Search Results (8)

Europe’s ambition to be the first climate-neutral continent and to achieve net-zero greenhouse gas emissions by 2050 will result in changes to the energy systems of many countries. This overlaps with the principles of circular economy, energy independence, and the continuity of operations enshrined in many national and regional documents. From the above, a scenario based on renewable resources emerges. However, in a country such as Poland, with conventional energy sources and large state participation in the sector, is this feasible? The authors assumed that the urgent need for a turbulence-sensitive analysis of energy sector changes can be met by using a new view, defined by the authors as a matrix of four oceans scenarios. Black, Grey, Red and Green scenarios are determined by the proportion of the state and the local-community sector. Then, assuming the possibility of introducing two of them by 2050—Green (radical) and Red (competitive)—empirical research was carried out on a purposively selected group of experts. The business model of the sector was analyzed in terms of six links that create economic and social value: energy sources, energy producers, transmission networks with infrastructure, energy storage, energy system management and energy consumers. According to experts, development of business model links will be based on the Red scenario. Thus, we get a picture of a model that should be considered by politicians, scientists, as well as a wide audience that absorbs the effects of environmental pollution. Full article

Cities are challenged by climate change impacts, such as extreme rainfall events that affect conventional urban water management systems via increased sewage water overflows resulting in water quality deterioration and urban floods causing infrastructure damage. Investments in blue–green infrastructure (BGI) are increasingly considered to address these issues. However, these should be cost-effective. In this study, the effectiveness of five different BGI strategies and one grey strategy are assessed for a peri-urban catchment area in Oslo (Grefsen) using a cost–benefit analysis. The strategies include (i) wadis; (ii) green roofs; (iii) raingardens, rain barrels and wadis; (iv) infiltration crates; (v) water squares, and (vi) a separate sewage system. Besides economic effectiveness, the study also aims to identify the proper protection level by comparing cost–benefit ratios and net benefits for 60-min rainfall events occurring once every 5, 20, and 100 years (M5, M20, and M100), concerning both the current situation and under future climate change (using the Representative Concentration Pathway 8.5). The analyses revealed the highest BC ratios for wadis (12.0–17.3), separate sewage systems (7.7–15.1), and a combination of raingardens, rain barrels, and wadis (1.6–2.3). Strategies dimensioned for less frequent but more intensive rainfall events yielded higher BC ratios. Results for infiltration crates were difficult to interpret and were found to be very sensitive to input parameters. The other strategies implied a negative BC ratio. The study concludes that investments in BGI in Grefsen, Oslo, can be positively judged from a social–economic perspective and provide suitable information for water-related decision makers to decide upon the strategy selection and the appropriate flood protection level. Full article

The Mediterranean region is a hot spot for climate change, and cities of this area will be exposed to both increasing temperatures and decreasing precipitations. Green Infrastructures (GIs) can lower urban temperatures through evapotranspiration with an adequate soil moisture content. Grey water reuse can both guarantee the right soil moisture content and reduce freshwater exploitation. In order to test the effectiveness of soil moisture on reducing air temperature, two modelling simulations ran with the microclimate CFD-based model ENVI-met 4.0. The chosen day was a registered heat wave (7 July 2019) in Lecce, a city of south Italy, which was selected as case study for the Mediterranean area. The results demonstrated the effectiveness of soil moisture on evapotranspiration in reducing air temperature. From a circular economy perspective, the supply of grey water for urban GIs represents a strategic adaptation strategy to the expected effects of climate change on the Mediterranean basin. Full article

This paper presents the performance quantification of different green-grey infrastructures, including rainfall-runoff and infiltration processes, on the overland flow and its connection with a sewer system. The present study suggests three main components to form the structure of the proposed model-based assessment. The first two components provide the optimal number of green infrastructure (GI) practices allocated in an urban catchment and optimal grey infrastructures, such as pipe and storage tank sizing. The third component evaluates selected combined green-grey infrastructures based on rainfall-runoff and infiltration computation in a 2D model domain. This framework was applied in an urban catchment in Dhaka City (Bangladesh) where different green-grey infrastructures were evaluated in relation to flood damage and investment costs. These practices implemented separately have an impact on the reduction of damage and investment costs. However, their combination has been shown to be the best action to follow. Finally, it was proved that including rainfall-runoff and infiltration processes, along with the representation of GI within a 2D model domain, enhances the analysis of the optimal combination of infrastructures, which in turn allows the drainage system to be assessed holistically. Full article

Water sensitive urban design (WSUD), as a typical green stormwater infrastructure (GSI), contains various facilities to decrease the urbanization impacts and enhance the values of amenity, ecosystem, and livability in Australia. Although WSUD has developed over 30 years, existing studies for WSUD performances have sometimes ignored its economic and social benefits, and there is still a lack of an integrated framework to optimize the GSI combinations based on various criteria in a site. This paper aims to utilize “score-rank-select” strategy to comprehensively assess WSUD combination scenarios from functional, economic, social, and environmental aspects, by taking the University of Melbourne (Parkville campus) as a case study. In detail, multi-criteria decision analysis (MCDA) was used for weight determination and scenario comparison. The results showed that scenario 4 with 52% green WSUD facilities had the highest assessment score (0.771) among the five scenarios, while the final score (0.758) of scenario 5 was lower than scenario 4 although its green facility proportion reached 69%. The trade-off relation between the proportion of grey and green WSUD facilities was further demonstrated. Additionally, this paper strongly recommends that the MCDA-based comprehensive assessment framework described here can be generally promoted for the water sector to solve the decision-making problems. The use of such a framework can further promote sustainable development by helping water managers to make informed and inclusive decisions involving a variety of factors. Full article

Nagpur is rapidly urbanizing, and in the process witnessing decline in its green status which is one of the identities of the city. The study aims to understand the current species diversity, composition and structure in different classes of greens prevalent in the city. As urban green spaces (UGS) are also reservoirs of carbon stock, the study estimates their biomass. Through rigorous field work, data were collected from 246 sample plots across various UGS classes as pre-stratification. Then the biomass was estimated using non-destructive method with species-specific equation. The diversity of tree species recorded in UGS varies, with high diversity recorded in avenue plantation and institutional compounds. The overall variation in species composition among UGS classes was 36.8%. While in managed greens the species composition was similar, in institutional greens and forest it was different. Particularly, in forest the evenness was high with low diversity and low species richness. The structural distribution indicate lack of old trees in the city, with high number of tree species between diameter classes of 10–40 cm. Biomass was recorded high in road-side plantations (335 t ha⁻¹) and playgrounds (324 t ha⁻¹), and trees with bigger girth size where the main contributors. The dominant species indicates that high growth rate, tolerance to drought and pollution are the key attributes considered for species selection by local authorities. Though the city holds green image, vegetation along the avenues and institutions are stressed, exposed, and threatened by felling activities for grey infrastructure expansions. In such scenario, protection and preservation of older trees is crucial to maintain the carbon stock of the city. In addition, local authorities need to focus on effective afforestation programs through public participation to achieve high survival rate and reduce the maintenance cost. For species selection in addition to phenology and growth rate, tree biomass and life span needs to be considered to significantly enhance the urban environment and increase the benefits derived from UGS. Full article

The present paper describes a methodological framework that combines ecosystem services (flood protection, education, art/culture, recreation and tourism) with economic analysis for selection of multifunctional measures for flood resilience. The framework includes active stakeholder participation and it consists of the four main components: (1) identification and valuation of ecosystem services pertinent to the project site under various mitigation scenarios, including baseline (pre-mitigation conditions); (2) evaluation of most effective flood mitigation measures through hydrodynamic simulations, and evaluation of economic viability using cost-benefit analysis; (3) selection of measures through consideration of ecosystem services, and solicitation of stakeholders’ inputs; (4) development of the conceptual landscape design. Application of the framework was demonstrated in a case study of Ayutthaya Island, Thailand. Results of our research suggest that taking a holistic perspective of ecosystem services and economic assessments, marshalled through active stakeholder participation, has the potential to achieve more ecologically sustainable and socially acceptable solutions for flood protection in areas with cultural heritage. However, there is still a considerable challenge in taking this framework to a full-scale practical implementation, and this mainly relates to the selection of indicators that can enable proper application of ecosystem services. Full article

Recent research suggests future alterations in rainfall patterns due to climate variability, affecting public safety and health in urban areas. Urban growth, one of the main drivers of change in the current century, will also affect these conditions. Traditional drainage approaches using grey infrastructure offer low adaptation to an uncertain future. New methodologies of stormwater management focus on decentralized approaches in a long-term planning framework, including the use of Green Infrastructure (GI). This work presents a novel methodology to select, evaluate, and place different green-grey practices (or measures) for retrofitting urban drainage systems. The methodology uses a hydrodynamic model and multi-objective optimization to design solutions at a watershed level. The method proposed in this study was applied in a highly urbanized watershed to evaluate the effect of these measures on Combined Sewer Overflows (CSO) quantity. This approach produced promising results and may become a useful tool for planning and decision making of drainage systems. Full article