Trees & Plants
Riverside and floodplain woodlands can play a vital role in water management within the catchment. They can reduce diffuse pollution from intensive land-use by creating a rough buffer zone that intercepts and filters sediment and nutrient rich runoff before it reaches watercourse. The planting of specialist trees such as alder (Alnus glutinosa) and willows (Salix sps.) help to bind together the river banks reducing erosion as well as any exposed roots providing shelter for fish and holt sites for otters. Mature river bank trees also provide woody debris into the river system in the form of large branches and whole trees. Woody debris is an important part of the river ecosystem as it provides shade and shelter for fish as well as habitat for many invertebrates.
With the potential increase in temperatures as a result of climate change, river temperature may reach over 22oC more regularly. If rivers reach this temperature for extended period of time it can be lethal to fish. The shade provided by riparian trees is also important for moderating stream temperatures. Floodplain woodland can also play a role in flood risk management as it roughens the floodplain and forces flood waters into a more sinuous route, slowing it down and allowing suspended sediment to drop out before it reaches the river.