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24 June 2010
Why we need projects
We live in a very special part of the country which may appear at first sight to be in pristine condition. It is quite understandable how appearances can sometimes deceive; the renowned scenery of this part of the world is both dramatic and calming in equal measure and may leave an impression that all is well, natural and undisturbed.
However, our water environment, its quality and the range of beneficial plants and animals it supports is under constant pressure. That pressure comes from all of us in all kinds of ways; how much water we use, what we allow to go down the drains, what food we expect farmers to produce on our behalf and how that food is produced are all examples of where there may be impacts to the quality of water in our rivers and lakes.
In addition to water quality concerns we need to be vigilant that physical barriers in our rivers, streams and becks are not preventing free access to the fish, eel and crustacean species that inhabit them. All need, to a greater or lesser extent, to be able to move between spawning, nursery and feeding areas within the river and its tributaries. Such barriers may include old weirs, perhaps the legacy of the industrial revolution, weirs designed to monitor river levels and measure flows, new weirs designed to convert water power into electricity, tide gates at the mouths of rivers to prevent tidal flooding, fish passes that allow access of some species but exclude others and so forth.
We also now face the threat of our water environment being invaded by “off comer” plant and animal species. These are species foreign to our rivers, lakes, tarns and wetlands but which can establish extremely rapidly. In so doing they will suppress or often completely replace some of our natural species, possibly forever if we let it happen. We have all seen this happen before with the decline of the red squirrel; a once common sight in South Cumbria but now sadly all but replaced by its foreign grey cousin. We must be alert to all such threats and prepare ourselves to defend against this invasion.
Projects are the life blood of South Cumbria Rivers Trust.
In all the examples above of where the pressures lie in the aquatic environment, South Cumbria Rivers Trust is actively carrying out on the ground work to remedy damage where it has already occurred or safeguarding against such damage occurring at all.
For example, South Cumbria Rivers Trust is involved in a program of work which will provide much improved eel and fish access at three tide doors located on becks in South Cumbria.
Gleaston(Deep Meadows), Newlands and Colton becks are all water courses governed by tide doors at their respective confluences with the Leven estuary. The purpose of a tide gate is to prevent upstream flooding. As the rising tide builds, the force of the incoming water closes the door and prevents the tides’ upstream advance. Unfortunately, as these doors are simple, self closing designs they cannot be governed to close only on selected higher tides when flooding is a real risk. They often close on all the tides that reach the door regardless of there being flooding risk or not. It is during this closed door period, which can be significant during a single tide cycle, that all species are prevented from migrating. The cumulative effect of exclusion on each tide is likely to be highly damaging. Total exclusion has probably been prevented only by chance blockage of the door either by silting, debris or other means. This delay or exclusion to migration affects many species but includes eel, salmon, sea trout and lamprey which are not only a very important part of our natural heritage in South Cumbria but need particular help as there is concern for their numbers.
The work that will take place involves retro-fitting “pet door” type fish apertures into the existing tide doors. These smaller doors will hang open during the incoming tide and close only at a tide height that is pre-determined and adjustable by a float mechanism. In essence, we can set the door to allow free access to the eels and fish over a longer period of the tidal cycle. This will create much greater opportunities for these important species to enter and colonise these water courses.
In combination with our work to open access at the point of entry to the river system we are also targeting eel passage at priority in-river obstructions in South Cumbria. European eel is a species subject to a dramatic decline in numbers. It is on the International Union for the Conservation of Natures’ red list-this means it is critically endangered!
We must do what we can to improve access to our river systems and make the maximum amount of habitat available to these creatures while it is not too late.
We have identified three weir sites in South Cumbria that require priority attention.
Eel passes will be fitted to three weirs on the Rivers Bela, Kent and Duddon. These passes are pre-fabricated, square channel troughs. The troughs are fixed to the wing walls of the weirs and ramped into the river in positions to encourage eel entry into the pass. The base of the troughs are lined with bristle board and water is trickled down the bristle board via a pumped feed. The eels make progress through the trough by using their sinuous, snake like wriggling through the bristles. The water trickle aids progress and prevents the small eels from drying out. The top of the trough is securely covered to prevent flood damage to the pass and keep the eels secure until they exit into safe water above the weir.
In both examples of the work being undertaken in tidal and freshwater to improve eel and fish passage we aim to achieve completion during the Autumn of 2010. Following completion we will monitor this work to inform our plans for eel and fish pass improvements at other identified locations.
Further habitat improvement work is planned following the recent production of a scoping report.
Investigations into perceived problems within the River Eea catchment have been investigated by South Cumbria Rivers Trust over the last two years. This work has involved a data trawl on all information held on the river, walkover and electrofishing surveys, a public meeting of landowners, farmers and other interested parties and liason with local anglers.
The scoping report makes a number of recommendations and SCRT has been awarded a DEFRA River Improvement Grant to put these into practice. During the Autumn and Winter of 2010/11 we will be talking these options and opportunities through with landowners and partners with a view to commencing habitat improvement works as soon as possible.
Fencing and trees along the Bela
