Afweging tussen generieke en regionale eutrofieringsmaatregelen

In order to improve water quality the Netherlands will have to reduce the high levels of nutrients in its surface waters. This report introduces a balancing framework that can be used for deciding upon/between national and/or regional measures. The EU Water Framework Directive (WFD) was adopted on 23 October 2000. The main objectives of this directive are to restore polluted waters to an acceptable status and to provide the assurance that the good status of these waters will be maintained. A major problem facing the Netherlands is the high levels of nutrients in the surface waters. These high nutrient concentrations are the primary causal factors for the transition of clear-water lakes and ditches, which provide habitats for water plants, pike and the stickleback, into turbid, algae- or duckweed-dominated waters. Various measures can be implemented to lower the high levels of nutrients and consequently restore these surface waters; these include the removal of duckweed and/or the introduction of pike into the body of water, the use of phosphate-free dishwasher detergents and/or stricter adaptations of the manure and fertilizer policy. Some of these measures are best implemented at the national level, while others are strongly dependent on the regional situation. Governmental policy is generally determined at the national level, while municipalities, provinces, water boards and/or nature organizations determine 'regional' measures. By order of the Ministry of Housing, Spatial Planning and the Environment (VROM) of the Netherlands, the National Institute for Public Health and Environment (RIVM) has developed a balancing framework aimed at differentiating national and regional measures. In accordance with this framework, measures that reduce the direct emissions from nutrients to soil and water, such as the manure and fertilizer policy or phosphate-free dishwasher detergents - termed 'generic' measures - are best implemented at the national level. In contrast, measures that reduce the indirect loads to the surface waters or limit the ecological effects of the nutrient concentrations, such as the removal of duckweed of the introduction of pike, are usually regarded as being 'regional'. For most measures the balancing framework works well, as has been verified in a test conducted by independent experts.