IMPACT OF WATER TRADING ON FRESHWATER ECOSYSTEMS: A UK RIVER SCENARIO

摘要

Anthropogenic impacts affect freshwater ecosystems around the world. These freshwater ecosystems provide many ecosystem services that are vital to the functioning of global ecosystems and human health. Despite this, in England and Wales alone, around 300 water bodies are at high risk of not achieving good ecological status (GES). Through the aims of the Water Framework Directive (WFD), many initiatives are being taken to get rivers to GES. However this is at a time where the need for water from both human populations and industries is ever increasing. Over-abstraction is a key threat to freshwater ecosystems, and whilst Environmental Flow Indicators (EFI's) and Hands-off-Flows (HOF's) aim to alleviate this threat, abstraction continues from water sources. Water trading is a scheme aimed at allocating abstracted water more fairly amongst stakeholders (Johansson et al., 2002), however the direct effect this has on the natural flow regime and consequently on freshwater ecosystems has not been assessed. This paper draws on findings from habitat models to show how different flow regimes affect three freshwater species: Fish (Salmo Trutta), Macrophytes (Ranunculus) and Benthic-macro invertebrate (Baetis Spp). Results from a water trading model were used to show how these habitats are affected under different trading scenarios. Conclusions are drawn on how water trading on a catchment scale affects these freshwater environments.