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A framework to include the (inter)dependencies of Disaster Risk Reduction measures in coastal risk assessment
Effective coastal risk management often involves the selection and appraisal of Disaster Risk Reduction (DRR) measures. Such measures, however, are rarely implemented in isolation and their (inter)dependencies need to be considered to assess the overall contribution to risk reduction. This paper presents a framework that utilises a pathway-based approach to consider such (inter)dependencies. The framework identifies measures that have the potential to directly influence risk reduction (primary measures) at the individual/household level and how these relate to the implementation of other measures (non-primary). These two types of measures are linked using intermediate pathway factors, which aggregate to the effective uptake and/or operation of primary measure(s) and subsequently represent the direct influence on risk reduction when included in a risk assessment. The approach is demonstrated utilising two coastal risk examples. The case of Varna Bay, Bulgaria highlights a pathway, which explores how developing a coastal Early Warning System (EWS), can enable assets to be moved and saved prior to an event. The Praia de Faro, Portuguese application provides an example of how local risk awareness meetings can support the uptake of property raising to protect against erosion. Past experience, poor trust in authorities, house type/feasibility, transient population and strong community networks are identified as key influencing variables across both cases. The process of considering the (inter)dependencies between measures has potential to lead to improved decisionmaking and strategy building. The framework developed is flexible in nature and can be applied in many different situations; however, it is one step towards accounting for these (inter)dependencies at the individual/household level. Ex-ante or ex-post survey data, expert judgement and literature have been used to estimate these factors. However, in many cases this good quality data is not available, and is something that national level monitoring strategies, along with the research community, must address.
The usability of the sand motor concept
This report describes the usability of the Sand Motor concept for managing the Dutch coast as an alternative to regular sand nourishments. The evaluation of the usability is based on experience with the Sand Motor pilot project before, during and after the construction in 2011 and by making an inventory of the functions and values along the Dutch coast in the present situation and the coming decades.
Beneficial use of dredged sediment to enhance salt marsh development by applying a ‘Mud Motor’
We test an innovative approach to beneficially re-use dredged sediment to enhance salt marsh development. A Mud Motor is a dredged sediment disposal in the form of a semi-continuous source of mud in a shallow tidal channel allowing natural processes to disperse the sediment to nearby mudflats and salt marshes. We describe the various steps in the design of a Mud Motor pilot: numerical simulations with a sediment transport model to explore suitable disposal locations, a tracer experiment to measure the transport fate of disposed mud, assessment of the legal requirements, and detailing the planning and technical feasibility. An extensive monitoring and research programme was designed to measure sediment transport rates and the response of intertidal mudflats and salt marshes to an increased sediment load. Measurements include the sediment transport in the tidal channel and on the shallow mudflats, the vertical accretion of intertidal mudflats and salt marsh, and the salt marsh vegetation cover and composition. In the Mud Motor pilot a total of 470,516m3 of fine grained sediment (D50 of ∼10 μm) was disposed over two winter seasons, with an average of 22 sediment disposals per week of operation. Ship-based measurements revealed a periodic vertical salinity stratification that is inverted compared to a classical estuary and that is working against the asymmetric flood-dominated transport direction. Field measurements on the intertidal mudflats showed that the functioning of the Mud Motor, i.e. the successful increased mud transport toward the salt marsh, is significantly dependent on wind and wave forcing. Accretion measurements showed relatively large changes in surface elevation due to deposition and erosion of layers of watery mud with a thickness of up to 10 cm on a time scale of days. The measurements indicate notably higher sediment dynamics during periods of Mud Motor disposal. The salt marsh demonstrated significant vertical accretion though this has not yet led to horizontal expansion because there was more hydrodynamic stress than foreseen. In carrying out the pilot we learned that the feasibility of a Mud Motor depends on an assessment of additional travel time for the dredger, the effectiveness on salt marsh growth, reduced dredging volumes in a port, and many other practical issues. Our improved understanding on the transport processes in the channel and on the mudflats and salt marsh yields design lessons and guiding principles for future applications of sediment management in salt marsh development that include a Mud Motor approach.
Annual review Deltares 2012
Adaptive water management for delta regions : towards GREEN Water Defense in East Asia
GREEN Water Defense is an innovation to traditional ways of flood protection. It uses ecosystem services to mitigate the flood hazard. The report describes best practices from the Netherlands, the USA and other OECD countries The report also identified good opportunities for applying the concept in the Mekong Delta, Vietnam and the Jakarta metropolitan area, Indonesia.
Annual review Deltares 2011
A framework for sandy strategy development, with a quick scan for (co-)financing potential
The Sand Motor is a partly emerged mega-nourishment at the Delfland coast in the Netherlands. It is an example of a Building with Nature (BwN) solution using natural processes to fulfil multi-functional purposes in coastal management, such as coastal protection, beach recreation and nature development. EcoShape wishes to explore the opportunities for sandy strategies like the sand motor in an international context. To this end, a framework for the development of sandy strategies is developed by a consortium of Deltares, Royal Haskoning DHV and Witteveen+Bos. This framework aims to assist the BwN community to quickly assess whether sandy strategies are feasible and beneficial for projects both in the Netherlands and abroad. The framework consists of five main steps to assess the feasibility of a project. It starts with the context and scope of the project at hand, followed by a system analysis, design and evaluation of strategies and, finally, an assessment of the (co-)financing potential. The framework explicitly accounts for (the capturing of potential) benefits resulting from the strategies from the early stages of the design process in order to increase the potential for (co-)financing for their implementation. This report presents the framework that has been developed, including guidelines and tools for its application in practice.
Ecosystem services of the groundwater and the subsurface : filling the knowledge gap
In densely populated areas, the use of groundwater and the subsurface for functions such as groundwater extraction, aquifer thermal energy storage and infrastructure is increasing. This results in a need for subsurface spatial planning and careful consideration of the use of groundwater for several (economic) activities. Since 2013, in the Netherlands special attention is given to ecosystem services (ES) of the groundwater and subsurface in order to assess how human activities make use of ES and influence ES. A technical assessment framework for the sustainable use of the groundwater and subsurface was developed based on the ES concept. In this paper, the goals of the framework are described, followed by the identified eleven ES and the thirty-one human activities influencing the ES and the relations between both. An example of elements in the framework is presented and the practical application of ES in policy is described.
Building the Netherlands climate proof : urban areas : a contribution to the study “Opportunities for climate adaptation in the Netherlands” of the Netherlands Environmental Assessment Agency
Vulnerability analysis of Dutch urban areas for flooding, drought and heat stress. Adaptive capacity and cost-efficient adaptation measures. Policy development.
R&D annual report Deltares 2010
One of the Deltares aims is to make Research and Development results more accessible to the public and the private sector. The R&D Highlights report is one step towards that goal. The chapters of the Highlights report follow the structure of the five social issues that are central to the Deltares mission.