Riparian buffer hydrology: representing catchment-wide implementation and the influence on flood risk

Linsey McLean, Lindsay Beevers, Mark Wilkinson, Gerry Starrs, Gareth Pender

Thursday 2 july 2015

16:30 - 16:45h at Europe 2 (level 0)

Themes: (T) Flood risk management and adaptation, (ST) Adaptation measures

Parallel session: 13K. Floodrisk - Adaptation

EU and UK legislation advocates a sustainable approach to flood management, which has been a catalyst for further consideration of adopting natural processes and features to reduce flood risk. Riparian buffers are traditionally implemented to address water quality and diffuse pollution issues. Research to date has focused on this function, as well as their hydraulic properties, which can also affect flood risk. Intuitively, hydrological theory would suggest that riparian buffers: increase infiltration, intercept rainfall, enhance evapotranspiration and attenuate surface runoff (as well as several other hydrological functions) however; there is limited research and evidence to support that riparian buffer hydrology can reduce flood risk. Additionally, there is an ongoing debate about the spatial scale of effectiveness, optimal buffer width and event threshold whereby riparian buffers cease being effective. This paper examines: plot scale riparian buffer hydrology using empirical field data; the use of the physically based semi-distributed hydrological model, Soil and Water Assessment Tool (SWAT model); and the approach to incorporating the catchment-wide riparian buffer scenario, which reflects the riparian hydrological behaviour. The Tarland sub-catchment of the River Dee in Aberdeenshire, Scotland, is used as a study site and field data is utilised to establish the hydrological behaviour of riparian buffers to enable adequate representation in SWAT model, where data permits.