War on the Waters

In the swelling industrial towns and cities gradually overshadowing their boundaries, spilling and tumbling out to smother nearby paddocks and ancient meadows.

Rivers running through these conurbations and out beyond were mostly heavily polluted, merely drains and dumps for industry. There now to carry away storm water from the spreading tarmac. Many waterways sotoxic that it was inconceivable back then, that any life could, or would ever return to them.

The River Irwell in Manchester when I was a kid was so badly polluted from the two rivers that formed it. One the Medlock ran through the city centre and the old cotton mills. When it rained, which is often in Manchester, huge detergent foam would rise over the bridges, into the main road like swelling candy floss and then blow white detergent tumbleweed suds down the cold grimy grey shivering shopping street.

It just looked wrong!

Many rural rivers and streams now functioning as muddy drains from the farmers’ fields.

Industrialised farming had pushed back, ripped up or shut out the countryside from the comfort of its tractor seat. Directed from an accountant’s leather chair, orsome office in the dark corridors of Whitehall. Those rural communities now at their most remote from the Industrial farms encircling and besieging the villages.

Those farmers were informed by the ministry boffins that by canalising the river courses, it would take the water away quickly and efficiently. And with huge increaseduse of Inorganic Nitrate fertilisers would they therefore maximise the yields.

Unbeknownst to them they created a time bomb for any community or property or ancient bridge down-stream unable to drain these new lightning-fast floods of water rampaging downstream.  

And so began the yearly British cycle of previously dry towns and villages flooded or even wiped out in a flash as the lands no longer holds back the soak, gradually releasing it, but let rip!...

This policy of government lead canalising of old water ways continued through the 1980’s.

Villages across the country noticed the areas of nearbyfields that once became ponds over winter or puddled up into duck and seagull havens. Elder residents remembered using these areas as the towns curling ponds and skating rinks as they froze over, now stayed dry. But their villages, that had never flooded in history, were now suffering as lower houses and businesses either flooded or the drains backed up and blocked. In one extreme case a tree washed down stream blocked against a bridge by a shopping street. As more flotsam washed down and gathered, building up against the tree, a damn was created and the force on that bridge grew and grew. Eventually the old stone arched bridge gave way and a wall of water laden with rocks and logs gouged through the village ripping away shop fronts and bedrooms.

As these floods continue, yearly, the older farmers andpoliticians still talk about dredging as a remedy not the cause. They dismiss any of the case studies about River capacity and holding increased from naturalisation, and consider along with repairing the uplands, not as scientific or proven models, but the “woke rantings of ‘nut-job’ environmentalists and tree huggers, Unfortunately.

So back wading the Brook in the present day, inspecting what we had done as a club for a dozen or more years to correct the polices of this Whitehall led river “management”.

(While being ever sensitive to the needs of Mr Farmerwho is wonderfully patient with me and my little projects).

The plan when we decided to stop stocking was to return to a more natural habitat and diverse ecology for all the life that does or should inhabit the waters and banks of the Brook. To put the annual membership subscription not to buying stockfish, but for habitat work.

We focused on the full life cycle of the Wild Trout and its environmental needs. 

From eggs in the gravels, through juvenile habitat, to the deeper pools for the adults in clean oxygen rich watersand the rich fauna and flora found in that habitat...

The focus on wild trout could have been seen as a selfish or self-serving choice, I guess.

In my defence, Willow brook is the fastest little stream in the county and very capable of nurturing a population ofTrout in its natural state.

Where the main river meets the sea in the Wash estuary there is a great population of Sea Trout, which no doubt would have come up stream once, but the flood defence barriers across the Fens make migration impassable… for now!

And let’s face it, Trout are a good PR, a great ‘keystonespecies’ for a ‘downgraded environment’ in soundbite speak.

A Wild Trout stream has kudos in the UK, its special and deserves protection. Trout are the champions of pristine waters, Trout fishermen are handy recruits to help with the improvements and monitoring, as they are rewardedwith better catch returns from a more beautiful environment to splash around in.

They dream of fabulous hatches of Grannom or Mayfly, thick clouds of Blue winged olives returning with olive green egg balls to return to the surface in a summers evening and the pristine waters ahead dimpled with the circles of rising fish.

Those dreams are coming true.

In the years after stocking and concentrating on environment we’ve achieved that.

The Mayfly hatch may not be River Test Biblical proportions, but compared with the handful when I joined the club, the tens of thousands we see now are a New Testament, and the Trout and the Songbirdshammer them.

The banksides are busy early in the season with clumsy crashing little Grannom sedges. It’s not spectacular butwas unknown a dozen years back.

Only when you’re wading and look at your leg coated in the sedges trying to crawl back down into the water do you realise just how many there are.

And all sizes of Trout love them after the winter fast.

Ask any fly fishermen would he rather be catching Wild Trout or stocked Trout?

So, early November, looking now at what work the storm flood had spared and predict where more help might be needed.:-

Where a farmer’s bank is now threatened, and we needed to divert the force of that flow back into the stream.

Where the silt is built up mid-stream, we needed it flushed through with water of a flow rate capable of carrying a larger particle away (but not so much to move those gravels).

Where to add some brush wood in the slack water, to settle and trap those particles into harmless beds in the wider shallow margins or the back waters that may become fry habitat in time.? 

What new fresh woody debris newly dropped in the brook with the storms? And wonder if it’s a welcome new habitat feature here where its fell, or better moved down stream to a more useful and productive placement.?

It’s all a gift from above, quite literally, and none of it will be wasted.

The other assessment now, though is the priority for me.

It’s really getting quite urgent.

I’ve been delayed by the weather, and I am late this year.

The Trout in the Willow Brook come to the Redds very early for the UK, usually by the second week of November.

I have noted where I last saw them and the favoured areas, but in the dynamics of a small stream these sites shift and sometimes get badly silted.

Gravel beds wash down stream, new gravel beds occur as the current carries and dumps, creates, and sculpts over time, constantly changing the Brook.

That you never do enter the same river twice is not just a philosophical conundrum. 

On this search as I wade upstream, I have Six criteria that I am considering: -

The bed profile; I am looking for a mound of gravel where the water flow is accelerating and is forced under or into the gravel, usually at the back of a pool or after some fast water, where the current has slackened in high water and dumped the gravel in a mound. Then with normal water levels and flows, these mounds of gravel in turn squeeze the water over the rising bed against the surface, accelerating the flow. Perfect.

The Gravel size; This is a Goldilocks decision not too fine and gritty and not too big and stubborn for a Brown Trout tail to dig and waft away, From 10mm (a third of an inch) up to about 50mm (two inches) is ideal.

Depth; The depth of flow really should be from my ankle depth to just above my knee 12-45cm. ( 5-18inches ) with a gardeners fork I also dig down or I ‘Mince’ my boot heel down to make sure there is at least a 6 -8 inches (15-20cm) of good gravel. Not just a fresh skinny deposit with no real productive depth to it. We don’t want her encouraged to an area with no chance of a through flow.

These criteria I am learning over time, are not an exact science however and Hen Trout don’t always agree with me.

Flow; My small digging fork is barely a metre long, a twig or leaf dropped on the surface that takes roughly two seconds to pass along its length is about the right flow. My rule of thumb. Around 50cm (20 inches) per second, and I am happy as….!.

Fry Habitat; When the hatchlings emerge from the egg there is a complex little tale for another time also. But for now, close downstream from the prospective redds there needs to be some shallower water in the margin with lots of twigs or reeds or Irises for the young fry to settle around and start feeding. Not so deep that the burden of energy spent to get to the surface and back to the bed, or holding in the current is more than the worth of the tiny morsels they are eating.

They need to grow and fast.

A foot or so with a slow steady flow is the limit.

Again, no point encouraging her to lay eggs when the hatchlings have no suitable refuge close downstream.

Fry hate eyeballing each other.

They will actively avoid the sight of their neighbours, (their brethren) hence the need for obstacles in the shallows.

No tolerance at all, unless forced into close contact in the hatchery, this is the sliding doors moment that sets the behaviour pattern onwards, through its life and its choices.

Those thrown closely together in a hatchery bucket and then densely crowded in a stock pond are reset for a different behaviour.

For our wild fish the more twigs/ leaf’s obstacles and cover an area provides, the more Trout fry the area will hold.

These little fellows do not fight for territory, they may puff themselves up, spread pectoral fins and open gills, but they are not actively aggressive fighters. They will back down and move off when faced with a challenge…

This is crucial to learning the way of the stream and how their lives will be mapped out and behaved. Their territory, their feeding stations and their predator awareness all ingrained in this fundamental behaviouras hatchlings, remote in the shallows, or it will be erased in the catch bucket of the hatchery.

It’s the basic understanding of this infant behaviour that is needed to effectively manage a stream like this for the benefit of Wild trout. In the argument against putting larger stocked fish in with a wild population it’s the opening salvo.

Percolation; This finally is the thing we hope to improve when we clean the gravels, I check with the fork after gently disturbing the lower stones with the tines. I await a few seconds for the water to clear and then in an ideal spot I will notice small cloudy trickles of water seeping up from below the gravel carrying out the silt and sediment you have just disturbed.  Sometimes it is seen at the back of the mound.  

This shows me that water is percolating through the gravel.

No flow just may mean heavily silted gravel and if thoseother conditions exist, that’s where we need to concentrate our efforts of cleaning.

To each of those considerations I mark as; Ideal; adequate; borderline; or not ideal.

The ones with the best marks we return to a cleanup. I realise I am vainly trying to get into the head of a hen Trout and it’s far from an exact science.

One site I noted last year where the flow was ideal, the profile ideal, but I also noted the fry habitat, the depth, gravel size, were only adequate and the percolation was at best borderline.

In such a state It was one of the lower scorings of the 12 areas that I had selected to clean up.

When the Trout got to choose a few weeks later however, this was the best attended Redd of the year with at least three females over a week or two selecting it. The first of which I watched cutting and filling four nests in succession. She seemed to love it!

(I manged to film on the phone the third cutting of the redd with her tail to cover over the freshly laid eggs, sent to club members it really stirs up some enthusiasm for volunteers)

One gravel bed that I selected as a fabulous 3x ideal and 3x adequate, I subsequently didn’t see one Trout visit nor note any disturbance. The trout didn’t share my enthusiasm.

Another spot that I tested with my boot, wiggling it down to see how the gravel felt and I rejected it as a potential site, all that remained was a pale circular patch of disturbed gravel.

I twice noted hens on this old boot mark waiting for the men to turn up.

I try my best. Of the six patches we eventually cleaned last year five were selected by Trout for redds. By cleaning them were helping play natures numbers game.

In a heathy river a hens 800 eggs will produce 750 fry. In our silted gravels it will be nowhere near that percentage I couldn’t even guess our losses. 300 hatchlings 100 less?

(That’s why I am obsessed with cleaning the gravels to try and get these numbers up, when you consider what happens the next few years of the Trout’s life’s you will see why).

Still, it sounds a lot ,750 fry, a great percentage. Of them in the ‘ideal’ river 20 only will survive the stream to yearling size.

That is why Fry habitat is so important to us, we could be only talking ten or five yearlings from the 800 eggs in our silted gravels.

Half of what’s left survive the next year, then half again.  So, 5 Trout from those 800 eggs will make it to three-year-olds in a healthy ‘Ideal’ river. In ours could be 1 it could be none. Ours are breeding from year two and may make a second breeding year. 

It’s a very rare fish that makes the third in Willowbrook.

By playing the numbers game and maximising that first crucial percentage with gravel cleaning and then focusing on fry habitat during the populations most vulnerable age, were hoping to nudge up by a few, the numbers of fish that will one day return to the redds one day.

‘Da capo”, return to the beginning, the perfect loop.

As this is posted up I fully expect Trout to be on the redds, the waters up and coloured and a bit fast in the Brook today, the water temp is 8.5c down where I expect it , those day lengths and light levels don’t change with global warming,.

So, this is when it usually occurs.

I need to wait for the water to drop before I can start looking for evidence and marking the spots.

Have a great week wherever you are, whatever you do,in whatever the weather your facing.

Whinging Pom