Integrated modelling of Priority Pollutants in stormwater systems

The increasing focus on urban diffuse sources of Priority Pollutants (PPs) has highlighted stormwater as an important contributor to contamination of natural water bodies. This study presents an example of an integrated model developed to be able to quantify PP loads discharged by stormwater systems.

The integrated model includes three submodels that simulate (a) stormwater pollutant sources in the catchments, (b) runoff quality and quantity and (c) stormwater treatment. These submodels employ all the generic available information that can be retrieved without extensive on-site data collection campaigns.

Given the general lack of data regarding stormwater PPs and the inherent uncertainty of stormwater quality models, the Generalized Likelihood Uncertainty Estimation (GLUE) technique was applied to estimate the results’ uncertainty. The integrated model was used to estimate the total suspended solids (TSS) and copper (Cu) loads discharged from an industrial/residential catchment in Albertslund (Denmark).

The results of the runoff estimation were affected by a high level of uncertainty, which was consequently transferred to the other submodels. The estimation of the model uncertainty and its inclusion in the results enables a wider application of this model and provides a tool for assessing PPs pollution reduction strategies.