River Glaven

A major river restoration project was completed on the River Glaven at Hunworth in North Norfolk in August 2010.  The work was a partnership effort between the landowners, Stody Estate, and Wild Trout Trust, Environment Agency, Norfolk Wildlife Trust, River Glaven Conservation Group, Professor Richard Hey, University College of London and the Centre for Environment Fisheries and Aquaculture Science (CEFAS).

The project took place on a 400-metre reach which, at sometime in the distant past, had been straightened and moved to the edge of the floodplain, probably for the purposes of milling.  The project involved restoring the river’s natural form by putting back pools, riffles, and meanders, narrowing the river and reconnecting it with its flood plain.  The restoration was designed and closely supervised by Professor Richard Hey, a professional fluvial geomorphologist recently retired from the University of East Anglia. 

“Rivers like these small chalkstreams simply don’t have the energy to restore their natural form once it has been disturbed by man,” said Professor Hey.  “It would take the river literally thousands of years to recover if it was left to nature, but with careful planning and by working with the river’s natural processes, this can be reduced significantly, to a matter of a few years.”

Before work commenced, the site already contained an impressive number of species of conservation interest including water voles, white-clawed crayfish, brook lampreys, otters, bullheads and wild brown trout.  This meant detailed planning was required to minimise the impact of the works upon the existing biodiversity of the site.   Close co-operation between Wild Trout Trust, Norfolk Wildlife Trust and the Environment Agency ensured the works were carried out sensitively and at the appropriate time of year.  Water vole surveys were carried out by Steve Henson of Norfolk Wildlife Trust, ably assisted by fellow River Glaven Conservation Group stalwart, Ian Shepherd.  Tim Jacklin of the Wild Trout Trust, working under the Anglian Sea Trout Project banner, organised the prior rescue of fish and crayfish from the site and oversaw the works.

Left: Crayfish, bullheads, eel, trout and brook lamprey needed to be protected during the works

 

Rescuing white-clawed crayfish

The works were completed in two phases, with a large volume of earth being moved in 2009 by the Environment Agency’s local Operations Delivery team to reconnect the river to its floodplain.  The same team returned in August 2010, with driver Mick Hicks again expertly at the helm of the excavator, to complete the project. 

“It was amazing to see the river taking shape,” said Tim. “The new meanders were dug in the dry and the levels of the new pools and riffles were set.  Then the flow was diverted into its new course and the old course blocked off.  Imported gravel was introduced to fine-tune the level of the riffles and it was great to see how many good trout spawning areas could be created with a relatively small amount of gravel.”

Stody Estate and Farm Manager, Ross Haddow said “We are delighted with the outcome of this project.  It is an excellent example of all the different parties working towards improving the river and its surroundings.  We are committed to sensitive management of this site in the future and all the surrounding land has now been put into Higher Level Stewardship.”

The site is being closely monitored.  In-stream and meadow biological communities are being studied by a research team from University College London, Queen Mary University of London, CEFAS and the Environment Agency.  Thus far two PhD and four MSc studies have been focused on the site. CEFAS and the Environment Agency also have good data on the fish stocks from this site and it will be interesting to see how the recovery proceeds.

The newly completed project

Wild Trout Trust contact: Tim Jacklin

A team of scientists lead by Hannah Clilverd carried out a study alongside the work to measure the effect of embankment removal on the floodplain. To see a summary of the work, click here

The re-connected floodplain functioning as intended during high water in June 2012 (Photo: Carl Sayer)

galven hunworth flood

 

The restored site in May 2013

Glaven Hunworth May 2013