Pressure layer combines all human activities that cause changes to hydrological conditions.

The human activities were presented as point data which were given spatial extents (given below). The pressure value was given as the proportion of the grid cell under the pressure.

The following human activities were combined into the changes to hydrological conditions layer;

- Hydropower dams (a 1km2 grid cell in the river estuary was selected)

- Water course modification (1 km)

- Wind turbines (operational, 0.3 km, linear decline)

- Oil platforms (0.5 km, linear decline)

The human activity datasets were first processed separately covering the whole Baltic Sea and then summed together and overlapping areas were dissolved to remove double counting. Attenuation gradients are assigned to each layer as described above. Area effected decreases when distance from avtivity increases. Layer was normalized.