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Fowey River Water - A brief fisherman's review

December 8 2008

Bill Eliot, Hon Sec. Liskeard & District A.C.

The River Fowey is a prime Cornish spate river giving excellent salmon and seatrout fishing. It is one of only two rivers in the south west of England holding its targets for sustainable salmonid stocks.

Both salmon and seatrout prosper by breeding in the clean waters of the high country which is Bodmin Moor. However the nature of the water in the River Fowey is made complex because the river is used by the water utility company (S.W.W.) as a water conduit. From their reservoirs at Colliford and at Siblyback on Bodmin Moor, water is released according to the needs of the seasonal population of Cornwall to the treatment plant at Restormel just above the tidal limit. This complexity affects the migratory salmon and seatrout using the river to breed and it affects where they lie and how we may fish for them.

The Fowey catchment has five important feeders, all of which start high on Bodmin Moor and tumble down off the moor into the right hand bank or northwestern side of the main river

1) The Cardinham River runs from the edge of the Bodmin Moor through Cardinham Woods not far from Bodmin town and into the river near Bodmin Parkway station.

2) The Warleggan River runs off the moor from Shallow Water Common, collects the run off from Hawks Tor lake above the A30, and then falls steeply through Warleggan woods into the river at Wainsford.

3) The St Neots River is the water conduit from Colliford and collects little other water on its way to the main river above Trago Mills.

4) Trenant Stream runs off the moor east of Colliford Lake, collects the outflow from the old china clay works at Park Pit, which is now a big deep lake, and joins the main river soon after it has tumbled down through Golitha Falls.

5) The main river itself runs all across Bodmin Moor from Brown Willy and collects Siblyback water at Trekieve Steps before it tumbles down through Golitha Falls.

Consequently we have several sources of the water running into the river, which have a variable content of reservoir water according to the demands of the public water system. The population doubles in summer. The long term rainfall pattern also has a strong effect on the quality of water lying in the reservoirs which will be very low if two or three dry years follow one another. When the reservoirs are very low the water is clouded by peat dust and is sour.

In summary the water in the river is a mixture of:

a) GROUND WATER from the springs which is good clean water and the foundation of all things good. Cattle on the moor will fight to drink this water in preference to all others, but the springs depend on the previous winter rainfall and they will have less flow and some will dry up in summer time after a dry winter.

b) RAIN WATER from Heaven is the original source of all things good but is not always good all the time. The first flush of water from rain runs into the river from the road drains and it is often black and oily. This is called “ROAD WASHINGS” and fish and fishermen hate it. Luckily there are few urban sites in the catchment and not much ploughed land either so these flushings are not long lasting.

c) The quality of rain water RUN OFF from the moor and fields depends upon the grass cover. Clean grassland is fine but heavily poached ground and wild boar farms, for example, yield very dirty black peaty water. The heavy rains of winter and spring, if sustained, wash the fields and clear out the drains and the river runs with CLEAR GREEN water, which is the best for catching the big spring seatrout and winter salmon.

d) STORMWATER at any season is good news after the first flush. A big storm will fill the catchment and the river will run high and muddy and over its banks in places, so that fishing is impossible. However spates send a powerful message out to sea from the estuary and bring in those fish that have been lying off or even way out in the Channel. As a spate subsides the fishing will be excellent for a day or two.

As the muddy colour clears and the water level drops back the fish will run and the angler will find fish everywhere. Do not wait for the fine weather to settle in or you will be too late.

e) The volume of RESERVOIR WATER from COLLIFORD via the St Neot is greater in summer when the holiday crowds are in Cornwall than it is in winter. At first sight this is a blessing because it holds up the river level in the dry season. If Colliford was full in the spring, this water is clean and sweet, but if Colliford has had a couple of dry years the water coming down the St Neot is brown and sour and the water is loaded with peat dust and sludge which the fish dislike intensely. Since this happens in summer, the volume of natural water is least available to dilute it and the river below Twowatersfoot may turn brown but clear. In the worst case, brown cloudy and dirty, the fishing is unproductive.

f) RESERVOIR WATER from SIBLYBACK runs into the river above Golitha and the same rules apply as for Colliford water, but Siblyback is a smaller reservoir and not always running to provide water for Restormel works. If Siblyback is discharging and low water conditions apply, the diluting benefit of the main river on Colliford water coming down the St Neot is minimal. Incidentally, Siblyback is a well stocked rainbow trout fishery and the odd rainbow from Colliford gets over or through the dam into the river where they should always be killed if caught.

g) Waters from the Trenant, Warleggan and Cardinham tributaries and the main river above Trekieve Steps are the only ones that are truly NATURAL WATER. These are the key breeding grounds for migratory fish, but salmon and seatrout juveniles are found everywhere and also in the main river, so the Fowey catchment

is still very successful for salmon and seatrout breeding and it currently meets its sustainable stock targets.

h) WATER RUNNING OVER THE WEIR AT RESTORMEL depends upon the natural flow and how much is taken out by the water processing works for public use in Cornwall. South West Water are obviously entitled to take out at least as much water as they release from their reservoirs. They are not under any obligation to release extra water to make up the flow over the weir to any specific level in low water conditions and if there is lots of natural water, they don’t have to release as much as they take out, so there is sometimes very little flow over the weir in dry weather.

There is a FISH COUNTER on this weir and it tells us, as expected, that more fish come up over the weir when there is a spate or increased flow over the weir, but that some fish do come up over the weir even in very low flows. On balance, the weir probably has very little effect over and above the natural water flow in the river, but it is naturally viewed with suspicion by the fishermen in low water conditions. There is a “waterbank” of water in the reservoirs that may be released at the behest of the Environment Agency. It is probably not enough to mitigate low water flows at Restormel, but it has been used experimentally to draw salmon into the St Neot river to spawn.


The effect of the various components of the water in the fishing beats is interesting. Basically high water is good and low water is bad.

High clear green winter water is best of all. High muddy brown spate water makes fishing impossible but it is soon followed by clearing high water and that is when the fish are most active, running and likely to be out in the stream and catchable. When sour “road washings” or peat water from the reservoirs comes, it puts the fish off. In extreme cases they will always swim up through the pollution and get into a sidestream or clean tributary. If you think about it, an instinct to turn and flee downstream to escape pollution would be a recipe for disaster. Fish will always hold their noses and swim upstream above the source of pollution, until they get into clean water or die in the attempt.

Sometimes you will find the old Junction Pool, above the junction with the St Neot, or the main river at Trekieve Steps, above the inlet from Siblyback, quite black with fish packed in there like cobbles in a roadway to avoid bad water downstream. They are not catchable but they are a sight to see.

So, peaty water specially in summer is not a good sign even if the water is up a bit and otherwise clean but if the river is low and clean, night fishing for seatrout and fine tackle for salmon by day are the best methods and night fishing can be highly successful. If rains come and the river rises and colours, fish early and fish big and lighten your tackle as the water clears.

The Fowey is a fine river and the fishing is excellent and it helps if you read the signs to see when and where to concentrate your efforts. Above all keep fishing, for you will catch nought sitting at home in front of the fire!