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Advancing disaster risk reduction through the integration of science, design, and policy into eco-engineering and several global resource frames
By the later part of the 21st Century, our planet will be faced with compelling climatic circumstances requiring tradeoffs to maintain viable environmental conditions and standards of living. The prognosis for people near coastlines and waterways is particularly dire without decisive actions that capitalize on shared strengths such as ecosystems. One clear opportunity is the regenerative services and co-benefits of natural infrastructure that reduce the impacts of environmental disasters as magnified by climatic change. Certainly, nature-based solutions are increasingly being viewed as critical actions to reduce societal risk. However, to advance the use of natural infrastructure through eco-engineering, there is a need to clarify the science regarding risk reduction effectiveness, develop agreeable principles, standards, and designs, and grow a demonstration site network responsive to circumstances faced by communities around the globe. In addition, there is a need to consider the legal, policy, and regulatory obstacles and opportunities for natural infrastructure within local to national contexts (i.e., science-based building codes, architectural design criteria, incentive policies, etc.). Ultimately, the integration of science, designs, and policy coupled with installation within several globally recognized resource frames (IWRM, ICZM, etc.) will help establish eco-engineering standards. Supportive coastal, river, and urban examples from around the world are used to illustrate the current state of knowledge, model this integration of science, design, and policy, serve as initial “benchmark site”, and finally help define guiding principles for the emerging field of eco-engineering.
Challenges in developing sustainable sandy strategies
Sandy nourishments are worldwide applied along sandy shores as maintenance strategy and to enhance the values of coastal areas. In this context, there is a challenge in developing competitive sandy strategies that optimally suit local demands and needs. Within the Building with Nature innovation program three pilots projects based on sandy strategies are explored and discussed in this paper. The pilot projects are based on existing concepts reinvented for new environments in which the challenge is to better suit a local context with respect to conventional approaches. This obviously is a design challenge in which the capacity to 1) develop designs with controlled morphodynamics and 2) engineer with vegetation are both critical.
Building with economic nature : market based instruments for risk management to promote spatial adaptation to climate change
Currently water management faces such challenges as high climate adaptation costs, scarcity of land, and low individual flood risk perception. This report reviews pros and cons of economic instruments (e.g. flood insurance, tradable development rights) that can be complementary to the structural defense measures in responding to these 3 challenges.
How ecological engineering can serve in coastal protection
Traditionally, protection of the coastal area from flooding is approached from an engineering perspective. This approach has often resulted in negative or unforeseen impacts on local ecology and is even known to impact surrounding ecosystems on larger scales. In this paper, the utilization of ecosystem engineering species for achieving civil-engineering objectives or the facilitation of multiple use of limited space in coastal protection is focused upon, either by using ecosystem engineering species that trap sediment and damp waves (oyster beds, mussel beds, willow floodplains and marram grass), or by adjusting hard substrates to enhance ecological functioning. Translating desired coastal protection functionality into designs that make use of the capability of appropriate ecosystem engineering species is, however, hampered by lack of a generic framework to decide which ecosystem engineering species or what type of hard-substrate adaptations may be used where and when. In this paper we review successful implementation of ecosystem engineering species in coastal protection for a sandy shore and propose a framework to select the appropriate measures based on the spatial and temporal scale of coastal protection, resulting in a dynamic interaction between engineering and ecology. Modeling and monitoring the bio-physical interactions is needed, as it allows to upscale successful implementations and predict otherwise unforeseen impacts.
Offshore wind farms as potential locations for flat oyster (Ostrea edulis) restoration in the Dutch North Sea
The “Dutch Energy Agreement” motivates governments and industries to invest in renewable energy sources, of which offshore wind energy is one of the solutions to meet the agreed target of 16% of the total energy budget from renewable resources by 2023. An option for the multi-use of wind farms is nature-inclusive building, in which the design and construction of wind farms make use of the potential for co-design with oyster bed restoration. This can support the government’s ambitions, for the Dutch North Sea, to achieve biodiversity goals, restore ecosystem functions, and enhance ecosystem services, including future seafood production. For the recovery of flat oyster (Ostrea edulis) beds, knowledge is required about the conditions under which active restoration of this species in the North Sea can be successfully implemented. This paper gives a framework and presents results to determine suitability of wind farms for flat oyster restoration, and provides recommendations for pilot studies. Our analysis showed that a number of wind farms in the Dutch section of the North Sea are suitable locations for development of flat oyster beds. Combining oyster restoration and oyster culture, as a protein source, is a viable option worth investigating.
Shifting the discharge mindset from harmful to habitat : exploring inventive designs and benefits of underwater discharge structures
A zero discharge seawater desalination approach still appears to be very optimistic, especially when it comes to the large volumes of product water and associated brine (concentrate) that requires appropriate disposal. In addition to this, and although the technology advancements of mining for precious metals from brine show promising potential, it is still a challenge to use a single method to selectively extract valuable minerals from complex brine matrices. These two alternatives, (i) zero discharge and/or (ii) mining for minerals (from brine) may not be the best selections when designing underwater discharge structures (at least for the foreseeable future). With the aim to protect the marine environment, regulations have been set to regulate the brine discharges and defining environmental criteria in the area close to the outfall. It was however noted, that such criteria are often adopted from generic benchmarks and sometimes from unadoptable locations. Robust and in situ research on the effects of the brine effluent on the marine environment is also lacking. Recent surveys, however, suggest that the ecological impact of brine outfalls can be very limited or even result in an improvement of biodiversity and marine abundance on the outfall structure. Such observations suggest that some environmental criteria may be archaic, which may result in needlessly expensive outfall designs. Additionally, the hard substrate that the outfall structure provides appears to be a good habitat for the enhancement of marine growth. We therefore propose, instead of only aiming to minimize impact, also to promote the ecological habitat function by optimizing the design criteria of underwater discharge structures. Our paper presents first guidelines/examples (of shapes and material use e.g., Coating with eco concrete) to promote coral growth, nursery ground for fish, etc. Furthermore, we provide initial ideas for the treatment of the desalination effluent to help the advancement of such marine habitats.
Rich reefs in the North Sea : exploring the possibilities of promoting the establishment of natural reefs and colonisation of artificial hard substrate
This project, carried out on the instructions of the Ministry of Economic Affairs, is a preliminary study aiming to give an overview of possibilities and knowledge gaps pertaining to hard substrate in relation to ecological added value. It intends to provide input for the national policy on “Building with North Sea Nature”, which aims to bolster the conservation and sustainable use of species and habitats native to the Dutch section of the North Sea. As a result of various human activities, past and present, the North Sea is currently severely impoverished, not only in terms of the decline of species, but also in terms of loss of different types of habitat, in particular hard substrate.
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.
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