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The Puget Sound Basin, US Pacific Northwest, is experiencing rapid population and urban growth. This growth adversely impacts local ecosystems, especially the spawning and rearing habitat for several salmonid species. Sustainable urban design strategies such as green stormwater infrastructure (GSI) are required in the region to manage stormwater onsite when new development occurs. However, the effectiveness of any GSI depends on its location relative to where stormwater is produced. This study aimed to develop a Geographic Information System (GIS)‐based framework for the optimal placement of GSI, specifically bioretention systems. We computed the Hydrologic Sensitivity Index (λHSI, indicating runoff generation potential at a landscape location) for the lower Puyallup River Watershed study area. The index and federal and state feasibility criteria were used to identify suitable sites for bioretention systems. The suitability of identified sites was verified through ground‐truthing, including soil sampling and infiltration testing. We found that 2.5% of the watershed area was suitable for bioretention, concentrated in the center and north of the study watershed. The method described in this study can be readily applied to watersheds for which spatial data (topography, soil, and land use) are available. We recommend choosing locations with high λHSI when resources are limited since these locations contribute most to runoff generation and urban flooding. [ABSTRACT FROM AUTHOR]

Previous studies have proven the efficiency of LID practices in mitigating surface runoff in urban watersheds; however, the impact of their placement strategy over the urban drainage system, under continuous temporal hydrological simulation, has not been explored yet. This study simulated, under continuous time scale, five LID practices and four LID placement strategies (downstream, center, upstream and uniformly) on the drainage system of the Universidade Federal de Lavras urban area, in the state of Minas Gerais, Brazil. Under the conditions analyzed, it was found that there were no significant statistical differences between the efficiency of the different LID practices, individually or combined, within the same placement strategy. The uniform placement strategy proved to be more efficient, but in soils with higher Ksat values, other strategies showed better results. Therefore, it was found that soil Ksat is a parameter that should be carefully analyzed for LID practices implementation. [ABSTRACT FROM AUTHOR]

The acceleration of urbanization has disrupted natural water cycles, resulting in increased impervious urban surfaces and non-point source pollution from stormwater runoff. Addressing urban stormwater recharge has become crucial. This study introduces a novel silica sand-based permeable filtration material, investigating its surface characteristics, pore structure, permeability, and pollutant interception capabilities. The results demonstrate that hydrophilic binder coating modification of the permeable surface sand aggregate, combined with hydrophilic inorganic additives, having a porous structure with an average pore size of less than 50 μm and a porosity between 15% and 35%, significantly enhances surface hydrophilicity, achieving a permeation rate of up to 6.8 mL/(min·cm²). Moreover, it shows exceptional filtration and anti-clogging properties, achieving over 98% suspended solids interception and strong resistance to fouling. Dynamic biofilm formation experiments using simulated rain and domestic wastewater explore biofilm morphology and function on silica sand filtration well surfaces. Mature biofilms sustain COD removal efficiency exceeding 70%, with levels consistently below 50 mg/L, NH4+ decreasing to 2 mg N/L, and total nitrogen maintained below 10 mg N/L. The system features anoxic, anoxic, and aerobic zones, fostering synergistic organic matter and nitrogen removal by diverse microorganisms, enhancing pollutant mitigation. Silica sand-based permeable filtration material effectively mitigates urban stormwater runoff pollutants—suspended solids, organic matter, and nitrogen—offering an innovative solution for sponge city development and rainwater resource management. [ABSTRACT FROM AUTHOR]

The hydrologic performance and cost-effectiveness of green stormwater infrastructure (GSI) in climates with highly variable precipitation is an important subject in urban stormwater management. We measured the hydrologic effects of two bioretention basins in San Antonio, Texas, a growing city in a region prone to flash flooding. Pre-construction, inflow, and outflow hydrographs of the basins were compared to test whether the basins reduced peak flow magnitude and altered the metrics of flashiness, including rate of flow rise and fall. We determined the construction and annual maintenance cost of one basin and whether precipitation magnitude and antecedent moisture conditions altered hydrologic mitigation effectiveness. The basins reduced flashiness when comparing inflow to outflow and pre-construction to outflow hydrographs, including reducing peak flow magnitudes by >80% on average. Basin performance was not strongly affected by precipitation magnitude or antecedent conditions, though the range of precipitation magnitudes sampled was limited. Construction costs were higher than previously reported projects, but annual maintenance costs were similar and no higher than costs to maintain an equivalent landscaped area. Results indicate that bioretention basins effectively mitigate peak flow and flashiness, even in flash-flood-prone environments, which should benefit downstream ecosystems. The results provide a unique assessment of bioretention basin performance in flash-flood-prone environments and can inform the optimization of cost-effectiveness when implementing GSI at watershed scales in regions with current or future similar precipitation regimes. [ABSTRACT FROM AUTHOR]

This study evaluated erosion rates and sediment production in streams, and factors potentially influencing them throughout the Anacostia, Patuxent, and Potomac (non‐Anacostia) River watersheds within Prince George's County, Maryland, US. As part of the County's watershed‐scale biological monitoring program, from approx. 1999 to 2008, permanent monuments were established to allow measurement of stream channel cross‐sectional (XS) area. The intent of this study was to characterize the intensity and spatial distribution of fluvial geomorphic instability across the county and use the results to target and plan stormwater management and stream restoration actions. For this study, 78 stream locations were re‐surveyed in 2020, representing a time lapse of from 12 to 21 years. Data collected included XS dimensions, modified Wolman 100‐particle pebble counts, and reach‐specific soil bulk density. Land use/land cover data were compiled from the National Land Cover Dataset (NLCD), precipitation from the National Weather Service Center for Environmental Information (NCEI), and soils from the Natural Resources Conservation Service Web Soil Survey (NRCS/WSS). We calculated percent change in XS area, rates of erosion, sediment yield, and assigned geomorphic classifications, and interpreted them in the context of spatial positions relative to changes in land cover characteristics. Sediment yields among the 78 reaches exhibited a combination of those undergoing enlargement/erosion (67.9%), reduction/deposition (25.6%), and the remaining 6.4% with essentially no change over the period of record. Of the top 20 most geomorphically active reaches surveyed in the County, 12 are in the Anacostia River basin, with the other scattered among the Patuxent River and Potomac River basins. [ABSTRACT FROM AUTHOR]

The presence of polycyclic aromatic hydrocarbons (PAHs) pollution on urban road surfaces is one of the major environmental concerns. However, knowledge on the distribution variability of PAHs in road dusts (RDS) and stormwater is limited, which would restrict the further risk evaluation and mitigation implementation of PAHs in road stormwater runoff. This study collected RDS samples and stormwater samples on fourteen urban roads in Shenzhen, China. This study investigated the variation of sixteen PAHs species in RDS and stormwater, and further evaluated the intrinsic and extrinsic factors which influence PAHs accumulation on urban road surfaces. The research outcomes showed significant differences on spatial distribution of PAHs in RDS and in stormwater. The land use types, industrial, commercial and port areas and vehicular volume have a positive relationship with PAHs abundance while dust particle size showed a negative correlation with PAHs abundance. For two phases in stormwater, fluctuation of PAHs with the rainfall duration in total dissolved solid (TDS) was more intensive than in dissolved liquid phase (DLP). This indicated when PAHs attached to RDS enter stormwater, most of PAHs still tend to be on solid particles than in liquid. The study outcomes are expected to contribute to efficient designs of PAHs polluted stormwater mitigation. [ABSTRACT FROM AUTHOR]

Flooding is one of the main social impacts in urban areas, especially in larger, densely impermeable cities. Therefore, developing studies capable of identifying areas that are vulnerable to this type of event is crucial to provide early warning and a quick and effective response to reduce damages. Thus, this study sought to identify areas vulnerable to flood in the Igapó Lake Basin, a densely urbanized area in Lodrina city, southern Brazil. The methodology was based on four main steps: (1) basin characterization, (2) elaboration of the conditioning factors of the flooding by using the analysis hierarchical process (AHP), (3) vulnerability analysis in the GIS environment, (4) and model sensitivity analysis. The parameters considered in this study were as follows: flow concentration, land use, slope, distance from the discharge channel, and altimetry. The proposed methodology has proven to be robust in identifying flood-vulnerable areas. The results revealed that approximately 3.1 km2 (10.3%) of the basin are considered areas of high or very high vulnerability to flood events, affecting many residential buildings, the most abundant land use class in the investigated area. In conclusion, this study sheds light on the intricate interplay between vulnerability to flooding, land use changes, urban development patterns, and resilience measures, offering valuable insights for policymakers and urban planners striving to mitigate the impacts of extreme weather events. [ABSTRACT FROM AUTHOR]

Stormwater transports directly into rivers eroded soil, animal wastes, pesticides, fertilizers and other potential pollutants. Bioretention is often designed to capture and treat it using the natural properties of soil and plants. However, selection of appropriate media structure and plants need to be adequately studied. This study investigated the performance of bioretention system in removing stormwater pollutants using Dracaena, a local plant, also called Song of India Plants. Physical model of three Columns A, B and C were developed having five layered filter media of different configurations whose materials were analyzed to meet the design standards. The plants were introduced into Columns A and C leaving out B as control experiment. The quality parameters were determined before and after treatments at ages 10, 20, 30 and 40 days when Dracaena plants were introduced into bioretention models. The results showed that the bioretention model drastically improved stormwater quality by reducing values of Electrical Conductivity, Total Coliforms (TC), fecal Coliforms (FC), Total Suspended Solids (TSS) and Biochemical Oxygen Demand (BOD) as compared to the tested raw stormwater samples. The filter media in both Columns A and C substantially reduced the pollutant levels to standard discharge limits for all parameters tested such as TSS, TC, FC, BOD and nitrates. BOD fell within the recommended standard after 20 days of treatment in Column C with considerable reduction in TC and FC by 68.9 % and 75.4 % respectively when compared to raw stormwater sample. However, Column C completely removed TC and FC at 40 days which are pathogen indicators in wastewater. This study would be useful to the stakeholders for sustainable stormwater treatment and management.

Alternative storm water management focuses on channeling rainwater to underground reservoirs, decreasing the surface flow, and reducing the load of wastewater treatment systems in urban planning. However, soil permeability is a major hindrance to alternative management techniques. Increasing soil permeability is necessary to manage rainwater harvesting and increase groundwater recharge. Additionally, earthworm density directly affects soil properties. In this study, we investigated the effects of earthworm density and species on the permeability of clay loam soil by a gravity-driven film flow. We conducted indoor and outdoor experiments by installing boxes/tanks with layers of materials (gravel, textile, clay loam soil, and organic matter). In the indoor experiments (IE), these materials were used to feed individuals of Lumbricus terrestris with an initial density of 25/m², 50/m², 100/m² while the outdoor experiments (OE) had the initial density of 108/m². All experiments were conducted in triplicate. The permeability velocity was measured using the gravity-driven film flow method with a flow rate of 1 cm/unit time. The coefficient of determination R² of 0.86, 0.93, 0.93 between infiltration velocity and time variable was determined using the data on the initial earthworm density in the IE in one year. Moreover, the growth percentage of L100 was the highest value at 1347% in 391st days. Meanwhile, in the OE, compared to the OE with two earthworms (Lumbricus terrestris and Aporrectodea caliginosa), the infiltration velocity of contained tanks by A. caliginosa were significantly greater than the ones by L. terrestris at 289% and 155%, respectively. The coefficient of determination R² of 0.89, 0.89, 0.98 between infiltration velocity and time variable was collected by the initial presence of two earthworm species for one year. The results of the experiment showed that burrowing earthworms can significantly facilitate the infiltration velocity of clay loam soil, and the density of earthworms was found to affect the capacity of permeability, based on the gravity-driven film flow methodology. This also illustrates that the two functional groups have different interactions with the infiltration velocity. Data provided in this study could be used to apply the functional earthworms in ameliorating the alternative techniques in stormwater management systems. [ABSTRACT FROM AUTHOR]

Implementing rain garden (RG) designs is widespread worldwide to reduce peak flow rates, promote stormwater infiltration, and treat pollutants. However, inadequate RG design degrades its hydrological behaviour, requiring the development and validation of an appropriate hydrological model for the design and analysis of structures. This study aimed to improve a hydrological infiltration model based on Darcy's law by taking into account the height of the water column (HWC) at the surface of the RG and the filtration coefficients of soil materials. The model was tested by simulating the hydrological characteristics of a rain garden based on a single rain event of critical intensity (36 mm/h). Using the validated model, design curves were obtained that predict the performance of the RG as a function of the main design parameters of the structure: water column height, ratio of catchment area to structure area, layer thickness, and soil filtration coefficient. The hydrological efficiency of the RG was evaluated in terms of the time of complete saturation, filling of the structure with water, and determining the change in HWC caused by changes in the parameters. The filtration coefficient and thickness of the upper and intermediate infiltration layers of the RG are the main parameters that affect the depth of saturation of the layers of the structure and the HWC on the surface. The model is not very sensitive to the model parameters related to the lower gravel layer. If the top layer's thickness increases by 10 cm, it takes longer to fill the structure with water, and the HWC on the surface reaches 0.341 m. The rain garden's performance improves when the filtration coefficient of the top layer is 7.0 cm/h. Complete saturation and filling of the structure with rainwater do not occur within 7200 s, and the water column reaches a height of 0.342 m at this filtration coefficient. However, the rain garden's effectiveness decreases if the filtration coefficient of the upper and intermediate layers exceeds 15 cm/h and 25 cm/h, respectively, or if the catchment area to RG area ratio decreases to values below 15. The modelling results confirm that considering the HWC in RG hydrological models is essential for designing structures to minimise the risk of overflow during intense rainfall events. [ABSTRACT FROM AUTHOR]

Bioretention is a type of stormwater best management practice that can reduce stormwater runoff volume, and with appropriate design, simultaneously reduce nitrogen loads. To meet the water quality potential of bioretention systems, improved simulation models of the transport and transformations of nitrogen are needed. In this work, two versions of a three-nitrogen-pool (3P) model (3P-1 and 3P-m) are applied to simulate observed nitrogen transport through a field bioretention system. The 3P models provide predictions of net export of dissolved organic carbon, dissolved organic nitrogen, and inorganic nitrogen species. The 3P-m model has promising results: (1) relative to the Storm Water Management Model (SWMM), it reduced the prediction error of percent removal of total dissolved nitrogen by up to 10.6% and reduces the scaled root-mean square error of total dissolved nitrogen loads by up to 53.0%; (2) it successfully captured the correlation between impactful environmental factors and event mean concentrations of total dissolved nitrogen and nitrate nitrogen in underdrain effluent; (3) its predictions on denitrification showed good alignment with observed isotope results; and (4) it demonstrated higher stability in simulated time series among calibration results than 3P-1. The 3P-m is expected to assist the design of bioretention system and valve control strategies by providing more accurate predictions on nitrogen removal under the impacts of soil moisture content and temperature. Future research and collaboration opportunities are also proposed in this article. [ABSTRACT FROM AUTHOR]

Climate change is impacting urban areas, especially through extreme rainfall that stresses conventional water management systems. Rainwater resulting from impervious runoffs, stormwater leads to an increase in the amount of wastewater that requires treatment and an overflow of the combined sewer system. Therefore, untreated wastewater is released into the surroundings or, in some cases, causes damage to urban systems. Nevertheless, many cities in the world are in the process of establishing a sustainable approach to urban water management. Sustainable stormwater management practices are essential for overcoming various environmental challenges and promoting community sustainability and resilience. The purpose of this paper is to communicate Oslo's success in implementing sustainable stormwater management in urban areas. By analyzing successful cases, researchers may be able to record patterns that offer potential answers to the stormwater management challenge. The present case study presents an approach that can enlighten urban planners and policymakers about the potential outcomes of sustainable stormwater management under the conditions presented. [ABSTRACT FROM AUTHOR]

Stormwater transports directly into rivers eroded soil, animal wastes, pesticides, fertilizers and other potential pollutants. Bioretention is often designed to capture and treat it using the natural properties of soil and plants. However, selection of appropriate media structure and plants need to be adequately studied. This study investigated the performance of bioretention system in removing stormwater pollutants using Dracaena, a local plant, also called Song of India Plants. Physical model of three Columns A, B and C were developed having five layered filter media of different configurations whose materials were analyzed to meet the design standards. The plants were introduced into Columns A and C leaving out B as control experiment. The quality parameters were determined before and after treatments at ages 10, 20, 30 and 40 days when Dracaena plants were introduced into bioretention models. The results showed that the bioretention model drastically improved stormwater quality by reducing values of electrical conductivity, total coliforms (TC), fecal coliforms (FC), total suspended solids (TSS) and biochemical oxygen demand (BOD) as compared to the tested raw stormwater samples. The filter media in both Columns A and C substantially reduced the pollutant levels to standard discharge limits for all parameters tested such as TSS, TC, FC, BOD and nitrates. BOD fell within the recommended standard after 20 days of treatment in Column C with considerable reduction in TC and FC by 68.9% and 75.4% respectively when compared to raw stormwater sample. However, Column C completely removed TC and FC at 40 days which are pathogen indicators in wastewater. This study would be useful to the stakeholders for sustainable stormwater treatment and management. [ABSTRACT FROM AUTHOR]

Green roofs (GRs) are a widely recognized green infrastructure (GI) strategy that helps reduce runoff volume and runoff pollution caused by the significant increase in impervious urban areas. However, the leaching of several nutrients from GR substrates is a growing concern. Biochar, a carbon-rich material, possesses advantageous properties that can help address such environmental challenges associated with GRs. Therefore, this paper aimed to undertake a field study to investigate the impacts of various biochar application methods, particle sizes, and amendment rates on the quality of runoff from GRs. Observational data of runoff quality were collected over a two-month period from five newly established 1 m × 1 m biochar-amended GR test beds and a control test bed without biochar, with all test beds subjected to artificially simulated rainfall. The results indicated that the addition of biochar did not result in a significant improvement in runoff pH, whereas the electrical conductivity (EC) was higher in runoff from GRs with biochar-amended substrates. When comparing the total nitrogen (TN) concentration in runoff from the non-biochar GR (ranging from 3.7 to 31 mg/L), all biochar test beds exhibited higher TN release (4.8 to 58 mg/L), except for the bed where medium biochar particles were applied at the bottom of the substrate (ranging from 2.2 to 21 mg/L). Additionally, all biochar-amended GRs exhibited higher TP concentrations in runoff (0.81 to 2.41 mg/L) when compared to the control GR (0.35 to 0.67 mg/L). Among the different biochar setups, GR with fine biochar particles applied to the surface of the substrate had the poorest performance in improving runoff water quality. Despite these mixed results, biochar holds significant potential to improve runoff quality by significantly increasing water retention, thereby reducing pollutant loads. [ABSTRACT FROM AUTHOR]

This research explored the denitrification potential of a submerged zone incorporated into the present permeable interlocking concrete pavement (PICP) design. The following three main factors controlling denitrification were investigated through a laboratory study: (i) detention time, (ii) inclusion of a carbon source (newspaper), and (iii) submerged zone depth. The study used 10 columns, each fully packed with 50– 63 mm washed aggregate and including a 1.5 m deep submerged zone. Columns were paired according to detention time (1, 2, 5, 10 and ‘varied’ days) with one set including newspaper, the other set not. All columns were loaded with synthetic stormwater over a 4-month period. Samples were taken from different submerged depths (0, 300, 600, 900, 1200 and 1 500 mm) and analysed for concentrations of ammonia (NH3), nitrate (NO3 −) and phosphate (PO4 3−) every 10 days. This study found that 10 – or more – days detention and the provision of a carbon source had the most significant impact on denitrification – providing an overall mean NO3 − and nitrogen removal above 41% and 59%, respectively. Moreover, a submerged depth of 300 mm was sufficient to achieve a minimum NO3 − removal of 41% in columns which included a carbon source and had 10 days detention. Generally, an increase in detention time resulted in an increase in NH3 and PO4 3− removal with overall mean values of 86% and 30%, respectively, achieved with 10-day detention periods. [ABSTRACT FROM AUTHOR]

As stormwater management embarks on a new journey of resource allocation and disparity, addressing the contamination resulting from deicing salts is a growing concern for designers and land planners. Turf and native grass variety are currently one of the most readily available and adaptive resources to address some of these ever increasing hydrologic concerns. However, little is known about the water quality efficiency and optimal design layout of turf and native grasses in urban or rural landscapes with regards to salt remediation. In this study, a five plot series of grass swales was utilized in this study to measure water quality efficiency and salt tolerance of turf and native grasses. The grass varieties that were tested in this study include; Common hard fescue (Festuca trachyphylla), Chewings fescue (Festuca rubra commutata), and sheep fescue (Festuca ovina). Results showed that the grass swales that made up of a blend of grass variety were the most successful at reducing saline and TDS levels as compared to their monoculture counterparts. The findings reveal that a relatively simple grass swale could provide excellent salt and TDS reduction when utilizing a blend of grass varieties; specifically a hard fescue and sheep fescue blend. [ABSTRACT FROM AUTHOR]

Water-resource challenges, encompassing both quality and quantity, pose significant threats to Florida's ecosystems, especially in the face of climate change, rising sea levels, and rapid urbanization. This paper explores the innovative stormwater-management system implemented at Naples Botanical Garden as a model for addressing these challenges. The Garden's approach, treating stormwater as a valuable resource, involves dry and wet retention areas, created lakes, and a unique River of Grass, mimicking natural ecosystems. This system not only mitigates flooding, but also effectively removes pollutants, recharges the aquifer, and provides a habitat for diverse wildlife. The paper emphasizes the economic, environmental, and social impacts of traditional stormwater-management practices in Florida. Naples Botanical Garden's case serves as a guide for botanical gardens and zoos globally, showcasing the pivotal role these institutions can play in sustainable water-resource management. The collaborative design process involving landscape architects, engineers, and horticulturists ensures a holistic and aesthetically pleasing approach to stormwater management. The paper underscores the role of botanical gardens in promoting nature-based solutions, educating the public, and offering tangible steps for implementing similar systems worldwide. It can help guide regional adaptation strategies to manage stormwater as a resource. [ABSTRACT FROM AUTHOR]

Vegetation is an important component of stormwater control measures, as vegetation can reduce erosion and runoff. While grass is typically used in stormwater control measures, wildflowers can be planted to reduce maintenance and improve pollinator habitat. Previous studies have established that tillage followed by establishment of a vigorous vegetation stand can increase infiltration relative to compacted soils. Compost can also improve soil physical properties and fertility. The goal of this study was to evaluate potential improvements in infiltration using tillage together with compost and either grass or wildflowers. Wildflowers or grass were planted on tilled soil with or without compost at three sites in North Carolina. Bulk density, infiltration rate, root mass density, and penetration resistance were measured every 6 months over a 30‐month period. A subset of plots received wheel traffic from a mower. Compost application reduced bulk density compared to tillage alone. Compost improved infiltration at two sites (46%–50%). Wildflowers improved infiltration at all sites (30%–43%) compared to grass. Few differences were observed in root mass and penetration resistance. Mower traffic reduced soil improvements more in grassed plots than wildflower plots due to higher mowing frequency. Results suggest compost and/or wildflowers together with tillage (at establishment) provide viable options to improve soil conditions and infiltration rate in construction impacted soils. [ABSTRACT FROM AUTHOR]

We examined socially influential residents' beliefs about pro-environmental outreach in a Midwestern city, identifying factors influencing willingness to participate in an urban water quality outreach campaign. The sample included self-identified leaders (opinion leaders) residing in neighborhoods surrounding a small urban lake. Participants answered questions about using less salt on sidewalks and driveways, removing leaves from the street before it rains, allowing rainwater to soak into the ground on their property, and encouraging neighbors to do these behaviors. Favorable beliefs about outreach and experience with outreach were associated with greater willingness to do pro-environmental outreach. Favorable beliefs about pro-environmental behaviors and experience with pro-environmental behaviors were not associated with willingness to do pro-environmental outreach. We discuss how understanding opinion leaders' beliefs about pro-environmental outreach and navigating their misgivings about reaching out to their neighbors can inform campaigns fostering neighborhood water advocacy and outreach. [ABSTRACT FROM AUTHOR]

Recently, increasing attention has been paid to antibiotic resistant bacteria (ARB) in stormwater runoff. However, there were little data on ARB removal through electrocoagulation (EC) treatment. In this study, batch experiments were conducted to investigate key designs for ARB removal, role of SS, effects of water matrix, and potential risks after EC treatment under the pre-determined conditions. EC treatment with 5 mA/cm2 of current density and 4 cm of inter-electrode distance was optimal with the highest ARB removal (3.04 log reduction for 30 min). The presence of SS significantly improved ARB removal during EC treatment, where ARB removal increased with the increase of SS levels when SS less than 300 mg/L. Large ARB removal was found under particles with size lower than 150 μm with low contribution (less than 10%) of the settlement without EC treatment, implying that the enhancement of ARB adsorption onto small particles could be one of the reasonable approaches for ARB removal through EC treatment. ARB removal increased firstly and then decreased with the increase of pH, while had proportional relationship with conductivity. After the optimal condition, there were weak conjugation transfer but high transformation frequency (5.5 × 10−2 for blaTEM) for target antibiotic resistance genes (ARGs), indicating that there could be still a risk of antibiotic resistance transformation after EC treatment. These suggested that the combination of EC and other technologies (like electrochemical disinfection) should be potential ways to control antibiotic resistance transmission through stormwater runoff. [ABSTRACT FROM AUTHOR]

Due to the critical impacts of microplastic (MP) aggregation on their fate, mobility, and bioavailability, this study developed a simple approach to examine their aggregation under varying water chemistry and MPs' surface aging conditions. An accelerated photodegradation experiment was conducted for 6 weeks. The water chemistry conditions varied by altering pH, using natural organic matter (NOM), and conducting experiments in ultrapure water and synthetic stormwater. The surface chemistry analysis of photodegraded MPs revealed the formation of carbonyl and vinyl functional groups. Zeta potential measurements revealed a more negative surface charge for photodegraded MPs compared to new MPs. The aggregation kinetics of MPs were studied by comparing the number of MP clusters formed over time after intense dispersion in water. The results showed that the presence of NOMs reduces the aggregation tendency of new low‐density polyethylene MPs due to enhanced steric hindrance and electrostatic repulsion. However, variations of pH and utilizing synthetic stormwater versus ultrapure water did not alter the aggregation kinetics of new MPs. The aggregation behavior of photodegraded MPs was significantly different from new MPs. A greater tendency for aggregation of photodegraded MPs was found in the stormwater compared to the ultrapure water. This study contributes to a better understanding of the transport and fate of MPs within the aqueous environment and their subsequent environmental risks. [ABSTRACT FROM AUTHOR]

The new trend in urban stormwater management is to preserve natural hydrological conditions by addressing changes from urbanization. The software Chaak: Urban Hydrological Impact Modeling is a new hydroinformatics tool designed for sustainable modeling, simulation, and analysis of stormwater sewer networks. It emphasizes two key aspects: enhancing planning for Sustainable Urban Drainage Systems (SUDS) to restore natural hydrological conditions and providing an alternative to conventional storm drainage designs. Additionally, it encourages global scientific collaboration to quickly advance the tool's capabilities through structured development and quality control.

The increasing rate of urbanisation and extreme climatic events represent a constant threat for urban water resources management. In recent decades, Milan Metropolitan Area (Lombardy Region, Northern Italy) has been affected by a) frequent extreme rainfall events, responsible for the flooding of major surface water courses, and b) groundwater management problems, both from a quantitative (i.e. interaction with underground infrastructures) and qualitative point of view. Moreover, the increasing use of groundwater geothermal systems also requires further considerations. This work analyses the literature available in the area regarding surface floods, groundwater quantity, quality, and temperature. Finally, a discussion is provided to understand a) which approaches could promote an effective management of both surface water and groundwater resources b) which points of contact emerge between these two aspects of the urban water cycle, and c) which possible urban interventions could contribute to an integrated and functional management of water resources, also reducing some current issues.

ABSTRACT Water scarcity and increasing urbanization are forcing municipalities to consider alternative water sources, such as stormwater, to fill in water supply gaps or address hydromodification of receiving urban streams. Mounting evidence suggests that stormwater is often contaminated with human feces, even in stormwater drainage systems separate from sanitary sewers. Pinpointing sources of human contamination in drainage networks is challenging given the diverse sources of fecal pollution that can impact these systems and the non-specificity of traditional fecal indicator bacteria (FIB) for identifying these host sources. As such, we used a toolbox approach that encompassed microbial source tracking (MST), FIB monitoring, and bacterial pathogen monitoring to investigate microbial contamination of stormwater in an urban municipality. We demonstrate that human sewage frequently contaminated stormwater (in >50% of routine samples), based on the presence of the human fecal marker HF183, and often exceeded microbial water quality criteria. Arcobacter butzleri, a pathogen of emerging concern, was also detected in >50% of routine samples, with 75% of these pathogen-positive samples also being positive for the human fecal marker HF183, suggesting human municipal sewage as the likely source for this pathogen. MST and FIB were used to track human fecal pollution in the drainage network to the most likely point source of contamination, for which a sewage cross-connection was identified and confirmed using tracer dyes. These results point to the ubiquitous presence of human sewage in stormwater and also provide municipalities with the tools to identify sources of anthropogenic contamination in storm drainage networks.IMPORTANCEWater scarcity, increased urbanization, and population growth are driving municipalities worldwide to consider stormwater as an alternative water source in urban environments. However, many studies suggest that stormwater is relatively poor in terms of microbial water quality, is frequently contaminated with human sewage, and therefore could represent a potential health risk depending on the type of exposure (e.g., irrigation of community gardens). Traditional monitoring of water quality based on fecal bacteria does not provide any information about the sources of fecal pollution contaminating stormwater (i.e., animals/human feces). Herein, we present a case study that uses fecal bacterial monitoring, microbial source tracking, and bacterial pathogen analysis to identify a cross-connection that contributed to human fecal intrusion into an urban stormwater network. This microbial toolbox approach can be useful for municipalities in identifying infrastructure problems in stormwater drainage networks to reduce risks associated with water reuse.

The purpose of the study was to develop a simple and rapid method for measuring the average settling velocity of particles in stormwater ponds. Water samples with suspended particles were collected from the bottom of a stormwater pond in Lund, Sweden. The absorbance in various samples was measured over 24 h (at 600 nm wavelength) and then translated into total solids concentrations. A one-dimensional model based on the Mason–Weaver equation was coded in Python and solved. The absorbance measurements were used to calibrate the model, thereby quantifying settling velocities and dispersion coefficients for samples from different zones of the stormwater pond. The quantified settling velocities ranged from 40 to 200 mm/h for fast-settling particles and from 2 to 8 mm/h for slow-settling particles. The developed methodology provided a mass estimate of the two modelled particle groups (i.e., fast- and slow-settling particles). Based on the model estimates, fast-settling particles dominated all samples, constituting 70–90% of the total solid mass. Due to its simplicity and inexpensiveness, this methodology is a potential alternative to more demanding and complicated methodologies used for measuring particle velocities in sedimentation systems. HIGHLIGHTS Convection–dispersion equation was adapted to represent particle sedimentation.; Absorbance data (at 600 nm) were used to calibrate the convection–dispersion model.; Calibrated parameters are estimates of particle settling velocity and dispersion.; Settling characteristics of two or more groups of particles can be quantified.; The methodology is inexpensive and fast, thus suitable for the frequent use.;

Water-resource challenges, encompassing both quality and quantity, pose significant threats to Florida’s ecosystems, especially in the face of climate change, rising sea levels, and rapid urbanization. This paper explores the innovative stormwater-management system implemented at Naples Botanical Garden as a model for addressing these challenges. The Garden’s approach, treating stormwater as a valuable resource, involves dry and wet retention areas, created lakes, and a unique River of Grass, mimicking natural ecosystems. This system not only mitigates flooding, but also effectively removes pollutants, recharges the aquifer, and provides a habitat for diverse wildlife. The paper emphasizes the economic, environmental, and social impacts of traditional stormwater-management practices in Florida. Naples Botanical Garden’s case serves as a guide for botanical gardens and zoos globally, showcasing the pivotal role these institutions can play in sustainable water-resource management. The collaborative design process involving landscape architects, engineers, and horticulturists ensures a holistic and aesthetically pleasing approach to stormwater management. The paper underscores the role of botanical gardens in promoting nature-based solutions, educating the public, and offering tangible steps for implementing similar systems worldwide. It can help guide regional adaptation strategies to manage stormwater as a resource.

This study investigated how nitrogen and dissolved organic matter (DOM) from stormwater runoff and rainfall support the growth of Karenia brevis and Pyrodinium bahamense. Excitation–emission matrix spectroscopy coupled with parallel factor analysis tracked changes in the optical properties of DOM in each bioassay, revealing greater reactivity of terrestrial humic-like DOM. Significant increases in cell yield and specific growth rates were observed upon additions of runoff for both species, with significant increases in specific growth rates upon the addition of a 2 in simulated rain event for P. bahamense only. By hour 48, 100% of the dissolved organic nitrogen (DON) in each treatment was utilized by P. bahamense, and by hour 72, over 50% of the DON was utilized by K. brevis. The percentage of bioavailable dissolved organic carbon (DOC) was greater for P. bahamense compared to K. brevis, suggesting a greater affinity for DOC compounds by P. bahamense. However, the bioavailability of DOM for each species could be owed to distinct chemical characteristics of labile DOM conveyed from each site. This study demonstrates that stormwater runoff and rainfall are both sources of labile DOM and DON for K. brevis and P. bahamense, which has implications for blooms of these species in Tampa Bay waters. [ABSTRACT FROM AUTHOR]

Exposed soils associated with active construction sites provide opportunities for erosion and sediment transport during storm events, introducing risks associated with excess sediment to downstream infrastructure and aquatic biota. A better understanding of the drivers of sediment transport in construction site runoff is needed to improve the design and performance of erosion and sediment control measures (ESCMs). Eleven monitoring locations on 3 active road construction sites in central Ohio were established to characterize runoff quality from points of concentrated flow during storm events. Grab samples were analyzed for total suspended solids (TSS), turbidity, and particle size distribution (PSD). Median TSS concentrations and turbidity levels across all samples were 626 mg/L (range 25–28,600 mg/L) and 759 NTU (range 22–33,000 NTU), respectively. The median PSD corresponded to a silty clay loam, mirroring the soil texture of much of Ohio's subsoils. TSS concentrations and turbidity were significantly positively correlated with the rainfall intensity 10 min prior to sample collection, suggesting that higher flow rates created greater shear stress on bare soil which resulted in more erosion. Conversely, rainfall duration was negatively correlated with particle size, indicating that prolonged moisture from rainfall promoted the dispersion of soil aggregates which mobilized smaller particles. Multivariable linear regression models revealed that higher rainfall intensities corresponded to higher turbidity values, while higher TSS concentrations were associated with higher rainfall intensities, depths, and durations. Results from this study highlight the importance of reducing raindrop impact and subsequent shear stress applied by concentrated flows through the use of ESCMs to limit sediment export from construction sites. [ABSTRACT FROM AUTHOR]

Although many might consider the Australian city of Sydney as defined by golden beaches and a glittering harbour, the city actually has an abundance of wetlands—swamps and marshes laid out across the eastern Sydney region. Dramatic transformations of these waterscapes have taken place since 1788, when British colonists landed to form the settlement there. Environmental exploitation has been a key part of settler‐colonial projects across the world. Sydney is no different. To contextualise this exploitation, I explore the ways in which a specific water infrastructure system in Sydney—the Tank Stream—has been entangled with, and is emblematic of, settler‐colonial politics. I argue that to reimagine futures where such ecologically and culturally damaging infrastructures no longer have a presence in the city requires a nuanced interpretation of both water and history. I suggest that “conventional” stormwater design features emerged from colonial viewings of Sydney’s waterscapes. The transformation of these geographies was imposed on existing water management systems, set within local, First Nations knowledges. Thus, I also consider the Tank Stream as a site with potential to present an anti‐colonial hydraulic urban co‐design framing. I draw on colonial archival material and field site visits to question the importance that settler‐colonial urban design has had in shaping contemporary ways of thinking about watery spaces. I conclude by arguing that the hydro‐imperial knowledges must make way for a culturally inclusive urban water design that centres and elevates First Nations design. [ABSTRACT FROM AUTHOR]

A paradigm shift process has begun in stormwater governance and management in the United States, away from centralized infrastructure and toward more decentralized practices. This transition is prompted by heightened climate change, increased urbanization, and an intense call for change in regulatory measures. Within this shift, two key and related developments have arisen: (1) the implementation of small-scale, green infrastructure, and (2) the increasing involvement of individuals and communities in managing stormwater. Despite a perceived need for this paradigm shift by most experts, there continues to be slow progress toward achieving decentralization due to changes involving redefining who is responsible for managing stormwater and how and where stormwater management is being managed. Through semi-structured interviews and Q-methodology within two urban watersheds in Maryland and Washington DC, we assess perspectives on the evolving stormwater paradigm among residents and stormwater professionals, such as nonprofit organizations, funders, policy makers and researchers. We evaluated differences in stakeholder perspectives related to who is responsible for management, the best ways to do it, and the future of stormwater management. We identified three hydrosocial relationships that stakeholders have with stormwater: Market Decentralists, Anti-Market Decentralists, and Technocratic Opportunists. Across these hydrosocial relationships, we demonstrate that there is agreement for decentralizing stormwater management through infrastructural changes and involvement of residents and communities. Nevertheless, substantial differences remain as to how stormwater is viewed, the role and responsibilities of residents, and the most effective policies to engage with residents and communities. We highlight how these differences represent significant hurdles toward implementing decentralized infrastructure and involving residents and communities in managing stormwater. Using these insights, we discuss the potential for alignment and cooperation among these diverging hydrosocial relationships and continuing the shift toward decentralized stormwater management. [ABSTRACT FROM AUTHOR]

Urban areas produce large amounts of stormwater runoff due to vast areas of impervious surfaces. Stormwater inlets, or catch basins, are commonly used for collecting and directing stormwater runoff away from streets and sidewalks. The conveyances used to direct flow to surface waters may be part of a municipal separate storm sewer systems (MS4s). Typically, MS4s redirect runoff without providing a means for removing harmful pollutants. These pollutants are then often discharged directly into local lakes, rivers, and streams, potentially harming native aquatic ecosystems. Post-construction stormwater practices are commonly used to treat runoff from urban areas by reducing the total runoff volume, lowering peak flow rates, and/or removing harmful pollutants from runoff. However, some post construction stormwater practices require large footprints, construction, and maintenance. Catch basin inserts (CBIs) are one type of post-construction best management practice that are installed within existing catch basins and require no additional land use while still providing a means for removing pollutants from stormwater runoff before entering the MS4. However, limited data is available to demonstrate the expected performance of various CBIs to ensure that these practices meet the pollutant removal standards set forth by the US Environmental Protection Agency (USEPA). The objective of this study was to evaluate the sediment removal capabilities of eight different proprietary CBI products for potential use as a post-construction stormwater practice for Department of Transportation projects. Results indicate that only two basket-type CBIs met the 80% sediment retention benchmark established for the study. While not surpassing the benchmark, three bag-type CBIs did achieve more than 70% sediment retention. The remaining three CBIs (one basket-type, one bag-type, and one cartridge type) fell notably short of the performance benchmark. [ABSTRACT FROM AUTHOR]

Bioretention systems use plants and soil media to treat pollutants in stormwater. Biochar can be an effective amendment to bioretention soil media for removing pollutants due to its adsorption properties. This study evaluates biochar as an amendment to bioretention soil media for the removal of contaminants in stormwater. Columns with varying ratios of biochar to bioretention soil media (0%, 25%, and 50% biochar) were tested to evaluate the removal efficiencies of copper, zinc, phosphorus, nitrogen, and microplastics from stormwater. Five trials were conducted with stormwater collected from parking lot runoff. Results show that the addition of biochar in bioretention systems improves the removal efficiency of zinc (average of 79% in columns with 50% biochar compared to 54% in columns without biochar) and copper (average of 73% in columns with 50% biochar compared to 25% in columns without biochar). Stormwater effluent from the biochar-amended columns also had significantly lower turbidity (21 NTU) than that of the control columns (58 NTU). Consistent leaching of nitrogen and phosphorus species was evident in the control as well as the biochar-amended columns, with average removal efficiencies of −1,114% for total nitrogen and −703% for total phosphorus. Microplastics were effectively removed by all columns, regardless of biochar amendment, with an average removal of 86%. This study indicates that biochar has the potential to reduce metal concentrations in stormwater when used as an amendment to bioretention systems but has a limited impact on nutrients and microplastics. [ABSTRACT FROM AUTHOR]

Machine learning (ML) is increasingly implemented to model water infrastructure dynamics. Common ML models are primarily data-driven and require a significant amount of data for robust training. Often, obtaining robust data at higher temporal and spatial resolutions in water systems can be challenging due to cost and time considerations. In such scenarios, integrating the existing scientific knowledge into an ML model as physics-informed ML can be advantageous to enhance predictive capability and generalizability. This study examines the predictive capability and generalizability of physics-informed ML and common ML models for typical unit operation and process (UOP) system dynamics in urban water treatment. The systems studied are (1) a continuous stirred-tank reactor, (2) activated sludge reactor, and a (3) fixed-bed granular adsorption reactor. Applications of physics-informed neural networks (PINNs) are presented. Results demonstrate when the availability of data is limited: (1) common ML models are not necessarily robust for predicting water system dynamics, except when system dynamics exhibit simpler periodic patterns. Common ML models also do not generalize across different loading conditions. (2) In contrast, the developed PINN models yield high predictive capability and generalizability. (3) Benefiting from the embedded prior knowledge, PINNs require significantly reduced data sets for robust predictions. These results suggest hybridizing physics principles and domain knowledge into the ML framework can be critical for robust UOP and water systems modeling. [ABSTRACT FROM AUTHOR]

Stormwater harvesting is a promising solution for global freshwater depletion, particularly in tropical regions with abundant rainfall. However, it is not widely used due to the lack of suitable treatment technologies for domestic applications. Multi-stage filtration (MSF) is an effective integrated treatment technology that provides a cost-effective alternative for stormwater treatment. This study investigated MSF's capacity for treating stormwater at different stages. The MSF designed and built comprised the down-flow roughing filter (DRF) and slow sand filter (SSF). The results achieved by the MSF for the treated effluents were: pH (7.1-8.1), temperature (27.6-29.4°C), electrical conductivity (EC) (100-190 µS/cm) and total dissolved solids (TDS) (70-130 mg/L). Turbidity removal efficiency of the MSF was in the range of 36-99% (5.825-164.05 NTU) and the overall average removal efficiency of the MSF was 74%, 90% and 86% for total coliforms (TC) (360-11 800 CFU/100 mL), faecal coliforms (FC) (0-1 300 CFU/100 mL) and Enterococcus spp. (120-1 400 CFU/100 mL), respectively. The study identified stormwater reuse potentials based on international guidelines and benchmarks. For the treated effluent, pH, temperature, EC and TDS were all within the permissible limits for toilet, laundry, bathing, recreational and agricultural water reuse, while turbidity suited agricultural (non-food crop) and restricted urban reuse. 46% of the effluent was suitable for recreational purposes as this satisfied the 50 NTU standard. 62.5% of the effluent satisfied the FC standard for toilets and urinals and agricultural reuse (non-food crop) purposes, while 87.5 % of the effluent satisfied urban reuse purposes (restricted access). 66.67% of the effluent satisfied the Enterococcus spp. standard for agricultural reuse (non-food crop). All treated effluents satisfied the TC bathing standard. This study shows that after minimal disinfection, stormwater effluents offer potential reuse in household applications, thereby reducing potable water demand. [ABSTRACT FROM AUTHOR]

The response to flood disasters is of great importance to protect people's lives. Proper recognition of the factors affecting floods will lead to the prevention of negative consequences. In this study, three types of Archimedean copulas, including Clayton, Gumbel, and Frank, have been applied to the depth and duration variables of maximum annual precipitation in four rain gauges' data sets (eight variables) throughout the primarily urban eastern catchment of Tehran, Iran. The results indicated that the Gumbel copula is the most suitable function of the Archimedean copulas. The average depth of rainfalls produced by the selected copula increased up to 24% compared with different varieties of single-station scenarios. Also, the average duration of produced rainfalls differed up to 14% difference compared with the single-station scenarios. Finally, the average volume of surface flooding varied between +54% and −154% with respect to the single-station scenarios. As a result, taking into account spatial distribution in rainfall will have a significant impact on the generation of runoff. The overall distribution pattern of runoff is significantly influenced by several factors. Firstly, the simultaneous impact of four rain gauge stations on synthetic runoffs plays a crucial role. The second factor is the spatial distribution of precipitation within the catchment, which is influenced by the distribution of rain gauge stations and the interpolation technique used. Additionally, the routing of synthetic surface runoff through the channel system also contributes to the overall distribution pattern of runoff. [ABSTRACT FROM AUTHOR]

Rain gardens are an alternative to traditional drainage, able to lower flood risk and reduce environmental contamination from stormwater. Removal of contaminants by rain gardens is driven by both physical processes (such as filtration and sedimentation) and biological metabolic processes by soil microorganisms. To better understand rain garden performance, this study explored the impact of rain gardens on pollution removal and microbial composition and function using rain gardens fed real stormwater from a busy road. Each rain garden had different grain size and hydraulic conductivities as these parameters have been argued to impact pollution removal. All four rain gardens were able to reduce the contaminant load in the stormwaters, reducing the concentration of dissolved metals, suspended solids and chemical oxygen demand. Significantly, road salting in the winter did not cause dissolved metals to be released from the rain gardens, suggesting that rain gardens can continue to reduce contaminant loads during winter salting regimes. Some variation in pollutant removal was seen between the soils tested, but overall no clear trend could be identified based on grain size and hydraulic conductivity with all rain gardens performing broadly similarly. The rain garden soil altered the microbial community in the stormwater, resulting in greater taxonomic evenness and functional richness in the effluent water compared to the influent. Functional richness of the soils was also higher than that of the input waters, indicating that the microbes in the rain gardens were able to perform a wider range of functions than those of the influent. Effluent and soil microbiology was more impacted by sampling date than soil grain size, which may be a result of the soil communities maturing and changing over time. As greater numbers of rain gardens are installed to tackle flooding from climate change, it is important to ensure the environment is protected from urban contaminants in the stormwater. The results in this study further highlight the ability of rain gardens to undertake this important task.

Erbil has been undergoing rapid urbanisation and population growth for the last ten years. The impervious surface areas increased, so the volume of runoff generated from stormwater increased. For this reason, the storm sewer system is faced with additional runoff from the urban areas, and the existing sewer system is inadequate. This study focuses on the storm sewer system design using SewerGEMS and AutoCAD Software in Mass City, which is located in the east of Erbil. The topographic map of the study area was created using Civil 3D software and the total station in surveying, and rainfall storm data were collected from Erbil Meteorology Station and the General Directorate of Water and Sewage. Geometric design and hydraulic modelling were done using AutoCAD and SewerGEMS, respectively. The results show hydraulic design parameters such as flow velocity, sewer pipe size, slopes, manholes, pipe profiles, hydraulic grade line, minimum depth of excavation, and the minimum number of drops. Such a model allowed the project to be accomplished in a short time, with high efficiency and low costs; the model effectively demonstrated its ability to improve design and analysis by examining hydraulic performance.

A study was implemented to determine whether stormwater from Oscar 1 Pier outfall is a contributing source of polychlorinated biphenyls (PCBs) to Decision Unit (DU) N-2, Pearl Harbor Sediment Site, Honolulu, Hawaii USA. Results suggested that PCBs were discharged from the outfall, remained in suspension, and dispersed elsewhere before settling. Stormwater PCBs were characterized by heavier congeners, likely associated with particles. Surface water PCB samples collected throughout DU N-2 exhibited heavier congeners and lighter congeners that are typically associated with the dissolved phase. These lighter congeners could have originated from a different source(s) and/or partitioned from the suspended phase.

The sustainable management of groundwater resources in developing countries is often challenging due to limited measurement and monitoring infrastructure to collect data necessary for decision support. To make a contribution towards addressing these challenges, this study investigated the use of Internet of Things (IoT) technology and low-cost sensors to collect the required groundwater-level data and develop a model to map the recharge potential with stormwater. The study focused on two stormwater ponds located in a highly urbanised area in Cape Town, South Africa. A combination of Geographic Information System and analytic hierarchy process was integrated to generate a groundwater recharge potential zone map of the study area. The IoT-based data were used to develop and calibrate a numerical groundwater model in MODFLOW. The study determined that retrofitted stormwater ponds are potential groundwater augmentation zones and can provide opportunity for stormwater recharge in urban areas. Overall, this study highlights the potential of IoT to collect hydrogeological data with low-cost sensors. Data can be collected at high temporal resolution, and the spatial scale can be increased due to availability of low-cost sensors. HIGHLIGHTS Internet of Things (IoT)-based data were leveraged to address challenges in groundwater management.; Rapid battery drain powering the IoT system was mitigated by reducing the data collection frequency and dead sleep mechanisms.; Geographic Information System–based analysis and analytic hierarchy process were employed to map the recharge potential in a highly urbanised area in Cape Town.; This study demonstrated that stormwater ponds have the potential to recharge groundwater aquifers through infiltration.;

Treatment wetlands are recognized as an effective technology for mitigating the impacts of urban runoff. However, there is no consensus on the design guidelines, and the effects of some design features, such as the underdrain system, remain unexplored. A simple analog model has been developed to mimic the underdrain network (when operating at saturation) and to evaluate the spatial heterogeneity of the flow entering it. The model has been applied to a treatment wetland in the Paris area and shows that the underdrain network was largely undersized, likely causing an uneven distribution of infiltrating flow along the length of the treatment wetland. It was also shown that this analog model can be used for optimization purposes and that it is important to use conservative values of the rugosity coefficient when designing an underdrain network. HIGHLIGHTS A brand-new analog model has been developed to mimic the hydraulic functioning of the underdrain.; Inflows into the underdrain decrease with the distance to the outlet.; Undersized underdrains can create uneven distribution of the percolating flow along the length of a treatment wetland (TW).; The analog model allows optimizing the design of underdrains for TWs with a saturated layer at the bottom.;

In the present study, Amaravati, a proposed city of Andhra Pradesh, India, is identified for stormwater reuse analysis and for various efficient options for reuse. Peak runoff from the entire catchment is determined for the management of stormwater using different models such as soil and water assessment tool (SWAT), stormwater management model, and intensity–duration–frequency curves by the log Pearson Type III method. Further, the bio-retention cell low-impact development option with 60% impervious area, 60% zero depression impervious area, bio-retention cell for 40% area for each sub-catchment, and the underground stormwater network system, for part of peak runoff reduction, remaining peak runoff is considered for reuse. The remaining peak runoff is proposed to be reused for irrigation purposes (option 1), and storage retention ponds as extended detention ponds (option 2). Also, in situ storage/percolation is recommended for unaccounted stormwater within or around each premise. The findings can help to propose, implement, and maintain various stormwater reuse measures and/or practices for any city. HIGHLIGHTS The methodology adopted is novel in regard to considering urban hydrologic study as an integrated study for various stormwater reuse efficient options.; The present study is an integrated study considering climate change, water quality, and so on, and further study on various efficient options for stormwater reuse considering low-impact development and irrigation canal options is novel of its kind.;

The hydrologic performance and cost-effectiveness of green stormwater infrastructure (GSI) in climates with highly variable precipitation is an important subject in urban stormwater management. We measured the hydrologic effects of two bioretention basins in San Antonio, Texas, a growing city in a region prone to flash flooding. Pre-construction, inflow, and outflow hydrographs of the basins were compared to test whether the basins reduced peak flow magnitude and altered the metrics of flashiness, including rate of flow rise and fall. We determined the construction and annual maintenance cost of one basin and whether precipitation magnitude and antecedent moisture conditions altered hydrologic mitigation effectiveness. The basins reduced flashiness when comparing inflow to outflow and pre-construction to outflow hydrographs, including reducing peak flow magnitudes by >80% on average. Basin performance was not strongly affected by precipitation magnitude or antecedent conditions, though the range of precipitation magnitudes sampled was limited. Construction costs were higher than previously reported projects, but annual maintenance costs were similar and no higher than costs to maintain an equivalent landscaped area. Results indicate that bioretention basins effectively mitigate peak flow and flashiness, even in flash-flood-prone environments, which should benefit downstream ecosystems. The results provide a unique assessment of bioretention basin performance in flash-flood-prone environments and can inform the optimization of cost-effectiveness when implementing GSI at watershed scales in regions with current or future similar precipitation regimes.