Latest “Climate Proofing” Rivers

“Climate Proofing” Rivers

Thursday 29th November, 2018

Climate change and species extinction have been high on the news agenda in recent weeks.

And protecting rivers and their occupants from the extremes of climate has become an increasingly important part of the Foundation’s remit.

Blocking forestry drains to restore upland bogs in the upper Irfon catchment was an important part of our EU Life+ funded ISAC projectOne area of our work that does this is natural flood management, which results in more water being soaked up and stored by the land. This has so far involved us restoring bogs in the upper Irfon previously drained for forestry and improving farming practices further down the catchment to increase the permeability of land.

The work is very effective in reducing the flood risk to people and property during wet periods. It also means more water is held back and released into the rivers at times when they need it most, such as the drought conditions experienced this summer.

However, there is another, equally important arm of the Foundation’s drive to “climate-proof” rivers. Ensuring water abstraction and reservoirs are managed in a way that is beneficial to the rivers and their fish is also another priority for us.

Complex water resource modelling is possibly not the most captivating area of river restoration. Yet it is an increasingly important one

The Usk Wye Abstraction Group (UWAG), which includes Dwr Cymru Welsh Water, Natural Resources Wales, the Canal & Rivers Trust and the Wye & Usk Foundation (represented by Advisory Director Dr Stephen Marsh-Smith OBE) have been working in this area for the last decade. With the expertise of John Lawson, former head of Halcrow’s water resources division, the group have been instrumental in devising and delivering changes to the management of abstraction and reservoir discharges in both catchments.

Anyone who needs convincing of the benefits of this pioneering work only has to cast their minds back to the summer. The extreme low flows and high water temperatures meant that in July especially, our rivers were severely tested.

Things could have been much worse without UWAG. The extra releases from the reservoirs in the Usk catchment and the continued regulated flows from Elan were a godsend during that period. During the drought, the Elan was often making up around 75% of the flow at the confluence with the Wye. Without this extra, cooler water we could easily have faced the kind of fish kills experienced in 1976.

The confluence of the Elan (flowing left to right in the picture and the Wye in July this year. The tributary was estimated to be making up over 75% of the flow at the timeMore progress was announced by UWAG last week and it was good news for the Usk in particular. Manorafon pumping station is now operational on the Tywi, reducing the demand from the Usk reservoir which currently supplies the Tywi Gower region. This will allow the reservoir to support the abstraction, during low flows, by the Monmouth and Brecon Canal. The driver for all these changes is both the Habitats Directive and, more recently, the requirement for ‘Abstractions of Right’ to be brought into the current regulatory system.

The Usk reservoir will now be used to support the Brecon & Monmouth CanalFurther downstream, a new pumping station is being built near Usk Town that will be used to fill Llandegfedd reservoir quickly, during winter months, instead of the previous method of taking water during late spring and summer when the river is naturally lower. New fish screens are also being fitted.

Finally, new valves have been fitted to the Elan reservoirs and will be fitted on those that supply the Usk. These will enable them to release extra water to support natural spates that would otherwise be shortened by the reservoir. Supporting these spates will extend the “running” opportunities for migratory fish and return the rivers to a more natural flow regimen. In combination, all these changes will optimise conditions for fish to migrate both up and downstream.

For many people, complex water modelling is possibly not the most captivating area of river restoration. Yet we hope that everyone with an interest in the Wye or Usk can appreciate the achievements of UWAG and its importance to both rivers.

A major portion of the Foundation’s costs of this work have been borne by our very generous supporters who, along with our partners in UWAG, we would like to thank.

Anyone who has made a donation to the Foundation in the last ten years can be proud of their own contribution to this vital work. You have helped make some changes for the good.

All the best from WUF.

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