scholarly journals Urban runoff source partitioning using isotopic analysis of nitrate and sulfate

2021 ◽  
Author(s):  
Victoria Rexhausen ◽  
Ania Szynkiewicz ◽  
Jon Hathaway
Keyword(s):  
Urban Runoff ◽  
Isotopic Analysis ◽  
Source Partitioning

Laboratory and in-situ analysis of comet dust

1988 ◽  
Vol 46 ◽  
pp. 8-9
Author(s):  
D.E. Brownlee ◽  
A.L. Albee
Keyword(s):  
Electron Microscopy ◽  
Solar System ◽  
Laboratory Study ◽  
Isotopic Analysis ◽  
Building Blocks ◽  
Sem Analysis ◽  
Early Solar System ◽  
Cometary Material ◽  
Comet Dust

Comets are primitive, kilometer-sized bodies that formed in the outer regions of the solar system. Composed of ice and dust, comets are generally believed to be relic building blocks of the outer solar system that have been preserved at cryogenic temperatures since the formation of the Sun and planets. The analysis of cometary material is particularly important because the properties of cometary material provide direct information on the processes and environments that formed and influenced solid matter both in the early solar system and in the interstellar environments that preceded it.The first direct analyses of proven comet dust were made during the Soviet and European spacecraft encounters with Comet Halley in 1986. These missions carried time-of-flight mass spectrometers that measured mass spectra of individual micron and smaller particles. The Halley measurements were semi-quantitative but they showed that comet dust is a complex fine-grained mixture of silicates and organic material. A full understanding of comet dust will require detailed morphological, mineralogical, elemental and isotopic analysis at the finest possible scale. Electron microscopy and related microbeam techniques will play key roles in the analysis. The present and future of electron microscopy of comet samples involves laboratory study of micrometeorites collected in the stratosphere, in-situ SEM analysis of particles collected at a comet and laboratory study of samples collected from a comet and returned to the Earth for detailed study.

Urban Greening and Human-Wildlife Relations in Philadelphia: From Animal Control to Multispecies Coexistence?

2020 ◽  
Vol 29 (1) ◽  
pp. 67-87 ◽  
Author(s):  
Christian Hunold
Keyword(s):  
Public Health ◽  
Green Infrastructure ◽  
Urban Areas ◽  
Urban Runoff ◽  
Urban Wildlife ◽  
Wildlife Habitat ◽  
Wild Animals ◽  
Urban Greening ◽  
Human Needs ◽  
Animal Control

City-scale urban greening is expanding wildlife habitat in previously less hospitable urban areas. Does this transformation also prompt a reckoning with the longstanding idea that cities are places intended to satisfy primarily human needs? I pose this question in the context of one of North America's most ambitious green infrastructure programmes to manage urban runoff: Philadelphia's Green City, Clean Waters. Given that the city's green infrastructure plans have little to say about wildlife, I investigate how wild animals fit into urban greening professionals' conceptions of the urban. I argue that practitioners relate to urban wildlife via three distinctive frames: 1) animal control, 2) public health and 3) biodiversity, and explore the implications of each for peaceful human-wildlife coexistence in 'greened' cities.

Large-Scale Application of Biofiltration Swale Runoff Management Practices

2007 ◽  
Vol 2 (2) ◽  
Author(s):  
William C. Lucas
Keyword(s):  
Large Scale ◽  
Management Practices ◽  
Peak Flow ◽  
Low Impact Development ◽  
Urban Runoff ◽  
Management Model ◽  
Check Dams ◽  
Runoff Reduction ◽  
Impervious Area ◽  
Hydrologic Responses

Retaining rainfall where it lands is a fundamental benefit of Low Impact Development (LID). The Delaware Urban Runoff Management Model (DURMM) was developed to address the benefits of LID design. DURMM explicitly addresses the benefits of impervious area disconnection as well as swale flow routing that responds to flow retardance changes. Biofiltration swales are an effective LID BMP for treating urban runoff. By adding check dams, the detention storage provided can also reduce peak rates. This presentation explores how the DURMM runoff reduction approach can be integrated with detention routing procedures to project runoff volume and peak flow reductions provided by BMP facilities. This approach has been applied to a 1,200 unit project on 360 hectares located in Delaware, USA. Over 5 km of biofiltration swales have been designed, many of which have stone check dams placed every 30 to 35 meters to provide detention storage. The engineering involved in the design of such facilities uses hydrologic modeling based upon TR-20 routines, as adapted by the DURMM model. The hydraulic approach includes routing of flows through the check dams. This presentation summarizes the hydrological network, presents the hydrologic responses, along with selected hydrographs to demonstrate the potential of design approach.

Laboratory Prediction of Phosphorus Release from Deciduous Leaves to Urban Runoff

1995 ◽  
Vol 30 (2) ◽  
pp. 243-246 ◽  
Author(s):  
Heather Culbert ◽  
Robert France
Keyword(s):  
Total Phosphorus ◽  
Empirical Equation ◽  
Urban Runoff ◽  
Phosphorus Release ◽  
Total Export ◽  
Forested Watershed ◽  
Distilled Water ◽  
Trembling Aspen ◽  
Urban Catchments

Abstract In urban centres, leaves are customarily gathered and temporarily stored in large roadside piles prior to their transport to disposal sites. To simulate the release of total phosphorus to urban runoff, birch and trembling aspen leaves were leached with distilled water in laboratory flasks. There was no difference in rate of total phosphorus release between oven-dried and non-dried leaves. An empirical equation developed from these data and knowledge of the litterfall rates for southern Canada indicated that leaves yielded from 11 to 45 mg TP m−2 of forested watershed. This amount represents up to 5% of the total export of total phosphorus from urban catchments and has the potential to exacerbate eutrophication of municipal waters if leaf pickup is not promptly enforced.

Incorporating concepts from physical theory into stochastic modelling of urban runoff pollution

1998 ◽  
Vol 37 (1) ◽  
pp. 179-185
Author(s):  
Morten Grum
Keyword(s):  
Stochastic Model ◽  
Continuous Time ◽  
Measurement Errors ◽  
Physical Theory ◽  
Oxygen Demand ◽  
Stochastic Modelling ◽  
Urban Runoff ◽  
Primary Input ◽  
Deterministic Modelling ◽  
Runoff Pollution

On evaluating the present or future state of integrated urban water systems, sewer drainage models, with rainfall as primary input, are often used to calculate the expected return periods of given detrimental acute pollution events and the uncertainty thereof. The model studied in the present paper incorporates notions of physical theory in a stochastic model of water level and particulate chemical oxygen demand (COD) at the overflow point of a Dutch combined sewer system. A stochastic model based on physical mechanisms has been formulated in continuous time. The extended Kalman filter has been used in conjunction with a maximum likelihood criteria and a non-linear state space formulation to decompose the error term into system noise terms and measurement errors. The bias generally obtained in deterministic modelling, by invariably and often inappropriately assuming all error to result from measurement inaccuracies, is thus avoided. Continuous time stochastic modelling incorporating physical, chemical and biological theory presents a possible modelling alternative. These preliminary results suggest that further work is needed in order to fully appreciate the method's potential and limitations in the field of urban runoff pollution modelling.

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