The Netherlands, like the other industrialized countries in the northern
hemisphere, is faced with increas- ing environmental pro blems. Being a
country rich in water - at least in terms of surface area - and
low-lying, problems related to water are as old as the nation itself.
The problems in regard to water quality are becoming more acute and
complicated due to the progressive rise in air and ground pollution.
Glaring examples are the acid rains and contamination of ground-water
resources by toxic, and often illegal, waste dumps. Being a delta
country, the Netherlands is also very vulnerable to pollution from
the-water sources outside the country's national boundaries, i.e. the
rivers Rhine, Meuse and ScheIdt. Not only the national but also the
international authorities are active in developing measures to both
prevent and combat water pollution, and to restore as far as possible
the natural balance or a 'reasonable' water quality. The pollution
abatement programmes are based on ecological theories; accepting
waterbodies as aquatic ecosystems, the authorities concerned try to
influence and lead the progresses in the systems to reach or maintain
the desired ecosystem structure. Suter II (1981) mentioned a number of
reasons why the attempts to use ecosystem theories to assess the impacts
on the environment have been disappointing to date. It is clear that one
of the reasons for the failure is lack of proper knowledge.