A traditional first flush assessment of E. coli in urban stormwater runoff

2009 ◽  
Vol 60 (11) ◽  
pp. 2749-2757 ◽  
Author(s):  
D. T. McCarthy
Keyword(s):  
First Flush ◽  
Regression Analyses ◽  
Urban Stormwater ◽  
Explanatory Variables ◽  
E Coli ◽  
Statistical Inferences ◽  
Treatment Technologies ◽  
Urban Catchments ◽  
Urban Stormwater Runoff ◽  
Crucial Part

The behaviour of microorganisms in urban stormwater should be thoroughly investigated and understood to (a) design treatment technologies that can reduce the human health risks of utilising stormwater and (b) develop models which can accurately predict the levels of microorganisms in urban stormwater to aid in health risk assessments. A crucial part of understanding the behaviour of pollutants in urban stormwater is to determine whether the pollutant experiences higher levels in certain portions of the event (e.g. does the pollutant experience a first flush?). The aim of this paper is twofold: (a) determine if the first flush phenomenon exists for a commonly used microbial indicator, Escherichia coli, and (b) determine whether the presence of a first flush is dependent on antecedent climatic and/or hydrologic characteristics. E. coli data collected from the wet weather flows of four urban catchments in Melbourne was used in the paper. Cumulative mass versus volume curves were used in conjunction with standard statistical inferences to determine that the first flush phenomenon was not consistently present, and that the presence and magnitude of a first flush varied considerably between each site. Regression analyses were used to determine that this variation was probably not caused by the same governing processes for all four sites, with different explanatory variables significantly explaining the first flush at each site.

The influence of particle size on the first flush strength of urban stormwater runoff

2017 ◽  
Vol 76 (8) ◽  
pp. 2140-2149 ◽  
Author(s):  
D. Morgan ◽  
P. Johnston ◽  
K. Osei ◽  
L. Gill
Keyword(s):  
Particle Size ◽  
Stormwater Runoff ◽  
Drainage System ◽  
Storm Event ◽  
Rain Event ◽  
First Flush ◽  
Urban Stormwater ◽  
Treatment Facilities ◽  
Urban Stormwater Runoff ◽  
Rain Events

The presence of a first flush (FF) of suspended solids (SS) in stormwater runoff has important implications for the design of treatment facilities, as does the particle size of solids. Whilst numerous studies have examined the FF behaviour of SS, few have disaggregated FF trends by particle size. In this study, the FF behaviour of SS was investigated in five size ranges, sampled from an urban stormwater drainage system located in Dublin, Ireland. A weak FF was exhibited in the gross fraction of SS, with just two events from 14 transporting more than 50% of the SS mass in the first 25% of runoff, implying that treatment structures should be capable of removing SS throughout the storm event. In the majority of rain events, the FF strength increased with decreasing particle size, probably related to the lower intensities required to dislodge solids at the onset of rainfall. Although FF strength was correlated with rain event characteristics, prediction intervals were too broad to confirm FF presence based on rainfall data alone. Therefore, the design of smaller treatment volumes based on an assumption of FF must be justified by local monitoring data.

Escherichia coli in urban stormwater: explaining their variability

2007 ◽  
Vol 56 (11) ◽  
pp. 27-34 ◽  
Author(s):  
D.T. McCarthy ◽  
V.G. Mitchell ◽  
A. Deletic ◽  
C. Diaper
Keyword(s):  
Escherichia Coli ◽  
Health Risks ◽  
Rainfall Intensity ◽  
Climatic Conditions ◽  
Urban Systems ◽  
Regression Analyses ◽  
Urban Stormwater ◽  
E Coli ◽  
Wet Weather ◽  
Urbanised Catchments

The development of a model that predicts the levels of microorganisms in urban stormwater will aid in the assessment of health risks when using stormwater for both recreational uses and as an alternate water resource. However, the development of such a model requires an understanding of the dominant processes that influence the behaviour of microorganisms in urban systems. Using simple and multiple regression analyses this paper determines the dominant processes which affect the inter-event variability of the microbial indicator Escherichia coli (E. coli ) in four urbanised catchments. The results reveal that a number of antecedent climatic conditions, together with rainfall intensity, can significantly explain the inter-event variation in wet weather E. coli levels.

scholarly journals Taxonomy of influential factors for predicting pollutant first flush in urban stormwater runoff

2019 ◽  
Vol 166 ◽  
pp. 115075 ◽  
Author(s):  
Thamali Perera ◽  
James McGree ◽  
Prasanna Egodawatta ◽  
K.B.S.N. Jinadasa ◽  
Ashantha Goonetilleke
Keyword(s):  
Stormwater Runoff ◽  
Influential Factors ◽  
First Flush ◽  
Urban Stormwater ◽  
Urban Stormwater Runoff

scholarly journals Impact of roof surface runoff on urban water quality

2012 ◽  
Vol 66 (7) ◽  
pp. 1527-1533 ◽  
Author(s):  
P. Egodawatta ◽  
N. S. Miguntanna ◽  
A. Goonetilleke
Keyword(s):  
Water Quality ◽  
Stormwater Runoff ◽  
Urban Water ◽  
Urban Stormwater ◽  
Urban Water Quality ◽  
Impervious Area ◽  
Road Surfaces ◽  
Urban Catchments ◽  
Urban Stormwater Runoff

The pollutant impacts of urban stormwater runoff on receiving waters are well documented in research literature. However, it is road surfaces that are commonly identified as the significant pollutant source. This paper presents the outcomes of an extensive program of research into the role of roof surfaces in urban water quality with particular focus on solids, nutrients and organic carbon. The outcomes confirmed that roof surfaces play an important role in influencing the pollutant characteristics of urban stormwater runoff. Pollutant build-up and wash-off characteristics for roads and roof surfaces were found to be appreciably different. The pollutant wash-off characteristics exhibited by roof surfaces show that it influences the first flush phenomenon more significantly than road surfaces. In most urban catchments, as roof surfaces constitute a higher fraction of impervious area compared with road surfaces, it is important that the pollutant generation role of roof surfaces is specifically taken into consideration in stormwater quality mitigation strategies.

scholarly journals First flush analysis of urban stormwater runoff from an urban catchment in Johor, Malaysia

2018 ◽  
Vol 250 ◽  
pp. 06014
Author(s):  
Noor Atiqah Zuraini ◽  
Noraliani Alias ◽  
Zainab Mohamed Yusof ◽  
Muhammad Nassir Hanapi ◽  
Sobri Harun
Keyword(s):  
Suspended Solids ◽  
Stormwater Runoff ◽  
First Flush ◽  
Storm Events ◽  
Urban Stormwater ◽  
Urban Catchment ◽  
Rainfall Events ◽  
Field Investigations ◽  
Initial Stage ◽  
Urban Stormwater Runoff

An increase of pollutants that are present in the initial stage of stormwater runoff hydrograph compared to a later stage of runoff is defined as a first flush phenomenon. This study aims to investigate the occurrence of first flush from samples of urban stormwater runoff obtained from the grounds of a University in Skudai, Johor, Malaysia. In order to achieve the study’s objective; field investigations, manual sampling of urban stormwater runoff, laboratory testing and data analysis were carried out and the evaluation of the first flush phenomenon was calculated using concentration-based first flush (CBFF) and mass-based first flush (MBFF. A total of 90 stormwater samples were collected from six (6) rainfall events and were tested for total suspended solids (TSS). For each rainfall event, the pollutographs and the dimensionless curves of the cumulative pollutant mass versus the cumulative discharged volume were plotted. The first flush coefficient was also determined in order to evaluate the occurrence of first flush. The results indicated that the storm events demonstrated a weak presence of first flush.

scholarly journals Pollutant Concentration Patterns of In-Stream Urban Stormwater Runoff

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2534
Author(s):  
Laurel Christian ◽  
Thomas Epps ◽  
Ghada Diab ◽  
Jon Hathaway
Keyword(s):  
Temporal Distribution ◽  
Pollutant Transport ◽  
Transport Processes ◽  
Urban Watersheds ◽  
First Flush ◽  
Urban Stormwater ◽  
Initial Portion ◽  
Explanatory Variables ◽  
Transport Dynamics ◽  
First Flush Effect

Although a number of studies have investigated pollutant transport patterns in urban watersheds, these studies have focused primarily on the upland landscape as the point of interest (i.e., prior to stormwater entering an open stream channel). However, it is likely that in-stream processes will influence pollutant transport when the system is viewed at a larger scale. One initial investigation that can be performed to characterize transport dynamics in urban runoff is determining a pollutant’s temporal distribution. By borrowing from urban stormwater literature, the propensity of a pollutant within a system to be more heavily transported in the initial portion of the storm can be quantified (i.e., the “first flush”). Although uncommon for use in stream science, this methodology allows direct comparison of results to previous studies on smaller urban upland catchments. Multiple methods have been proposed to investigate the first flush effect, two of which are applied in this study to two streams in Knoxville, TN, USA. The strength of the first flush was generally corroborated by the two unique methods, a new finding that allows a more robust determination of first flush presence for a given pollutant. Further, an “end flush” was observed and quantified for nutrients and microbes in one stream, a novel outcome that shows how the newer methodology that was employed can provide greater insight into transport processes and pollutant sources. Explanatory variables for changes in each pollutant’s inter-event first flush strength differed, but notable relationships included the influence of flow rate on microbes and influence of rainfall on Cu2+. The results appear to support the hypothesis that in-stream processes, such as resuspension, may influence pollutant transport in urban watersheds, pointing toward the need to consider in-stream processes in models developed to predict urban watershed pollutant export.

Urban hydrogeomorphology and the urban stream syndrome

2015 ◽  
Vol 40 (3) ◽  
pp. 480-492 ◽  
Author(s):  
Geoff J. Vietz ◽  
Christopher J. Walsh ◽  
Tim D. Fletcher
Keyword(s):  
Flow Regime ◽  
Stormwater Runoff ◽  
Control Measures ◽  
Urban Stream ◽  
Urban Stream Syndrome ◽  
Stream Morphology ◽  
Research Areas ◽  
Urban Catchments ◽  
Urban Stormwater Runoff ◽  
The Impact

The urban stream syndrome is an almost universal physical and ecological response of streams to catchment urbanization. Altered channel geomorphology is a primary symptom that includes channel deepening, widening and instability. While the common approach is to treat the symptoms (e.g. modifying and stabilizing the channel), many stream restoration objectives will not be achieved unless the more vexing problem, treating the cause, is addressed in some way. Research demonstrates that the dominant cause of geomorphic change in streams in urban catchments is an altered flow regime and increase in the volume of stormwater runoff. Thus, managers can choose to treat the symptoms by modifying and controlling the channel to accommodate the altered flow regime, or treat the cause by modifying the flow regime to reduce the impact on channel morphology. In both cases treatments must, at the least, explicitly consider hydrogeomorphology—the science of the linkages between various hydrologic and geomorphic processes—to have a chance of success. This paper provides a review of recent literature (2010 to early 2015) to discuss fluvial hydrogeomorphology in the management of streams subject to urbanization. We suggest that while the dominant approach is focused on combating the symptoms of catchment urbanization (that we refer to as channel reconfiguration), there is increasing interest in approaches that attempt to address the causes by using stormwater control measures at a range of scales in the catchment (e.g. flow-regime management). In many settings in the oft-constrained urban catchment, effective management of stream morphology may require multiple approaches. To conclude, we identify five research areas that could inform urban hydrogeomorphology, one of the most challenging of which is the extent to which the volume of excess urban stormwater runoff can be reduced to mitigate the impact on stream geomorphology.

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