Right Place

Targeting RBZ to key locations may be more cost-effective than universal installation. An option to support strategic targeting of buffer zones may be through the use of remote sensing technology (e.g. LiDAR) to determine Digital Elevation Models (DEM) or their derivatives (e.g. “wetness index”). Digital elevation models can identify morphological features such as slope, aspect, flow, length, contributing areas, drainage divides and channel networks. DEMs can be linked to soil risk factors (related to source and transport) to identify critical “breakthrough” areas of converging flow, where sediment and nutrient rich runoff are most likely to occur. Often, flow models neglect to include soil factors that can greatly inform risk of critical source areas (CSA’s; a combination of delivery and source risks) where RBZ targeting will have the most gains in buffering efficacy. The DiffuseTOOLS project is using this approach to develop maps of Hydrologically Sensitive Areas (HSA; delivery routes and stream interception points) and CSAs. Previously, this approach has indicated that by targeting buffer zones, a reduction in overland flow of sediment and nutrients was achieved with smaller land-area and reduced financial cost; by 66% and 91% over 1 and 5 years respectively, compared to blanket implementation (as per agri-environment schemes).