Urban Basins Research Articles

Complementarity of road salt and heavy metal pollutant removal through invasive Typha and Phragmites harvest in urban wetland detention basins

Plant-based bioremediation has been proposed as a strategy to mitigate the growing risks associated with freshwater salinization, but large-scale experimental field tests of how harvesting plants can reduce deicing salts and heavy metals common in roadside environments are lacking. We implemented a three-year, large-scale field experiment (across 180 ha) in ten urban wetland detention basins in the Chicago region (Illinois, USA) to investigate the potential of plant biomass harvest to remove salts and heavy metals from roadside environments. Harvesting both Typha and Phragmites, ubiquitous plants that co-occur in wetlands around the globe, has the potential to remove both salts (Na, Cl, Ca, Mg) and heavy metals (Zn, Cu, Fe, Mn), as we observed complementarity in the pollutants concentrated in the aboveground tissues of these two species. We observed greater salt stocks in Typha biomass while heavy metals (especially Zn) were more abundant in Phragmites. Salts associated with deicing salts (Na, Cl) were particularly concentrated in live green Typha tissue, while metals tended to be more abundant (>50% of total stocks) in senescent litter, suggesting that plant phenology is important to consider when mitigating target pollutants via harvesting. Although repeated harvests reduced aboveground biomass and associated salt and metal stocks relative to unmanipulated controls, rotational harvest of common macrophytes growing in road-adjacent wetlands could maximize the reduction of roadside pollutants through harvesting. However, our data suggest that harvesting invasive macrophytes from urban roadside detention basins is not a silver bullet to remedy freshwater salinization, as it mitigates only a small fraction of added road salt loads.

Composition of soil bacterial communities associated with urban stormwater detention basins and their predicted functional roles in N cycle.

Stormwater detention basins serve as vital components in mitigating the adverse effects of urban runoff, and investigating the microbial dynamics within these systems is crucial for enhancing their performance and pollutant removal capabilities. The aim of this study was to examine and compare the soil bacterial communities in two stormwater detention basins located on the Edwards Aquifer in Bexar County, Texas, USA, and evaluate how soil physiochemical properties may affect them. Each basin soil was sampled in two different seasons at varying depths and the structure of microbial communities was examined using paired end Illumina sequencing using V3 and V4 region of 16S rRNA gene. PICRUSt2 was used to predict functional genes in the nitrogen cycle. In addition, soil physicochemical properties such as pH, carbon, nitrogen, and phosphorus and particle size were examined. A beta diversity analysis revealed that basins had distinctive microbial communities. Additionally, soil particle size, phosphorus and ammonia significantly correlated with some of the dominant phyla in the basins. Proteobacteria and Acidobacteria showed a positive correlation with the relative abundances of nitrogen-cycling genes, while Actinobacteria showed a negative correlation. This study evaluated the associations between soil physicochemical properties and microbial community dynamics in stormwater basins. The study also predicts the relative abundance of nitrogen cycling genes, suggesting shared functional traits within microbial communities. The findings have implications for understanding the potential role of microbial communities in nitrogen cycling processes and contribute to developing sustainable stormwater management strategies and protecting water quality in urban areas.

Hydrochemical Delineation of Spring Recharge in an Urbanized Karst Basin, Central Kentucky

ABSTRACT Because of well-integrated surface and subsurface drainage in karst terrains, springs can exhibit relatively rapid hydraulic, chemical, and thermal responses to storms. In urbanized karst basins, impervious cover, stream channelization, and utility infrastructure can alter infiltration, provide alternate pathways for subsurface flow, and affect ambient water quality. We combined continuous logging of electrical conductivity (EC) and water temperature with analyses of stable isotopes (deuterium and oxygen-18) to differentiate focused and diffuse recharge in a karst basin in Lexington, Kentucky, during 2018. Logging occurred at the McConnell Springs Blue Hole and a sinkhole that drains to it; isotopes, specific conductance, and temperature were manually monitored at those sites and along two losing stream reaches. Water temperature at McConnell Springs and stable isotope abundances showed seasonal variability. The Blue Hole responded within hours to stormwater infiltration at the sinkhole (∼2.1 km upgradient), with recharge events marked by colder stormwater in winter and warmer stormwater in spring to early autumn. Stable isotopes indicated that sinkhole infiltration was minimally affected by evaporation during periods of ponding (up to 9 days). Spring discharge appeared to represent a mixture of focused and diffuse, partly evaporated recharge, consistent with a simple hydrologic model of rainfall, runoff, and infiltration in the basin. EC spikes at the spring during January–March were consistent with pulses of road salt or brine in runoff or snowmelt. Despite limited monitoring data, results suggest that restoration of the sinkhole and its inlet stream were effective in stormwater management during an unusually wet year.

A hydrodynamic-machine learning coupled (HMC) model of real-time urban flood in a seasonal river basin using mechanism-assisted temporal cross-correlation (MTC) for space decoupling

The intricate nature of urban waterlogging models arises from the compounding effects of human activities and dynamic alterations in the natural environment. Based on extensive data correlation and hydrodynamic process analysis, this study offers an a priori index mechanism-assisted temporal cross-correlation (MTC) for model space decoupling, which helps to reduce the computational complexity of the urban flood model. Furthermore, a hydrodynamic-machine learning (ML) coupled (HMC) model is proposed for predicting the river and drainage pipe water levels in urban seasonal river basins. The observations of the rainfalls, water levels of the river and manholes during 10 rainstorm events are gathered, with 8 of which serving as training datasets and 2 as prediction datasets. The simulation results show that MTC can provide a thorough evaluation of the impact of input parameters on predicting objects. It can also demonstrate the causality of hydrological processes behind monitoring data correlation. In addition, in comparison to ML and hydrodynamic models, the simulation stability of the HMC model is observed to be superior. Meanwhile, the NSE of the river channel and manhole is observed to be higher than 0.95 and 0.90, respectively, and the simulation uncertainty is found to be reduced by 42.2 %. The HMC model requires an average of 25 s to simulate an 8-hour rainfall event. This approach is found to be effective for space decoupling and rapid urban flood simulation.

Inferring microbial community assembly in an urban river basin through geo-multi-omics and phylogenetic bin-based null-model analysis of surface water

Understanding the community assembly process is a central issue in microbial ecology. In this study, we analyzed the community assembly of particle-associated (PA) and free-living (FL) surface water microbiomes in 54 sites from the headstream to the river mouth of an urban river in Japan, the river basin of which has the highest human population density in the country. Analyses were conducted from two perspectives: (1) analysis of deterministic processes considering only environmental factors using a geo-multi-omics dataset and (2) analysis of deterministic and stochastic processes to estimate the contributions of heterogeneous selection (HeS), homogeneous selection (HoS), dispersal limitation (DL), homogenizing dispersal (HD), and drift (DR) as community assembly processes using a phylogenetic bin-based null model. The variation in microbiomes was successfully explained from a deterministic perspective by environmental factors, such as organic matter–related, nitrogen metabolism, and salinity-related parameters, using multivariate statistical analysis, network analysis, and habitat prediction. In addition, we demonstrated the dominance of stochastic processes (DL, HD, and DR) over deterministic processes (HeS and HoS) in community assembly from both deterministic and stochastic perspectives. Our analysis revealed that as the distance between two sites increased, the effect of HoS sharply decreased while the effect of HeS increased, particularly between upstream and estuary sites, indicating that the salinity gradient could potentially enhance the contribution of HeS to community assembly. Our study highlights the importance of both stochastic and deterministic processes in community assembly of PA and FL surface water microbiomes in urban riverine ecosystems.

Spatial and temporal evaluation of groundwater hydrochemistry in an active phreatic zone of developed basin in selangor, Malaysia

Groundwater provides freshwater supply for multiple purposes such as drinking water, irrigation, and industrial processes. Due to intensive developments, contaminants from various land use practices infiltrate into the groundwater system and jeopardized the existing quality. Besides, uncontrolled groundwater extraction exacerbate the existing issue due to improper management and uncontrolled extraction; especially in developing areas. This study centralized in Kuala Langat; an urbanized basin with mix of land use practices (residential, industrial, and agricultural) with the aim to observe the impacts of land use activities towards groundwater hydrochemistry on seasonal and temporal scale. A total of 30 groundwater samples were collected along Langat River Basin to assess the physicochemical parameters, concentration of major ions and heavy metals. Application of multivariate and graphical analysis as well as pollution indices were incorporated in this study to evaluate the degree of heavy metals contamination. The order of cations concentration evaluated in pre- and post-monsoon seasons are Na > Ca > K > Mg and Na > Mg > Ca > K, respectively while the order of anions concentration is HCO3>Cl > SO4 for both monsoon seasons. Both calculated HPI and Cd value suggested that agricultural activity is the main contributor for groundwater pollution. Overall, most of the stations are potable to be consumed as stated from HPI and Cd results except for station SSG10. It is suggested that for a better precaution, the groundwater in Langat River Basin shall undergo prior treatment before further consumption.

Multi-criteria site selection and hydraulic modeling of green flood retention measures in a highly urbanized basin in Costa Rica

Green flood retention measures (GFRMs) are nature-based solutions applied to. mitigate floods by slowing and storing floodwater. This study employed a hydraulic, model developed in HEC-RAS to analyze the effects of GFRMs in the Quebrada Seca-Burío basin in Costa Rica. A multi-criteria methodology was developed to select. suitable sites for implementing the measures. A baseline representing the status quo, scenarios with individually assessed measures implemented at different sites, and a scenario with all measures combined were compared concerning their flood retention. potential. Twelve suitable sites capable of providing multiple socio-ecological benefits. were identified, of which three were implemented in the model to evaluate their. hydraulic performance. The results indicate that all scenarios are effective in reducing. peak flow, volume, and inundation areas, but to varying degrees. The combination of. all measures presented the most effective results, with peak flow reductions of 5.6 –15.3% and flood volume reductions of 3.6 – 9.9%.

Seasonal variations of dissolved rare earth elements and anthropogenic gadolinium in the highly urbanized river basin, Busan, Korea

Anthropogenic gadolinium (Gdanth) has been reported in rivers as a result of magnetic resonance imaging. We collected seasonal water samples from the Suyeong River Basin, to investigate seasonal variations in dissolved rare earth elements (REEs) and Gdanth in highly urbanized areas. The post-Archean Australian shale-normalized REE patterns indicate a significant influence of terrestrial source inputs during the summer. Although higher concentrations of dissolved REEs were measured in summer than in winter, the Gdanth concentrations exhibited similar levels. During winter, the concentrations of Gdanth showed conservative mixing trends downstream of the wastewater treatment plant (WWTP), whereas no clear trend was observed in summer. Moreover, the estimated daily discharge of Gdanth accounts for approximately 11–22% of the number of MRI tests performed, when the WWTP treats only 6% of Busan area size. Our results suggests that the elevated Gdanth level in the highly urbanized river basin is a major concern.

Intra- and inter-annual variations in metal concentrations in the superficial water of a highly polluted urban basin of Argentina.

To protect ecosystems impacted by human activities and prevent their degradation, it is imperative to evaluate variations in the concentration of environmental pollutants over time. Here, we evaluated the intra- and inter-annual variations of several metals from 15 sites in the Matanza Riachuelo River basin (one of the most polluted in the world) and determined the physicochemical and meteorological parameters associated with these changes from 2008 to 2015. For this, in each site, we used Asymmetric Eigenvector Maps and Redundancy Analysis. The results highlighted temporal patterns of metal concentrations and several factors associated with them, perhaps related to the actions performed in the area since 2008. Additionally, we found that the effects of physicochemical and meteorological factors on metal concentrations were site-dependent, possibly related to the presence of different local sources of pollution or characteristics of the river in each site, such as its sediments. This approach could be applied to different scenarios (aquatic and terrestrial) and could provide a tool to help decision-makers address the harmful consequences of the continuous advance of human activities on human and ecosystem health.

Establishment and Application of a Specialized Physical Examination Indicator System for Urban Waterlogging Risk in China

With the rapid development of urbanization in China, urban waterlogging has become a significant problem in constructing the safety of the human environment. As an essential manifestation of the modernization of the urban governance system and capacity, the city physical examination establishes a multi-criteria evaluation system for problem diagnosis, rectification, and improvement. In order to accurately identify the risk of urban waterlogging, the concept of special physical examination of urban waterlogging risk was established, and the evaluation mechanism and indicator definition were improved on the basis of the “four-factor method” of flooding disaster assessment. From the perspective of urban basin flood control capacity, background disaster-bearing conditions, “Major-Minor-Micro” drainage system capacity, crucial locations and personnel protection, and emergency management capacity, twenty-four indicators in five categories were selected. The interaction between multiple factors is considered to establish a special physical examination indicator system as a characteristic evaluation mechanism of waterlogging with the goal of urban safety and resilience. The results of the study could provide theoretical and technical support for the diagnosis of urban waterlogging risk problems and the formulation of prevention and control strategies.

Anthropogenic Changes in the Hydrochemical Regime and Water Quality in an Urban Watercourse: Case Study of the Likhoborka River, Moscow Region

The article presents the results of hydrochemical monitoring of a small river flowing in an urbanized basin in Moscow. Probabilistic estimate is given to the compliance of river water quality with regulatory requirements and the occurrence of high level river pollution (high and extremely high pollution). Specific features of river hydrochemical regime that distinguish the urban watercourse from natural water objects are revealed. The representativeness of the observation data from the institution that controls river water quality is estimated, and the time step of the series of measured water quality characteristics was shown to be insufficient to fully reflect their variations. The reliability of the monitoring data presented by the control institution is too low to adequately assess the level of river water pollution and the efficiency of the measures taken to protect the river

Urban flood forecasting using a hybrid modeling approach based on a deep learning technique

Abstract Climate change is contributing to the increasing frequency and severity of flooding worldwide. Therefore, forecasting and preparing for floods while considering extreme climate conditions are essential for decision-makers to prevent and manage disasters. Although recent studies have demonstrated the potential of long short-term memory (LSTM) models for forecasting rainfall-related runoff, there remains room for improvement due to the lack of observational data. In this study, we developed a flood forecasting model based on a hybrid modeling approach that combined a rainfall-runoff model and a deep learning model. Furthermore, we proposed a method for forecasting flooding time using several representative rainfall variables. The study focused on urban river basins, combined rainfall amounts, duration, and time distribution to create virtual rainfall scenarios. Additionally, the simulated results of the rainfall-runoff model were used as input data to forecast flooding time under extreme and other rainfall conditions. The prediction results achieved high accuracy with a correlation coefficient of >0.9 and a Nash[ndash]Sutcliffe efficiency of >0.8. These results indicated that the proposed method would enable reasonable forecasting of flood occurrences and their timing using only forecasted rainfall information.

Range extension of Isthmoheros tuyrensis, a threatened species of fish (Cichlidae) in Panama: including new ecological and morphological data

There are two endemic species of Cichlidae in southern Central America, both found in the Pacific Slope of Eastern Panama (PSEP). One is Isthmoheros tuyrensis, which until now was presumed to be distributed in the Darien Province and the Bayano River basin. Information on distribution and ecology of I. tuyrensis is relatively scarce. In this investigation we report a new range extension for the species and provide additional morphological and ecological data. Fish were sampled using electrofishing and cast nets, in three river basins of the Panama District (Matasnillo, Juan Díaz, and Pacora) from August–September (rainy season) of 2020, February–March (dry season), and April (transition season) of 2021. Fish diversity, water quality, and physical parameters were gathered within the upper, middle, and lower portions of the three basins. This study focused on the localities where specimens of I. tuyrensis were found (i.e., Pacora river basin). The presence of the species in localities with significant anthropogenic threats results in a potential barrier for distribution, along with the possibility of extirpation due to heavy pollution – in particular from the rivers on the western side of Panama City. In addition, we note an increase in urban threat from the east of the city due to expanded development and agricultural activities. I. tuyrensis, the virtually unknown “Aveinte” in Spanish or the “Isthmian Hero”, is listed as Vulnerable by the International Union for Conservation of Nature (IUCN)’s Red List and inhabits some river basins lacking effective protection, being the only endemic fish species located in an urban basin in the Pacific of Mesoamerica. The information on distribution, morphology, and ecology provided here will contribute to a better understanding of the species’ biology and will aid the creation and implementation of management and conservation measures.

Initial Conditions and Resilience in the Atmospheric Boundary Layer of an Urban Basin

The possibilities of micrometeorological resilience in urban contexts immersed in a basin geographical configuration are investigated. For this purpose, time series data with measurements of meteorological variables (temperature, magnitude of wind speed and relative humidity) and atmospheric pollutants (PM2.5, PM10, CO) are analyzed through chaos theory, calculating the coefficient of Lyapunov (λ), the correlation dimension (Dc), the Hurst coefficient (H), the correlation entropy (SK), the fractal dimension (D) and the Lempel–Ziv complexity (LZ). Indicators are built for each measurement period (2010–2013 and 2017–2020), for each locality studied and located at different heights. These indicators, which correspond to the quotient between the entropy resulting from the meteorological variables and that of the pollutants, show sensitivity to height. Another important indicator, for identical measurement conditions, arises from the calculation of the fractal dimensions of the meteorological variables and that of the pollutants, which allows for comparative studies between the two periods. These indicators are conclusive in pointing out that, in a large city with basin geographical characteristics, subjected to an intensive urbanization process, there is no micrometeorological resilience and a great variation occurs in the initial conditions.

Load quantification and effect evaluation of urban non-point source pollution in the Licun River based on SWAT model.

With the gradual control of point source pollution, the impact of urban nonpoint source pollution on river water quality is becoming more prominent. Regarding the current problem that nonpoint source pollution loads in urban basins are difficult to quantify and the impact on water quality is difficult to analyze, the Licun River basin in Qingdao was selected as the research object. Through the field survey and surface accumulation sampling analysis of the basin, the evaluation model of urban nonpoint source pollution was constructed by revising the land type data of the basin and the urban database of the SWAT model. The results showed that concentration of nitrate in precipitation was most sensitive to the simulation of nitrogen loading; organic P in baseflow was most sensitive to the simulation of phosphorus loading. The Nash-Sutcliffe efficiency coefficient (ENS) and the coefficients of determination (R2) of the SWAT model for runoff, total phosphorus (TP), and total nitrogen (TN) in the simulation validation period meet the model requirements,indicating a good model fit. In addition, the spatial and temporal distribution characteristics of urban nonpoint source pollution of TN and TP in 2021 were analyzed. In July, rainfall-runoff from the Licun River basin was the most polluted.

Spatial-Temporal Dynamics of Anthropogenic Nitrogen Inputs in the Rapid Developing Chaohu Lake Basin

Due to the agricultural and industrial activities in rapidly urbanized basins, nitrogen (N) inputs have increased significantly, causing a variety of environmental issues. These challenges require an accurate assessment of the contributions of the driving factors, particularly in the Chaohu Lake Basin, which faces the double pressures of urban expansion and agricultural production. The research shows: (1) From 1990 to 2018, the trajectory of net anthropogenic N inputs (NANI) exhibited a three-stage pattern (uptrend stage, fluctuation stage, and downtrend stage), with an average value of 13,482 kg N km−2 year−1. The primary source was fertilizer N application, which made up approximately 79% of the NANI. Human food and animal feed imports, biological nitrogen fixation, and atmospheric N deposition composed 8%, 6%, and 6%, respectively. (2) Rapid urbanization enhanced the NANI in a short time stage. However, long-term analysis had shown a declining trend in nitrogen inputs, indicating that urbanization could improve fertilizer efficiency and introduce cleaner energy sources. (3) The NANI in urban watersheds were estimated at 20,700 kg N km−2 year−1, which was 3.4 times higher than in agricultural watersheds. Fertilizer N application was used in urban watersheds, as well as human food and animal feed imports. Urbanization drove the N input of food and feed mainly in urban watersheds but had no influence in agricultural watersheds and mixed watersheds. Since urban basins were the main source of nitrogen inputs, it was crucial to support environmental management efforts to reduce N pollution.

Fingerprinting Sediment Origin of the Silting Process of Urban Reservoirs

The silting process of urban reservoirs has been occurring in many regions across the world. However, identifying the main sources of sediment and controlling the silting process in urban reservoirs are still unsolved problems in many regions, mainly in developing countries such as Brazil. In this study, we identify which land use most influences the siltation of reservoirs, and how the different tributary streams contribute to this process in two urban reservoirs located in Campo Grande, Midwestern Brazil. Thus, we applied a sediment source fingerprinting (SSF) approach, associated with land use analysis, and the bathymetric data of reservoirs connected to the stream and drainage network, obtained between the years 2008 and 2018. The reduction in the volume and area of the reservoir during the study period were 45% and 39%, respectively. We found a proportional relationship between the reduction in the reservoir volume and the increase in the impermeable areas of the studied basin. We also noted that the sediments deposited in the reservoir originate from bare soil, banks, and bed in the proportions of 46.9%, 37.1%, and 17.2%, respectively. Our findings show that the use of bathymetric surveys and data on land use and land cover, associated with the source tracing technique, are useful alternatives to identifying sediment mobility in urban basins, especially in those where the drainage network is connected to water courses. We conclude that the factors that most contribute to the silting up of reservoirs are the erosion of banks and beds, sediment remobilization and the connectivity of the drainage network with water courses.

Bottom-up multilevel flood hazard mapping by integrated inundation modelling in data scarce cities

With increasing urban flood risk due to urbanisation and climate change, flood hazard prediction is ever more crucial for flood risk management and emergency response. However, when sufficient high-quality data are lacking, a standard flood inundation modelling approach has significant uncertainties. Therefore, this study develops a bottom-up approach for urban flood hazard mapping at multiple levels (grid-kilometre-district), built upon the integration of grid-based flood modelling with data acquisition from open sources. This reduces the adverse effects of data scarcity and quality on hazard modelling. In the paper, we first set out an integrated approach for gridded inundation mapping in an urban basin using a hydrodynamic model supported by crowd-sourced social media data. Then, applying the model to flooding in Chengdu in August 2020, we articulate how input data bias and parameter uncertainty both affect urban inundation modelling. The results show that the choice of terrain data and the quantification of urban drainage flows significantly influence the modelled urban inundation extent, depth and duration. This indicates the potential for large variation when using urban inundation mapping merely relying on a single-scale flood hydrodynamic modelling even when supported by crowd-sourced data. The multilevel hazard mapping approach developed here presents multi-layered and comprehensive inundation mapping; thus the effects of data bias or availability are reduced and the coarser hazard mapping shows less sensitivity to the data input quality and model uncertainty, indicating relatively higher reliability at this higher spatial scale. The grid-kilometre-district three level approach provides more reliable flood hazard mapping, which can support rainstorm-induced flood management in data scarce cities.

Specific Features of the Formation and Regulation of Diffuse Pollution in Urban Areas: Case Study of the Yauza R.

Specific features of water quality formation are considered for the Yauza R. flowing in an urbanized drainage basin containing Moscow City and nearest Moscow region. It has been found that the deep transformation of the natural hydrographic network along with diffused pollution from sources scattered over its basin have an adverse effect on water quality formation in the urban watercourse and its self-purification potential. The current ecological state of the river can be evaluated as unsatisfactory, notwithstanding the water protection measures taken in its basin. The existing system for managing the urban surface runoff has been analyzed. It is shown that monitoring the volumes and formation conditions of pollution runoff from the urban territory is not effective enough for an objective estimate of the environmental conditions of water bodies and reduces the efficiency of water protection measures.

Assessment of economic impacts in flood events in Lages/SC, Brazil

Flood processes become increasingly harmful to communities due to factors such as climate change and land use. This study aims to evaluate the economic damages of flood events in an area of the urban basins of Lages/SC. Thus, four plans were considered for economic evaluation: one referring to conditions without protective measures and three with the application of elevation of structures at different heights, as well as two scenarios of the evolution of urban occupation. The rainfalls were obtained through the Gumbel probabilistic model to estimate the maximum accumulated precipitations over 5 days, with the hydrological modeling carried out at the HEC-HMS. The hydrodynamic modeling was performed in HEC-RAS through the simulation of a 1D model. The HEC-FDA model was used to perform the risk reduction analysis of damage caused by floods, where the expected annual damages (EAD) were calculated for the four proposed plans as well as for the urban growth scenarios. The results showed that the application of the mitigating measure of raising the structures reduced the EAD by up to 83.10%. As for the scenario of the evolution of urban growth, there was an increase in EAD of 62.09%, in the interval of 20 years. The HEC-FDA model has been demonstrated as good software for assessing the economic damage of floods in different scenarios, showing results that can help decision-makers in the development of public policies.