Bathing water zones of influence (ZOI) are defined as an area where if heavy rainfall occurs may lead to surface water runoff causing a reduction in water quality at a designated bathing water. These Bathing waters are often impacted by either surface water or streams & rivers. Not all bathing waters have zones of influence, very small catchments or run off areas have not been defined. They were originally designed to be presented on PDF maps for use in bathing water profiles as per the bathing water directive 2006/7/EC in 2012 and therefore of low resolution. The polygons were derived from a range of sources from digital elevation models to being manually digitised. They are annual updated with any changes to the designated bathing water inventory. Attribution statement: © Environment Agency copyright and/or database right 2015. All rights reserved.
