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The restoration of the fen

Project Summary and Awards

The fen restoration has been a mammoth task, involving a wide range of innovative measures. The total cost of the restoration was approximately £3.4 million.

The restoration has received critical acclaim, with the Project being chosen to demonstrate wetland recovery by the EU LIFE fund, which also awarded 50% of the Project costs. In 1997, the project was the overall UK winner for the Henry Ford European Conservation Award. The East of England Tourist Board highly commended the project and new Visitor Centre in their 'Tourism and the Environment' category for the 'England for Excellence' awards 1998. In March 2000, the project was highly commended for the Chris Binnie Award for Sustainable Water Management (granted by the Chartered Institution of Water and Environmental Management). In October 2001, the most recent accolade has been to win the Eurosite 2001 award for habitat restoration on a Natura 2000 site. Such accreditation helps reinforce that the future of this spectacular reserve now looks very bright indeed.

The borehole

Borehole History

Back in late 1950's, there was an increasing local demand for good quality water in the locality, primarily for housing and local business. The natural supply of pure groundwater in the aquifer below Redgrave and Lopham Fen was seen as an excellent source of water to meet this demand. In 1957, a borehole and pumping station was sited within 30m of the fen, being commissioned in 1959 to remove removed approximately 3600 cubic metres of water on a daily basis from the chalk aquifer below the fen.

Project aim: To re-establish the original fen water regime by moving the borehole

At the start of the restoration project, the search began for a new borehole. It had to provide enough water of the right quality to supply the Company's customers. It had to be near enough to the old site to be economic to build, yet far enough from the Fen and other wetlands to be safe. The search involved enormous scientific investigations. Many candidate sites were drilled and tested; most were rejected. One favourite emerged. It was tested in great detail, including extensive environmental monitoring. It failed because it did not produce sufficient water. A second site was tested, and succeeded.

Project aim: To ensure that the new borehole provides a secure public water supply without damaging nearby wetlands

By far the most important recent restoration success has been the relocation of this borehole 3km southeast of the reserve. The planning, development and construction of the new borehole cost the Project approximately £1.2 million, and has been a significant achievement not only in financial terms, but in the fact that this has been the first time a public water borehole has been relocated on environmental grounds alone.

Borehole relocation and changes seen on the fen

The borehole was shut down in early July 1999. The event was marked with a large ceremony attended by Prof. David Bellamy and set in motion the long-depleted artesian groundwater supply upward to the fen soils. Within a month, significant physical changes were occurring on the fen surface and large increases in water levels were recorded in the 50 dipwells on the reserve. Massive flushing-out of ochreous sediments from the fen soils resulted in the River Waveney appearing 'brick' red for almost 2 months, and then continuously brown ochre-coloured for another 30 months.

The groundwater cleaning-up process has been fascinating. Relating field observation to theory, it is likely that the extreme drop in water levels in the fen soils that had occurred every summer for 4 decades, had resulted in regular deposits of ochre (oxides of iron) precipitating in the fen soils. In early summer 2002, the appearance of ochre in the river ceased. It is believed that the maximum level of groundwater recharge has now been attained, and that the level has settled slightly. It is now expected that only extreme rainfall or drought events will be the determinant factors in producing significant quantities of ochre. To date, the hydrological recovery in the river catchment has responded closely to groundwater modelling undertaken by ENTEC UK as part of the restoration project.

In many respects, the return of the natural artesian groundwater supply has solved the major hydrological problems of the fen. Peat soils now remain significantly wetter during the growing season than before, with tolerable drawdowns in the surface and chalk water levels. The formerly desiccated sedge beds typically have water at, or near fen surface, as opposed to a minimum of 0.5m below fen surface prior to borehole relocation. Old peat cuttings, which exist in their thousands all over the reserve, now resemble small ponds in various stages of ecological succession, many of which will be left to close over with a floating mat of fen vegetation.


The River Waveney

Project aim: To raise water levels in the River Waveney and restore the river habitats

As Redgrave and Lopham Fen is divided by the River Waveney, the river corridor habitat is extremely important within the framework of the reserve.

Sluice Installation

Between the late 1960's and 70's, long before the restoration project began, 2 simple sluices were installed in the River Waveney to help reduce the effects of water loss from the reserve. Although these structures helped maintain higher water levels in the river for some years, they were not ideal in the long term, having little in the way of fine adjustment.

The most significant achievement on the river corridor has been the removal of the old sluices and the installation of 2 fully adjustable sluices on the river. One of the new sluices has been sited in a new location on the river, affording increased protection to the eastern-most region of the reserve. Prior to the restoration Project partnership, this area had no sluice to protect it from rapid drainage of the fen soils. The installation of this new structure would also have been dismissed as unachievable, there being several private landowners potentially being affected by restoration of this section of the river channel. Much work has gone on behind the scenes during the Project negotiating with landowners. The Ramsar and Special Area of Conservation (SAC) designations have significantly helped in raising the international profile of the fen, and its essential requirement for a suitably intact hydrological regime.

Reprofiling the banks of the River Waveney

As part of the restoration project works, sections of the almost vertically-sided river bank have been graded back to an angle of approximately 25 degrees, affording a wider channel with greater marginal interest for wildlife. Material removed from the bank has been incorporated into a discrete flood defence bund, that channels eutrophic winter floodwater downstream, away from the sensitive fen habitats. Other work has been undertaken in autumn 2002, with shallow shelves also being incorporated along sections of the channel between the two river sluices. These recent works have been deliberately undertaken prior to operation of the new river sluice, and will provide immediate additional bankside burrowing habitat for water voles when the river level is restored.

We are monitoring the quality of water that comes off the surrounding agricultural fields so that controls can be adopted in the future. Between them, these measures should cure the problems caused by agricultural intensification in the surrounding catchments.

The fen habitats

Project aim: to re-create the habitat conditions which will allow the most important fen communities to reestablish.

Scrub and Tree Clearance

The restoration project identified approximately 80 hectares of invasive scrub and trees that required complete removal. Over 36 hectares had already developed into mature scrub and young secondary woodland with the remainder being scattered throughout the remaining pockets of open fen vegetation. The scrub removal programme has been completed successfully, with all the targeted dense and scattered scrub felled and removed from the reserve. This was a massive undertaking, particularly considering the extremely awkward wet soils and hazardous topography that had to be to negotiated.

Many hectares of scrub and woodland edge will remain on the fen as a valuable contrasting habitat to the open fen vegetation. Annual scrub clearance now focuses on maintaining the open fen, and preventing rapid reinvasion of young scrub species again, rather than trying to remove all the scrub from the reserve.

Peat Stripping Operations

At the start of the project, Sheffield University measured the fertility of the peat. This was compared to the fertility of peat associated with fen vegetation types we wanted to reestablish As expected, four decades of significant groundwater abstraction from the reserve had resulted in a significant percentage of the surface fen peat becoming highly desiccated, oxidised and very eutrophic. The only restoration option was to strip off the degraded surface layers down to undamaged, saturated peat.

By late 2002, a total of some 26 hectares has been stripped, removing approximately 250,000 tonnes of peat. These areas currently comprise predominantly open water. In all these areas the annual cycle of vegetation growth and dieback will gradually restart the process of fresh peat formation.

Peat Path and Bund Creation

A by-product of many of the peat stripped areas on the reserve has been a number of relatively linear, landscaped peat baulks, comprising the degraded peat. The majority of these have been utilised to form a combination of protective flood banks, or public, livestock or machinery access paths. Due to the volumes of peat arisings, some baulks have remained on site more as visual intrusions than practical solutions. Additional work has been undertaken in 2001 and 2002 to restore several kilometres of degraded access and management paths, utilising material from these features. This has had the combined beneficial effects of removing unattractive strips of peat whilst vastly improving access and management possibilities. The majority of restored paths have had a 4m wide polymer geogrid laid under the surface, affording greater stability, and restricting 'poaching' of path surfaces by livestock, machinery wheels and visitors' feet. The raised paths have also had several pipes laid in at the path base, to prevent ponding of surface water within the open fen beside them, and to prevent wet and structurally-weak areas forming.

Machinery Used

Regular flooding and the soft, uneven terrain means very specialised equipment was required to undertake all the project work. A great deal of time was spent developing innovative yet cost effective machinery, from the digger, through to transporters, tractors and cutting gear. These developments have been made widely available to wetland managers, through site visits, articles in relevant journals and in the press.

More on the diggers and large machinery


A grazing regime has been introduced to maintain the vast expanse of the Fen at low cost - mowing is too slow and expensive. To maximise fen diversity, we graze with Hebridean sheep, Sussex cattle and Tarpan horses.

More on the Tarpans

Fen Raft Spider

To maintain the population of fen raft spider, Essex and Suffolk Water installed an irrigation network to their core breeding pools. This combined with management work on the pools stabilised the population during the restoration work, particularly during the very dry summers in the mid to late 1990's. It is extremely rewarding to report that this irrigation pipe network has not been required since the borehole was relocated in July 1999, as the natural groundwater levels have been recovered.

More on the fen raft spider

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