Barton Broad
What was the problem?
Like all the broads connected to the rivers, by the 1970s Barton was severely affected by decades of nutrient enrichment with nitrates and phosphates, from water running off agricultural land and from the two local sewage treatment works.
Professor Brian Moss of the School of Biological Sciences, University of Liverpool, who has been studying the Broads for decades, described the appearance of the nutrient-rich mud as being like "a great black tongue" on the bed of the broad extending south from where the River Ant flows in. This nutrient overload led to excessive growth of algae and occasional 'blooms' of blue-green algae, in what had been, even in the 1950s and 60s, a lake dominated by water lilies and submerged plants.
The algae, growing unchecked in the nutrient-rich water, shaded out the other water plants, and at the start of the Clear Water 2000 project, the broad appeared murky and lifeless, with a thick layer of mud on the bottom, which restricted boating to the central navigation channel.
From darkness to light - the restoration of Barton Broad (pdf document) [255kb]
The Broads Authority's role
Since it was set up in 1978, the Broads Authority and its partner agencies such as the Environment Agency have funded and carried out extensive research to work out how to restore the Broads waterways.
Restoring water quality is the basis of all the other conservation work in the Broads. We worked closely with Anglian Water who invested in better sewage treatment facilities upstream of the broad. As a result, the quality of the water flowing into the broad has now improved greatly.
Many of the methods used in the project are also suitable for other lakes with the same problems and there is keen interest in the project from researchers all over Europe and from other inland waterway authorities.
Measuring success
In spring 1998, a three year contract was set up for a Broads Research Technician, employed by the Broads Authority and based at the Environment Agency's Broads Restoration Team laboratory at Haddiscoe. The research has continued the monitoring of the water quality of the broad and the lagoon area, concentrating mainly on the effectiveness of the dredging programme, the effects of the biomanipulation on all the water life and the chemistry of the water it lives in, and the re-establishment of reed swamp at the edges of the broad.
Some project facts and figures . . .
- The dredging sucked out at least 50 tonnes of phosphorus from the broad. The phosphorus dredged out represents 20 years' worth of phosphorus loading.
- After dredging there is now 60% less phosphorus release from the sediment.
- There are now 75% fewer algal cells in the area behind the fish barrier.
- The scientists have counted and recorded the species of 300 million algal cells from Barton to date!
- There were around 9 fish per cubic metre behind the barrier before the electro-fishing - that's a density of 90,000 per hectare! Most of these were the Daphnia-eating young roach.
- There are at least 4,000 - 7,000 roach per hectare in the open water of Barton Broad, almost all of them less than one year old. Their favourite food is Daphnia!
- In summer 2000, a tufted duck family successfully reared six chicks in the safety of the enclosure; none was eaten by pike.
- The biomanipulated areas are a haven for all sorts of wildfowl, without boat disturbance. But this means that the wildfowl eat the plants as they begin to regrow, although the plants don’t seem to mind.
