Abstract
Urban development modifies the natural hydrologic patterns by producing higher and more rapid peak discharges with
higher runoff volumes. Sustainable Drainage Systems (SuDS) aim at minimizing the impacts on local hydrology by
reducing the amount of impervious surfaces promoting infiltration and disconnecting flow paths to reduce runoff volumes
and peak flows.
Recovering natural hydrology by sustainable stormwater management produces clear benefits in the urban water cycle,
like reduction of combined sewer overflows (CSO), mitigation of flood risk by detaining and reducing stormwater
discharges, and reduction of stormwater inflows into sewer systems, hence reducing the costs and energy consumption in
treating and pumping runoff.
The EU-MED Programme E²STORMED project (improvement of energy efficiency in the water cycle by the use of
innovative storm water management in smart Mediterranean cities, www.e2stormed.eu) has developed a holistic Decision
Support Tool (DST) that includes energy efficiency and environmental criteria in the decision making process for
stormwater management. Within this tool, guidance is provided to estimate the hydraulic performance of drainage
infrastructures, especially SuDS. With this data, economic benefits and energy savings produced by runoff infiltration and
detention are quantified. They include flood protection benefits, aquifer recharge and savings in treating and pumping
runoff. The E²STORMED Decision Support Tool introduces these results in a multi-criteria analysis to support the decision
making process in storm water management.
The paper focuses on the hydraulic features of the DST. The main purpose of the tool is to compare and evaluate different
drainage options for stormwater management, analyzing different drainage system scenarios. Each scenario is defined by
different drainage infrastructures from a catalogue of several types of conventional infrastructures and SuDS. Hydraulic
criteria are based on the estimation of runoff produced, runoff reduction, peak flow reduction and CSO mitigation.
Finally, a case study in Spain is presented to compare two different drainage strategies (conventional vs SuDS). As the
DST results show, hydraulic performance of SuDS provides stormwater management benefits like lower runoff volumes to
be treated.