Project Storm
Conceptual basis of planning wet weather water
protection measures
The official design guidelines for CSOs and CSO tanks for
Switzerland (AfU, 1977) are outdated and do not comply with the current urban
drainage strategy anymore. Thus, a new conceptual planning strategy is to be
developed in accordance with both the Swiss water protection legislation (GSchG,
1991; GSchV, 1998) and the Swiss water pollution control association’s (VSA)
master plan of urban drainage (GEP).
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Mainly due to this reason, the Swiss federal environmental
protection authorities (Buwal) decided to assign the Swiss Federal Insitute for
Environmental Science and Technology (Eawag) to develop a new conceptual basis
for planning wet weather water protection measures. This project covers the
following aims:
• publication of a manual, covering the subject of
wet weather water protection,
• definition of wet weather water quality
standards,
• development of a new procedure for planning protection
measures,
• development of a software
tool in order to support the planning process.
Swiss water protection legislation asks for a receiving water
impact based view, not an emission based. This means, that the planning
procedure has to consider the cause-effect relationship between urban storm
drainage and resulting impacts on the aquatic environment and ecosystems. The
receiving water impact based planning of water protection measures is very
complex because of variability (e.g. rain) and uncertainties in parameters and
model structure. For instance, the exact cause-effect relationship of urban
storm drainage on receiving water ecosystems is very difficult to quantify.
Because of these considerations, a probabilistic planning approach will be
implemented in the new planning procedure for wet weather water
protection.
Project Development
Vladimir Krejci
Luca Rossi
Rolf Fankhauser
Simon Kreikenbaum
Contact
Eawag
Urban Water Management
CH-8600
Duebendorf
Switzerland