Remediation

Those responsible for the Broads decided that a programme of works to rectify the situation needed to be carried out. There would be four parts to the process, which would involve a substantial reduction in the amount of phosphorus discharged into the river system, a similar reduction in the amount of nitrogen entering the waterways, the removal of large volumes of sediment containing these chemicals from the Broad, and some bio-manipulation of the water.^[15]

Anglian Water operated two main sewage treatment works that affected Barton Broad, at Stalham and North Walsham. At Stalham they installed tertiary treatment in 1977, and a phosphate-stripping plant in 1982, to remove phosphorus from the treated effluent. At North Walsham, the effluent was diverted away from the river in 1980, and carried by pipeline to be discharged into the North Sea. This resulted in a step change in the levels of phosphorus found in the water.^[16][9][17] To reduce nitrogen levels, local farmers were given advice about how to use chemicals more responsibly through an education programme.^[16] Responsibility for the Broads changed in 1988, when they became a National Park, and the Broads Authority was set up in 1989 to manage the park.^[9] The cost of removing huge volumes of contaminated sludge was significant, but an application was made to the National Lottery's Millennium Commission, as the restoration of wetland habitat seems a good fit to the requirements of that fund. The scheme was called the Barton Broad Clear Water 2000 project, and the bid was successful when £1.2 million was awarded to the Broads Authority. This was supplemented by £200,000 from the Soap and Detergent Industry Association, and £1.5 million from the Broads Navigation Committee.^[16]

A series of lagoons were created on nearby agricultural land, and a suction dredger was used to pump sludge from the bottom of the Broad through a floating pipeline to the lagoons. The volume of sludge would gradually reduce to about one third of its size through drying and shrinkage. The lagoons covered 52 acres (21 ha), and eventually held some 340,000 cubic yards (260,000 m³) of silt.^[18] This operation started in November 1995 and was completed in August 2000. During this period, Anglian Water installed DynaSand filters at Stalham sewage treatment works, to further reduce levels of phosphorus.^[9] Once the sludge had dried out, it was covered with the original top soil from the site, and the land was returned to agriculture.^[19]

The fourth stage used bio-manipulation, a process developed by the Broads Authority and the Environment Agency. This uses daphnia, commonly known as water fleas, which naturally filter water and remove bacteria and algae from it. However, they are usually eaten by small fish at a faster rate than they can remove the algae. To overcome this problem, pike and perch were introduced to the Broad, and significantly reduced the numbers of small fish, allowing the daphnia to thrive. This process could not be applied to the whole lake, and so controlled areas were created, separated from the body of the Broad by butyl rubber skirts, attached to a floation collar at the top and a weighted collar at the bottom to act as a seal onto the bed of the lake. Gauze filters at intervals along the skirts allowed water to pass between controlled and non-controlled areas, but prevented the passage of fish. Pleasure Island was reconstructed using gabions filled with stone pebbles to rebuild the edge of the island, which were covered in coir matting planted with reed-swamp flowers. The surface of the island was built up with dredgings topped with peat, and planted with wild flowers.^[20]

There is public access to the Barton Broad reserve. The Millennium Commission grant was conditional on public access being improved, and a number of boardwalks were created to allow pedestrians to view and enjoy the broad and nature reserve. The Clear Water 2000 project also included funding for an electric boat and charging shed, but by the time it was purchased, the design had changed a little, and the boat had a roof covered in solar cells to recharge the batteries. The boat was named Ra, and the facilities provided for it on shore were fully compliant with the access for all legislation, enabling wheelchair users to use them and to access the boat. A second boat, the Electric Eel, offered trips along the narrow channels at the edge of the Broad, and canoes can be used to investigate the really narrow connecting waterways. Norfolk Wherries are again able to enter the Broad because of its increased depth, and it is possible to hire one, including a skipper and a cook for a leisurely cruise.^[21] Both Ra and Electric Eel have since moved to other locations.