Stefan Fach


Sustainable stormwater management - infiltration of surface runoff

My homepage provides primarily information on my diploma thesis and Ph.D. thesis. In both projects I was engaged deeply in infiltration of stormwater. Altering of pervious surfaces into impervious surfaces due to urbanization produces an increased surface runoff during rain events. Because of economic and operational matter drainage systems are designed for a specific discharge. This is the reason why heavy rain events cause storm water overflows into receiving water. Thus the receiving water is stressed hydraulically and with pollutants additionally. The objective of a sustainable stormwater management is to adapt the runoff rates of a built up area to the situation of the undeveloped area. The decentral infiltration of surface runoff is an adequate instrument to rehabilitate the water circle in small scale. Because sealing of landscape increases with allocation of new land for development, infiltration of surface runoff become more and more important since beginning of the nineties. Precipitation contains more or less contaminants because of atmospheric pollution. After contact with roofs, yards and roads the pollutant load of surface runoff rises.

I have investigated existing infiltration facilities with regard to deficits in planning, construction and maintenance in my diploma thesis. Objective of my diploma thesis was to highlight the cause for these deficits. Because pollutants in surface runoff can enter into soil and partly into groundwater once infiltrated, I have investigated the risk potential of infiltration facilities for groundwater exemplarily for the heavy metals cadmium, lead, copper and zinc.

Surface runoff should be infiltrated via the activated soil due to the pollutants as far as possible. Often sufficient free space to implement topsoil infiltration facilities, like aerial infiltration or infiltration swales does not exist in Germany. Additionally road space has a somewhat high ratio on urban areas. Therefore the transformation of impervious surfaces into pervious surfaces is suited for road space especially. Consequently I have investigated the hydraulic capacity and pollutant retention capacity of different selected permeable pavements in my Ph.D. thesis.