Statistical analysis water quality in Flanders

The Flemish Land Agency aims for a customized implementation of the manure legislation regulations for farmers located in areas where water quality does not meet the standards of the Nitrates Directive. IMDC studied the underlying causes of poor water quality with global statistical analysis for different geospatial aggregation levels of the variables.

The objective of this study was to acquire insight into the causes of the good or bad water quality in certain areas by carrying out a statistically based analysis of available data. The study consisted of 4 parts: 

  • Part 1: Exploration of the available data. The purpose of this section was to define the relevant variables, to build a uniform dataset for the continuation of the study, to describe the necessary transformations and normalizations and to acquire first insights in the data by exploring the data.
  • Part 2: Global statistical analysis of available data in Flanders. The aim of this section was to gain insight in the underlying causes of good or bad water quality by drawing up statistical models that predict the water quality and then analyse the model structure and performance of the models. 
  • Part 3: Targeted statistical analysis of available data. The aim of this section was to increase the understanding of the underlying causes of good or bad water quality by continuing to build on the main conclusions of the global statistical analysis. Causal relationships between predictor and response variables were investigated using a range of algorithms: principal component, multivariate regression, non-parametric causal random forest, multi cross convergent spatial mapping, ....
  • Part 4: Recommendations for the implementation of the research results. The aim of this section was to transfer the results of the statistical analysis to recommendations on measures and instruments that should improve water quality, and to implement the results in an adjusted manure policy.  


  • client: Flanders Environment Agency
  • start date: 2018
  • completion date: 2018