Where have all our wild rivers gone?

Since the retreat of the ice sheets and the return of humans to the British Isles about  10,000 years ago  the truly wild places have been in steady decline, even our highest mountains carry the scars of mining or quarrying or the erosive power of the trekkers boot. Our wild woodlands have all been managed in some way or another and this loss of wildness has been very keenly felt by the reduction of our wild rivers into shadows of their former wilful and winding glory. Where rivers have been allowed to continue along their sinuous courses there is much to enjoy but the evidence of human driven modification is all too very apparent.

Rain falls across all or part of a catchment, in time the rainwater gathers and collects into a channel which is joined by other tributaries as it flows eventually to the sea. Watercourse bring us water to drink, sustains plants and animals, allows us produce food, make things with, support biodiversity which makes our world work, regulates temperature, captures carbon and looks after our health and well-being. A river and its catchment is an easily understandable item of natural capital, it provides ecosystem services such as clean water and if we don’t look after them we will all be the poorer.

Running water and the plant and animal community it supports  is a highly complex system,  it is able  process nutrients such as fallen leaves and other organic matter, reduce eutrophication impacts, sift sediments, capture carbon, reduce local temperatures and ultimately provide sufficient easily treatable  clean water for drinking and agriculture. A truly natural river system will be characterised by a highly complex river bed, riverside tree shade, diverse aquatic plant community, oxygenating features such as riffles and a structural variety of backwaters, slacks and meanders. This river will be replenished by a steady source of new water not only form rain but from its headwaters to create an average base flow to support aquatic life and leave a reserve to spare.  The loss of these features and functions reduces the rivers ability to produce clean water for people and wildlife.

Agricultural improvement  

Since the 17^th Century with the arrival of Dutch engineers in East Anglia marginal land has been drained and brought under the plough. The challenge of  cultivating low lying seasonally flooded land and of installing drainage for arable and food production has taken advantage of all forms of technical advance whether wind pump or steam excavator. By the 20^th Century with mechanisation of agriculture the modification of the conveying networks of watercourses increased in complexity and extent.

For low-lying areas Acts of Parliament created Internal Drainage Boards who had powers to levy a local tax and carry out drainage maintenance. By the 1980’s millions of riverside trees had been removed, spawning river gravels removed by dredging, water courses straightened and many smaller streams put under in culvert. A culvert may resolve a land/water movement issue or create a simpler space above ground but is a purely hostile environment ecologically. It was somewhere at that time that a realisation of what harm had been done by this simplistic pursuit of a rivers as merely providers of drainage. The pace of improvement slowed and a much more complex and sensitive view has taken hold and slowly gains acceptance.

Obstacles to migration

The River Severn as it passes through Shropshire is a free navigation as it used to be an important trade route in the age before railways. Since then major locks have been installed downstream in Worcestershire and beyond, each lock is accompanied by a huge weir. These were some of the last obstacles to be constructed across the river but are the largest of over a thousand weirs which bar easy access upstream for our native migratory fish. Weirs are constructed for many reasons, for many their purpose has been forgotten. In an age where global pressures on our fish populations have increased these barriers are becoming even more of a challenge to cross and get to allow us to reach a tipping point to species recovery.

Barriers across rivers are not all bad and with reflection and imagination can become a positive feature along the river.  In Shropshire there are very remaining watermills still in operation. More watermill buildings still stand and in some cases the machinery and wheels hang still, but barely, since their last turning. Watermills served either farming or industry, a leat channel collected water from a weir arrested river, header reservoir or mill pool then released the water to either overshoot or undershoot the wheel. For some watermills such as the Dinham Mill in Ludlow a new future beckons as the wheel now turns a generator to produce electricity. At Dinham the weir represented a major obstacle to migratory fish such as the Atlantic salmon and Brown trout. A new fish pass has been installed to help. To top this it is a regular viewing spot for the local European otter”

Taming the flow

Our Shropshire canals are artificial waterways and as such they are examples of the water engineers art with locks, by-pass channels, reinforced banks, piling, aqueducts and sluices. This expressly man-made waterway supports its own wildlife community adapted to the structure and limits of a canals design. In part we can see similar construction solutions being used on our rivers, hard embankments to prevent erosion, rock armouring to protect bridge abutments, dredging to maintain conveyance but the inappropriate canalisation of a natural river reduces its functions and impoverishes its intrinsic value to us and wildlife. Natural solutions, green engineering or merely making space for a river and its floodplain are better options, more complex but deliver better results. Catchment and  river management is highly challenging and so it should be as there is so much to lose when we take a narrow view.