Development of a GIS-based multi-criteria flood risk assessment tool

Climate change has become a global threat and is putting stress on various sectors, such as
the economy and biodiversity. Because of climate change more events of extreme rainfall are
occurring, which increases the chances of flooding. In the Netherlands, rainfall events cause
water nuisance on local and regional levels. Therefore, cities are preparing themselves to
keep up with climate change by implementing adaptation efforts, such as Green
Infrastructure (GI) alternatives. This thesis will elaborate on both the determination of the
flood risk in urban areas, as well as the effect of GI alternatives on the flood risk. This is
achieved through the development of a flood risk assessment tool (FRAT), that incorporates
the indicators of the urban flood risk and elements included in GI alternatives. The indicators
are included in the framework for flood risk determination (FFRD), which represents the
functioning of an area in relation to the flood risk. The overall index of the framework is the
Flood Risk Level (FRL), which is represented by the categories of runoff and capacity. The
category runoff is further divided into the sub-categories of land cover and geography. The
sub-category land cover consists of the indicators building, vegetation, pavement, and water.
The sub-category geography consists of the indicators elevation and slope. The other
category, capacity, is divided into the indicators groundwater level, sewage system, and soil.
Based on the FFRD the FRAT is developed following a multi-criteria analysis (MCA), in the form
of an Analytical Hierarchy Process (AHP), while using a Geographical Information System (GIS).
The working of the newly developed FRAT was shown in a case study of the city of Tilburg.
The newly developed FRAT provides a methodology for the support of decision-making in
urban planning, in which different aspects can be evaluated based on their contribution to
the FRL. Because the aspects of GI alternatives are also taken into consideration, the FRAT
can also clarify the influence of the adaptations that will be made for the implementation of
GI alternatives. Thereby, the tool contributes to the understanding of the effect of flood risk
when changing urban aspects.