ECN site code: L06
ECN monitoring by: UK Centre for Ecology & Hydrology

Loch Leven is the largest, shallow, relatively nutrient-rich, lowland loch in Scotland. It is situated about 35km north of Edinburgh at an altitude of 107m. It has a surface area of 13.3km2 and has a mean depth of 3.9m. The Loch Leven catchment covers 145 km2, consisting mainly of arable crops (38.6%) and improved pasture (31.5%), but also upland moor (11.6%), coniferous woodland (3.8%), heathland (3.5%), rough grazing (3.5%), suburban/rural development (2.2%) and the rest - deciduous woodland, bog, bare ground, inland water - (5.3%). The highest part of the catchment is at 497m.

Loch Leven is particularly renowned for its large numbers of migratory, breeding and overwintering waterfowl and its world famous brown trout fishery. It is a Site for Special Scientific Interest (SSSI), a National Nature Reserve (NNR), a Special Protected Area (SPA) and a Ramsar site. Loch Leven is also a water supply source for downstream paper mills and textile factories. Although the overall quality of the site is good, the loch has suffered from periodic cyanobacterial (‘blue-green algal’) blooms for many years. These have occurred, largely, as a result of substantial amounts of phosphorus entering the loch, combined with a relatively low flushing rate and a favourable light-climate. The blooms have a direct impact on the various users of the loch, on the local economy, and occasionally pose a potential risk to human health. In terms of conservation interest, algal blooms also reduce light penetration into the water, reducing macrophyte (aquatic plant) growth, with associated impacts on macroinvertebrate, fish and the significant bird communities.

The UK Centre for Ecology & Hydrology (UKCEH) and its various predecessor bodies have been monitoring the lake since the mid 1960s and have built up long-term data sets of various biological and chemical parameters. You can read more about UKCEH monitoring and research at Loch Leven on the UKCEH website.