Two of the largest Broads in Norfolk will have their underwater ecology ‘manipulated’ to restore their clear water and in turn the water plants that were once commonplace across Broadland’s waterways.
Norfolk Wildlife Trust has received almost half a million pounds for its ambitious project in the Bure and Ant Valleys called ‘Tipping the Balance’.
Following lessons learned from past projects at their Cockshoot and Barton Broads, NWT will create three zones – the size of fifteen international rugby pitches - separated from the main water body of Ranworth and Barton Broads using floating barriers.
These areas will have their fish populations altered and balanced to restore clear water. Fish species involved in maintaining poor water quality will be removed from these zones and released elsewhere.
A balanced fish population is a critical component in restoring clear water. Fish that bottom feed can stir up nutrient-laden sediment, while other fish devour the algae grazing Daphnia (water fleas). Keeping these fish species at balanced levels over large areas of water – 10.7ha at Ranworth and 4.2ha at Barton – will restore lost water quality, allowing rare water plants such as holly-leaved naiad to flourish.
There is a cascade effect to the restoration too. The clear water ultimately makes fishing easier for birds such as osprey and common tern, as they can see the fish in the water. Because of this, the fish behave differently in clearer water and tend to hide in plants near the edge for safety, rather than out in the open water. This allows zooplankton to thrive and they are the crucial grazers of algae. The ecology of the water is therefore even further balanced.
To strengthen this effect, Essex & Suffolk Water Branch Out fund has provided support for new tern rafts to help grow the tern colonies at Ranworth.
The project will also promote the recovery of around 800 metres of emergent plants, and habitat for water voles, at the edge of Ranworth Broad. Water quality, plant regeneration and fish movements will be monitored both inside and outside these fish barriers, to assess their impact across the Broads and their associated dykes.
Chief Executive of Norfolk Wildlife Trust, Pamela Abbott said:
"I think it's really exciting. It has the opportunity to be a really tranformative project. Our visitors will be able to see what we are doing and the effects of the biomanipulation. The biodiversity potential of the Broads is immense and we are hugely grateful to Biffa Award for the funding to enable us to ‘tip the balance’.”
Head of Nature Reserves at Norfolk Wildlife Trust, Kevin Hart said:
“With phosphate concentrations at a 50-year low in Broads water, and nearby Hoveton Great Broad being restored under a separate biomanipulation project, we hope that Tipping the Balance will live up to its name, freeing enough open water in the Bure and Ant Valleys from the impact of high nutrients and algal domination for the entire area to become clear, healthy water as it once was.”
The project will be done alongside partners including the Broads Authority, Natural England, the Environment Agency and ECON Ecological Consultancy. It is funded by Biffa Award’s Partnership Scheme, a multi-million pound environment fund managed by Royal Society of Wildlife Trusts, which uses landfill tax credits donated by Biffa Waste Services.
Gillian French, Head of Grants, said: “Biffa Award is delighted to be able to support Norfolk Wildlife Trust in its work to restore and manage this valuable habitat. This is a long-term investment which will bring real improvements. Organisations across the country are working tirelessly to protect our natural environment, and we are keen to support more worthwhile projects such as this one.”