There are many relict weirs and control structures along the river and several reaches where the already modest gradient was removed to maintain a head of water to power waterwheels or to spill water into the meadows. These man-‐made features are part of our industrial and agricultural heritage but can be in conflict with aspirations for a fast-‐flowing, silt-‐free river. 2.5. Ecosystems Services Ecosystems services can broadly be described as the benefits we receive from the natural environment. Unlike the traditional geographic units that have been used to manage society, such as parish, borough and county boundaries, river catchments offer a natural management unit (a hydrological ecosystem) from which to identify the mechanisms via which the natural environment provides benefits to society. We derive an array of ecosystems services from our river catchment landscapes, including: Ø The provision of clean drinking water Ø The disposal of waste water Ø The regulation and attenuation of water e.g. flood water storage in extreme rainfall events Ø Habitats for wildlife Ø Water supply for Industrial abstraction Ø Agriculture Ø Aquaculture & fisheries Ø Shellfisheries Ø Culture and recreation, particularly recreational angling Ø Port activities Ø Power generation However, over the past century our catchment ecosystems and the services they provide have come under increasing pressure from conversion of natural habitats, pollution of land and water, exploitation of terrestrial and freshwater resources, invasive species and climate change. The result is that the provision of the ecosystems services we depend on has been skewed in favour of the production of food, fibre and fuel to the detriment of many other vital services. A healthy water environment is essential in preventing further development of this trend and for sustaining the on-‐going delivery of ecosystems services.