Anne Loes Nillesen

An integrated approach to flood risk management and spatial quality for a Netherlands’ river polder area

Deltas throughout the world are confronted with increasing flood risks. Flood risk can be defined as the product of probability and consequences of flooding (Hall et al. 2003). Flood risk management strategies in effect aim to reduce the probability and/or consequences of flooding events. These strategies evolve as flood risks increase, driven by factors such as subsidence, climate change, population growth and economic development. There is a strong relationship between flood risk management and spatial quality: New or improved flood defence infrastructure can have a significant impact on spatial quality, especially in urbanised deltas with (historic) built environments, such as the Netherlands (Klijn et al. 2013). Because of a growing appreciation of this relationship, spatial quality is increasingly incorporated in the objectives to be achieved in the development of flood risk management strategies. Flood risk management strategies in the Netherlands traditionally focus on reducing the probability of flooding (Klijn, this issue). The country is divided in dike-ring areas, i.e. areas that are protected against flooding from rivers, major lakes and the North Sea, through closed systems of dikes, dunes, dams, barriers and natural high grounds. Mitig Adapt Strateg Glob Change (2015) 20:949–966 DOI 10.1007/s11027-015-9675-7

Rotterdam: A City and a Mainport on the Edge of a Delta

Within Europe, Rotterdam is by far the largest port and supplier of fossil energy sources. City and port have a “sandwich” position in the low lands between a sea with a rising level and rivers with increasing peak discharges. It is certainly no exaggeration to say that sustainability forms a matter of life or death for Rotterdam as a Delta City. The question of a sustainable Rotterdam or not is related to the following issues: (1) water management (preventing hazards; the restoration of the estuary; salinization); (2) urban renewal; (3) the spatial and climate footprint of the ever-growing port and (4) energy transition. Currently all these issues are dealt with largely independently of one another. For a genuinely sustainable future, linkages have to be made between strategies, projects and actors.

Improving the allocation of flood-risk interventions from a spatial quality perspective

This paper describes an integral approach to flood-risk protection and spatial design that allows for an active involvement of landscape architects and urban designers in the allocation of flood-risk interventions within the Dutch Delta. The Dutch Rijnmond–Drechtsteden area is used as a case study to demonstrate how choices regarding the scale and layer of a flood-risk intervention can shift the location of that intervention. A spatial assessment framework is used to test the spatial impact of different flood-risk interventions at different locations, and determine where the intervention is most required from a spatial point of view.