Monitoring of micropollutant loads in urban stormwater on city scale - Strategy and realization

Monitoring of micropollutant loads in urban stormwater on city scale - Strategy and realization

In recent years, organic micropollutants have been detected in urban storm runoff in several European studies. As rain water runoff in Berlin and other German and European cities is often discharged untreated in separated sewer systems, urban stormwater is a large potential source of micropollutants affecting receiving surface waters. As a consequence, it is important to know the local extent of the issue to be able to evaluate potential measures. In this study, a one year monitoring programme is conducted in the city of Berlin to estimate yearly loads of micropollutants from urban stormwater entering Berlin surface waters. Five different catchment types typical for Berlin were determined after analysis of GIS data (old building areas <1930, newer building areas >1950, single houses with gardens, roads and commercial areas) and monitoring points were selected fulfilling a number of criteria (including representativeness of catchment type, accessibility, sufficient flow, manhole size). Samples are taken using automatic samplers and a sampling strategy was developed to obtain best possible representative composite samples representing the average concentration of the sampled storm event. Results will then be used with measured flow data to calculate micropollutant loads of individual catchment types. A runoff model for Berlin applied to the individual catchment types and coupled with pollutant concentration relationships will be used to extrapolate results to city scale.