroding banksides, fewer break-outs over the banks ruining of cropped fields, and less likelihood of sweeping away a collection of flotsam and jetsam, to wreak potential havoc downstream. 

This, when new trees fall in the brook is my biggest concern. Them floating away, bulking up against any structures creating a growing blockage and an increasing dam wall of force to burst,  in extreme cases taking away a bridge or sweeping away a tree to add to the jeopardy of the flood.

Willow brook in our beats is now a place for very well behaved flood waters, which, with our globally increasingly energetic weather systems and rainfall, is a very good thing indeed.

During the high floods of last winter that cut off many roads and villages around the district, the results of bad drainage, soil compaction, and some naughty little water courses.  I walked the length of our Brook and was so proud of the way it kept control of the extra waters it was being burdened to carry away.

So everything is ‘tickety boo’ and everyone’s happy.

No! not me.

As I wander up the Groynes in this first season back, I am again concerned about some changes to my stream.

Like with the Nassington Road Bridge area and its new mysterious deposits of gravel, that I needed to get to the bottom of! There’s something arrived in the Groynes and it’s ominously getting established. Reed mace and Bullrushes coming downstream from above the Bugger of a Bridge; the Culvert.

These plants of slow flowing waters and ponds and drains, have always been in the area that’s deeply canalized above that Culvert bridge. Mostly waist to chest deep water, and beneath even higher bunded banks than the groynes. Not many anglers fish in this area, the waters are slow, and the escape route from the deeper pools is often a scramble and scale up a sheer, high slippy bankside of nettles that threaten you with a face full of stings if you slip. Or alternatively, if you can manage to cross over the stream somehow, the soft swampy ground on the other bank sucks in your feet, knee deep in places and makes it really hard to move and extract yourself from the gloop. (and there’s no phone reception in this area and no public paths… you are remote and on your own).

However, after a few hour’s fishing in that stretch, you return to the car an exhausted and scruffy, mud covered grublet, but often a very happy one.

Those deep silty waters are the home to many of the adult Trout, the larger residents of Willow brook.

As the season starts and the areas between the Rushes is more open, these often 3lb+ Trout seem to patrol the waters picking off food. In the flat surface their presence is betrayed from a long distance for us seeking them, and I often have 3 or 4 targeted ahead of me to cover.

As the Mayfly season arrives this silty bottom is ideal habitat for the nymphs, and the hatch seems most prolific in this area of the Brook, not just the amount of hatching insects floating down towards you, erect and proud of the glossy, smooth glide of a surface; and the caterpillar like empty shucks floating down stream that seem to dot the entire surface. But also the numbers of Reed Buntings, Warblers and Wagtails that congregate here to reap the aerial harvest, even the Black Birds and Sparrows of the area change their feeding habits and become acrobatic bandits of the air, for a few weeks.

By the end of Mayfly season the open surface is greatly reduced by the sheer amount of Reeds and Rushes choking the channel. Fishing areas are reduced to smaller openings, and in places just the long thin ribbons of open water that remain. Here, casting up a channel of half a meter width, in tall reeds, thankfully they also filter the breeze and help keep your aim true.

The fish then seem to sit in the reeds and ambush passing food. Hooked, they attempt to regain that cover, often managing, and with barbless hooks in use, the odds between angler and fish are more evenly balanced, or remarkably, even skewed somehow towards the fish.

With the hooks being left snagged in reeds and woody debris, the ghostly Trout no longer anywhere to be seen. I don’t know how they do it, but it’s a neat trick. Last night, before writing this, I had five Trout on, four of them (the biggest ones) vanished, leaving just a fly embedded in a bullrush stalk, the rod tip still quivering as if a fish was on, but only a fleshy stalk rattled with the water current.

I firmly believe that devilish little water imps or mischievous gremlins live in these pesky bullrush beds, probably distant relatives of the poaching ‘pikies’, working in a thuggish gang. Some tug on your line in a team, keeping you fooled and hopeful long enough, while others unhook the fish carefully and then drive the hook into a thick plant stem, they then all retreat just a little out of view and fall about giggling mercilessly at the puzzled look of a frustrated angler with all that equipment and paraphernalia, his hopes dashed. Their peals of laughter, usually completely muffled by the sounds of water, wind in the reeds, and the harsh cursing of the angler himself, just occasionally though, you chillingly catch a glimmer of their mockery as they blend away into the bullrushes. When all options are considered, this can be the only rational explanation that remains.

If only I could learn what offering I could leave to appease these little monsters, my catch returns would be so much better.

It’s about this time of the season that I notice in this area particularly, though also in the Groynes; the tiny fish fry of what I presume are the Chub and / or maybe the Dace. Often in what look like tight shoals around the size of a soccer ball, sometimes you see an area of water broken by numbers of these jumping briefly clear and rattling back onto the surface;to avoid an attack below the water.

The only predators around being large Chub or Trout, and without stomach samples we can only guess that this is one of the protein sources that give the Willow brook fish such fantastic growth rate.

It’s an interesting question, but not an answer that will directly change anything at present, nor benefit the population. Sadly I see no practical way of finding out without killing enough of our bigger fish to explore the eating habits. And by mid-season they are nigh on impossible to target and extract from the waters by fair means, for this particular buffoon.

Not that I want to kill fish any way and actively avoid unnecessary suffering, so that remains an unanswered question for now.

It is possible to get some of the stomach contents out without killing the fish. But in early season when we mostly encounter them, they are gorging on Grannom and Mayfly, so that wouldn’t give us an answer. By the time I suspect they are fattening up on fry, the water temps are rising and the flows in this area slowing, thus there is so little available oxygen in the water for them to recover from the rough handling of stomach sampling; it’s unnecessary and expensive stress as they are starting to build and store up energy towards the breeding and business end of the year.


The Reeds and Rushes of this area used to be sprayed yearly by the old secretary, it wouldn’t kill them all, but kept them controlled to an extent, it was a check on their encroachment. The Environment agency recommended Round-up BiactiveGL, which apparently is safe around water courses and neutralizes when in contact with water. Quite how that works I am never sure, and my trust in Monsanto’s safety advice of their products, which have been questioned so often here and overseas, that I remain cautiously prejudiced against them and skeptical of any of their claims.

In any case, it’s a long schlepp up there through thick long grasses and weeds, with a big back pack sprayer. We tried using wands which you just brushed on the tips of the plants, but it wasn’t practical. If anyone was to restart this activity we either need to get a contractor in and trust their care and diligence with our precious habitat, or one of our members need to do it, which, being the resident horticulturalist whose been trained in spraying, is probably me.

The thought of waiting out for a calm windless day with no rain due, in late summer in the UK. And then using that rare lovely day gifted to me, to walk a few kilometers with 20 litreback pack sprayer, P.P.E; and then wearing a mask for a few hours; to use a product I don’t trust; doing a task; that I’m not sure of the benefits. It is not an inspiring prospect.


I’ve always looked at that area of water, above the bugger of a bridge, as a necessary evil for the system that we fish in the club. It would be lovely if it was a crystal clear series of pools runs and riffles. But it’s not and it’s a long way from ever being that, with the nature of the surrounding land and its usage, and past agricultural abuse this stretch has suffered as a natural habitat. 

I suspect that the reasons the Groynes and the Nassington Road bridge are so clear in stark contrast, is because this long reed bed catches much of the silt and diffuse pollution running out of the banksides from cattle fields and back gardens upstream in the upper beats, and effectively traps it safely there.

This description makes it sound terrible. but if Trout are our indicator species, it holds plenty of them in various stages from parr up to larger, older adults. With the silty stream base and the light here in the reeds, the trout tend to be more Golden, rather than the deep olive green , brown fish of lower down stream or the silvery fish of the open riffles.

And even when it appears deep, slow and completely choked with weeds from the bankside, if you adventure in there, you discover the occasional, inexplicable little thin ribbons of knee deep water remaining open, the water looking pure and clear, crystal like, over a harder base with the occasional bed of gravel, just yards from the choked up deep silty glides on either side. A magical little trout streams living in this muddy bog.

Casting, or rather flicking a fly upstream in these areas, usually catches some tubby little parr marked trout of 6- 10 inches, or the occasional two year old of over a foot. I wonder if this is the last remnants of the stream that was dredged out into a straight canal, when the soil was piled up as high banks, spared from the digger bucket and appearing Brigadoon like when the conditions are right.


Seeing the Reeds and Rushes appear in the Groynes though was disturbing, especially when I saw the size of the patches that had established in my absence. As a fishermen at first it’s fun and helps somewhat. The fish that seem to be around it and use it for cover, a place to ambush. They are generally larger specimens of the area, and your casting is more targeted, rather than exploring the waters on those evenings when nothing much appears to be happening. Often your taken with an explosive rise just under the rod tip that fires off the adrenalin.

Anything rising in open water nearby is usually  parr or a different species avoiding these big boys (and girls) lurking in the shadows of the fringes of these Rushes.

Wearing your environmental hat however, you can feel how much silt is gathering and being stored up in the areas around it, how those recently exposed gravels in the region are being silted up before they can gather into any depth and add benefit to the Brook. The new rich ranunculus beds of the Grounds appear stringy and thin and dying back just downstream of these new reed beds, allowing other weeds, not really beneficial to aquatic insects to get established.

Now, the pressure of a few grazing swans in the area is even more devastating on the Ranunculus, as these new vigorous plant invaders find purchase in the spoil from the grazing, displacing our precious water buttercups.  The rich insect habitat and the essential oxygen they once added to the stream, gone now, and replaced with gathering silt and stagnation. 

I had been gone for a few years but not that long surely. It was disturbing the amount of area that it had established. By July it had choked up the flow in 4 areas and there were many small patches starting to establish to expand and fill out. We were losing the Groynes, at that moment ten to fifteen percent of the stream-bed was affected and now storing up silt midstream, but if those small patches filled out and established,  we would soon be looking at forty to fifty percent lost and fast approaching a replication of the water above the Culvert bridge.

One patch I explored in gardener mode with my heavy duty garden fork teasing at the roots to see how quickly and easily it came out, it didn’t. I realised to clear it manually, roots and all, would be a biblical undertaking for one man. Regular cutting to keep it weak, or chemicals to kill it seemed the only practicable options available to us.

I need to re-read the safety notes of Monsanto’s devilish brew, Roundup bioactive GL and see if it mentions an exemption of harm to water Gremlins and Imps, it might be useful after all.

The tightest of lines and driest of waders to all out in Sexyloops land. I’m off to sharpen the scythe.

Chris Avery