The lake at Llandrindod Wells—a restoration comedy?

Abstract

1. The lake at Llandrindod Wells, Wales, UK, is a typical urban shallow lake. Created in the 19th century for amenity, it has a long history of management for various, often conflicting, purposes. After the 1950s, the once clear water became turbid with phytoplankton, and aquatic plants became very scarce. 2. The most likely reason for this was introduction of common carp, for angling, into a fish community that contained no piscivores. Mobilization of phosphorus from the sediments by activities of the fish led to severe internal phosphorus loading, culminating ultimately in a requirement to close the lake, temporarily in summer, to water contact activities, because of a risk of toxic cyanophyte blooms. 3. The lake-owners decided to restore the lake to greater amenity and conservation value by biomanipulation of the fish community and associated works. The restoration was successful in restoring clear water and plant communities, but because of the nature of the plants reintroduced, there were new problems of dense plant growth. Ownership of the lake then changed and, in a somewhat confused situation, the lake has been returned to a carp fishery. 4. Documents on the history of management of the lake, and available limnological data, are reviewed in relation to a general strategy for lake restoration and general lessons are drawn for future restoration projects. Copyright © 2002 John Wiley & Sons, Ltd.