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'FAQs' Compiled by Richard Tyler for Save the Wye, Wye-July (2022 Event)

Ranunculus

Ranunculus fluitans or River Water-crowfoot is a luxuriant plant that grows from the gravel at the bottom of the river. It is one of the buttercup family and has bright white (or white & yellow) flowers that emerge out of the water from its frond-like leaves that sway in the current.

Ranunculus fluitans is a key part of the river ecosystem that, like trees in a woodland, provides the shelter and habitat for invertebrates and young fish. Remove the trees from a woodland and you get a wasteland – exactly what is happening here. Invertebrates and young fish are not protected and waterbirds like swans cannot feed on them.

Wye and Usk Foundation undertook a survey in 2021 that showed we had lost some 95% of this crucial species along the length of the Wye. Various theories have been advanced as to why but the most likely reason is that the storms in the winter of 2000/1 produced massive floods that ripped the Ranunculus out of the river gravels. This is happens every so often in a river like the Wye but two factors are causing serious concern.

Firstly flooding is becoming much more frequent and intense – see below – and secondly the river is increasingly cloudy because of pollution and the resulting algal blooms, reducing the plants ability to regenerate.

If we don’t get the Ranunculus back fairly swiftly, we will lose the next generation of the rarer species of fish as well as reducing waterbird numbers. This is one of the key reasons why we only have two years to Save the Wye.

Two Years to Save the Wye

Whilst many may have felt that this was the approximate timescale left, the estimate was given greater credence when Simon Evans, CEO of WUF, mde such a statement at a meeting of the Nutrient Management Board in early 2022.

Many of the important fish species live for around 4 years. If the lack of Ranunculus prevents them from reproducing in sufficient numbers, this means there will be a drastic reduction in fish population numbers after the next 2 years. We need to reduce pollution levels urgently to minimise this impact.

Flooding

A river like the Wye has always flooded but several factors are increasing the intensity and frequency of these events:

* Global Heating More rain in more intense storms seems to be one of the impacts of a warming climate. There is little that folk worried about the Wye can do about this on our own so we must find ways of reducing the impact of the flooding we know is coming.

* Faster Rainwater Runoff Old pasture is very good at absorbing rain into the soil and then releasing it slowly into ditches and watercourses. Unfortunately, most of the old pasture has been ploughed up and replaced with farming systems that are designed to move the water away from the crops swiftly, meaning that the peak flows occur soon after the rain storm. Where this happens on slopes the effect is multiplied. We need to re-design our farming systems to slow down water runoff from the land. More permanent pasture, more woodland, more ponds and lakes, the re-wetting of peatlands – all have their place in a catchment level approach to land management.

* Urban Development In built-up areas, the increase in concrete and tarmac moves water even faster into the rivers. Much more investment in our urban infrastructure is needed to reduce peak flows. This may potentially compete with the drive to reduce CSOs (see below) which may at present allow some slight cushioning against peak flows as prior to operation of a CSO the first bit of rainwater runoff may be briefly held back at Sewage plants.

Combined Sewage Overflows ( CSOs)

Excessive new development without corresponding increases in Sewage treatment capacity have resulted in excessively frequent (indeed routine) use of CSOs which were originally intended as a ‘relief valve’ for operation during exceptional conditions. More sewage treatment capacity, and separation of surface water run-off from foul water are both required (see also SUDS). In Victorian times, combining the two was less illogical, given the amount of droppings falling on the road surface from horse-drawn transport, but times have changed...