The pressure layer was created using three different datasets converted to the EEA 10 km grid:

1. Urban agglomerations reported under the Urban Waste Water Treatment Directive (UWWTD)

2. EMODnet dataset of ports with passenger information

3. Intestinal enterococci and Escherichia coli at bathing sites as measured under the Bathing Waters Directive reporting obligations.

Urban agglomerations (reported under UWWTD) laying no further than 5 km from the coast were identified and compiled in a common layer. Only agglomerations with more than 5% untreated waste were selected. The information of load (PE) generated by specific agglomerations was kept. Pressure data was extrapolated to the neighbouring cells using 2 buffer belts (6 km-30% reduction) and 12 km-60% reduction.

All ports (EMODnet) lying on the sea coast were selected. Information on number of passengers (annual average 2006-2016) was also obtained, which can be used as proxy for pressure intensity. Pressure data was extrapolated to the neighbouring cells using buffer belts (6 km-30% reduction) and 12 km-60% reduction. More information on https://www.emodnet.eu/geonetwork/emodnet/spa/catalog.search?node=emodnet#/metadata/c0c12986-4373-4cef-a1a4-75db11a4eafd.

Intestinal enterococci and Escherichia coli data at bathing sites (as measured under the Bathing Water Directive reporting obligation, average 2008-2016) was extrapolated to the neighbouring cells using 5 km buffer belt (50% reduction).

The three datasets were classified into quantiles (with the values 0.25/0.5/0.75/1.00 representing the quantiles, and 1.00 being the highest pathogen pressure) and then combined into a single pressure layer. Where the datasets overlapped, the cell was assigned the largest (maximum) value.