689 research outputs found

    Evaluating the Variability of Urban Land Surface Temperatures Using Drone Observations

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    Urbanization and climate change are driving increases in urban land surface temperatures that pose a threat to human and environmental health. To address this challenge, we must be able to observe land surface temperatures within spatially complex urban environments. However, many existing remote sensing studies are based upon satellite or aerial imagery that capture temperature at coarse resolutions that fail to capture the spatial complexities of urban land surfaces that can change at a sub-meter resolution. This study seeks to fill this gap by evaluating the spatial variability of land surface temperatures through drone thermal imagery captured at high-resolutions (13 cm). In this study, flights were conducted using a quadcopter drone and thermal camera at two case study locations in Milwaukee, Wisconsin and El Paso, Texas. Results indicate that land use types exhibit significant variability in their surface temperatures (3.9–15.8 °C) and that this variability is influenced by surface material properties, traffic, weather and urban geometry. Air temperature and solar radiation were statistically significant predictors of land surface temperature (R2 0.37–0.84) but the predictive power of the models was lower for land use types that were heavily impacted by pedestrian or vehicular traffic. The findings from this study ultimately elucidate factors that contribute to land surface temperature variability in the urban environment, which can be applied to develop better temperature mitigation practices to protect human and environmental health

    Evaluation of Continuous Monitoring as a Tool for Municipal Stormwater Management Programs

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    The purpose of this study is to evaluate the uncertainty attributable to inadequate temporal sampling of stormwater discharge and water quality, and understand its implications for meeting monitoring objectives relevant to municipal separate storm sewer systems (MS4s). A methodology is presented to evaluate uncertainty attributable to inadequate temporal sampling of continuous stormflow and water quality, and a case study demonstrates the application of the methodology to six small urban watersheds (0.8-6.8 km2) and six large rural watersheds (30-16,192 km2) in Virginia. Results indicate the necessity of high-frequency continuous monitoring for accurately capturing multiple monitoring objectives, including illicit discharges, acute toxicity events, and stormflow pollutant concentrations and loads, as compared to traditional methods of sampling. For example, 1-h sampling in small urban watersheds and daily sampling in large rural watersheds would introduce uncertainty in capturing pollutant loads of 3–46% and 10–28%, respectively. Overall, the outcomes from this study highlight how MS4s can leverage continuous monitoring to meet multiple objectives under current and future regulatory environments

    Stormwater Management Actions Under Regulatory Pressure: A Case Study of Southeast Wisconsin

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    In the United States, new legislation has given regulatory authorities greater oversight of municipal stormwater management programs. However, estimating the impact of greater oversight on municipal actions is difficult due to the uncertainty in current compliance efforts and their associated costs. This paper seeks to fill this gap through a case study of NPDES stormwater runoff permit reports from municipalities in Southeast Wisconsin. Specifically, this study evaluates the reported actions and expenditures against socioeconomic variables to identify the relationships between cost, socioeconomics, and the best management practices (BMPs) used for compliance. Results indicate that there are distinct differences between municipalities with and without financial and personnel resources, clear high- and low-cost BMPs, and large variation in the practices municipalities implement to meet regulatory requirements. Furthermore, results suggest that regulators should take a flexible and pragmatic approach that considers individual municipal constraints and limitations when exercising greater regulatory authority

    Impact of hurricane Harvey on the results of regional flood frequency analysis

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    Hurricane Harvey was an unprecedented event that resulted in immense damage to life and property. As a result, it is important to determine how this event, as well as past and future events like it, will impact engineering design equations that are based upon historical data, such as flood frequency analysis equations. This study seeks to contribute to this discussion by evaluating the extent to which Harvey influenced estimations of instantaneous peak discharges in rural ungauged basins in southeast Texas. Results indicate that Harvey significantly increased the computations of design floods using Log‐Pearson Type III analysis (e.g., 3–55% for 2‐year flood and 3–80% for the 100‐year flood). This subsequently impacted the estimation of instantaneous peak discharges through regional flood frequency analysis by up to 28%. These results highlight the influence that recent and future hurricanes can have on engineering design equations that are used for managing floodplains, assessing flood risk, and designing infrastructure such as levees, bridges, and culverts

    Improved Reliability of Stormwater Detention Basin Performance Through Water Quality Data-informed Real-time Control

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    Stormwater detentions basins are designed to capture stormwater to reduce and delay peak flows and to improve water quality. A novel technology proposed to improve basin performance is real-time, active control of the basin outflow, in so-called “smart” stormwater systems. Existing studies demonstrate the performance of active controls that respond in real-time to basin water level, detention time, and rainfall forecast for one or a small number of rainfall events. We hypothesize that the performance of these active controls can be improved by incorporating real-time water quality data into the control algorithm. In addition, we hypothesize that active control performance depends on hydrologic variability, specifically the frequency and intensity of runoff inputs. In this paper, we test these hypotheses using a numerical modeling framework for systems-level reliability analysis of active and passive stormwater basin outflow control using a Monte Carlo method. The analysis is performed using the urban hydrology model EPA-SWMM driven by stochastic rainfall time-series generated from the Modified Bartlett-Lewis Rectangular Pulses Model. Water quality-informed real-time active control algorithms are developed, tested, and shown to display an improvement over traditional, passive (no control) systems and other storage-based active controls for water and pollutant capture. Seasonal and duration curve analysis showed that water level- and water quality- informed control performance varied for different storm return periods and this variability could partly be attributed to the fraction of time the valve is closed. In addition, control performance was sensitive to rainfall variability, generally decreasing as storms become less frequent and more intense. Therefore, control system performance may depend on seasonal and longer time-scale variability in climate and rainfall-runoff processes. We anticipate this study to be a starting point to incorporate theories of reliability to assess detention basin and conveyance network performance under more complex real-time control algorithms and failure modes

    Seasonal and Spatial Patterns Differ Between Intracellular and Extracellular Antibiotic Resistance Genes in Urban Stormwater Runoff

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    Antibiotic resistance is a public health threat that is exacerbated by the dispersion of antibiotic resistance genes (ARGs) into aquatic environments. Urban stormwater runoff has been recognized as a source of and a mechanism by which intracellular ARGs (iARGs) can be transported into receiving environments. The prevalence and behavior of extracellular ARGs (eARGs) in stormwater, however, has yet to be considered. This study quantified four iARGs and eARGs under baseflow and stormflow conditions. Urban stormwater runoff was found to be a source of all the ARGs examined, with the absolute concentration of all iARGs and two eARGs (ermF and tetC) increasing significantly (p \u3c 0.05) between baseflow and stormflow. The occurrence of iARGs and eARGs in stormwater runoff was also investigated across three seasons to differentiate temporal trends. All eARGs were found to be most abundant in the fall, while the iARGs did not display a consistent seasonal trend. Following, spatial patterns of the ARGs were elucidated by targeting four sampling locations, including direct runoff from a curbside storm inlet and a stormwater outfall, and two receiving environments, the Menomonee River and Lake Michigan. Stormwater was found to have the largest impact, in terms of the percent increase in ARG concentrations between baseflow and stormflow, on the outfall location where on average the iARGs and eARGs increased 16% and 12.3%, respectively. The variability in seasonal and spatial trends between the iARGs and eARGs suggests a difference in sources and transport mechanisms of the ARGs into the environment. Moreover, the results of this study revealed that eARGs are relevant contaminants to consider when determining the threat of antibiotic resistance originating from stormwater runoff

    Impacts of AKST on development and sustainability goals.

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    Assessment and analysis of AKST impacts; Agriculture productivity, production factors and consumption; impacts of akst on sustainability, through integrated technologies and the delivery of ecosystem services and public goods; Impacts of akst on livehoods, capacoty strenthening and empowerment; relationshipsbetween akst, coordination and regulatory processes among multipl3e stakeholders

    Probing Adsorption Interactions in Metal-Organic Frameworks using X-ray Spectroscopy

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    We explore the local electronic signatures of molecular adsorption at coordinatively unsaturated binding sites in the metal-organic framework Mg-MOF-74 using X-ray spectroscopy and first-principles calculations. In situ measurements at the Mg K-edge reveal distinct pre-edge absorption features associated with the unique, open coordination of the Mg sites which are suppressed upon adsorption of CO2 and N,Nâ€Č-dimethylformamide. Density functional theory shows that these spectral changes arise from modifications of local symmetry around the Mg sites upon gas uptake and are strongly dependent on the metal-adsorbate binding strength. The expanded MOF Mg2(dobpdc) displays the same behavior upon adsorption of CO 2 and N,Nâ€Č-dimethylethylenediamine. Similar sensitivity to local symmetry is expected for any open metal site, making X-ray spectroscopy an ideal tool for examining adsorption in such MOFs. Qualitative agreement between ambient-temperature experimental and 0 K theoretical spectra is good, with minor discrepancies thought to result from framework vibrational motion. © 2013 American Chemical Society

    Is Incarceration a Contributor to Health Disparities? Access to Care of Formerly Incarcerated Adults

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    Despite the disproportionate prevalence of incarceration in communities of color, few studies have examined its contribution to health disparities. We examined whether a lifetime history of incarceration is associated with recent access to medical and dental care. We performed a secondary data analysis of the 2007 Los Angeles County Health Survey, a population-based random-digit-dialing telephone survey of county households. Any history of incarceration in a prison/jail/detention center as an adult was assessed for a random subsample. Bivariate and multivariate logistic regression analyses examined whether incarceration history was associated with access to care, controlling for other characteristics. Ten percent of our study population reported a history of incarceration. While persons with an incarceration history were similar to their peers with regard to health and insurance status, their access to medical and dental care was worse. Incarceration history was independently associated with disparities in access to care. Interventions to improve the health of communities affected by high rates of incarceration could include efforts that enable access to care for formerly incarcerated adults
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