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Multi-objective optimization of rainwater infiltration infrastructures along an urban–rural gradient
Abstract
Many cities are developing infiltration infrastructures aimed at restoring natural hydrological processes. Among those, Nature-Based Solutions (NBS) can generate co-benefits, which contribute to cities’ adaptation to climate change. However, choosing optimal locations for infiltration infrastructures within limited available urban space is a complex spatial problem. It requires taking into account spatial patterns of infiltration potential as well as urban-rural gradients of costs and benefits. To address this, we apply a multi-objective optimization on a simple monocentric model city designed to give generic insights into location choices. We test a series of hypotheses: in comparison with a reference situation, we test the impact of the impossibility to infiltrate rainwater in city centers, the impact of substitution effects due to the presence of urban parks, and the possibility to mix NBS with grey infrastructures. The solutions reveal two polar strategies: locating infrastructures in the city center with higher co-benefits despite higher opportunity costs, or selecting suburban locations with the highest infiltration potential and lower opportunity costs - and a diversity of hybrid solutions. Substitution effects lead to discarding locations near urban parks, especially in centric locations. Finally, mixing NBS and grey infrastructures leads to a specialization of solutions by area and the potential to reach higher benefits at less opportunity costs.
... The effects of thermal discomfort are expected to become more pronounced in urban areas as global warming intensifies [34,[75][76][77]. Based on the importance of these effects, in this research, temperature measurements were made in neighborhood parks in order to determine the elements regulating thermal comfort. ...
According to current studies, the thermal effects of global warming will affect urban areas more intensely. In the face of this situation, strategies for the improvement and management of urban green spaces are becoming increasingly important in sustainable landscape design. These strategies promote social sustainability by positively affecting individuals’ physical and psychological well-being, taking into consideration ecological sustainability. Projections regarding global warming emphasize that the density of hardscapes and green spaces, the selection of plant species, and the distribution of plants considered within the scope of this study should be taken into account. This research was conducted in the Görükle neighborhood of Bursa, focusing on the role of temperature-regulating elements in 14 neighborhood parks. Systematic temperature measurements were carried out in the research area on the 10th, 20th, and 30th of July and August, specifically between 12:00 and 13:00, during peak temperature hours. The presence of parks that are close to each other and relatively far away from each other in the study area was seen as advantageous to filter the effects of plant differences in similar conditions. Furthermore, evaluating these various factors together highlights the multifaceted nature of thermal comfort. Designated temperature measurement points included three points (hard surfaces and hard surfaces surrounded by vegetation and planted green spaces) in each park. An analysis utilizing SPSS and the RayMan program revealed that parks with a softscape to hardscape ratio of approximately two to one experienced temperature reductions of 2.5 to 3 °C. Furthermore, the findings indicate that coniferous trees have a more significant impact on thermal comfort compared to deciduous trees. The significant differences identified in this study underscore essential considerations for urban design processes aimed at achieving sustainability.
Urbanization and climate change are producing an escalation in the prevalence of urban problems, particularly those connected to flooding, prompting authorities and stakeholders to recognize the need for sustainable solutions. Nature-Based Solutions are progressively replacing traditional engineering solutions as an alternative since they are more eco-friendly. By re-activating the urban hydrological cycle processes, NBS intends to increase the natural water storage capacity to help decrease urban flooding. The work described here outlines a framework for optimising the efficacy of NBS for flood risk reduction and its co-benefits, as well as defining the trade-offs among these co-benefits. The framework integrates 1D hydrodynamic models with multi-objective optimisation techniques. To demonstrate the applicability of the framework and its methods it has been used in Sint Maarten, which is an island located in the Caribbean Sea. Four NBS measure were identified as having good potential to be applied in the case study, namely: green roof, permeable pavement, bio-retention pond, and open detention basin. The results showed that the developed framework has the ability to represent the link between benefits and costs when evaluating various NBS, hence aiding the decision-making process to select and implement NBS.
This research is being carried out to study how best management practices (BMPs) can mitigate the negative effects of urban floods during extreme rainfall events. Strategically placing BMPs throughout open areas and rooftops in urban areas serves multiple purposes of storage of rainwater, removal of pollutants from surface runoff and sustainable utilisation of land. This situation is framed as a multiobjective optimisation problem to analyse the trade-offs between multiple goals of runoff reduction, construction cost and pollutant load reduction. Output includes a wide range of choices to choose from for decision makers. Proposed methodology is demonstrated with a case study of Greater Hyderabad Municipal Corporation (GHMC), India. A historical extreme rainfall event of 237.5 mm which occurred in 2016 and extreme rainfall event of 1,740.62 mm corresponding to representative concentration pathway (RCP) 2.6 were considered for analysis. Two multiobjective optimisation algorithms, namely non-dominated sorting genetic algorithm-III (NSGA-III) and constrained two-archive evolutionary algorithm (C-TAEA) are used to solve the BMP placement problem, following which the resulting Pareto-fronts are ensembled. K-Medoids-based cluster analysis is performed on the resulting ensembled Pareto-front. The proposed ensembled approach identified ten possible BMP configurations, with costs ranging from Rs. to surface runoff reduction ranging from to and pollutant load removal ranging from tonnes. Use of BMPs in future events has the potential to reduce surface runoff from , while simultaneously removing tonnes of pollutants for cost ranging from The proposed framework forms an effective and novel way to characterise and solve BMP optimisation problems in context of climate change, presenting a view of the urban flooding scenario today, and the likely course of events in the future. HIGHLIGHTS
The multiobjective BMP problem is solved using NSGA-III and C-TAEA.;
Cluster analysis is performed using K-Medoids.;
Accounting for climate change through RCP 2.6.;
As a consequence of climate change and urbanization, many cities will have to deal with more flooding and extreme heat stress. This paper presents a framework to maximize the effectiveness of Nature-Based Solutions (NBS) for flood risk reduction and thermal comfort enhancement. The framework involves an assessment of hazards with the use of models and field measurements. It also detects suitable implementation sites for NBS and quantifies their effectiveness for thermal comfort enhancement and flood risk reduction. The framework was applied in a densely urbanized study area, for which different small-scale urban NBS and their potential locations for implementation were assessed. The overall results show that the most effective performance in terms of flood mitigation and thermal comfort enhancement is likely achieved by applying a range of different measures at different locations. Therefore, the work presented here shows the potential of the framework to achieve an effective combination of measures and their locations, which was demonstrated on the case of the Sukhumvit area in Bangkok (Thailand). This can be particularly suitable for assessing and planning flood mitigation measures in combination with heat stress reduction.
Climate change is presenting one of the main challenges to our planet. In parallel, all regions of the world are projected to urbanise further. Consequently, sustainable development challenges will be increasingly concentrated in cities. A resulting impact is the increment of expected urban flood risk in many areas around the globe. Adaptation to climate change is an opportunity to improve urban conditions through the implementation of green-blue infrastructures, which provide multiple benefits besides flood mitigation. However, this is not an easy task since urban drainage systems are complex structures. This work focuses on a method to analyse the trade-offs when different benefits are pursued in stormwater infrastructure planning. A hydrodynamic model was coupled with an evolutionary optimisation algorithm to evaluate different green-blue-grey measures combinations. This evaluation includes flood mitigation as well as the enhancement of co-benefits. We confirmed optimisation as a helpful decision-making tool to visualise trade-offs among flood management strategies. Our results show that considering co-benefits enhancement as an objective boosts the selection of green-blue infrastructure. However, flood mitigation effectiveness can be diminished when extra benefits are pursued. Finally, we proved that combining green-blue-grey measures is particularly important in urban spaces when several benefits are considered simultaneously.
Cities face increasing environmental, social and economic challenges that together threaten the resilience of urban areas and the residents who live and work there. These challenges include chronic stresses and acute shocks, amplified by climate change impacts. Nature-based solutions have emerged as a concept for integrating ecosystem-based approaches to address a range of societal challenges. Nature-based solutions directly address and contribute to increased urban resilience. However, implementing nature-based solutions is inherently complex, given the range of ecosystem services, their multi-functionality and the trade-offs between functions, and across temporal and spatial scales. Urban planning can play a substantial role to support the implementation of nature-based solutions and to manage trade-offs and conflicts, as well as how social equity dimensions are considered. This paper presents a framework that guides the application of urban planning to nature-based solutions’ implementation, by addressing key trade-offs across temporal, spatial, functional and social equity aspects. The framework highlights the key questions, and the supporting information required to address these questions, to underpin the inclusion of nature-based solutions for urban resilience. We find that while urban planning can contribute substantially, there are continuing gaps in how the inherently anthropocentric urban planning processes can give voice to non-human nature.
Urban green spaces are considered an appropriate way to reduce urban heat island effects and provide comfort to the nearby occupants. In addition to cooling the actual space, urban green spaces are also able to influence the surrounding area, and this phenomenon is called the urban green space cooling effect. The most important issues with regard to the cooling effects of urban green spaces are the intensity and density of the cooling, which can play a major role for urban designers and planners in dealing with urban heat island. This article reviews the latest studies that have examined the cooling effects of urban green spaces in recent years. Based on the method of evaluation of their samples, the studies are divided into three groups. The first category consists of research into a set of urban green spaces in one part of or in an entire city, mainly conducted through remote sensing and satellite maps. The second category investigates city parks or several urban parks with recognizable shapes and locations. In this section, information was mainly gathered by virtue of field observations. The third category relates to studies in which a part of urban space according to different scenarios of green space placement was modeled by simulation. The results of the present study illustrate that the highest cooling effect distance and cooling effect intensity are for large urban parks with an area of more than 10 ha; however, in addition to the area, the natural elements and qualities of the urban
This chapter describes the history of metaheuristics in five distinct periods, starting long before the first use of the term and ending a long time in the future. The field of metaheuristics has undergone several paradigm shifts that have changed the way researchers look upon the development of heuristic methods. Most notably, there has been a shift from the method-centric period, in which metaheuristics were thought of as algorithms, to the framework-centric period, in which researchers think of metaheuristics as more general high-level frameworks, i.e., consistent collections of concepts and ideas that offer guidelines on how to go about solving an optimization problem heuristically. Tremendous progress has been made in the development of heuristics over the years. Optimization problems that seemed intractable only a few decades ago can now be efficiently solved. Nevertheless, there is still much room for evolution in the research field, an evolution that will allow it to move into the scientific period. In this period, we will see more structured knowledge generation that will benefit both researchers and practitioners. Unfortunately, a significant fraction of the research community has deluded itself into thinking that scientific progress can be made by resorting to ever more outlandish metaphors as the basis for so-called "novel" methods. Even though considerable damage to the research field will have been inflicted by the time these ideas have been stamped out, there is no doubt that science will ultimately prevail. © Springer International Publishing AG, part of Springer Nature 2018. All rights reserved.
Green space is fundamental to the quality of life of residents, and as such, urban planning or improvement projects often include strategies directly or indirectly related to greening. Although green space is well established to generate positive effects such as cooling, runoff reducing, and ecological corridor, a few studies have examined the comprehensive process of greening in the urban planning context. To fill this gap in the literature, this study seeks to identify a planning model that determines the location and type of greens based on its multiple effects (e.g., cooling and enhancement of connectivity) and calculates the implementation cost using meta-heuristic optimization algorithms. We obtained 30 Pareto-optimal plans by applying our model to the hypothetical landscape at a neighborhood scale. The results showed a synergistic relationship between cooling and enhancement of connectivity, as well as a trade-off relationship between greenery effects and implementation cost. We also defined critical lots for urban greening that are commonly selected in various plans. We expect our model to contribute to the improvement of existing planning processes by repeating the positive feedback loop: from plan modification to quantitative evaluation and selection of better plans. These optimal plans can also be considered as options for “co-design” by related stakeholders.
An expanding literature addresses spatial dimensions related to the elicitation, estimation, interpretation and aggregation of stated preference (SP) welfare measures. Recognizing the relevance of spatial dimensions for SP welfare analysis and the breadth of associated scholarly work, this article reviews the primary methods, findings, controversies and frontiers in this important area of contemporary research. This review is grounded in a typology that characterizes analytical methods based on theoretical foundations and the type of statistical modelling applied. The resulting interpretive appraisal seeks to (1) summarize and contrast different theoretical arguments and points of departure within the spatial SP literature, (2) synthesize findings, insights and methods from the literature to promote a more holistic perspective on the treatment of spatial dimensions within SP welfare analysis, (3) evaluate and reconcile divergent approaches in terms of theoretical grounding, ability to identify relevant empirical effects, and relevance for SP valuation, and (4) discuss outstanding questions and research frontiers.
In almost no other field of computer science, the idea of using bio-inspired search paradigms has been so useful as in solving multiobjective optimization problems. The idea of using a population of search agents that collectively approximate the Pareto front resonates well with processes in natural evolution, immune systems, and swarm intelligence. Methods such as NSGA-II, SPEA2, SMS-EMOA, MOPSO, and MOEA/D became standard solvers when it comes to solving multiobjective optimization problems. This tutorial will review some of the most important fundamentals in multiobjective optimization and then introduce representative algorithms, illustrate their working principles, and discuss their application scope. In addition, the tutorial will discuss statistical performance assessment. Finally, it highlights recent important trends and closely related research fields. The tutorial is intended for readers, who want to acquire basic knowledge on the mathematical foundations of multiobjective optimization and state-of-the-art methods in evolutionary multiobjective optimization. The aim is to provide a starting point for researching in this active area, and it should also help the advanced reader to identify open research topics.
Distributed, infiltration‐based approaches to stormwater management are being implemented to mitigate effects of urban development on water resources. One of the goals of this type of stormwater management, sometimes called low impact development or green infrastructure, is to maintain groundwater recharge and stream base flow at pre‐development levels. However, the connection between infiltration‐based stormwater management and groundwater recharge is not straightforward. Water infiltrated through stormwater facilities may be stored in soil moisture, taken up by evapotranspiration, or contribute to recharge and eventually base flow. This study focused on a 1.1 km2 suburban, low impact development watershed in Clarksburg, Maryland, USA that was urbanized and contained 73 infiltration‐based stormwater facilities. Continuous water table measurements were used to quantify the movement of infiltrated stormwater. Time series analyses were performed on hydrographs of seven wells and the episodic master recession method was used. Persistence in water levels, as measured by autocorrelation function, was found to be positively related to depth to water. Storm properties (precipitation rate and duration) and well location (proximity to the nearest stream) were significant in driving episodic recharge to precipitation ratios. The well that had the highest recharge to precipitation ratios and water table rises of up to 1.5 m in response to storm events was located furthest from the stream and downgradient of stormwater infiltration locations. This work may be considered in evaluating the effects of planned watershed‐scale infiltration‐based stormwater management on groundwater flow systems.
To meet increasing urban water requirements in a sustainable way, there is a need to diversify future sources of supply and storage. However, to date, there has been a lag in the uptake of managed aquifer recharge (MAR) for diversifying water sources in urban areas. This study draws on examples of the use of MAR as an approach to support sustainable urban water management. Recharged water may be sourced from a variety of sources and in urban centers, MAR provides a means to recycle underutilized urban storm water and treated wastewater to maximize their water resource potential and to minimize any detrimental effects associated with their disposal. The number, diversity and scale of urban MAR projects is growing internationally due to water shortages, fewer available dam sites, high evaporative losses from surface storages, and lower costs compared with alternatives where the conditions are favorable, including water treatment. Water quality improvements during aquifer storage are increasingly being documented at demonstration sites and more recently, full-scale operational urban schemes. This growing body of knowledge allows more confidence in understanding the potential role of aquifers in water treatment for regulators. In urban areas, confined aquifers provide better protection for waters recharged via wells to supplement potable water supplies. However, unconfined aquifers may generally be used for nonpotable purposes to substitute for municipal water supplies and, in some cases, provide adequate protection for recovery as potable water. The barriers to MAR adoption as part of sustainable urban water management include lack of awareness of recent developments and a lack of transparency in costs, but most importantly the often fragmented nature of urban water resources and environmental management.
Spatial planning has to deal with trade-offs between various stakeholders’ wishes and needs as part of planning and management of landscapes, natural resources and/or biodiversity. To make ecosystem services (ES) trade-off research more relevant for spatial planning, we propose an analytical framework, which puts stakeholders, their land-use/management choices, their impact on ES and responses at the centre. Based on 24 cases from around the world, we used this framing to analyse the appearance and diversity of real-world ES trade-offs. They cover a wide range of trade-offs related to ecosystem use, including: land-use change, management regimes, technical versus nature-based solutions, natural resource use, and management of species. The ES trade-offs studied featured a complexity that was far greater than what is often described in the ES literature. Influential users and context setters are at the core of the trade-off decision-making, but most of the impact is felt by non-influential users. Provisioning and cultural ES were the most targeted in the studied trade-offs, but regulating ES were the most impacted. Stakeholders’ characteristics, such as influence, impact faced, and concerns can partially explain their position and response in relation to trade-offs. Based on the research findings, we formulate recommendations for spatial planning.
Green infrastructure (GI) revitalizes vegetation and soil, restores hydro-ecological processes destroyed by traditional urbanization, and naturally manages stormwater on-site, offering numerous sustainability benefits. However, despite being sustainable and despite being the object of unrelenting expert advocacy for more than two decades, GI implementation remains slow. On the other hand, the practice of traditional gray infrastructure, which is known to have significant adverse impacts on the environment, is still ubiquitous in urban areas throughout the world. This relationship between knowledge and practice seems unaccountable, which has not yet received adequate attention from academia, policy makers, or research communities. We deal with this problem in this paper. The specific objective of the paper is to explore the barriers to GI, and suggest policies that can both overcome these barriers and expedite implementation. By surveying the status of implementation in 10 US cities and assessing the relevant city, state and federal policies, we identified 29 barriers and grouped them into 5 categories. The findings show that most of the barriers stem from cognitive limitations and socio-institutional arrangements. Accordingly, we suggest 33 policies, also grouped into 5 categories, which span from conducting public education and awareness programs to changing policies and governance structures.
Note: Free access to this article is available (for other than commercial purpose) till September 23, 2017 through the following link: https://authors.elsevier.com/a/1VV4S14Z6tTGHM
To address challenges associated with climate resilience, health and well-being in urban areas, current policy platforms are shifting their focus from ecosystem-based to nature-based solutions (NBS), broadly defined as solutions to societal challenges that are inspired and supported by nature. NBS result in the provision of co-benefits, such as the improvement of place attractiveness, of health and quality of life, and creation of green jobs. Few frameworks exist for acknowledging and assessing the value of such co-benefits of NBS and to guide cross-sectoral project and policy design and implementation. In this paper, we firstly developed a holistic framework for assessing co-benefits (and costs) of NBS across elements of socio-cultural and socioeconomic systems, biodiversity , ecosystems and climate. The framework was guided by a review of over 1700 documents from science and practice within and across 10 societal challenges relevant to cities globally. We found that NBS can have environmental, social and economic co-benefits and/or costs both within and across these 10 societal challenges. On that base, we develop and propose a seven-stage process for situating co-benefit assessment within policy and project implementation. The seven stages include: 1) identify problem or opportunity; 2) select and assess NBS and related actions; 3) design NBS implementation processes; 4) implement NBS; 5) frequently engage stake-holders and communicate co-benefits; 6) transfer and upscale NBS; and 7) monitor and evaluate co-benefits across all stages. We conclude that the developed framework together with the seven-stage co-benefit assessment process represent a valuable tool for guiding thinking and identifying the multiple values of NBS implementation .
Nature is perceived and valued in starkly different and often conflicting ways. This paper presents the rationale for the inclusive valuation of nature’s contributions to people (NCP) in decision making, as well as broad methodological steps for doing so. While developed within the context of the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES), this approach is more widely applicable to initiatives at the knowledge–policy interface, which require a pluralistic approach to recognizing the diversity of values. We argue that transformative practices aiming at sustainable futures would benefit from embracing such diversity, which require recognizing and addressing power relationships across stakeholder groups that hold different values on human nature-relations and NCP.
We are increasingly confronted with severe social and economic impacts of environmental degradation all over the world. From a valuation perspective, environmental problems and conflicts originate from trade-offs between values. The urgency and importance to integrate nature's diverse values in decisions and actions stand out more than ever.
Valuation, in its broad sense of ‘assigning importance’, is inherently part of most decisions on natural resource and land use. Scholars from different traditions -while moving from heuristic interdisciplinary debate to applied transdisciplinary science- now acknowledge the need for combining multiple disciplines and methods to represent the diverse set of values of nature. This growing group of scientists and practitioners share the ambition to explore how combinations of ecological, socio-cultural and economic valuation tools can support real-life resource and land use decision-making.
The current sustainability challenges and the ineffectiveness of single-value approaches to offer relief demonstrate that continuing along a single path is no option. We advocate for the adherence of a plural valuation culture and its establishment as a common practice, by contesting and complementing ineffective and discriminatory single-value approaches. In policy and decision contexts with a willingness to improve sustainability, integrated valuation approaches can be blended in existing processes, whereas in contexts of power asymmetries or environmental conflicts, integrated valuation can promote the inclusion of diverse values through action research and support the struggle for social and environmental justice.
The special issue and this editorial synthesis paper bring together lessons from pioneer case studies and research papers, synthesizing main challenges and setting out priorities for the years to come for the field of integrated valuation.
In this paper, we reflect on the implications for science, policy and practice of the recently introduced concept of Nature-Based Solutions (NBS), with a focus on the European context. First, we analyse NBS in relation to similar concepts, and reflect on its relationship to sustainability as an overarching framework. From this, we derive a set of questions to be addressed and propose a general framework for how these might be addressed in NBS projects by funders, researchers, policy-makers and practitioners. We conclude that:
Nature-based Solutions (NbS) are defined by IUCN as actions to protect, sustainably manage and restore natural or modified ecosystems, which address societal challenges (e.g. climate change, food and water security or natural disasters) effectively and adaptively, while simultaneously providing human well-being and biodiversity benefits. The NbS concept, as used in environmental sciences and nature conservation contexts, has emerged within the last decade or so, as international organisations search for ways to work with ecosystems – rather than relying on conventional engineering solutions (such as seawalls) – to adapt to and mitigate climate change effects, while improving sustainable livelihoods and protecting natural ecosystems and biodiversity.
NbS is a relatively ‘young’ concept, still in the process of being framed. There is a need now to deepen our understanding of NbS and confirm the principles upon which NbS is based, in order to move towards an operational framework that can guide applications of the NbS concept. The following set of NbS principles are proposed.
Nature-based Solutions:
1. embrace nature conservation norms (and principles);
2. can be implemented alone or in an integrated manner with other solutions to societal challenges (e.g. technological and engineering solutions);
3. are determined by site-specific natural and cultural contexts that include traditional, local and scientific knowledge;
4. produce societal benefits in a fair and equitable way, in a manner that promotes transparency and broad participation;
5. maintain biological and cultural diversity and the ability of ecosystems to evolve over time;
6. are applied at the scale at a landscape;
7. recognise and address the trade-offs between the production of a few immediate economic benefits for development, and future options for the production of the full range of ecosystems services;
8. are an integral part of the overall design of policies, and measures or actions, to address a specific challenge.
NbS is best considered an umbrella concept that covers a range of different approaches. These approaches have emerged from a variety of spheres (some from the scientific research domain, others from practice or policy contexts) but share a common focus on ecosystem services and aim to address societal challenges. These NbS approaches can be classified into: (i) ecosystem restoration approaches (e.g. ecological restoration, ecological engineering and forest landscape restoration); (ii) issue-specific ecosystem-related approaches (e.g. ecosystem-based adaptation, ecosystem-based mitigation, and eco-system-based disaster risk reduction); (iii) infrastructure-related approaches (e.g. natural infrastructure and green infrastructure approaches); (iv) ecosystem-based management approaches (e.g. integrated coastal zone management and integrated water resources management); and (v) ecosystem protection approaches (e.g. area-based conservation approaches including protected area management).
A lack of operational clarity presents a major obstacle to the credibility and applicability of new concepts in the fields of conservation and development. Several parallel exercises are currently underway to develop operational parameters for specific NbS approaches (such as Ecosystem-based Adaptation and REDD+), each proposing its own set of criteria. Many of these criteria could be relevant for other approaches within the NbS ‘family’ and there is likely an overarching set of parameters, or ‘standards’, that can guide implementation of all types of NbS interventions. To help in this endeavour, five preliminary parameters are proposed: ecological complexity, long-term stability, scale of ecological organisation, direct societal benefits and adaptive governance. By unifying NbS approaches under a single operational framework, it becomes possible to scale up their implementation and strengthen their impact in mitigating the world’s most pressing challenges.
La gestion des eaux pluviales constitue un enjeu important pour les collectivités. En 2006, l'explicitation du service public dédié a conforté leur rôle et a confirmé la primauté donnée à la gestion à la source des eaux pluviales. Infiltrer les eaux pluviales deviendrait le principe premier visé par les politiques territoriales, portées par différents niveaux de gouvernance. L’analyse de l’aptitude des sols à l’infiltration des eaux pluviales constitue alors un élément essentiel d’aide à la décision pour le choix et l’évaluation des principes techniques par les collectivités, les aménageurs et les services instructeurs. Plusieurs collectivités en France se sont dotées de cartes synthétisant cette aptitude. Cependant, peu de connaissances et de retours d’expérience sont disponibles sur ces cartes, ainsi que sur la coordination des acteurs et des échelles mobilisées dans les processus de planification et d’urbanisation. Dans ce contexte, nous nous sommes intéressés aux conditions d’émergence, d’élaboration, d’utilisation et d’évaluation des cartes d’aptitude des sols à l’infiltration des eaux pluviales produites par 6 collectivités aux caractéristiques diverses. Ces retours d’expérience nous ont permis de caractériser, analyser puis comparer les méthodologies d’élaboration mises en œuvre et de comprendre les conditions d’émergence de telles cartes, variables selon les territoires et acteurs impliqués.
The principle of urban-rural gradients can reveal the spatial variations of ecosystem services and socioeconomic dimensions. The interrelations between ecosystem services and socioeconomics have scarcely been considered in the context of urban-rural areas.
We investigated the spatial gradients and the mutual linkages of several ecosystem services and socioeconomic variables in the urban-rural areas of Leipzig, Germany, and Kunming, China. The results showed some regularities in the spatial patterns of ecosystem services and socioeconomic dimensions in both study areas. Habitat quality and f-evapotranspiration of Leipzig and habitat quality of Kunming demonstrated apparent increasing trends along all gradient patterns. However, the other ecosystem services presented divergent spatial variabilities in different gradient patterns. Road density, urban fabric and population density showed identical declining trends in both case study areas. Differently, household
size, housing area as well as unemployment rate in Leipzig presented inconsistent spatial dynamics with considerable fluctuations. With regard to the gradient interrelations, road density, urban fabric and population density were strongly correlated with most ecosystem services in both case study areas.
In contrast, the gradients of household size, housing area and unemployment rate of Leipzig showed inconsistent correlations with the ecosystem services gradients. Our study provides evidence to the argument that typical patterns of ecosystem service gradients do not exist in different urban-rural areas.
The management of urban stormwater has become increasingly complex over recent decades. Consequently, terminology describing the principles and practices of urban drainage has become increasingly diverse, increasing the potential for confusion and miscommunication. This paper documents the history, scope, application and underlying principles of terms used in urban drainage and provides recommendations for clear communication of these principles. Terminology evolves locally and thus has an important role in establishing awareness and credibility of new approaches and contains nuanced understandings of the principles that are applied locally to address specific problems. Despite the understandable desire to have a ‘uniform set of terminology’, such a concept is flawed, ignoring the fact that terms reflect locally shared understanding. The local development of terminology thus has an important role in advancing the profession, but authors should facilitate communication between disciplines and between regions of the world, by being explicit and accurate in their application.
A green park can be an effective contributor to the reduction of higher temperatures caused by urban heat island effects. A park's cooling effect extends beyond its boundary into the surrounding streets and buildings. Up to now, the measurement of the extent of the cooling effect beyond the park has relied mainly on on-site observations. An alternative method is to calculate the extent of cooling using remote sensing. The principle of the method is that the cooling effect will decline from the boundary into the surrounding areas to a distance at which the effect is longer felt. Analysis of Landsat TM/ETM+ images of Beijing revealed that cooling effects extend as much as 840 m away from the park in cone case, but as little as 35 m in another. While related in part to park size, the extent of the cooling effect is also influenced by the character of the area around each park. Remote sensing provides a viable alternative to ground temperature measurements, but attention has to be paid to the actual cityscape and characteristics of each park as well as to the resolution of the imagery.
The principle of multifunctionality has been observed as one of the key attractions of the emerging concept of green infrastructure, being recognized as a means of achievement of several environmental, social, cultural and economic urban policy aims. Concomitant with this growing popularity, there are increasing concerns and criticisms about its applicability. One of the major criticisms is that there is often a misinterpretation of green infrastructure as a straightforward way to promote multifunctionality without the need to make choices among functions. In this article, we develop a method that informs spatial priority areas towards green infrastructure planning by taking into account the assessment of different functions. Two indicators of green infrastructure functions were selected: local temperature regulation by green areas and population proximity to public green spaces. The results suggest the existence of spatial synergies and conflicts between those spatial priorities and confirm that spatial policies for Porto green infrastructure would be reasonably different depending on the favoured green infrastructure function. Two main conclusions are drawn from the results: planning for multifunctional green infrastructure calls for a shift from general consensuses to designed policies and from generic assumptions to local assessments.
Urbanization destroys or modifies native habitats and creates new ones with its infrastructure. Because of these changes, urban landscapes favor non-native and native species that are generalists. Nevertheless, cities reveal a great variety of habitats and species, and, especially in temperate cities, the diversity of vascular plants and birds can be higher than in the surrounding landscapes. The actual occurrence of a species, however, depends on habitat availability and quality, the spatial arrangements, species pools, a species’ adaptability and natural history, and site history. In addition, cities are particularly human-made ecological systems. Top-down and bottom-up activities of planners, land managers, and citizens create the urban biodiversity in general and in detail. Plants and animals in cities are the everyday life contact with nature of the most humans on our earth. The intrinsic interplay of social and ecological systems with a city often forms unique biotic assemblages inherent to that city. To support native biodiversity, landscape architects, conservation biologists, and other groups are linking landscape design with ecosystem structure and function to create and restore habitats and reintroduce native species in cities.
This paper explores the role of landscapes in generating ecosystem
services while maximizing gross margin associated with agricultural
commodity production. Ecosystem services considered include the
reduction of nonpoint source pollutants such as sediment, phosphorous,
and nitrogen yields from a watershed. The analysis relies on an
integrative modeling framework that combines a comprehensive watershed
model (SWAT) with a multiobjective evolutionary algorithm (SPEA2).
Application of the resulting model to a watershed in southern Illinois
demonstrates the effectiveness of the approach in providing tradeoff
solutions between gross margin and the generation of ecosystem services.
These solutions are important to policy makers and planners in that they
provide information about the cost-effectiveness of alternative
agricultural landscapes.
Environmental justice (EJ) addresses the unequal distribution of environmental goods and harms and promotes people's right to be involved in environmental decision-making. In recent years, EJ considerations have expanded to the use of Nature-based solutions (NbS) in urban areas, mainly how their planning and implementation can impact human well-being and social justice. However, what constitutes a just solution and how the concept is treated in the literature can take many forms. This study reviews how EJ is conceptualised and analysed in urban NbS research and documents the potential outcomes of diverse interventions. We developed a conceptual framework for the review process, focusing on the EJ definitions transferable to NbS research. We then conducted a systematic review of 152 articles published between 2000 and 2021. Selected articles addressed urban NbS from the recognitional, procedural and distributional interpretations of justice. Publication trends, methods, and demographic variables were recorded for each article. Furthermore, we focused on the means for assessing EJ in empirical terms, such as the framing of justice-related challenges, assessment indicators , and the reported justice outcomes. Findings demonstrate the dominance of research themes, the skewness towards the distributive dimension of justice, and a large variety of metrics and indicators used to assess EJ implications. Our results also show that EJ outcomes have mostly been reported to be mixed or negative. The results are used to identify research gaps and issues that need to be addressed to enhance EJ effects in urban NbS.
Urban community gardens can reduce food insecurity and serve as green spaces alleviating extreme temperatures. Such co-benefit synergy may prove especially significant for arid-land metropolises. Despite these synergistic roles, planning for community gardens is largely undertaken in an ad-hoc manner. To date, few studies have addressed the full potential (co-benefits) of developing urban vacant land into community garden-green spaces. We addressed this in a spatially-optimized way, developing a model seeking to mitigate food desert and urban heat, and applied it to the fast sprawling Phoenix metro-area, Arizona (USA). Examining more than 5,000 vacant parcels for potential garden-green spaces, we found that the optimal number and locations of community gardens needed for different mitigation goals can vary significantly. In the Phoenix metro-area, the gardens required for extreme heat mitigation is about twice the number for food desert mitigation because high-temperature areas are more prevalent and expansive in semi-arid desert environment compared to the relatively small number low income, food desert areas. Furthermore, we found that the existing 76 community gardens were mostly clustered around urban cores, leaving two-thirds of the metro-area underserved. If sited in a spatially-optimized way, the co-benefits gained from the 76 gardens could be doubled, and covering more high-need neighborhoods. Integrating fine-scale vacant parcel data, our model identified high potential community garden-greening sites in priority neighborhoods with a precision not capable in conventional planning methods. Our findings demonstrate that spatially-optimized planning is of particular importance to avoid clustering of community gardens and ensure more equal access to local food and outdoor cooling benefits.
The necessity of incorporating a resilience-informed approach into urban planning and its decision-making is felt now more than any time previously, particularly in low and middle income countries. In order to achieve a successful transition to sustainable, resilient and cost-effective cities, there is a growing attention given to more effective integration of nature-based solutions, such as Sustainable Drainage Systems (SuDS), with other urban components. The experience of SuDS integration with urban planning, in developed cities, has proven to be an effective strategy with a wide range of advantages and lower costs. The effective design and implementation of SuDS requires a multi-objective approach by which all four pillars of SuDS design (i.e., water quality, water quantity, amenity and biodiversity) are considered in connection to other urban, social, and economic aspects and constraints. This study develops a resilience-driven multi-objective optimisation model aiming to provide a Pareto-front of optimised solutions for effective incorporation of SuDS into (peri)urban planning, applied to a case study in Brazil. This model adopts the SuDS's two pillars of water quality and water quantity as the optimisation objectives with its level of spatial distribution as decision variables. Also, an improved quality of life index (iQoL) is developed to re-evaluate the optimal engineering solutions to encompass the amenity and biodiversity pillars of SuDS. Rain barrels, green roofs, bio-retention tanks, vegetation grass swales and permeable pavements are the suitable SuDS options identified in this study. The findings show that the most resilient solutions are costly but this does not guarantee higher iQoL values. Bio-retention tanks and grass swales play effective roles in promotion of water quality resilience but this comes with considerable increase in costs. Permeable pavements and green roofs are effective strategies when flood resilience is a priority. Rain barrel is a preferred solution due to the dominance of residential areas in the study area and the lower cost of this option.
As a response to increasing urbanization and changing weather and climatic patterns, urban green infrastructure (UGI) emerged as a concept to increase resilience within the urban boundaries. Given that implementing these (semi-) natural solutions in practice requires a clear overview of the costs and benefits, valuation becomes ever important. A range of decision-support tools for green infrastructure and ecosystem services exist, developed for various purposes. This paper reviews the potential of 10 shortlisted and existing valuation tools to support investment decisions of urban green infrastructure. In the assessment, the functionality is regarded specifically from the urban planning and decision-making viewpoint. The toolkits were evaluated on 12 different criteria. After analyzing the toolkits on these criteria, the findings are evaluated on the (mis)match with specific requirements in the urban planning and management context. Secondly, recommendations and guidelines are formulated to support the design of simple valuation tools, tailored to support the development of green infrastructure in urban areas. Approaching the valuation toolkits biophysically and (socio-)economically provides an integral overview of the challenges and opportunities of the capacities of each framework. It was found that most tools are not designed for the peculiarities of the urban context. Several elements contribute to the hampering uptake of GI valuation tools. Firstly, the limited effort in the economic case for green infrastructure remains a burden to use toolkits to compare grey and green alternatives. Secondly, tools are currently seldom designed for the peculiarities of cities: urban ecosystem (dis)services, multi-scalability, life-span assessments of co-benefits and the importance of social benefits. Thirdly, toolkits should be the result of co-development between the scientific community and local authorities in order to create toolkits that are tailor made to the specific needs in the urban planning process. It can be concluded that current tools, are not readily applicable to support decision making as such. However, if applied cautiously, they can have an indicative role to pinpoint further targeted and in-depth analyses.
Urban parks are of great importance for residents’ health and well-being. As two main factors influencing park visit, distance to park and park size have been studied and adopted in practice such as park planning and guidelines. This study aims to examine how travel distance and park size associated with park visits and how these effects may vary across different types of park visits in Beijing, China. We conducted a city-wide survey in 78 neighborhoods, and interviewed 7,362 residents on their park visit behaviors. Constraint line analysis, Pearson correlation analysis, and significant differences analysis were employed. We found that travel distance had an exponential limiting effect on park visit. The maximum park visits dropped exponentially as the travel distance to parks increased. No such effect was observed for park size. Visitors to nearby, medium-distance, and distant parks varied significantly in terms of park visit frequency, travel mode, time spent in park, and activity. Their destination parks also differed in size, vegetation cover and whether water area is present. Furthermore, we identified four cut-off points (1, 2, 5, and 10 km) based on the constraint line functions as the accessible and maximum travel distance regarding different travel modes and visit frequencies of park visits. Our findings provided empirical evidence on the association among travel distance, park size and visit, which have important implications for future park studies and planning.
Urban water problems (e.g., increased runoff, inhibited infiltration, and groundwater recharge) are becoming increasingly serious, and green infrastructure (GI) has been demonstrated to be effective in tackling these problems and restoring the pre-development hydrologic cycle. However, shallow groundwater limits the implementation of infiltration-based GI. Although projects and studies have been conducted, knowledge of the hydrologic performance of infiltration-based GI, and the impact on shallow groundwater environments, has not been comprehensively summarized. In this review, we first identify the challenges of implementing infiltration-based GI in shallow groundwater environments, and then evaluate and compare the potential approaches to evaluating GI in such environments. We also summarize progress in the understanding of the performance and impact of GI in shallow groundwater environments from previous and ongoing engineering projects and academic studies. The main topics include the evaluation of the potential reduction in runoff control performance of GI, the formation of groundwater mounds, and groundwater contamination. We also assess the exploration of strategies for optimally allocating and designing GI in shallow groundwater environments. The distance between the bottom of the GI and the groundwater table, the selection of the media soil, and the design of underdrain pipes are the main considerations when implementing GI in shallow groundwater environments. The review is concluded with recommendations for future studies, which include conducting tracer monitoring and variably saturated modeling to track subsurface flows of GI, improving existing hydrological models, developing new multi-scale models, and utilizing more advanced data-driven artificial intelligence models to predict the performance and impact of GI and to process the monitoring data for model calibration.
Urban environments provide opportunities for greater resource efficiency and the fostering of urban ecosystems.
Brownfield areas are a typical example of underused land resource. Brownfield redevelopment projects that include
green infrastructure allow for further ecosystems to be accommodated in urban environments. Green infrastructure
also deliver important urban ecosystem services (UES) to local residents, which can greatly contribute to improving
quality of life in cities. In this case study, we quantify and assess the economic value of five UES for a brownfield
redevelopment project in Antwerp, Belgium. The assessment is carried out using the “Nature Value Explorer”
modelling tool. The case includes three types of green infrastructure (green corridor, infiltration gullies and green roofs)
primarily intended to connect nature reserves on the urban periphery and to avoid surface runoff. The green
infrastructure also provides air filtration, climate regulation, carbon sequestration and recreation ecosystem services.
The value of recreation far exceeds other values, including the value of avoided runoff. The case study raises crucial
questions as to whether existing UES valuation approaches adequately account for the range of UES provided and
whether such approaches can be improved to achieve more accurate and reliable value estimates in future analyses.
This paper reviews the progress made over the past few years in evaluating and controlling for spatial heterogeneity in stated preference valuation, focussing on applications to environmental valuation. Spatial heterogeneity can strongly impact value estimates, so failure to account for it can compromise their validity and reliability. Incorporating spatial factors into valuation studies not only helps to control for some potential biases, but also produces more precise evaluation of amenities that have mixed use and non-use values. For these reasons and considering the ever-growing need for non-market valuation studies, spatial heterogeneity deserves more attention in the stated preference valuation literature.
In this review we discuss the current state-of-knowledge and identify some of the main issues that have been raised in the literature in relation to spatial heterogeneity in stated preference valuation, including distance-decay, substitution, embedding effects and scale factors. We present several techniques that have been used so far, mostly originating from spatial econometrics and spatial statistics, to control for spatial heterogeneity. Some of the ongoing challenges that require further attention are also highlighted. We conclude by suggesting potential directions for future research in light of recent progress made in related disciplines and the evolution of modern technologies.
Low-impact development (LID), best management practice (BMP), and green infrastructure (GI) are semi-engineered stormwater management practices that have been widely studied and implemented worldwide. Implemented in the complex environment of urban areas, LID-BMP-GI practices often intertwine with a very large number of hydro-environmental and socio-economic considerations and constraints. Therefore, they need to be carefully selected, designed, and allocated within an urban area. Both planning and optimization can lead to more systematic and strategic approaches to address this multi-scale, multi-parameter problem of practice allocation. In this review, we first identify the main components of the strategic planning cycle, their scope and inter-relationships, and their corresponding mathematical representations. We then present a comprehensive review of the existing literature on spatial allocation optimization tools (SAOTs) for LID-BMP-GI practices and summarize the generic structure and the systematic typology of the existing SAOTs. We conclude with a discussion of several current research gaps in the spatial allocation of LID-BMP-GI practices. In this review, we aim to summarize the strategies and optimization tools for the spatial allocation of LID-BMP-GI practices that are beneficial to practitioners. The other aim is to provide recommendations for future research on the development of more advanced and comprehensive SAOTs.
In recent years, the concept transition from fail-safe to safe-to-fail makes the application of resilience analysis popular in urban drainage systems (UDSs) with various implications and quantifications. However, most existing definitions of UDSs resilience are confined to the severity of flooding, while uncertainties from climate change and urbanization are not considered. In this research, we take into account the functional variety, topological complexity, and disturbance randomness of UDSs and define a new formula of resilience based on three parts of system severity, i.e. social severity affected by urban flooding, environmental severity caused by sewer overflow, and technological severity considering the safe operation of downstream facilities. A case study in Kunming, China is designed to compare the effect of green and grey infrastructure strategies on the enhancement of system resilience together with their costs. Different system configurations with green roofs, permeable pavement and storage tanks are compared by scenario analysis with full consideration of future uncertainties induced by urbanization and climate change. The research contributes to the development of sustainability assessment of urban drainage system with consideration of the resilience of green and grey infrastructure under future change. Finding the response measures with high adaptation across a variety of future scenarios is crucial to establish sustainable urban drainage system in a long term.
The urban heat island effect is especially significant in semi-arid climates, generating a myriad of problems for large urban areas. Green space can mitigate warming, providing cooling benefits important to reducing energy consumption and improving human health. The arrangement of green space to reap the full potential of cooling benefits is a challenge, especially considering the diurnal variations of urban heat island effects. Surprisingly, methods that support the strategic placement of green space in the context of urban heat island are lacking. Integrating geographic information systems, remote sensing, spatial statistics and spatial optimization, we developed a framework to identify the best locations and configuration of new green space with respect to cooling benefits. The developed multi-objective model is applied to evaluate the diurnal cooling trade-offs in Phoenix, Arizona. As a result of optimal green space placement, significant cooling potentials can be achieved. A reduction of land surface temperature of approximately 1–2 °C locally and 0.5 °C regionally can be achieved by the addition of new green space. 96% of the potential day and night cooling benefits can be achieved through simultaneous consideration. The results also demonstrate that clustered green space enhances local cooling because of the agglomeration effect; whereas, dispersed patterns lead to greater overall regional cooling. The optimization based framework can effectively inform planning decisions with regard to green space allocation to best ameliorate excessive heat.
Multi-Criteria Decision Analysis (MCDA) methods has been promoted as an alternative approach to monetary economic valuation of ecosystem services in Cost-Benefit Analysis framework (CBA). We discuss the potential of MCDA in providing a framework for integrated valuation of ecosystem services. We conclude that MCDA does in general perform better than CBA and associated monetary valuation techniques in several aspects that are essential in ecosystem service valuation. These include the ability of a valuation method to account for multiple dimensions of well-being, including ecological and economic as well as cultural and moral aspects of a policy or management problem and to facilitate open and transparent public debate on the pros and cons of alternative courses of action, including the distribution of gains and losses across beneficiaries of ecosystem services. The capacity of MCDA to articulate values related to ecosystem services depends on individual methods used in the MCDA process. More importantly, it depends of the ways in which the process is organized and facilitated. However, MCDA cannot provide representative information of the values of wider population. Further empirical and theoretical research is needed on the potential of hybrid methodologies to combine monetary valuation and MCDA in fruitful ways.
Land-use planning is an important determinant for green space policy in cities. It defines land covers and hence the structure and function of urban ecosystems and the benefits these provide to humans, such as air purification, urban cooling, runoff mitigation, and recreation. The ecosystem service approach has helped to attract policy attention to these benefits but the concept remains poorly implemented in urban policy and governance. To address this gap, we advance a framework to bridge ecosystem services into policy processes through Multi-Criteria Decision Analysis (MCDA) as decision support tool. The paper is organized in three main parts. First, we conduct a systematic literature review to assess state-of-the-art knowledge on ecosystem service assessments through MCDA. Next, we build on insights from the literature review to develop the ‘ecosystem services policy-cycle’, a conceptual framework that merges the ‘ecosystem service cascade’ and ‘policy cycle’ models to reinforce the link between ecosystem service assessments and practical applications in urban policy and governance. Next, we illustrate the applicability of the proposed framework along an example about conflicting interests on land use and green space planning following the closure of the Airport Tempelhof in Berlin, Germany. Our results highlight the scope of MCDA as a decision support tool for integrating ecosystem service assessments in green space governance. We discuss advantages and disadvantages of different methodological choices in the use of MCDA in ecosystem service assessments and note that a key strength of this tool in informing green space policies lies in its capacity to accommodate conflicting stakeholder perspectives and to address trade-offs between ecological, social and economic values.
Land use and land use change have been proven to be leading causes of local climate change. In cities that undergo rapid urbanization, the urban heat island (UHI) can generate serious problems for the urban living environment. An appropriate overall land use plan can mitigate the detrimental effects of an UHI because it can reduce its development. However, land use decisions are driven by social and economic factors that cannot be made on the basis of moderating an UHI alone. To make a sound land use plan for Shenzhen in 2020, a rapidly urbanizing city in China suffering from UHI due to its fast land development, a genetic algorithm-based multiobjective optimization (MOO) approach was develped that addresses the objectives for future land use. The MOO provides a set of Pareto solutions and then the decision maker or planner can choose from the set of solutions. Recognizing the definite development of certain nonurban land for the local economy, three objectives were considered: (1) minimizing the increase of surface temperature, (2) minimizing the incompatibility between land uses, and (3) minimizing the cost of land use changes from the status quo. To quantify the effects of land use patterns on the UHI in Shenzhen, a self-organizing maps (SOM) method and linear regression model were used to establish the interactive relation. The relation thus obtained was then used in the MOO to help evaluate the effects of alternative land use patterns on the development of the UHI. Four scenarios were examined. The first scenario took all three objectives into account, and one optimal plan was selected randomly from the Pareto set as the first scenario, whereas the other three scenarios considered one objective each. Results showed that MOO can make tradeoffs among the conflicting objectives, indicating that the optimized land use plans can minimize the increasing UHI effects and at the same time attempt to achieve other objectives in the process of land development.
In a site-selection choice experiment various hypotheses are tested related to spatial heterogeneity in willingness to pay (WTP) for environmental improvements. Spatial heterogeneity is measured through distance-decay effects, substitute sites inside and outside the experiment’s choice set, and spatial trend variables. We demonstrate that distance-decay functions differ between users and nonusers and across study sites. Also the distance to substitutes outside the choice set explains spatial variation in WTP. We show that further extending the model with spatial trend variables reveals additional spatial heterogeneity in choices. Accounting for spatial heterogeneity patterns results in significantly different WTP estimates for environmental improvements. (JEL Q25, Q51)
Soil infiltration is a critical component of most urban runoff models. However, it has been well documented that, during urbanization, soils are greatly modified, especially in relation to soil density. Increased soil compaction results in soils that do not behave in a manner predicted by traditional infiltration models. Laboratory and field tests were conducted to investigate detailed infiltration behavior of disturbed urban soils for a variety of soil textures and levels of compaction. The results from traditional permeability tests on several soil groups showed that, as expected, the degree of compaction greatly affected the steady-state infiltration rate. The field tests highlighted the importance of compaction on the infiltration rate of sandy soils, with minimal effect seen from antecedent moisture conditions. For the clayey soils, however, both the compaction level and antecedent moisture conditions were important in determining the steady-state infiltration rate.
Research on mitigating land use conflicts is characterized by a variety of projects from the global to various sub-global scales. These projects are aiming at disentangling feedbacks within changing socio-environmental systems to identify strategies for sustainable resource use. Our review shows that any global
analysis benefits from systematic synthesis of sub-global research from various scales, while sub-global investigations require embedding in global scenarios. There is an urgent need for improved methods to identify trade-offs at all scales as scenario analysis frequently results in a discrete set of options.
We argue that the use of optimization algorithms including Pareto-frontiers combined with scenario analysis can provide efficient options for sustainable land use from global to subglobal scales.