Permeable Asphalt Hydraulic Conductivity and Particulate Matter Separation With XRT

Permeable asphalt (PA) is a composite material with an open graded mix design that provides a pore structure facilitating stormwater infiltration. PA is often constructed as a wearing course for permeable pavements and on impervious pavements to reduce aquaplaning and noise. The pore structure of PA functions as a filter promoting particulate matter (PM) separation. The infiltrating flow characteristics are predominately dependent on pore diameter and pore interconnectivity. X-Ray microTomography (XRT) has successfully estimated these parameters that are otherwise difficult to obtain through conventional gravimetric methods. Pore structure parameters allow modeling of hydraulic conductivity (k) and filtration mechanisms; required to examine the material behavior for infiltration and PM separation. In this study, pore structure parameters were determined through XTR for three PA mixture designs. Additionally, the Kozeny-Kovav model was implemented to estimate k. PM separation was evaluated using a pore-to-PM diameter categorical model. This filtration mechanism model was validated with data from a rainfall simulator. The filtration model provided a good correlation between measured and modeled data. The identification of filtration mechanisms and k facilitate the design and evaluation of permeable pavement systems as a best management practice (BMP) for runoff volume and peak flow as well as PM and PM-partitioned chemical separation

Probabilistic Approach to Tank Design in Rainwater Harvesting Systems

Storage tanks from rainwater harvesting systems (RWHs) are designed to provide flow equalization between rainfall and water demand. The minimum storage capacity required to take into account the maximum variations of stored water volumes, i.e., the active storage, depends basically on the magnitude and the variability of rainfall profiles and the size of the demand. Given the random nature of the variables involved in the hydrological process, probability theory is a suitable technique for active storage estimation. This research proposes a probabilistic approach to determine an analytical expression for the cumulative distribution function (CDF) of the active storage as a function of rainfall moments, water demand and the mean number of consecutive storm events in a deficit sub-period. The equation can be used by developers to decide on the storage capacity required at a desired non-exceedance probability and under a preset water demand. The model is validated through a continuous simulation of the tank behavior using rainfall time series from Milan (Northern Italy)

Laboratory Assessment of the Infiltration Capacity Reduction in Clogged Porous Mixture Surfaces

Permeable pavements have been used widely across the world to manage urban stormwater. The hydrological behaviour of permeable surfaces is a complex process affected by many factors, such as rainfall intensity, rainfall duration, pavement geometrical conditions, and clogging level of the permeable surface, amongst others. This laboratory study was carried out to assess the influence of clogging level and rainfall intensity on the infiltration capacity of porous mixture surfaces used in Permeable Pavement Systems (PPS). Porous Concrete (PC) and Porous Asphalt (PA) mixtures with different air void contents (15%, 20%, and 25%) were subject to different clogging scenarios by using varying sediment loads (0, 500, and 1000 g/m2). Permeability experiments were carried out for each clogging scenario through a new rainfall simulator specially developed, tailored, and calibrated for the laboratory simulation of a wide range of rainfall events. Permeability measurements were taken under all different scenarios as a result of the combination of the different rainfall events (50, 100, and 150 mm/h) simulated over the specimens of porous mixtures and the sediment loads applied to them. The results showed that the PC mixtures tested perform better than the PA ones in terms of infiltration capacity, showing less potential for clogging and being more easily cleaned by the wash-off produced by the simulated rainfall events

Permeable Pavements Efficiency Under Clogging and Pollutants Load Removal

Permeable pavement is used to reduce stormwater volume, peak flow and promote pollutant load removal (Scholz and Grabowiecki, 2007, Brunetti et al., 2016, Marchioni and Becciu, 2014). The volume reduction depends on the base depth, while peak flow and loads removal are dependent on the surface layer, that must present a hydraulic conductivity capable of significantly limiting runoff; while the pore structure acts as a filter retaining particulate matter (PM), deriving from erosive phenomena and anthropogenic activities. The infiltration capacity tends to decrease over time due to the PM accumulation. An adequate maintenance program guarantees that hydraulic conductivity remains above a threshold. The infiltration capacity is a function of the characteristics of the material used in the surface layer, normally permeable concrete (PC), porous asphalt (PA) or interlocking concrete blocks. For this research a series of a rainfall simulation tests were used to analyze the hydrological and load removal response of permeable pavement surface under clogging. Results confirm the permeable efficiency under clogging on stormwater runoff reduction and pollutants removal

Soluções Baseadas na Natureza como instrumento de melhoria da arborização urbana, auxiliando na construção de cidades sensíveis à água e resilientes às mudanças climáticas

iante do contexto de mudanças climáticas, torna-se cada vez mais imperativa a adoção de estratégias para a construção de paisagens mais resilientes, que consigam responder aos eventos climáticos extre-mos, como as chuvas intensas e os períodos de estiagem prolongados, que já podem ser observados e segundo às previsões serão ainda mais críticos nas próximas décadas. O conceito de cidades sensíveis à água estabelece os princípios para a construção de um ambiente urbano saudável, onde sejam agregados serviços ecossistêmicos, desempe-nhado pelos elementos naturais, ao território e a sua comunidade. A arborização urbana é essencial nesse processo, já que atua na manu-tenção de diversos processos de regulação, de provisão, culturais e de suporte. Apesar de sua importância a arborização urbana encontra nas grandes cidades um ambiente altamente adverso ao seu desen-volvimento, principalmente no que se refere à disponibilidade hídrica, de nutrientes e de espaço para o seu crescimento adequado, sendo a queda das árvores urbanas durante chuvas intensas responsável por danos ao patrimônio e às pessoas. O pivotamento, ou seja, a queda com o soerguimento de todo o sistema radicular, é causado pelo de-senvolvimento inadequado do sistema radicular, que em áreas urbanas se dá devido principalmente a compactação do solo dos passeios pú-blicos ou calçadas; a má distribuição da umidade por todo o volume de solo abaixo do calçamento também contribui para limitar o desen-volvimento das raízes, somado a isso temos muitas vezes a escolha inadequada de espécies que não observa as características do local. As áreas dos canteiros, responsáveis pela captação das águas das chu-vas, não são suficientes para coletar um volume de água que permita um ambiente adequado desenvolvimento do sistema radicular e da árvore como um todo. Pavimentos permeáveis, que permitem a infil-tração da água no solo e armazenam parte das águas pluviais, podem potencializar um habitat favorável ao desenvolvimento vegetal. Neste estudo foram simulados os processos hidrológicos nos passeios públi-cos com diferentes configurações com o objetivo de verificar o efeito da implantação de pavimentação permeável na disponibilidade hídrica como instrumento da manutenção da arborização urbana. Os resul-tados obtidos demonstram a potencialidade do uso destes sistemas para aumentar a disponibilidade hídrica no solo para mantenimento da arborização urban

Children’s and adolescents’ rising animal-source food intakes in 1990–2018 were impacted by age, region, parental education and urbanicity

Animal-source foods (ASF) provide nutrition for children and adolescents’ physical and cognitive development. Here, we use data from the Global Dietary Database and Bayesian hierarchical models to quantify global, regional and national ASF intakes between 1990 and 2018 by age group across 185 countries, representing 93% of the world’s child population. Mean ASF intake was 1.9 servings per day, representing 16% of children consuming at least three daily servings. Intake was similar between boys and girls, but higher among urban children with educated parents. Consumption varied by age from 0.6 at <1 year to 2.5 servings per day at 15–19 years. Between 1990 and 2018, mean ASF intake increased by 0.5 servings per week, with increases in all regions except sub-Saharan Africa. In 2018, total ASF consumption was highest in Russia, Brazil, Mexico and Turkey, and lowest in Uganda, India, Kenya and Bangladesh. These findings can inform policy to address malnutrition through targeted ASF consumption programmes.publishedVersio

Incident type 2 diabetes attributable to suboptimal diet in 184 countries

The global burden of diet-attributable type 2 diabetes (T2D) is not well established. This risk assessment model estimated T2D incidence among adults attributable to direct and body weight-mediated effects of 11 dietary factors in 184 countries in 1990 and 2018. In 2018, suboptimal intake of these dietary factors was estimated to be attributable to 14.1 million (95% uncertainty interval (UI), 13.8–14.4 million) incident T2D cases, representing 70.3% (68.8–71.8%) of new cases globally. Largest T2D burdens were attributable to insufficient whole-grain intake (26.1% (25.0–27.1%)), excess refined rice and wheat intake (24.6% (22.3–27.2%)) and excess processed meat intake (20.3% (18.3–23.5%)). Across regions, highest proportional burdens were in central and eastern Europe and central Asia (85.6% (83.4–87.7%)) and Latin America and the Caribbean (81.8% (80.1–83.4%)); and lowest proportional burdens were in South Asia (55.4% (52.1–60.7%)). Proportions of diet-attributable T2D were generally larger in men than in women and were inversely correlated with age. Diet-attributable T2D was generally larger among urban versus rural residents and higher versus lower educated individuals, except in high-income countries, central and eastern Europe and central Asia, where burdens were larger in rural residents and in lower educated individuals. Compared with 1990, global diet-attributable T2D increased by 2.6 absolute percentage points (8.6 million more cases) in 2018, with variation in these trends by world region and dietary factor. These findings inform nutritional priorities and clinical and public health planning to improve dietary quality and reduce T2D globally.publishedVersio

Infiltration-Exfiltration System for Stormwater Control: A Full Scale Test

The current approach to stormwater management should focus on dealing with water on its source. The Sustainable Urban Drainage Systems (SuDS) promotes runoff peak flow and volume attenuation, load removal while providing amenites and biodiversities but can be difficult to apply in developed urban centers. An infiltration-exfiltration system (IES) placed on road gutters can function on receiving runoff from roads and directing them to the sewers system reducing peak flow and volume. This research follows up a full-scale test of an IES installed in São Paulo, Brazil. The IES has 49 × 1880 m dimension and a cross-section of 49 × 30 cm with a pervious concrete surface layer. The pervious concrete showed mechanical results acceptable for a low vehicular traffic and infiltration rate that allows water infiltration. Rainfall-runoff modeling showed that the proposed IES had a low effect on runoff peak flow and volume attenuation. A deeper gravel layers depth and outlet flow restrictor would improve performance. The proposed IES function on avoid ponding, promoting water treatment, and reducing inlet maintenance