The Flemish region cannot cope with the guidelines set out in the European Water Framework
Directive for good water quality, mainly due to excess nutrients. Over 80% of the rivers and lakes
exceed the phosphate (P) limit. The P concentrations in surface water fail to decrease despite
reduced P emissions during the last 20 years. We have recently shown that P concentrations in
Flemish waters are mainly affected by internal loading of the sediment, a process that is accelerated
by the specific geophysical conditions of a lowland river system that makes it susceptible to redox
cycling. The objective of this project is to estimate the natural fraction of that process, i.e. the preanthropogenic
concentration range of P in surface water of Flanders. In addition, this project wants
to quantify the role of human development on the current P concentration range. An archaeological
and geophysical approach will be used to infer historic time trends (10,000 y BP-current) in
sediment and surface water P in relation to the past population density and agricultural
development. The historical reconstruction will be complemented with emission modelling and
experiments on internal loading. The expected scientific outcomes is new information on past
population history and the role of human development on regional enrichment of sediments and
waters with P. The expected practical outcome is the provision of tools for the government to make
regional specific nutrient limits.