What is the problem with the lakes?

The lakes in the greater Windermere catchment are key features of this iconic landscape. Many are designated as nature conservation sites for their special wildlife habitats and are home to some rare species of plants and animals. However over the years human activity has had a detrimental impact, and the quality of the lakes have suffered a decline.

The good news is that many of these unwanted changes can be reversed, and there are now a lot of positive projects underway to tackle the issues.  We need to build on this good work and continue to promote the importance of restoring our lakes.

Nutrient enrichment

Nutrient enrichment occurs when additional plant nutrients (phosphates) enter the water and alter the ecology of the lake. It can stimulate excessive plant growth and dense blooms of microscopic algae. These prevent sunlight reaching down through the water and this limits the growth of more favourable aquatic plants such as lilies. When the algae die off, the deeper water becomes deoxygenated, forcing the fish up from the deeper cooler water into the warmer surface waters. Blooms of blue-green algae in particular are a specific hazard as they are potentially toxic.

Phosphates can enter the water through a variety of sources, including sewage discharges, agriculture, soil erosion, and even from too many geese grazing the lakeshore.

Invasive non-native species

Plants such as Himalayan Balsam can take over and dominate lakeshore and riverbank habitats. Volunteer groups are working to control its spread by hand-pulling the shallow-rooted plants. Other plants such as New Zealand Pygmy Weed (Crassula helmsii), once introduced can flourish and form dense mats. Prevention is better than control – so please wash nets and boats before taking them to a new water.

Sedimentation

The input of sediments into lakes is a natural process – but the rate of deposition has accelerated. Excessive silts can smother fish spawning grounds and affects plants and animals. Accelerated soil erosion can occur when the protective vegetation is reduced by intense livestock grazing, or from exposed footpaths.

Loss of shoreline habitats

Many of the lakes are recognised for their natural shoreline vegetation, such as wet woodland, reedbeds, and aquatic plants (macrophytes). However, human disturbance and poor water quality have affected these habitats, impacting on the richness of the landscape and wildlife.