The practice of allowing combined sewer overflows (CSOs) into our rivers – including the Devon Avon or Aune – has been going on, relatively unchallenged, for centuries. Originally, CSOs were allowed to prevent flooding of property under extreme weather conditions due to overloaded sewer systems full of rainwater. In these more enlightened times of environmental awareness, what unpolluted baseline should be used for assessing biodiversity? Fortunately, biology has an answer depending upon the differential sensitivity of bottom-dwelling macro-invertebrates to organic pollution. One might argue that South West Water – in their current forward looking consultation on resource management – should be helping to fund more extensive investigation of the impact of their CSOs on biodiversity and how the situation might be improved and assessed.
See file for detail:-