A marine water body or area can be identified as a high natural dispersion area if the discharge of waste water does not adversely affect the environment as a result of morphology, hydrology or specific hydraulic conditions which exist in that area.

When identifying high natural dispersion areas, the Secretary of State shall take into account the risk that the discharged load may be transferred to adjacent areas where it can cause detrimental environmental effects. The Secretary of State shall recognise the presence of sensitive areas outside England and Wales.

The following elements shall be taken into consideration when identifying high natural dispersion areas:

• open bays, estuaries and other coastal waters with a good water exchange and not subject to eutrophication or oxygen depletion or which are considered unlikely to become eutrophic or to develop oxygen depletion due to the discharge of urban waste water.