Environmental quality standards in the EC-water framework directive: consequences for water pollution control for point sources

The "combined approach" in the new EC-Water Framework Directive
(WFD) consisting of environmental quality standards in addition
to emission limit values promises improvements in the quality
characteristics of surface waters. However, the specification of
where in the water body the environmental quality standards
apply is missing in the WFD. This omission will limit its
administrative implementation. A clear mixing zone regulation is
needed so that the quality objectives of the WFD are not
jeopardized. This need is demonstrated using the examples
of point source discharges into rivers and coastal waters,
respectively. Furthermore, water authorities will have to make
increased use of predictive modeling techniques for the
implementation of the "combined approach".

Key words: water pollution control, surface waters, pollutants,
water framework directive, effluents, mixing zone, water quality
models