This DWA-Guideline includes recommendations how to treat rainwater quantitatively and qualitatively in modified drainage patterns or serperate sewerage systems. It analyzes and structures complexe correlations as follows: - pollution and quantity of rainwater regarding to utilisation and pavement of origin surface, - protection requirement of groundwater, - protection requirement of overland waters, - hence probably necessary rainwater treatment to avoid infiltration and discharge into overland waters. Contrary to ATV-A 128 which regulates treatment of storm sewage, this DWA Guideline recommends treatment of rainwater without mixture with sewage. It contains a simplified ranking system to consider pollution qualitatively and quantitatively of buried and overland water with rainwater from roof areas as well as traffic areas for pedestrians, cyclists and vehicles. This DWA-Guideline addresses to local authorities, duties of wastewater disposal and planer who wish to make basic decisions of urban land-use planning or master plan sewer systems. The Advisory Leaflet contains recommendations on the treatment of stormwater in terms of volume and quality in modified drainage or separated systems. It analyses and structures the following complex backgrounds: pollution and volume of the stormwater depending on usage and cover of the surface of origin; protection requirement of the groundwater; protection requirement of surface waters, derived from that, the required stormwater treatment that may be necessary prior to infiltration or discharge into surface waters. While Standard ATV-A 128E regulates the treatment of combined wastewater, the Advisory Leaflet makes suggestions on how stormwater should be treated without mixing it with wastewater.
It contains a simplified assessment method that allows users to take the load of underground and surface water, originating from stormwater of roof areas and of traffic areas, into account in terms of quality and volume for pedestrians, bicyclists and motor vehicles. The Advisory Leaflet provides municipalities, those obliged to dispose of sewage as well as planners with fundamental considerations regarding urban land-use planning or general drainage planning.