PROJECT DESCRIPTION
BACKGROUND
Although Redgrave and South Lopham fen only covers some 125 ha, it is still the largest of what remains of the calcareous valley fens in England and has long been recognised for its great botanical and entomological significance. It is also a priority habitat type under the Habitats Directive (92/43/EEC). The entire ecology of the site is dependent on a continuous seepage of calcareous ground water. However two relatively recent events have brought about an important hydrological disruption. One was the sinking of an abstraction borehole in the 1960s, the other was the deep dredging of the River Waveney which surrounds the fen on two sides. As a result, the site has been progressively drying out over the 20 years prior to project inception, and had reached the stage where it would have disappeared completely without immediate intervention. Another threat is nutrient enrichment: the catchment contains about 1 100 ha of intensively-managed farmland, and fens need ultra low fertility conditions. Concern for the long-term future of this important site led a consortium of conservation bodies, public authorities and private companies to propose an immediate rescue plan under the LIFE Programme.
OBJECTIVES
The project aims to:
(1) Re-establish, as far as possible, the hydrological conditions which prevailed prior to the opening of the Redgrave public water supply borehole and the over-deepening of the River Waveney; and
(2) Re-establish conditions on the fen that will allow the restoration and re-habilitation of the key fen types once the hydrology has been restored.
The project’s first action will be to relocate the borehole and associated treatment plants. Thereafter, active management work can begin on the river and the fen. By tackling an important and widespread problem this project should act as a valuable demonstration model, the results of which can be made available to a wide audience, both in the UK and in other parts of Europe. It should also foster greater co-ordination between commercial, governmental and non-governmental organizations.
RESULTS
The borehole was relocated – this was the first time in the UK that a borehole was moved for wildlife benefit. Sluice refurbishment, improvement of the river corridor (for example re-grading banks) and establishing embankments to prevent flooding and enrichment of the fen from surface water were all undertaken. However, nutrient enriched water was still getting into parts of the fen, and the deepened Waveney river still appeared to be drying the fen out. The beneficiary acquired 35 ha surrounding the fen to help tackle these problems;
A proposal was made to establish a downstream sluice to maintain water in the fen, but this was not acceptable to local farmers. The project identified some possible mechanisms to resolve these problems, but these would be for implementation after the project;
A management plan was produced for the site;
Innovative scrub removal (76.9 ha) and surface scraping techniques (23.0 ha) were developed and proved effective;
A total of 42 ponds were excavated for the Great Raft spider (Dolomedes plantarius), as the site is one of only three in the UK were this species is recorded;
An area of 15.4 ha was mown first in order to introduce grazing. Combined grazing methods using Tarpan horses were trialed successfully;
40 peizometers were installed to measure water levels;
30 vegetation monitoring plots were established;
2.3 km of improved paths and 6 km of wild paths were laid;
A new fen management option was introduced to the Environmentally Sensitive Area agri-environment scheme. This made the grazing regime economically viable; and
Project publicity included a website, video and leaflets.The borehole was relocated – this was the first time in the UK that a borehole was moved for wildlife benefit. Sluice refurbishment, improvement of the river corridor (for example re-grading banks) and establishing embankments to prevent flooding and enrichment of the fen from surface water were all undertaken. However, nutrient enriched water was still getting into parts of the fen, and the deepened Waveney river still appeared to be drying the fen out. The beneficiary acquired 35 ha surrounding the fen to help tackle these problems;
A proposal was made to establish a downstream sluice to maintain water in the fen, but this was not acceptable to local farmers. The project identified some possible mechanisms to resolve these problems, but these would be for implementation after the project;
A management plan was produced for the site;
Innovative scrub removal (76.9 ha) and surface scraping techniques (23.0 ha) were developed and proved effective;
A total of 42 ponds were excavated for the Great Raft spider (Dolomedes plantarius), as the site is one of only three in the UK were this species is recorded;
An area of 15.4 ha was mown first in order to introduce grazing. Combined grazing methods using Tarpan horses were trialed successfully;
40 peizometers were installed to measure water levels;
30 vegetation monitoring plots were established;
2.3 km of improved paths and 6 km of wild paths were laid;
A new fen management option was introduced to the Environmentally Sensitive Area agri-environment scheme. This made the grazing regime economically viable; and
Project publicity included a website, video and leaflets.