Optimization of planning, operation and maintenance of selected facilities for stormwater infiltration

Abstract

Sealing of urban areas causes an increased surface runoff during extreme rain events, which is discharged into receiving water in combined sewer systems at least partly or in separate sewer systems directly. Due to the discharge the receiving water is stressed hydraulically and by the pollutants in the runoff additionally. The objective of a sustainable water management is to adjust the runoff rates from urban areas to the situation before urbanization. The decentralized stormwater infiltration is a suited instrument to close or restore the water circle in small scale. Legal basis for the stormwater infiltration in the state North Rhine-Westphalia is its water directive. There is defined that stormwater runoff from real estates built up after 1st January in 1996 has to be infiltrated or discharged into a near located receiving water. Due to legal regulations, an altered environmental awareness and economical aspects stormwater infiltration is more and more applied. Nevertheless, in many places infiltration facilities showed failings with regard to construction and maintenance, which conflict with a proper operation. Because conservation of soil and groundwater has to be ultimate objective, the objective of the diploma thesis is to point out potential failures of existing facilities and to find out the reasons for these failures. Additionally, the risk potential of infiltration facilities for groundwater pollution by heavy metals contained in the runoff is investigated and assessed.