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1.
J Environ Manage ; 259: 109649, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32072941

RESUMO

In recent years, many studies have been conducted on using different filter media in bioretention systems for stormwater runoff treatment. This critical review paper provides a comprehensive review on the current state of water treatment residual (WTR), a recycled material that can be used as bioretention filter media for removals of key stormwater runoff pollutants (especially phosphorus) and future perspectives with innovative modification on WTR applied for pathogen removal from stormwater runoff. This review paper comprised (i) a brief summary of the reported WTR characteristics, (ii) a thorough evaluation of WTR performance on major pollutants removal from stormwater runoff (iii) a discussion on phosphorus removal mechanisms by WTR applied in the stormwater runoff treatment, and (iv) a review of the future perspectives of WTR for pathogen removal and other potential practical application in the field of stormwater treatment. As outlined in this review, WTR in stormwater runoff treatment has yet to be fully explored. The possible enhancements, especially metal surface modification on WTR are reviewed to bring about the widespread use of WTR in stormwater reuse practices.


Assuntos
Poluentes Ambientais , Poluentes Químicos da Água , Purificação da Água , Fósforo , Chuva , Abastecimento de Água
2.
Water Res ; 171: 115395, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31918386

RESUMO

Stormwater harvesting (SWH) provides multiple benefits to urban water management. Other than providing water for human use, it also reduces the volume of polluted stormwater discharge to the environment. There are currently no methods available to quantify the additional environmental benefits, which could encourage greater uptake of the practice. This paper investigates a number of factors (climate and catchment characteristics, pollutant reduction targets, etc.) that could impact upon the benefits of SWH for pollution reduction through sensitivity analyses. A method was developed and tested for quantification of the pollution mitigation benefits by SWH under different scenarios. A novel indicator, Impervious Area Offset (IAO), was proposed to reflect the additional impervious area that can be left untreated to achieve the equivalent pollution load reduction targets due to the introduction of SWH. Results indicate significant correlations (p < 0.01) between IAO values and extraction rate (proportion of total annual runoff removed due to the harvesting system and water use substitution), system type, and pollutant reduction targets. The proposed linear empirical relationships between IAO values and extraction rate for different types of system configurations and pollution reduction targets were well represented by observed linear regression (average R2 = 0.98 for all tested scenarios). Empirical relationships were validated successfully against different scenarios, with differences between predicted IAO and baseline IAO values being only ±4.5% for the majority of the validation scenarios. Using this simple and reliable method to rapidly quantify SWH benefits can further add to the growing business case of adopting SWH practices.


Assuntos
Movimentos da Água , Poluentes Químicos da Água , Monitoramento Ambiental , Poluição Ambiental , Chuva , Água
3.
J Environ Manage ; 256: 109971, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31989987

RESUMO

Wetland ecosystems have a disproportionally large influence on the global carbon cycle. They can act as carbon sinks or sources depending upon their location, type, and condition. Rehabilitation of wetlands is gaining popularity as a nature-based approach to helping mitigate climate change; however, few studies have empirically tested the carbon benefits of wetland restoration, especially in freshwater environments. Here we investigated the effects of passive rehabilitation (i.e. fencing and agricultural release) of 16 semi-arid rain-filled freshwater wetlands in southeastern Australia. Eight control sites were compared with older (>10 year) or newer (2-5 year) rehabilitated sites, dominated by graminoids or eucalypts. Carbon stocks (soils and plant biomass), and emissions (carbon dioxide - CO2; and methane - CH4) were sampled across three seasons, representing natural filling and drawdown, and soil microbial communities were sampled in spring. We found no significant difference in soil carbon or greenhouse gas emissions between rehabilitated and control sites, however, plant biomass was significantly higher in older rehabilitated sites. Wetland carbon stocks were 19.21 t Corg ha-1 and 2.84 t Corg ha-1 for soils (top 20 cm; n = 137) and plant biomass (n = 288), respectively. Hydrology was a strong driver of wetland greenhouse gas emissions. Diffusive fluxes (n = 356) averaged 117.63 mmol CO2 m2 d-1 and 2.98 mmol CH4 m2 d-1 when wet, and 124.01 mmol CO2 m2 d-1 and -0.41 mmol CH4 m2 d-1 when dry. Soil microbial community richness was nearly 2-fold higher during the wet phase than the dry phase, including relative increases in Nitrososphaerales, Myxococcales and Koribacteraceae and methanogens Methanobacteriales. Vegetation type significantly influenced soil carbon, aboveground carbon, and greenhouse gas emissions. Overall, our results suggest that passive rehabilitation of rain-filled wetlands, while valuable for biodiversity and habitat provisioning, is ineffective for increasing carbon gains within 20 years. Carbon offsetting opportunities may be better in systems with faster sediment accretion. Active rehabilitation methods, particularly that reinstate the natural hydrology of drained wetlands, should also be considered.


Assuntos
Ecossistema , Áreas Alagadas , Austrália , Dióxido de Carbono , Metano , Chuva , Solo
4.
Water Res ; 171: 115440, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31955059

RESUMO

Managing waterborne and water-related diseases is one of the most critical factors in the aftermath of hurricane-induced natural disasters. The goal of the study was to identify water-quality impairments in order to set the priorities for post-hurricane relief and to guide future decisions on disaster preparation and relief administration. Field investigations were carried out on St. Thomas, U.S. Virgin Islands as soon as the disaster area became accessible after the back-to-back hurricane strikes by Irma and Maria in 2017. Water samples were collected from individual household rain cisterns, the coastal ocean, and street-surface runoffs for microbial concentration. The microbial community structure and the occurrence of potential human pathogens were investigated in samples using next generation sequencing. Loop mediated isothermal amplification was employed to detect fecal indicator bacteria, Enterococcus faecalis. The results showed both fecal indicator bacteria and Legionella genetic markers were prevalent but were low in concentration in the water samples. Among the 22 cistern samples, 86% were positive for Legionella and 82% for Escherichia-Shigella. Enterococcus faecalis was detected in over 68% of the rain cisterns and in 60% of the coastal waters (n = 20). Microbial community composition in coastal water samples was significantly different from cistern water and runoff water. Although identification at bacterial genus level is not direct evidence of human pathogens, our results suggest cistern water quality needs more organized attention for protection of human health, and that preparation and prevention measures should be taken before natural disasters strike.


Assuntos
Tempestades Ciclônicas , Qualidade da Água , Fezes , Humanos , Ilhas , Chuva , Ilhas Virgens Americanas , Microbiologia da Água
5.
Ground Water ; 58(1): 125-131, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31037740

RESUMO

Locally collected precipitation water can be actively used as a groundwater tracer solution based on four inherent tracer signals: electrical conductivity, stable isotopic signatures of deuterium [δ2 H], oxygen-18 [δ18 O], and heat, which all may strongly differ from the corresponding background values in the tested groundwater. In hydrogeological practice, a tracer test is one of the most important methods for determining subsurface connections or field parameters, such as porosity, dispersivity, diffusion coefficient, groundwater flow velocity, or flow direction. A common problem is the choice of tracer and the corresponding permission by the appropriate authorities. This problem intensifies where tracer tests are conducted in vulnerable conservation or water protection areas (e.g., around drinking water wells). The use of (if required treated) precipitation as an elemental groundwater tracer is a practical solution for this problem, as it does not introduce foreign matters into the aquifer system, which may contribute positively to the permission delivery. Before tracer application, the natural variations of the participating end members' tracer signals have to be evaluated locally. To obtain a sufficient volume of tracer solution, precipitation can be collected as rain using a detached, large-scale rain collector, which will be independent from possibly existing surfaces like roofs or drained areas. The collected precipitation is then stored prior to a tracer experiment.


Assuntos
Água Subterrânea , Monitoramento Ambiental , Chuva , Água , Movimentos da Água
6.
Water Res ; 169: 115241, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31698150

RESUMO

This study examined whether the accumulation of nitrogen (legacy nitrogen) within and surrounding leaching pools for onsite wastewater treatment may act as a source of nitrogen contamination to groundwater upon changes to the quantity and/or composition of the influent to the pool. In this study, one concrete leaching pool with neutral pH (A, pH 6.9) and one leaching pool after acid washing (B, pH 3.7) were selected to examine the quantity and composition of legacy nitrogen in the surrounding soil, as well as evaluate the potential release of this nitrogen under two environmentally relevant leaching scenarios: (i) the concrete leaching pool serves as the final discharge unit for aerobic treatment unit (ATU) effluent; (ii) extreme weather events (flash flood/heavy rains) act to increase the quantity and dilute the composition of flow to the pool. Core sample analysis showed that organic nitrogen accounts for the majority (97.3-99.7%) of the total nitrogen (TN) at site A (4.1 ±â€¯0.6 mg N/g soil) and site B (3.0 ±â€¯0.4 mg N/g soil); while ammonium was the major form of inorganic nitrogen present at the sites. The TN accumulated under the two leaching pools was equivalent to approximately 17-39 days of nitrogen loading to the system. pH had a significant impact on the mass of TN leached from the soil, while no significant difference in leached TN was observed for the two leaching scenarios. The amount of TN leached from the soil matrix was not affected by the flow rate (18.6 mL/d in scenario i vs. 547.2 mL/d in scenario ii) or flow pattern (intermittent dosing vs. continuous flow). The quantity of TN leached from soils in both scenario (i) and (ii) was low and accounted for 2.6-8.9% of the total nitrogen in the soil.


Assuntos
Poluentes do Solo , Solo , Nitrogênio , Chuva , Águas Residuárias
7.
Water Res ; 169: 115257, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31726396

RESUMO

Stormwater biofilters have great potential to treat stormwater for harvesting and reuse, but their variable performance in pathogen removal requires further optimisation prior to widespread uptake. This paper provides the first evidence that real time control (RTC) of stormwater biofilters can mitigate the impact of operational characteristics that result in poor microbial removal. We developed two RTC strategies and validated them using long-term laboratory experiments, utilising biofilters with a raised outlet pipe that creates a submerged zone. The first RTC strategy focuses on delivering the best water quality for harvesting and reuse or for recreational waterways. It has two components which ensure adequate treatment (microbial die-off): (1) it retains water in the biofilter for at least two days before allowing any further inputs into the system, and (2) the input volume is restricted to the submerged zone's pore volume. This strategy was effective and significantly improved water quality in the biofilter effluent. However, since the system favours bypassing influent to ensure good quality effluent, only 28.4% of the stormwater was treated. This still resulted in a 62.3% reduction in the influent E. coli load because the system was effective at removing E. coli under controlled conditions. The second RTC strategy builds upon the first strategy, and focuses on delivering a balance between good water quality for harvesting and protecting the environment (i.e., lower bypass). Three hours before the next rainfall event begins, the water that has remained in the biofilter's submerged zone for at least two days is drained and collected for harvesting through a bottom pipe. When stormwater inflow begins, the bottom pipe is closed and the biofilter operates without control, with water leaving the biofilter to the environment via the raised outlet pipe. The harvested effluent of this RTC strategy met the Australian stormwater harvesting guideline requirements for dual reticulation with indoor and outdoor use and irrigation of commercial food crops. Although only 5.4% of stormwater was collected for harvesting in this strategy, the environment was better protected because of a significantly reduced bypass volume. Our experiments also showed that the nutrient and sediment removal was high for both RTC strategies. This study presents the first stepping stone toward RTC of stormwater biofilters, demonstrating that these systems can deliver safe stormwater for harvesting and reuse, and for active recreational uses.


Assuntos
Filtração , Purificação da Água , Austrália , Escherichia coli , Chuva , Qualidade da Água
8.
Water Environ Res ; 92(1): 106-114, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31344757

RESUMO

This study determines the exfiltration rates in six tree boxes with embedded sensors and analyzes their hydrologic performance for 2 years to quantify the effect of different parameters (i.e., water depth, temperature, and age) on the exfiltration rate. Each tree box is 1.5 m wide, 1.5 m long, and 1.8 m deep. A 46-cm-diameter shaft was drilled at the bottom of each tree box to reach the underlying permeable soil layer. The water level inside the shaft rose up to 500 cm. Exfiltration rate increased with water level and exfiltration rate in second year decreased significantly by 27%-37% compared with first year. Overall, in the second year, the decrease in geometric mean exfiltration rate was largest for moderate depths of the standing water inside the shaft, ranging between 100 and 130 cm from the bottom of the shaft. The exfiltration rate of the tree boxes was significantly larger for warmer season and significantly smaller for cooler season. The infiltration rate of the underlying soil is a controlling factor of the performance of tree box. PRACTITIONER POINTS: The study determines the exfiltration rates in six tree boxes and analyzes their performance over time. Exfiltration rate in second year decreased significantly by 27%-37% compared to first year. The exfiltration rate of the tree boxes was larger for warmer rain events and smaller for cooler rain events. Tree boxes with lower permeable underlying soil developed higher water level in the shaft.


Assuntos
Árvores , Movimentos da Água , Hidrologia , Chuva , Solo
9.
Water Res ; 170: 115336, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31841771

RESUMO

Bioretention systems are efficient at removing particulates, metals, and hydrocarbons from stormwater runoff. However, managing dissolved nitrogen (N) species (dissolved organic N, NH4+, NO2-, NO3-) is a challenge for these systems. This paper reports the results of a long-term field study comparing N removal of: 1) a modified bioretention system that included an internal water storage zone containing wood chips to promote denitrification and 2) a conventional bioretention system. The systems were studied, without and with plants, under varying hydraulic loading rates (HLRs) and antecedent dry conditions (ADCs). Both bioretention designs were efficient at removing NH4+ (83% modified, 74% conventional), while removal of NOx (NO2--N + NO3--N) was significantly higher in the modified system (81% modified, 29% conventional). Results show that the addition of an internal water storage zone promotes denitrification, resulting in lower effluent TN concentrations (<0.75 mg/L modified, ∼1.60 mg/L conventional). The lowest HLR studied, 4.1 cm/h, provided the longest hydraulic retention time in the internal water storage zone (∼3 h) and had the greatest TN removal efficiency (90% modified, 59% conventional). In contrast to prior short-term studies, ADCs between 0 and 13 days did not significantly affect DOC export or TN removal. A short-term study with Florida friendly vegetation indicated that TN removal performance was enhanced in the conventional bioretention system. This field study provides promising results for improving dissolved N removal by modifying bioretention systems to include an internal water storage zone containing wood chips.


Assuntos
Nitrogênio , Purificação da Água , Desnitrificação , Florida , Chuva
10.
Water Res ; 170: 115322, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31884396

RESUMO

Pervious pavements are one of the most used construction techniques among the Sustainable Urban Drainage Systems (SUDS). The objective of this article is to analyse the energy life cycle and the life cycle cost of stormwater harvesting systems using pervious pavements models in order to compare and evaluate the differences and verify what influences the profitability and sustainability. The method proposed started with the definition of pervious pavement models based on literature review. The main characteristic of the models analysed was the use of porous asphalt with different underlying layers, i.e. thickness and material. The hydrological-hydraulic design of the pavements was also assessed. The potential for potable water savings due to harvesting stormwater from a parking lot was estimated for a public building in Florianópolis, southern Brazil. The models were compared to identify what most influences the potable water savings, the profitability and the sustainability of the systems. The maximum potable water savings found were 42%. It was also observed that the overall consumption of the building has been decreasing over the years, and the yearly rainfall has increased, which leads to a higher potential. In the current water consumption pattern, none of the systems evaluated was profitable or presented sustainability, evaluated herein as negative energy balance. However, it was verified that if analysed comparatively with non-pervious pavement, it was profitable to use stormwater harvested from the pervious pavement. Thus, it can be concluded that stormwater harvesting systems in combination with pervious pavements are promising, serving as SUDS and saving money for users. It is also noticeable that the use of porous asphalt is not recommended when aiming for systems with low embedded energy.


Assuntos
Água Potável , Chuva , Animais , Brasil , Estudos de Viabilidade , Porosidade
11.
Sci Total Environ ; 700: 134421, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31693953

RESUMO

The elemental concentrations of both plants and soils are sensitive to variations in precipitation due to the limiting roles of water on soil processes and plant growth in karst ecosystems of Southwestern China; however, precipitation is predicted to increase in this region. Nevertheless, it is unclear how the elemental composition of soils and plants might respond to such increases in moisture. Particularly, how potassium (K) may behave as a key mediator in the regulation of the water potential of plants. For this study, the responses of the elemental composition of both soils and plants to the variable addition of water were investigated. Two grasses (Cymbopogon distans and Arundinella setosa) and two shrubs (Carissa spinarum and Bauhinia brachycarpa) were investigated under four levels of watering treatments 0%, +20%, +40%, and +60%, relative to the annual rainfall, respectively. Compared to the control (CK), the soil water content (SWC) increased to 3.75, 3.86, and 4.34 mg g-1 in T1, T2, and T3 groups, respectively (p < 0.05). Non-metal elements (C, H, N, S, and P, except for Si) in the soil were relatively stable with water addition; however, metal elements (Al, Na, Mg, Fe, and K, along with Si) increased significantly, whereas Zn and Ca decreased (p < 0.05). With water addition, leaf N and P remained unchanged in all four species, while K, Mg, and S decreased in both shrubs (higher C:K, N:K, and P:K). Increases in Fe, Si, and K were observed in both grasses (lower C:K, N:K, and P:K), which suggested that K played distinct roles for water regulation in shrubs and grasses. These findings implied that the elemental compositions of both soils and plants might be altered with increasing precipitation in the future, where different plant types may adopt distinct K-regulation strategies to cope with variable soil moisture.


Assuntos
Ecossistema , Monitoramento Ambiental , Plantas , Chuva , China , Poaceae
12.
Chemosphere ; 239: 124750, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31526995

RESUMO

Perfluoroalkyl substances (PFASs) were investigated in three types of vegetables (fruit, leafy, and root vegetables) that were cultivated and harvested from 2014 to 2017. The cultivated soil was mainly affected by perfluoroalkyl carboxylic acid (PFCAs; 91.8% detection rate) rather than perfluoroalkyl sulfonic acids (PFSAs; 8.2%). The cultivated soil (i.e., a volcanic cohesive soil) had a high total organic carbon (TOC = 3.4%) and therefore showed strong adsorption of long-chain PFASs. Short-chain PFCAs (i.e., under C9) were mainly detected in vegetables; specifically, PFBA showed high concentration in tomato shoots. Principal component analysis (PCA) plots clearly showed that PFASs in vegetables were different from those of cultivated soil, air, and rainwater. Interestingly, the whole potato (i.e., including peel) was in the same group as soil, indicating that the whole potato can easily be affected by the cultivated soil. Energy Dispersive X-ray Spectrometry-Scanning Electron Microscope (EDS-SEM) results showed that presence of unremovable micron-sized cultivated soil particles on the potato surface. Comparing the regional differences between the cultivated area of Tsukuba city (East Japan) and Osaka city (West Japan), PFASs patterns were similar in cucumber but differed in green perilla and potato.


Assuntos
Fluorcarbonetos/análise , Contaminação de Alimentos/análise , Verduras/química , Adsorção , Frutas/química , Japão , Análise de Componente Principal , Chuva , Solo/química , Poluentes do Solo/análise , Espectrometria por Raios X , Poluentes Químicos da Água/análise
13.
Chemosphere ; 239: 124734, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31494317

RESUMO

Dam construction and fish culture can change the biogeochemical processes in river, yet their impact on the spectral properties of particulate organic matter (POM) remains to be studied. This was investigated in a reservoir-type river (Minjiang river, SE China) using absorption spectroscopy and fluorescence excitation-emission matrices-parallel factor analysis (EEMs-PARAFAC). Five fluorescent components were identified from POM with PARAFAC. Four components C1-C4 were affected by the seasonal variations of rainfall and runoff, indicating the influences of hydrological condition and terrestrial inputs. The Chlorophyll a concentration (Chl a) correlated significantly with the humic-like C3 (p < 0.05) and the protein-like C4 (p < 0.01), indicating phytoplankton was an important source of C3 and C4. The Chl a and fluorescence intensities of C3-C4 were higher in the fish culture zones than in other areas, and the absorption coefficient a300 and C1-C4 were lower downstream the dam. These results indicated that fish farming in the reservoir probably promoted the production of POM. The a300 and C1 per unit mass of suspended particulate matter (a300/TSM and C1/TSM) correlated significantly with the median particle size (p < 0.01), which might be related to the contribution of micro-phytoplankton. The absorption spectra of POM showed a shoulder peak at ∼280 nm, and its intensity correlated significantly and positively with Chl a (p < 0.01). These results indicated that the peak was probably derived from phytoplankton production. Our results have implications for better understanding the influences of human activities on the dynamics of river POM.


Assuntos
Pesqueiros , Material Particulado/metabolismo , Rios/química , Espectrometria de Fluorescência/métodos , China , Clorofila A/metabolismo , Monitorização de Parâmetros Ecológicos , Monitoramento Ambiental/métodos , Análise Fatorial , Fluorescência , Tamanho da Partícula , Material Particulado/análise , Fitoplâncton , Chuva , Estações do Ano
14.
Sci Total Environ ; 700: 134513, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31689657

RESUMO

Excessive inputs of potentially toxic elements (PTEs) into the surface environment as a consequence of atmospheric deposition, imposes long-term burdens on agricultural ecosystems. Studying the spatial and temporal variation in PTEs in atmospheric deposition and their effects on plant shoot accumulation are important in understanding the sources and contributions of PTEs in soils and agricultural products. Here, the spatial and temporal variations in cadmium (Cd) concentration and atmospheric deposition fluxes were investigated in five rice-producing areas of the urbanized Chang-Zhu-Tan region over two years. Then, the effects of simulated wet precipitation on the uptake of Cd in rice seedlings in hydroponic culture was explored. The results showed substantial spatial variability in Cd concentrations and atmospheric deposition fluxes in this region. The Cd concentration of atmospheric deposition ranged from 0.07 to 114 µg L-1, and the annual Cd fluxes in the industrial area reached 61.0 g ha-1 but all were <10.0 g ha-1 in the rural areas. Rice seedling growth became significantly inhibited with increasing concentrations of Cd. Cadmium content in the shoots and white roots and dithionite-citrate-bicarbonate (DCB) extractable Cd on root surfaces were significantly and positively correlated with the concentration of Cd in the nutrient solution. Shoot Cd concentrations increased significantly (p < 0.05) when the annual Cd precipitation flux was ≥50 g ha-1 compared to the control with no Cd precipitation, and the concentration in the shoot was higher than that in roots of rice cultivar A159, when the annual simulated wet precipitation flux of Cd was 400 g ha-1. Thus, shoot Cd was directly related to the simulated wet precipitation when the flux exceeded 50 g ha-1a-1, indicating that air pollution is an important source factor affecting crop Cd uptake.


Assuntos
Cádmio/metabolismo , Oryza/metabolismo , Chuva , Poluentes do Solo/metabolismo , Atmosfera/química , Cádmio/análise , Poluentes do Solo/análise , Urbanização
15.
Water Res ; 171: 115372, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31865130

RESUMO

It is well known that rainwater harvesting (RWH) can augment water supply and reduce stormwater pollutant discharges. Due to the lack of continuous 2D modelling of urban flood coverage and its associated damage, the ability of RWH to reduce urban flood risks has not been fully evaluated. Literature suggests that small distributed storage spaces using RWH tanks will reduce flood damage only during small to medium flooding events and therefore cumulative assessment of their benefits is needed. In this study we developed a new integrated modelling framework that implements a semi-continuous simulation approach to investigate flood prevention and water supply benefits of RWH tanks. The framework includes a continuous mass balance simulation model that considers antecedent rainfall conditions and water demand/usage of tanks and predicts the available storage prior to each storm event. To do so, this model couples a rainfall-runoff tank storage model with a detailed stochastic end-use water demand model. The available storage capacity of tanks is then used as a boundary condition for the novel rapid flood simulation model. This flood model was developed by coupling the U.S. EPA Storm Water Management Model (SWMM) to the Cellular-Automata Fast Flood Evaluation (CA-ffé) model to predict the inundation depth caused by surcharges over the capacity of the drainage network. The stage-depth damage curves method was used to calculate time series of flood damage, which are then directly used for flood risk and cost-benefit analysis. The model was tested through a case study in Melbourne, using a recorded rainfall time series of 85 years (after validating the flood model against 1D-2D MIKE-FLOOD). Results showed that extensive implementation of RWH tanks in the study area is economically feasible and can reduce expected annual damage in the catchment by up to approximately 30 percent. Availability of storage space and temporal distribution of rainfall within an event were important factors affecting tank performance for flood reduction.


Assuntos
Inundações , Chuva , Cidades , Água , Movimentos da Água , Abastecimento de Água
16.
J Environ Manage ; 253: 109719, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31666214

RESUMO

This study sought to evaluate the cumulative effect of the implementation of green space depressions to promote disconnection of impervious areas within residential lots on runoff generation and temporal patterns in a small urban area characterized by high imperviousness. Three hypothetical scenarios were proposed with variations in the disconnection rate (α) within the lot, the soil infiltration conditions, and the rainfall patterns. Simulations were performed using the Storm Water Management Model (SWMM) with the implementation of a high spatial resolution model which allowed the explicit representation of the routing runoff between distinct surfaces. The results revealed a linear relationship trend between the total amount of rainfall (P) and total runoff (q), with identification of a possible precipitation threshold above the point at which a more critical condition of runoff generation is established. The value of this threshold was shown to be dependent on the degree of efficiency of the receptor permeable areas, which is associated with the disconnection rate and infiltrability of the soil. The results also showed that for a very high disconnection rate and lower infiltrability, runoff can increase substantially, with significant changes in the hydrographs simulated for longer storm events.


Assuntos
Chuva , Movimentos da Água , Solo , Água
17.
Sci Total Environ ; 699: 134285, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31520941

RESUMO

In the Mediterranean basin, diffuse-porous, semi-ring-porous and ring-porous tree species coexist in the same regions. Climate change might differently affect these types, but a mechanistic understanding of drought effects on their xylem structure is lacking. We investigated tree-ring width and xylem functional traits in ring-porous Quercus boissieri, semi-ring-porous Q. ithaburensis and diffuse-porous Q. calliprinos, at xeric (Galilee) and mesic (Golan) sites in the South-Eastern Mediterranean basin. We quantitatively assessed how dry and wet years affect growth and xylem traits in different porosity type oaks, and evaluated whether porosity type is preserved or altered during these years. We measured, counted or computed tree-ring width, vessel number, maximum lumen area, frequency, tree-ring and xylem theoretical hydraulic conductivity along 40-year ring series of 50 trees in total. We also quantified ring porosity in each year using two indices, the Gini coefficient and the porosity ratio of vessel area, and described vessel area intra-ring variations by distribution profiles. We then compared these parameters in the five driest and five wettest years of the 40-year period. Radial growth and functional trait variations were more similar between species in the same site (strong drought effects in Q. ithaburensis and Q. calliprinos in Galilee, moderate effects in Q. boissieri and Q. calliprinos in Golan) than between sites for the same species (Q. calliprinos was more affected in Galilee than in Golan). Ring porosity indices and distribution profiles showed that diffuse-porous xylem structure of Q. calliprinos was maintained even under dry conditions at both sites. However, Q. boissieri xylem shifted from ring-porous in wet and normal years to semi-ring-porous in dry years, i.e. the porous ring cannot be completely built under water constraint. This suggests that ring porous strategy, typical of temperate regions with strong seasonality, might not be realized under future drier conditions in the Mediterranean basin.


Assuntos
Monitoramento Ambiental , Quercus/crescimento & desenvolvimento , Chuva , Mudança Climática , Secas , Porosidade , Árvores/crescimento & desenvolvimento , Xilema
18.
Sci Total Environ ; 699: 134301, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31525544

RESUMO

The concentration, source and composition of dissolved organic matter (DOM) in aquatic ecosystems are associated with land use and hydrological connectivity between terrestrial and aquatic systems. However, direct evidence of the effects of rainfall and land use on the variability of DOM in aquatic ecosystems is very limited. In this study, chromophoric DOM (CDOM) absorption and fluorescence spectroscopy were used to elucidate how rainfall and land use affect the variability of CDOM in the watershed of Lake Tianmu, a key drinking water reservoir in the Yangtze River Delta. The mean values of the fluorescence intensity (Fmax) of parallel factor analysis-derived humic-like components (C1, C3, C6) and tryptophan-like components C5 were higher in the southeastern inflowing river mouths than those downstream of the lake outlet regions. The upstream tributaries were mainly dominated by humic-like materials, while the lake was mainly dominated by protein-like materials. The Fmax values of four humic-like components and two tryptophan-like components all increased significantly as the %woodland decreased, but %anthropogenic land use (%cropland+%urban construction area) increased. The Fmax of the humic-like components at the inflowing tributaries and the lake increased with increasing rainfall during storm events, and the value was especially pronounced at the inflowing river mouths. We concluded that land use and hydrological conditions play an important role in influencing the CDOM source and optical composition, and these findings provide insights for the understanding of aquatic ecosystem metabolism and reservoir water quality management.


Assuntos
Água Potável/química , Monitoramento Ambiental/métodos , Poluição da Água/análise , China , Ecossistema , Análise Fatorial , Fluorescência , Lagos/química , Chuva , Rios , Estações do Ano , Espectrometria de Fluorescência , Poluição da Água/estatística & dados numéricos , Qualidade da Água
19.
Sci Total Environ ; 699: 134404, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31678877

RESUMO

The climate change phenomenon has been occurring in every part of the world, including Malaysia. In particular, changes such as rising temperature, sea level rise, and unstable rain pattern are proven to affect the socio-economic routine of the community. Hence, it is necessary to learn how to adapt to it, especially those who heavily rely on nature stability. The present study examined the adaptation towards climate change among islanders in Malaysia. In addition, the current research was performed quantitatively using a developed questionnaire as the main data collection tool. In this case, a total of 400 islanders were selected as the respondents through a multi-stage sampling technique. The results revealed that the respondents recorded a moderate to high mean score for adaptation aspects namely awareness, dependency and structure. Accordingly, a number of recommendations that were highlighted can be utilized as a basis to develop community adaptation policy that is in line with the islanders' need, ability, and interests.


Assuntos
Mudança Climática , Aclimatação , Adaptação Fisiológica , Malásia , Chuva , Inquéritos e Questionários , Temperatura Ambiente
20.
Sci Total Environ ; 699: 134372, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31683220

RESUMO

This study compared plant growth, nutrient partitioning and total nutrient uptake by tall sedge (Carex appressa) plants in large-scale Constructed Floating Wetlands (CFWs). Two CFWs with a total area of 2088 m2 were installed in a 2.6 ha man-made urban lake to treat stormwater runoff during the construction phase of a 45-ha residential development. After 12 months of operation, parts of the CFWs, with a total area of 147 m2, were removed from the urban lake and relocated into a well-established 0.127-ha stormwater retention pond at another site. Biomass and nutrient concentrations of C. appressa shoots above the floating mat and roots below the mat were analysed at both sites 12, 16 and 25 months after initial planting. Plants at the urban lake maintained an extensive root network but there was no increase in total plant biomass at 16 and 25 months after planting. In contrast, the relocated plants in the stormwater pond showed extensive shoot growth but a significant decline in root biomass. C. appressa at the urban lake removed and sequestered 1.00 ±â€¯1.04 g m-2 N, 0.11 ±â€¯0.07 g m-2 P and 1.03 ±â€¯0.81 g m-2 K while plants at the pond removed 11.20 ±â€¯2.29 g m-2 N, 1.37 ±â€¯0.26 g m-2 P and 16.13 ±â€¯2.88 g m-2 K during 12 and 25 months after planting. This study demonstrated that C. appressa adapted rapidly to changes in nutrient availability. The implications are interesting as nutrient levels can be low in constructed lakes during the initial phase of urban developments but can increase rapidly as the development progresses. The study demonstrated multiple benefits of CFWs for stormwater treatment during the early construction stages of an urban development and the potential benefits of relocating and establishing CFWs in existing stormwater retention ponds and lakes.


Assuntos
Eliminação de Resíduos Líquidos , Áreas Alagadas , Biomassa , Carex (Planta) , Nitrogênio , Fósforo , Plantas , Tanques , Chuva , Poluentes Químicos da Água , Purificação da Água
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