Conservation
Dear Ray,
Here are articles written by river keeper Frank Sawyer attributed to the Field and Shooting Times and Country Magazine which basically describes some of the old style stewardship from 1962 to 1974.
My greatest fear, highlighted in part by your short film, is that the river habitat "might" be beginning to pay a terrible price with the advent of "modern machinery" being used for weed cutting. However, with labour costs being what they are in today's modern world, it was always inevitable that machines would take the place of men and scythes.
I would be interested to learn what times of the year these cutters are in operation and for what purpose exactly? Weed cutting has always been practised but never on such a grand scale or as this.
Regards,
Lee.
Any river as you know Ray, lives and breathes
CARE IN CUTTING RIVER WEEDS
THE FIELD, June 28 1962
By
Frank Sawyer
Learning by experience how to avoid doing long-term harm
as well as short-term good
How often we in our ignorance of Nature do commit blunders, and in our blindness do the very reverse of what is desired. Here are some cases for consideration. Throughout the south country the season of 1961 was a poor one for small fly and fly fishing suffered for good, continuous hatches of insects are the mainstay of any trout fishery. The exceptional floods in the autumn of 1960 was undoubtedly the cause of this scarcity of flies and it was noticeable that the insects which had suffered most were those of the Baetis group (large dark olive, iron-blue, medium olive, pale watery etc.) which go down into the water to lay their eggs. Many millions of eggs were destroyed during the flooding, and this caused concern on the Avon. But some survived to hatch and produce a fair number of duns. These in turn produced spinners and they laid eggs.
For those who may not be familiar with the habits of the Baetis insects a little explanation is necessary. These flies hatch throughout the fishing season and egg-laying is done during most months of the year. By far the greatest concentration is during the latter part of the summer and autumn. But, whereas eggs laid in the earlier part of the year will hatch quickly and produce larvae, those laid after the end of July may remain in egg form until early spring of the following year.
The eggs are laid beneath the water and on a great variety of different things but the favourite with the adult flies is stonework and whether this is fabricated or natural makes little difference. The eggs may be placed layer upon layer, one over the other and may extend downwards from 1in. or so beneath the surface of the water to the bottom and along it. The adult flies stick the eggs on very securely and, in these places, they can withstand a very fast current of water. However, if the eggs are to stand a chance of hatching successfully they must remain beneath the water and where they can continually receive a supply of oxygen. In the natural cause of events there is seldom any mistake.
I was very pleased with the way things were shaping as it was very apparent that Nature was doing her best to make up for the severe losses of the previous year and, as I have said, every opportunity had been given for the eggs in the main river. Then one day in early November I decided to clear one of our sidestreams in preparation for spawning trout. We have several of these streams along the fishery. They are invaluable for spawners, and in the spring when it is time to plant unfed trout fry from the hatchery. Usually I wait to do this job until there is a definite rise in the general water supply throughout the valley, but this year in November the river was still low.
The streams were choked by abnormal growths of watercress which checked the flow and held the level steady. I had no thought of fly eggs when starting work at the lower end of one of these streams. The watercress had reached the stage when it was quite easy to pull it free to float off with the current. As I worked upstream and as the obstructions were removed, so the level began to fall. When I reached the top, the water level had dropped by 8in.
The inlet from the main river is through a tunnel made of several precast concrete tubes which are 3ft. in diameter. Water had been passing through these in steady pace at a level of a little less than half way up. When I reached the pipes it was quite easy to see how the level had fallen but it was also easy to see something else too. For there, layer upon layer, extending downwards from the high level mark to the water were millions of fly eggs. Here was an egg-laying site I had not previously noticed and one which had been used extensively. High above the water the eggs were so thick they formed a yellowish-brown mass which tapered back into the tunnel as far as I could see. In those masses at each side of the tunnel were sufficient eggs, if all could have hatched, to have provided enough insects to keep fish rising freely all day long for a fortnight or longer. The work of thousands of flies had been wasted through my thoughtlessness.
There was nothing I could do, as in the short time I had left that day there was no possibility of raising the water level again. The eggs soon dried and that night there was a sharp frost. Now this is just one instance of many which can occur where the efforts of Nature are frustrated by man. The insects which laid those eggs did so with the knowledge that the water level would remain well above that of the topmost batches, and, had it been left to Nature to clear the sidestream, there would have been no trouble. The growths of watercress would have continued to hold the water until heavy rains swelled the river. Then they would have washed away. The additional supply of water in the valley would have held the required height on through the winter.
It is things like this which make such a difference in the well-being of a river and a knowledge of natural history is very essential. Twice during the past season I nearly made mistakes which could have cost us a lot of fly but these I noticed in time. At one place in the main river there was a strong growth of round rushes which obstructed the flow and looked unsightly on one of our shallows. The reeds are very tough and several fishermen had complained of losing artificial flies in them. So one morning in early July I took my scythe to cut them. As some popped to the surface at my first sweep I could see at once they were covered with fly eggs, so, abandoning my plans, I returned home taking a couple of the rushes with me.
The microscope soon showed me that many of these eggs had hatched and that others were just doing so. Amongst them were scores of tiny larvae. Now had I cut this batch of rushes all would have been destroyed as it had been my intention to pull them out on to the bank. The rushes had been used by the spring and early-summer Baetis flies.
The second instance was at one of the sets of controls we have on the fishery. Here a set of five big iron hatches control and regulate the upstream level. Only one was open, the other four seated down on to the sill where their bases, at the downstream side, were submerged in the tail water to a depth of about 1ft. These hatches had remained closed for several weeks when one day in late September I decided to lift and drain down the upper reach for a while. As I raised them clear of the water so I could see that on each were vast accumulations of fly eggs, many millions of them, all having been placed there by insects which thought they were quite safe to remain undisturbed through the winter. So far, they are safe because I dropped the hatches back into position once more. But if we have floods these iron hatches will have to be opened and opened wide and then the whole lot will be high and dry. There is nothing, I fear, that can be done about it.
In this instance it is just one of the tragedies which I fear cannot be averted whilst there are artificial things in a running stream. If we are to help Nature then everything must be done in a natural way.
RANUNCULUS IN THE RIVER
THE FIELD, February 28 1963
By
Frank Sawyer
A continuous flow of shallow water over a clean bed makes ideal conditions
for the growth of this weed
It was said by many a few years ago when we were in the throes of cleaning and removing old river controls and generally altering the character of the upper Avon fishery that we would completely ruin the river. It was hinted that by the removal of the existing weed-beds and digging up parts of the river bed that we would never again have the luxuriant growths of ranunculus of years past. I could wish it was partly true, for it seems I have made a rod for my own back. Instead of having to deal only with crops of ranunculus on the shallows, the whole fishery now demands attention, for the old-time deeps which used to exist upstream of every set of controls are now fast-running waters which produce quite as much weed as the old-time shallows.
Though weedcutting early in the season is always a tough job, I cannot recollect a time when the growths of ranunculus were as strong and tough as in April and early May of last year. I had my suspicions when we were cutting that we were in for a season of drought, and it proved. Nature seldom makes a mistake, and in the past years I have noted in the Avon that prolific growths of weed in early spring are an infallible sign that there will be a falling-off in the water supply.
In years past there were seasons when it was necessary to trim out the ranunculus on the shallows so that they could be fished early in the season, but these shallows where the growths were prolific only represented about half the fishery. It was quite safe to leave the other half until the latter part of June, at times even later. Then we had sets of hatches or other river controls about every half-mile along the fishery. In each case, upstream of these obstructions, the water was deep and generally sluggish, and it was not until the water temperature rose sufficiently to encourage growths of pond weeds and ribbon weeds that we needed to give it any attention.
Today, as I have indicated, these controls have gone. Where in years past we had soft summer weeds which were very easy to cut and to control, there is ranunculus quite as healthy and sturdy as any which grows on the old-time shallows. No longer is the water trapped and deep, to flow sluggishly over a bed of silt and mud. It runs fast over a bottom which was cleaned and graded.
One thing is now certain. If one wished to encourage growths of ranunculus, and indeed celery and the several other better classes of weeds in a trout stream, then fast running water is the answer. These weeds need oxygen, and much of this must come to the growths through the river bed. I know it is said by many that all aquatic weeds take their oxygen from the water. It is possible that some do, as for example Cladophora sp., the flannel or blanket weed, as it is called. But I feel quite certain that ranunculus extracts all it needs from the river bed. If it cannot get it from this source, the plants die.
So much has happened in the past few years which points in this direction. Without doubt ranunculus was present in the old river course long before any of the controls of milling and irrigation were thought about. At that time, when the river ran freely on its natural bed, it produced similar crops of weed throughout its length. With the impounding of the water the character changed. The weight of water held in the trap by the hatches or weir, as the case might be, acted to force air out of the bed, away from the roots, instead of allowing it to come freely to them. Then, as mud and silt accumulated, so the bed changed again, and this time to a condition which suited the types of weed which normally grow in static water. The true river weed had its place taken by the pond weed, and so it continued.
Even after years of experience I continue to be amazed how quickly ranunculus and the other good-class growths will appear when conditions are made to suit them, and how soon they will establish themselves into strong and healthy growths. During the past year I have had a hand in the making of three new sidestreams. All three are fast-running streams of water now, but when started, each was almost solid enough to walk over in a pair of shoes. All had at one time been waterways, but neglect through many years had allowed each to become so choked that it was difficult to imagine them as flowing streams.
To clean them out meant the employment of a dragline excavator, for in places as much as 3ft. of spoil across the width of about 10ft had to be taken out before the gravel of the original bed could be exposed and cleaned. When completed a stream would look like a great open trench, an ugly gash along the meadow, winding here and there to follow the low ground, it is true, but nevertheless a sight which marred the surroundings. No freshly dredged river course with piles of black muck at either side is nice to look at, but how quickly it can change and become interesting.
Each of the streams I have mentioned was linked to the main river after the bed had been cleaned, and a control hatch provided so that a flow into them could be directed and regulated. A few days with a fast flow passing along the dredged channel and the water would clear sufficiently to be able to see the gravel bed. Just the flow of water transforms the whole scene, for the dead trench changes to a living stream, and immediately there is character as the surface responds to the unevenness of the bed and the gradient from inlet to outlet.
A few weeks pass and one sees the first weed growths appearing. Tiny shoots showing dark green on the clean-washed gravel. Ranunculus, celery, starwort and milfoil starting life again after being dormant for scores of years, to increase as the days advance and spread their fronds to trail in the fast-running water. Six months pass along and it is hard to realise so much can happen in so short a time, for not only is the water living, but there is aquatic life all about the bed.
It is a joy to see a barren and neglected bog become productive of first-class river plants and animals, to see a liability turned into an asset. For in creating a running stream which can produce trout and trout food, one also improves the condition of the land at either side. So two good purposes are served at the price of one. But this is by the way. What I want to explain is how such streams came to be choked, for the gravel bed is sufficient proof that water travelled along these watercourses years ago. When this was happening all the good-class plants were thriving in the clean and well-aerated conditions.
One thing is certain. In one way or another, the flow of water along the stream bed was obstructed. Slowly, but surely, the mud from rotting vegetation formed over the clean gravel, increasing in depth each year and finally smothering the good-class vegetation. Other kinds were fostered and flourished. Sedges, rushes, watercress and pond weeds filled up the stream channel from bank to bank, and these remained to grow and to decay each year. Gradually the roots knit the bed of mud into a solid mass and this false bottom continued to rise.
The static water lifted on the top of the false bed higher and higher until it spread over the original stream banks to bog the meadows at either side, where more and more decay helped to fill in the old channel. Withy branches rooted and young trees grew to add falls of leaves each autumn, and then in times of flood the flotsam and jetsam would be deposited in the low ground, which formed a trap. It takes many years before a one-time running stream can be filled in completely, but I have seen some become almost as solid as the meadows at either side, making it extremely difficult to trace the original course.
Trapped beneath all the muck are the roots of the former aquatic plants, but the removal of all this spoil and the cleaning of the gravel bed is not enough. Even though water is allowed to fill the newly dug channel, this will not encourage new growth of the dormant roots of ranunculus, for this type of weed, and indeed others, need running water in which there is a sufficient supply of oxygen. Two things are important. First a clean bed through which air can enter into the river course from beneath, and secondly a continuous flow of water to carry the oxygen with it.
The combination of these two things is essential, but there is a third factor which must be considered. The flowing stream must be shallow, and if the bed is uneven so much the better. Ranunculus can only obtain oxygen where the pressure of water on the bed of the stream is less than that exerted by the surrounding land. If, for example, the water level in a stream is kept above the level of the land at either side, then the weight of the water forces air from the bed into the land. It is quite impossible for ranunculus to live in such conditions. Where the water runs thinly and fast, the plants will thrive, but only if the bed is open to the sunlight.
SHOOTING TIMES & COUNTRY MAGAZINE, May 29, 1971
BACKGROUND TO SPORT
Frank Sawyer, river keeper, discusses problems of weed-cutting
Ever since I started as a river keeper, now over 40 years ago, weed-cutting has presented my biggest problem each season. Rivers vary considerably in the amount of aquatic vegetation they produce but I feel very doubtful if there is a water anywhere where growths are more prolific than in the upper Avon which I look after.
Upper parts of rivers always grow more weeds than the middle and lower reaches. What is more, the general depth and the flow of water is much less and in consequence the cutting and clearance of the cut weed entails far more work. Weed-cutting is always hard work for most of it has to be done manually. So far no machine has been evolved which can tackle the heavy growths we get in the chalk and limestone waters and at the same time be manoeuvrable by one man. Weed-cutting launches, as they are called, are available, but these are at a price far beyond the pockets of the majority of fishery owners. What is more, they are so cumbersome and heavy that they can only be used in certain classes of water. None are light enough to be transported by ordinary manpower and this rules out their use in anything but big rivers and places where there are no obstructions to the passage of the boat upstream or down.
Providing a suitably powered weed-cutter has occupied my thoughts for many years, for the time is long past when it is easy to get labour to do this job. There are few who are willing to wade in water and use a hand-scythe and still less who will come along and help pull a length of linked blades. I have evolved and tried out many ideas which have failed for one reason or another but at last I have a powered cutter which shows considerable promise, a machine that can be transported by two men to any part of a river or lake and used by them.
This machine is not foolproof yet, but for the first time in my life I have been able to cut the weeds with one man to help, and with neither of us having to work much. Maybe it will take another year – perhaps two – before I am satisfied, but already I wish such a machine could have been available half-a-century ago. You would think, in this day and age of mechanics, that it would be a simple task to evolve something to cut river weeds effectively. Men can be transported to the moon and back safely and yet the cutting of weeds in our waterways has to be done by most people in the same manner as they were cut by their grandparents and for generations before them. Is it any wonder that labour is difficult to obtain?
Weed-cutting is an important job in all waterways, and in trout waters it is essential that control and arrangement is made. Heavy growths of weed can act in much the same way as a dam to obstruct the free passage of water and, in the meandering types of rivers such as those in the South Country, flooding of the banks of the fishery and adjacent meadowland can become serious.
Normally we plan for our main weed-cutting programme to start after the first week in June. Our most prolific crop is ranunculus and I prefer to wait until this is mature and flowering before making any attempt to cut it. This class of weed is much easier to cut when the fronds have grown to their full length and, what is more, the one cut then will check any further growth for the season.
I have to manage just over six miles of main river with various side-streams and small lakes. It is the river that is the biggest problem, for we often get a mass of weed from bank to bank. My photograph of one of the shallow reaches is typical of the general condition in early June. These weeds grow very fast, often as much as a foot in 24 hours. Normally we start at the lower boundary and work our way upstream. But we are never ruthless in the cutting. I try to leave bars of weed across the river at intervals which vary according to the depth of water. In the shallows we might cut a stretch of about 30 yards and then leave a bar about five yards wide. In the deeps we cut cleanly for perhaps a hundred yards and then leave a part, or parts, untouched.
Cover in a river is just as important for trout as it is cover on land for game birds. Trout like to have somewhere where they can feel secure and it is with this in mind that we plan our weed-cutting. Besides, the river-weeds, though perhaps a nuisance in some ways, do add greatly to the attraction in a fishery. If arranged systematically they can serve several very useful purposes. Apart from providing cover and security for trout, they also serve as a sanctuary and a feeding place for much of the food needed by trout, which of course includes the great variety of insects upon which the sport of dry-fly and nymph fishing must depend. A further and very important function is that the weed-bars filter the water and at the same time check and conserve the flow. Beds can be left to direct the flow to a desired position or to create feeding runs for trout.
On some rivers it is the law that all cut weed must be extracted. This adds greatly to the expense. River weed is heavy and where this extraction has to be done by hand the work of the lifting and pulling the great masses to dry land is far harder than cutting. In some rivers, and on some fisheries, arrangements have been made to by-pass the cut weed into side-streams or lagoons where it is trapped and allowed to rot. It is not a good plan to extract weed immediately it is cut, for on the fronds there can be a great variety of aquatic life which can be wasted if pulled on to dry land too soon. If allowed to float for a couple of days most of the more valuable types will have left to find a fresh home.
Weed growths vary considerably in the different classes of river but generally one can accept the fact that any river which can grow good classes of aquatic plants will also grow good trout. It is not that weed growths are essential, for I have known quite a number of waters where the fishing has been extremely good with no weeds of any kind except the mosses and algae of the river bottom. Luxuriant weed growths, however, are an indication of alkalinity and normally where a water or river bed is alkaline, the fish grow big.
SHOOTING TIMES & COUNTRY MAGAZINE, August, 1974
BACKGROUND TO SPORT
Weedcutting & Afterwards
By
Frank Sawyer
Alan, our keeper, and his helpers, have just finished the second weedcut throughout the six miles of the fishery and now, with the alternate transverse bars of weed they have left, and the pools between, the river looks very nice, and should remain in good fishing order for the rest of the season. This second weedcut is always a harder task than the first which normally is done in early June, as always there is far less water to carry away the cut weed. This year, like that of 1973, is worse than average, for we are very short of water in the upper Avon. To make matters worse there is a lot of flannel weed and this is hard to cut and get moving. The actual clearance of the cut weed is always far more laborious than the cutting.
On many rivers it is the responsibility of all fishery owners to extract any weed they cut and to do this weed racks across the river are used to stop the drift of the weed so that it can be pulled out on to the bank. On some fisheries, lagoons and old sidestreams are used, into which the cut weed can be by-passed from the main stream, and there left to rot. We are fortunate on the upper Avon in being allowed to pass all cut weed on to points many miles downstream, where River Authorities have booms, and excavators to extract. This saves a lot of hard work and expense for all fisheries in the upper valley, but arrangements have to be made so that cutting and clearance is only done at certain times allocated during the season. I think everyone now do their best to keep to this agreement, but it doesn’t always work out in the way planned.
The upper reaches of these south country streams always grow a much greater variety of aquatic plants than those in the middle and lower lengths. And there is always far more of each kind. Much of this is due to the shallow nature of the rivers and the higher oxygen content of the water. The speed with which a river can be cleared of cut weed depends entirely on the depth and the flow. In some seasons a day or two is quite sufficient to get all rafts of weed moving and away. In others, such as this year, it has to be a matter of moving from “pillar to post,†as the saying goes. Often the same lot has to be shifted a score of times and even more, before it can go through the last set of open hatchways and become the responsibility of a downstream neighbour.
Sometimes we get a jam at one or other of the sets of controls, when many tons will pack across the river as tightly as hay in a rick, indeed there have been times when we have had to use a hay-knife to cut it into bales to pass through a hatchway. In consequence, though we have these specified times for weedcutting, there can be no guarantee that all weed cut will arrive at the excavator during the period allowed. In our case here, we have to wait until our upstream neighbours have sent down their cut before making any attempt to clear our own. Should they have difficulty and be late, then we start with a handicap and this increases in the reaches down river.
It is all hard work, it is true, but, as I have said, the river can look very nice when it is done. In addition there is always the promise of a bit of sport afterwards in catching pike, and this can make up a little for the heaving and pulling. Usually, when the river is low the water is very clear and, after the weeds have been cut, there is a very good chance to see and to catch any pike that have been hiding in the pools. Often enough they are disturbed when weed cutting or clearance is in progress and these are marked down to be dealt with as soon as a suitable opportunity occurs. Sometimes, when you know a pike is in a pool it pays to leave a small fringe of weed in a likely eddy or backwater, just enough to give the pike a feeling of security but not enough to make it difficult to see through the fronds to the bottom. When a pool has been cut cleanly pike seek for some sort of shelter in which to lie up and by providing this for them it can lessen the search through the pool.
A clue to the presence of a big pike is when few other fish are to be seen rising, or about the pool. We have just had one glaring instance of this. For the past five years I have known something was wrong in this particular pool for, previous to that, it used to be one of the best in the fishery. There have been many times when I have seen a score of trout and as many grayling rising together on a late summer evening, yet recently it was difficult to find one. I had my suspicions that a big pike was in it but though we searched it a number of times, and fished a bait through it on various occasions, we saw no sign. This particular pool is a hatchpool and the deepest part, where the scour from the hatchway fall, it is quite nine feet deep. Snags in the bottom and at the sides prevented any successful netting and it is too deep for electrical apparatus.
During the five years many of our members have watched this pool in the hope of seeing a rising trout, and it is close to a road bridge where many people stop to look into it. I feel sure, had anyone seen an outsize fish we would soon have been notified. No weeds ever grow in the deep part but there is always a fringe around the sides and the tail. Alan had decided to cut these before clearing a bulk which had collected and jammed at the hatchways. The block of cut weed had checked a lot of the flow through the pool and made it possible to see to the bottom even in the deepest part. But it wasn’t only the bottom we saw. From where it had been lying in a weedbed there shot out one of the biggest pike I have seen in this part of the river, and with it, another of about quarter the size.
It was easy for me to keep both fish in sight while Alan went to get his harpoon outfit. Alan made no mistake, for a target such as this big one is not hard to hit. Soon it was on the bank a yard long and just over twelve pounds. Shortly afterwards he got the second, a three pounder. The smaller fish could well have escaped notice but how the big one managed to keep out of sight for so long will always be a mystery. During the five years I had suspected his presence he must have eaten at least a thousand fish. Many of these were trout of up to, and perhaps over, two pounds. An expensive customer to have in any fishery.
You must be forever vigilant in any stream where pike have been known, and always be ready whenever opportunities are presented. After weedcutting a few days spent in searching are never wasted.
