Nature-based approaches to flood risk management are increasing in popularity. Evidence for the effectiveness at the catchment scale of such spatially distributed upstream measures is inconclusive. However, it also remains an open question whether, under certain conditions, the individual impacts of a collection of flood mitigation interventions could combine to produce a detrimental effect on runoff response. A modelling framework is presented for evaluation of the impacts of hillslope and in-channel natural flood management interventions. It couples an existing semidistributed hydrological model with a new, spatially explicit, hydraulic channel network routing model. The model is applied to assess a potential flood mitigation scheme in an agricultural catchment in North Yorkshire, United Kingdom, comprising various configurations of a single variety of in-channel feature. The hydrological model is used to generate subsurface and surface fluxes for a flood event in 2012. The network routing model is then applied to evaluate the response to the addition of up to 59 features. Additional channel and floodplain storage of approximately 70,000m3 is seen with a reduction of around 11% in peak discharge. Although this might be sufficient to reduce flooding in moderate events, it is inadequate to prevent flooding in the double-peaked storm of the magnitude that caused damage within the catchment in 2012. Some strategies using features specific to this catchment are suggested in order to improve the attenuation that could be achieved by applying a nature-based approach.
NbS Target: Disaster Risk Reduction
Disaster risk reduction
Wetlands have many important functions. To a wide range of wildlife species, they offer critically important habitats. They also act to mitigate flooding, regulate micro and macro climate changes, degrade pollutants and control erosion etc. Wetland benefits are these functions, which provide direct, indirect, and non-use values to humans. In this study, field soil data are used to calculate the flood mitigation benefits of wetland soils within the Momoge National Nature Reserve, Jilin Province, the People’s Republic of China. Calculations are based upon environmental economic assessment methods and GIS techniques. The estimated flood mitigation capacity of wetland soils within the Momoge Reserve was 7.15 × 104 m3/hm2/yr. This translated into an economic benefit of 5700 $/hm2/yr due to flood mitigation. Spatial differences in the flood mitigation ability of soils were observed across the Momoge wetlands. Benefits associated with flood mitigation were highest within the middle reaches of the Momoge wetlands and least in the East. This quantitative analysis of flood mitigation benefit, with its investigation of wetland soils, will be a useful reference both for the assessment of wetland values in the local region and also for the greater understanding wetland function and value assessment methods.
Climate change is increasing the threat of erosion and flooding along coastlines globally. Engineering solutions (e.g. seawalls and breakwaters) in response to protecting coastal communities and associated infrastructure are increasingly becoming economically and ecologically unsustainable. This has led to recommendations to create or restore natural habitats, such as sand dunes, saltmarsh, mangroves, seagrass and kelp beds, and coral and shellfish reefs, to provide coastal protection in place of (or to complement) artificial structures. Coastal managers are frequently faced with the problem of an eroding coastline, which requires a decision on what mitigation options are most appropriate to implement. A barrier to uptake of nature-based coastal defence is stringent evaluation of the effectiveness in comparison to artificial protection structures. Here, we assess the current evidence for the efficacy of nature-based versus artificial coastal protection and discuss future research needs. Future projects should evaluate habitats created or restored for coastal defence for cost-effectiveness in comparison to an artificial structure under the same environmental conditions. Cost-benefit analyses should take into consideration all ecosystem services provided by nature-based or artificial structures in addition to coastal protection. Interdisciplinary research among scientists, coastal managers and engineers are required to facilitate the experimental trials needed to test the value of these shoreline protection schemes, in order to support their use as alternatives to artificial structures. This research needs to happen now as our rapidly changing climate requires new and innovative solutions to reduce the vulnerability of coastal communities to an increasingly uncertain future.
This paper analyzes the vicious spiral between climate change impacts, ecosystem degradation and increased risk of climate-related disasters; secondly, it defines the central role of ecosystem management in climate change adaptation and disaster risk reduction and their multifaceted linkages; and thirdly, it assesses the challenges for enhanced ecosystem management for climate change adaptation and disaster risk reduction. Given the increasing importance of ecosystem services and management in adapting and responding to climate change impacts and associated disaster risks, the paper concludes that political commitment at the highest level is urgently needed if ecosystem management is to have the adequate weight it deserves in the post-2012 climate change agreement. It is further recommended that adequate financial, technological and knowledge resources be allocated for integrating ecosystem management in the climate change and disaster risk reduction portfolios, including within national policy-setting, capacity building, planning and practices, particularly in developing countries vulnerable to climate change impacts and increased risks of climate-related disasters
Given the unfortunate, frequent occurrence of droughts, practical actions are ever more critical to ensure achieving food security in this region [Africa]. Understanding what has previously worked can provide a guiding vision as we proactively address the current crisis. Food security and human security are inextricably linked, and innovative initiatives are needed to create opportunities to face continental challenges regarding future food security requirements. Sustainable food security strategies must thus, among others, develop new opportunities, increase productivity in agriculture, and assist in the development of domestic markets that can withstand international economic volatility. Investment in EbA is one of the most important keys to job creation opportunities that simultaneously contribute to poverty eradication and to sustainable long-term food security. Such investments will improve the competitiveness of domestic production, increase farmers’ profits, and make food more affordable for the poor. Creative strategies supported by dynamic leadership and management are the only way that Africa will be able to achieve the envisaged food-secure society in which its population does not experience fear of want. With proper planning, transparent resource management, innovative food security policies, and integrative agriculture inputs and outputs, it is not too late to turn the Africa’s food crisis to the benefit of local communities.
As exposure to coastal hazards increases there is growing interest in nature-based solutions for risk reduction. This study uses high-resolution flood and loss models to quantify the impacts of coastal wetlands in the northeastern USA on (i) regional flood damages by Hurricane Sandy and (ii) local annual flood losses in Barnegat Bay in Ocean County, New Jersey. Using an extensive database of property exposure, the regional study shows that wetlands avoided $625 Million in direct flood damages during Hurricane Sandy. The local study combines these models with a database of synthetic storms in Ocean County and estimates a 16% average reduction in annual flood losses by salt marshes with higher reductions at lower elevations. Together, the studies quantify the risk reduction ecosystem services of marsh wetlands. Measuring these benefits in collaboration with the risk modelling industry is crucial for assessing risk accurately and, where appropriate, aligning conservation and risk reduction goals.
Communities worldwide are increasingly affected by natural hazards such as floods, droughts, wildfires and storm-waves. However, the causes of these increases remain underexplored, often attributed to climate changes or changes in the patterns of human exposure. This paper aims to quantify the effect of climate change, as well as land cover change, on a suite of natural hazards. Changes to four natural hazards (floods, droughts, wildfires and storm-waves) were investigated through scenario-based models using land cover and climate change drivers as inputs. Findings showed that human-induced land cover changes are likely to increase natural hazards, in some cases quite substantially. Of the drivers explored, the uncontrolled spread of invasive alien trees was estimated to halve the monthly flows experienced during extremely dry periods, and also to double fire intensities. Changes to plantation forestry management shifted the 1:100 year flood event to a 1:80 year return period in the most extreme scenario. Severe 1:100 year storm-waves were estimated to occur on an annual basis with only modest human-induced coastal hardening, predominantly from removal of coastal foredunes and infrastructure development. This study suggests that through appropriate land use management (e.g. clearing invasive alien trees, re-vegetating clear-felled forests, and restoring coastal foredunes), it would be possible to reduce the impacts of natural hazards to a large degree. It also highlights the value of intact and well-managed landscapes and their role in reducing the probabilities and impacts of extreme climate events.
The development of ecological networks could enhance the ability of species to disperse across fragmented landscapes and could mitigate against the negative impacts of climate change. The development of such networks will require widespread ecological restoration at the landscape scale, which is likely to be costly. However, little information is available regarding the cost-effectiveness of restoration approaches. 2. We address this knowledge gap by examining the potential impact of landscape-scale habitat restoration on the value of multiple ecosystem services across the catchment of the River Frome in Dorset, England. This was achieved by mapping the market value of four ecosystem services (carbon storage, crops, livestock and timber) under three different restoration scenarios, estimating restoration costs, and calculating net benefits. 3. The non-market value of additional services (cultural, aesthetic and recreational value) was elicited from local stakeholders using an online survey tool. Flood risk was assessed using a scoring approach. Spatial Multi-Criteria Analysis (MCA) was conducted, incorporating both market and non-market values, to evaluate the relative benefits of restoration scenarios. These were compared with impacts of restoration on biodiversity value. 4. Multi-Criteria Analysis results consistently ranked restoration scenarios above a non-restoration comparator, reflecting the increased provision of multiple ecosystem services. Restoration scenarios also provided benefits to biodiversity, in terms of increased species richness and habitat connectivity. However, restoration costs consistently exceeded the market value of ecosystem services. 5. Synthesis and applications. Establishment of ecological networks through ecological restoration is unlikely to deliver net economic benefits in landscapes dominated by agricultural land use. This reflects the high costs of ecological restoration in such landscapes. The cost-effectiveness of ecological networks will depend on how the benefits provided to people are valued, and on how the value of non-market benefits are weighted against the costs of reduced agricultural and timber production. Future plans for ecological restoration should incorporate local stakeholder values, to ensure that benefits to people are maximised.
The contribution of seagrasses to coastal protection is examined through the review of the most relevant existing knowledge. Seagrasses are the largest submerged aquatic vegetation ecosystem protected in Europe and it is worth examining their contribution to coastal protection. The review performed highlights incident energy flux, density, standing biomass and plant stiffness as the main physical and biological factors influencing the efficiency of the protection provided by seagrasses. The main conclusion achieved is that seagrass meadows cannot protect shorelines in every location and/or scenario. The optimal conditions for enhancing the protection supplied might be achieved in shallow waters and low wave energy environments, with high interaction surface, at the vertical and horizontal dimension, between water flow and seagrasses. Likewise, the most favorable protection might be provided by large, long living and slow growing seagrass species, with biomass being largely independent of seasonal fluctuations and with the maximum standing biomass reached under the highest hydrodynamic forcings. It is shown that seawater warming, increasing storms and sea level rise, together with the increasing population and anthropogenic threats in the coastal area may lead to rates of change too fast to allow seagrasses to adapt and keep their coastal defense service. Finally, to amend the decline of seagrasses and consequent coastal protection loss, different artificial and natural adaptation measures are provided.
Purpose – The purpose of this paper is to assess the potential for pastoral communities inhabiting Kenyan Masailand to adapt to climate change using conservancies and payments for ecosystem services. Design/methodology/approach – Multiple methods and data sources were used, comprising: a socio-economic survey of 295 households; informal interviews with pastoralists, conservancy managers, and tourism investors; focus group discussions; a stakeholder workshop. Monthly rainfall data was used to analyse drought frequency and intensity. A framework of the interactions between pastoralists’ drought coping and risk mitigation strategies and the conservancy effects was developed, and used to qualitatively assess some interactions across the three study sites. Changes in household livestock holdings and sources of cash income are calculated in relation to the 2008-09 drought. Findings – The frequency and intensity of droughts are increasing but are localised across the three study sites. The proportion of households with per capita livestock holdings below the 4.5 TLU poverty vulnerability threshold increased by 34 per cent in Kitengela and 5 per cent in the Mara site, mainly due to the drought in 2008-2009. Payment for ecosystem services was found to buffer households from fluctuating livestock income, but also generates synergies and/or trade-offs depending on land use restrictions. Originality/value – The contribution of conservancies to drought coping and risk mitigation strategies of pastoralists is analyzed as a basis for evaluating the potential for ecosystem-based adaptation.
Rajasthan presents evidence for the existence of one of the most advanced examples of ancient mining and accompanied deforestation to be found anywhere in the world. Mining continues to be an important economic activity contributing to 2% of the State Domestic Product and providing at least a 1.76 % share to the regular employment pool in Rajasthan. However, economic benefits of mineral extraction also accompany environmental, economic and social costs. Mine waste dumps and mined out areas viewed simply as the legacies of past may appear overwhelming environmental hazards presenting ugly picture of cultural landscape. However, mine wastes can be transformed into an opportunity for learning, adaptation and productivity enhancement for sustainable livelihoods through ecological restoration. Here we propose a strategy for mine spoil restoration aimed at creating a multifunctional ecosystem in mine waste dumps. We suggest that dredging and sediment removal from traditional tanks and ponds can potentially be used to prepare the substratum over the mine wastes for direct seeding. It will also create enhanced decentralized water storage capacity for wildlife and people. Our strategy combines the concomitant revival of traditional water harvesting systems, ground water recharge, enhanced biomass production and an adaptation to random recurrence of droughts in Rajasthan.
MPAs enhance some of the Ecosystem Services (ES) provided by coral reefs and clear, robust valuations of these impacts may help to improve stakeholder support and better inform decision-makers. Pursuant to this goal, Cost-Benefit Analyses (CBA) of MPAs in 2 different contexts were analysed: a community based MPA with low tourism pressure in Vanuatu, and a government managed MPA with relatively high tourism pressure, in Saint Martin. Assessments were made on six ES: fish biomass, scenic beauty, protection against coastal erosion, bequest and existence values, social capital and CO2 sequestration, which were quantified via different approaches that included experimental fishery, surveys and benefit transfer. Total operating costs for each MPA were collected and the benefit-cost ratio and return on investment based on 25-year discounted projections computed. Sensitivity analyses were conducted on MPA impacts, and discount rates (5%, 7% and 10%). The investment indicators all showed positive results with the impact on the tourism ES being the largest estimated for all MPAs, highlighting the importance of this relationship. The study also demonstrated a relatively high sensitivity of the results to different levels of impacts on ES, which highlights the need for reducing scientific knowledge gaps.
Globally, coastlines are under pressure as coastal human population growth and urbanization continues, while climatic change leads to stormier seas and rising tides. These trends create a strong and sustained demand for land reclamation and infrastructure protection in coastal areas, requiring engineered coastal defence structures such as sea walls. Here, we review the nature of ecological impacts of coastal structures on intertidal ecosystems, seek to understand the extent to which ecological engineering can mitigate these impacts, and evaluate the effectiveness of mitigation as a tool to contribute to conservation of intertidal habitats. By so doing, we identify critical knowledge gaps to inform future research. Coastal structures alter important physical, chemical and biological processes of intertidal habitats, and strongly impact community structure, inter-habitat linkages and ecosystem services while also driving habitat loss. Such impacts occur diffusely across localised sites but scale to significant regional and global levels. Recent advances in ecological engineering have focused on developing habitat complexity on coastal structures to increase biodiversity. ‘Soft’ engineering options maximise habitat complexity through inclusion of natural materials, species and processes, while simultaneously delivering engineering objectives such as coastal protection. Soft options additionally sustain multiple services, providing greater economic benefits for society, and resilience to climatic change. Currently however, a lack of inclusion and economic undervaluation of intertidal ecosystem services may undermine best practice in coastline management. Importantly, reviewed evidence shows mitigation and even restoration do not support intertidal communities or processes equivalent to pre-disturbance conditions. Crucially, an absence of comprehensive empirical baseline biodiversity data, or data comprising additional ecological parameters such as ecosystem functions and services, prohibits quantification of absolute and relative magnitudes of ecological impacts due to coastal structures or effectiveness of mitigation interventions. This knowledge deficit restricts evaluation of the potential of ecological engineering to contribute to conservation policies for intertidal habitats. To improve mitigation design and effectiveness, a greater focus on in-situresearch is needed, requiring stronger and timely collaboration between government agencies, construction partners and research scientists.
This paper considers an emerging group of coastal management approaches which offer the potential to reduce coastal flood and erosion risks whilst also providing nature conservation, aesthetic and amenity benefits. These solutions mimic the characteristics of natural features, but are enhanced or created by man to provide specific services such as wave energy dissipation and erosion reduction. Such approaches can include beaches, dunes, saltmarshes, mangroves, sea grasses, coral and oyster reefs. The paper describes a number of innovative projects and the lessons learned in their development and implementation. These lessons include the planning, design and construction of projects, their development following implementation, the engagement of local communities and the cost effectiveness of solutions.
The idea of ‘nature-based solutions’ (NBS) is now being used to reframe policy debates on biodiversity conservation, climate change adaptation and mitigation strategies, and the sustainable use of natural resources, among other issues. While interesting and potentially useful for those debates, it is a concept that still needs to be clearly defined; its use is not confined to discussions about ecosystem services and natural capital. For example, it is also used to describe such things as soft engineering approaches designed to enhance resilience and reduce risk to people in large settlements (e.g. Marton-Lefevre, 2012; van Wessenbeeck, 2014), and to work in the field of biomimicry and industrial design2 (e.g. Neves and Francke, 2012) – learning from nature, rather than finding strategies based on nature that would contribute to its conservation. However, by emphasising the utilitarian aspect of natural capital and ecosystem services, the idea of ‘nature-based solutions’ is clearly eye-catching and relevant to current debates about the links between people and nature. It is therefore wise to ask what new insights it brings. Is it intended to re-package the demand for sustainable development and nature conservation in a way that concepts of biodiversity and ecosystem services do not? Does it represent an approach to policy and management distinctly different from those already being applied? It is not altogether clear that it does. For example, the idea of NBS can be seen to encompass existing concepts such as ‘nature-based interventions’, ‘ecosystem-based solutions’, and particularly ‘ecosystem-based adaptation’ (see for example Rizvi et al, 2015; Andrade et al., 2011). A report from the Horizon 2020 Expert Group on NBS suggests that the concept “builds on and supports other closely related concepts, such as the ecosystem approach, ecosystem services, ecosystem-based adaptation/mitigation, and green and blue infrastructure” (EC, 2015). From another perspective, however, the use of the term ‘NBS’ might prompt positive changes in how some of these existing concepts are framed. It could refocus attention on sustainable development and encouraging consideration of biodiversity and ecosystems within solutions to wider societal challenges including climate change adaptation, food security, water crises etc.
Ecosystems provide important services that can help people adapt to climate variability and change. Recognizing this role of ecosystems, several international and nongovernmental organizations have promoted an ecosystem-based approach to adaptation. We review the scientific literature related to EbA (ecosystem-based adaptation) with forests and trees, and highlight five cases in which forests and trees can support adaptation: (1) forests and trees providing goods to local communities facing climatic threats; (2) trees in agricultural fields regulating water, soil, and microclimate for more resilient production; (3) forested watersheds regulating water and protecting soils for reduced climate impacts; (4) forests protecting coastal areas from climate-related threats; and (5) urban forests and trees regulating temperature and water for resilient cities. The literature provides evidence that ecosystem-based adaptation with forests and trees can reduce social vulnerability to climate hazards; however, uncertainties and knowledge gaps remain, particularly for regulating services in watersheds and coastal areas. Few studies have been undertake non ecosystem-based adaptation specifically, but the abundant literature on ecosystem services can be used to fill knowledge gaps. Many studies assess the multiple benefits of ecosystems for human adaptation or well-being, but also recognize trade-offs between ecosystem services. Better understanding is needed of the efficiency, costs, and benefits, and trade-offs of ecosystem-based adaptation with forests and trees. Pilot projects under implementation could serve as learning sites and existing information could be systematized and revisited with a climate change adaptation lens.
This book is a compilation of recent developments in the field of ecosystem-based disaster risk reduction and climate change adaption (Eco-DRR/CCA) globally. It provides further evidence that ecosystem-based approaches make economic sense, and showcases how research has progressively filled knowledge gaps about translating this concept into practice. It presents a number of methods, and tools that illustrate how Eco-DRR/CCA has been applied for various ecosystems and hazard contexts around the world. It also discusses how innovative institutional arrangements and policies are shaping the field of Eco-DRR/CCA. The book is of relevance to scientists, practitioners, policy-makers and students in the field of ecosystem management for disaster risk reduction and climate change adaptation.
The increasing worldwide trend in disasters, which will be aggravated by global environmental change (including climate change), urges us to implement new approaches to hazard mitigation, as well as exposure and vulnerability reduction. We are, however, faced with hard choices about hazard mitigation: should we continue to build dikes and walls to protect ourselves against floods and coastal hazards – though we have seen the limits of these – or should we consider alternative, ecosystem-based solutions? Ecosystem management is a well-tested solution to sustainable development that is being revisited because of its inherent “win-win” and “no-regrets” appeal to address rising disaster and climate change issues. It is one of the few approaches that can impact all elements of the disaster risk equation – mitigating hazards, reducing exposure, reducing vulnerabilities and increasing the resilience of exposed communities. Yet, the uptake of ecosystem-based approaches for disaster risk reduction (DRR) is slow despite some very good examples of success stories. Reasons for this are multiple: ecosystem management is rarely considered as part of the portfolio of DRR solutions because the environmental and disaster management communities typically work independently from each other; its contribution to DRR is highly undervalued compared to engineered solutions and thus not attributed appropriate budget allocations; finally, there are poor science-policy interactions on ecosystem-based DRR, which have led to unclear and sometimes contradictory scientific information on the role of ecosystems for DRR. The aim of this book is to provide an overview of knowledge and practice in this multi-disciplinary field of ecosystem management and DRR. It contains 17 chapters written by 57 professionals from the science and practice communities around the world, representing state-of-the-art knowledge, practices and perspectives on the topic. It will serve as a basis to encourage and further develop dialogues between scientists, practitioners, policymakers and development planners.
Strong decreases in greenhouse gas emissions are required to meet the reduction trajectory resolved within the 2015 Paris Agreement. However, even these decreases will not avert serious stress and damage to life on Earth, and additional steps are needed to boost the resilience of ecosystems, safeguard their wildlife, and protect their capacity to supply vital goods and services. We discuss how well-managed marine reserves may help marine ecosystems and people adapt to five prominent impacts of climate change: acidification, sea-level rise, intensification of storms, shifts in species distribution, and decreased productivity and oxygen availability, as well as their cumulative effects. We explore the role of managed ecosystems in mitigating climate change by promoting carbon sequestration and storage and by buffering against uncertainty in management, environmental fluctuations, directional change, and extreme events. We highlight both strengths and limitations and conclude that marine reserves are a viable low-tech, cost-effective adaptation strategy that would yield multiple cobenefits from local to global scales, improving the outlook for the environment and people into the future
Small island developing states (SIDS) are among the countries in the world that are most vulnerable to climate change and required to adapt to its impacts. Yet, there is little information in the academic literature about how SIDS are adapting to climate change, across multiple countries and geographic regions. This paper helps to fill this gap. Using a sample of 16 countries across the Atlantic, Indian Ocean and South China Sea, Caribbean and Pacific regions, this study has two main aims, to identify (1) national-level adaptation trends across climate, climate-induced and non-climate-induced vulnerabilities, sectors and actors, as reported in National Communications (NCs) to the United Nations Framework Convention on Climate Change (UNFCCC), and (2) typologies of national-level adaptation actions in SIDS. It identifies, codes and assesses 977 adaptation actions. These actions were reported as addressing 47 climate and climate-induced vulnerabilities and 50 non-climate-induced vulnerabilities and were undertaken in 37 sectors by 34 actors. The paper proposes five typologies of adaptation actions for SIDS, based on actions reported by SIDS. It specifically explores the implications of its findings for global adaptation strategies. As this work establishes a baseline of adaptation action in SIDS, it can assist national governments to gauge their adaptation progress, identify gaps in their adaptation effort and, thereafter, develop appropriate strategies for filling the gaps. It can also assist donors, whether bilateral or multilateral, to make more ‘climate-smart’ investment decisions by being able to identify the adaptation needs that are not being met in SIDS.
We investigated the coping strategies of rural communities in three countries in Africa to climate hazards. Forest ecosystems deliver food and shelter during extreme events (droughts and floods) and are thus key assets for increasing the resilience of poor communities. In some villages, forests and their NTFP serve as supplementary income during periods of climate stress at the community-level. These coping strategies can form a basis for dealing with future climate changes and can contribute to the development of planned adaptation strategies for anticipated changes. We identified factors that promote or prevent the use of sustainable coping strategies related to forest ecosystems.
Benefits humans rely on from the ocean – marine ecosystem services – are increasingly vulnerable under future climate. This paper reviews how three valued services have, and will continue to, shift under climate change: (1) capture fisheries, (2) food from aquaculture, and (3) protection from coastal hazards such as storms and sea-level rise. Climate adaptation planning is just beginning for fisheries, aquaculture production, and risk mitigation for coastal erosion and inundation. A few examples are highlighted, showing the promise of considering multiple ecosystem services in developing approaches to adapt to sea-level rise, ocean acidification, and rising sea temperatures. Ecosystem-based adaptation in fisheries and along coastlines and changes in aquaculture practices can improve resilience of species and habitats to future environmental challenges. Opportunities to use market incentives – such as compensation for services or nutrient trading schemes – are relatively untested in marine systems. Relocation of communities in response to rising sea levels illustrates the urgent need to manage human activities and investments in ecosystems to provide a sustainable flow of benefits in the face of future climate change.
A healthy natural coastal ecosystem can function as one of the components in reducing potential risk of coastal disasters. The impacts of tsunamis, storm surges and coastal erosions can be reduced at a certain limit by the existence of coastal forest and dunes. In Indonesia, tsunami occurs once twice a year in average. It means, tsunami hit quiet frequently even though the return period in a specific location mostly is several tens to hundred years. To reduce potential impacts of tsunamis in coastal area, construction and rehabilitation of coastal forest is one of the main efforts. The existence of a healthy coastal forest not only provides a suitable protection for high frequency but relatively minor to medium scale tsunamis, but also promotes economic activity based on eco-tourism that will ensure the sustainability of the coastal forest maintenance in the later phase. This paper aims to describe milestones of tsunami mitigation by using greenbelt in Indonesia. Conception, tsunami hazards assessment, challenges and lessons learnt in applying tsunami mitigation by using greenbelt are described so the initiative can be replicated in other tsunami prone areas.
Massive deforestation induced by unplanned urbanization in the hilly watersheds of Brahmaputra basin, India, has led to ecological imbalance and is gradually transforming this basin into a multi-hazard zone. Removal of green cover is also becoming a matter of global concern, as it can accelerate the adverse impacts of climate change. People coming in search of work generally reside in the hills, as they cannot afford the high cost of land in plains. This has led to deforestation of the hilly area and has resulted in increased surface erosion from the upper catchments. Though sediment and water yield from these degraded watersheds could have been minimized by implementing ecologically sustainable management practices (EMPs), such as grass land, forest land and detention pond, poor economic conditions of the people stands in the way of field implementation. On the other hand, major industries, which can be held responsible for emission of greenhouse gases, can be asked to finance greenery development in these hilly watersheds through implementation of selected EMPs to earn carbon credit for them. To convert this concept into reality, the EMP combination must be selected in such a way that it restricts sediment and water yield from the watershed within the permissible limit and maximizes its carbon sequestration capacity at minimum possible cost. Such optimal planning is a prerequisite for preparing an acceptable logical agreement between Government and private companies. Keeping this in mind, an optimization model was developed and applied to a micro watershed of Guwahati to explore its applicability in actual field. The model developed in this study provides most logical carbon credit negotiation, subject to the availability of reliable value of CO2 sequestration for different EMPs.
The brief look at NBSs from the viewpoint of flood risk management suggests that the relatively new concept seems to be worthwhile for further consideration in both science and practice. Not at least as the need for a close cooperation between various scientific disciplines and multiple sectoral and local stakeholders seems to open up some room for joint innovation.