Long-term monitoring of the water quality in Loch Leven has been undertaken by the Natural
Environment Research Council since the late 1960s. Over this period, the lake has suffered
serious degradation due to the combined effects of eutrophication, pesticide pollution and
climate change. However, following management intervention aimed at improving the water
quality of the lake, the site has undergone a slow recovery. The recovery trajectory has, at
times, seemed somewhat erratic. This is due to inter-annual variations in the in-lake
processes that regulate the release of legacy phosphorus from the sediments following a
reduction in catchment sources, although climatic variation and changes in biological
interactions have also affected the recovery in the loch.
This report summarises the findings of 40 years of research on Loch Leven and presents
additional data from samples collected between 2008 and 2010. The more recent data are
integrated into the longer term perspective to provide an indication of whether the recovery
of Loch Leven is continuing. The implications of the findings from the Loch Leven Long Term
Monitoring Project, in terms of achieving water quality targets and providing key ecosystem
services, are discussed