scholarly journals Relationships between rainfall intensity, duration and suspended particle washoff from an urban road surface

2011 ◽  
Vol 42 (4) ◽  
pp. 239-249 ◽  
Author(s):  
Ian M. Brodie ◽  
Prasanna Egodawatta
Keyword(s):  
Rainfall Intensity ◽  
Suspended Particle ◽  
Measured Data ◽  
Storm Event ◽  
Storm Events ◽  
Constant Intensity ◽  
Urban Road ◽  
Road Surfaces ◽  
Basic Understanding ◽  
Average Rainfall

A basic understanding of the relationships between rainfall intensity, duration of rainfall and the amount of suspended particles in stormwater runoff generated from road surfaces has been gained mainly from past washoff experiments using rainfall simulators. Simulated rainfall was generally applied at constant intensities, whereas rainfall temporal patterns during actual storms are typically highly variable. This paper discusses a rationale for the application of the constant-intensity washoff concepts to actual storm event runoff. The rationale is tested using suspended particle load data collected at a road site located in Toowoomba, Australia. Agreement between the washoff concepts and measured data is most consistent for intermediate-duration storms (duration <5 h and >1 h). Particle loads resulting from these storm events increase linearly with average rainfall intensity. Above a threshold intensity, there is evidence to suggest a constant or plateau particle load is reached. The inclusion of a peak discharge factor (maximum 6 min rainfall intensity) enhances the ability to predict particle loads.

Estimating Errors in Sizing LID Device and Overflow Prediction Using the Intensity-Duration-Frequency Method

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1853
Author(s):  
Tang ◽  
Xu ◽  
Jia ◽  
Luo ◽  
Shao
Keyword(s):  
Rainfall Intensity ◽  
Relative Difference ◽  
Absolute Difference ◽  
Storm Event ◽  
Process Data ◽  
Frequency Method ◽  
Average Rainfall ◽  
Standard Deviations ◽  
Intensity Duration Frequency ◽  
Design Depth

Low impact development (LID) devices or green infrastructures have been advocated for urban stormwater management worldwide. Currently, the design and evaluation of LID devices adopt the Intensity-Duration-Frequency (IDF) method, which employs the average rainfall intensity. However, due to variations of rainfall intensity during a storm event, using average rainfall intensity may generate certain errors when designing a LID device. This paper presents an analytical study to calculate the magnitude of such errors with respect to LID device design and associated device performance evaluation. The normal distribution rainfall (NDR) with different standard deviations was employed to represent realistic rainfall processes. Compared with NDR method, the error in sizing the LID device was determined using the IDF method. Moreover, the overflow difference calculated using the IDF method was evaluated. We employed a programmed hydrological model to simulate different design scenarios. Using storm data from 31 regions with different climatic conditions in continental China, the results showed that different rainfall distributions (as represented by standard deviations (σ) of 5, 3, and 2) have little influence on the design depth of LID devices in most regions. The relative difference in design depth using IDF method was less than 1.00% in humid areas, −0.61% to 3.97% in semi-humid areas, and the significant error was 46.13% in arid areas. The maximum absolute difference in design depth resulting from the IDF method was 2.8 cm. For a LID device designed for storms with a 2-year recurrence interval, when meeting for the 5-year storm, the relative differences in calculated overflow volume using IDF method ranged from 19.8% to 95.3%, while those for the 20-year storm ranged from 7.4% to 40.5%. The average relative difference of the estimated overflow volume was 29.9% under a 5-year storm, and 12.0% under a 20-year storm. The relative difference in calculated overflow volumes using IDF method showed a decreasing tendency from northwest to southeast. Findings from this study suggest that the existing IDF method is adequate for use in sizing LID devices when the design storm is not usually very intense. However, accurate rainfall process data are required to estimate the overflow volume under large storms.

scholarly journals Mathematical interpretation of pollutant wash-off from urban road surfaces using simulated rainfall

2007 ◽  
Vol 41 (13) ◽  
pp. 3025-3031 ◽  
Author(s):  
Prasanna Egodawatta ◽  
Evan Thomas ◽  
Ashantha Goonetilleke
Keyword(s):  
Simulated Rainfall ◽  
Urban Road ◽  
Road Surfaces ◽  
Mathematical Interpretation

scholarly journals Adsorption of heavy metals by road deposited solids

2013 ◽  
Vol 67 (11) ◽  
pp. 2622-2629 ◽  
Author(s):  
Chandima Gunawardana ◽  
Ashantha Goonetilleke ◽  
Prasanna Egodawatta
Keyword(s):  
Heavy Metals ◽  
Kinetic Studies ◽  
Field Studies ◽  
Water Soluble ◽  
Trivalent Cation ◽  
Urban Road ◽  
High Charge Density ◽  
Road Surfaces ◽  
Adsorption Desorption ◽  
Exchangeable Form

The research study discussed in the paper investigated the adsorption/desorption behaviour of heavy metals commonly deposited on urban road surfaces, namely, Zn, Cu, Cr and Pb, for different particle size ranges of solids. The study outcomes, based on field studies and batch experiments, confirmed that road deposited solids particles contain a significantly high amount of vacant charge sites with the potential to adsorb additional heavy metals. Kinetic studies and adsorption experiments indicated that Cr is the most preferred metal element to associate with solids due to the relatively high electronegativity and high charge density of trivalent cation (Cr3+). However, the relatively low availability of Cr in the urban road environment could influence this behaviour. Comparing total adsorbed metals present in solids particles, it was found that Zn has the highest capacity for adsorption to solids. Desorption experiments confirmed that a low concentration of Cu, Cr and Pb in solids was present in water-soluble and exchangeable form, whilst a significant fraction of adsorbed Zn has a high likelihood of being released back into solution. Among heavy metals, Zn is considered to be the most commonly available metal among road surface pollutants.

scholarly journals The effects of the big storm events in the first half of 2015 on the radiation belts observed by EPT/PROBA-V

2016 ◽  
Vol 34 (1) ◽  
pp. 75-84 ◽  
Author(s):  
V. Pierrard ◽  
G. Lopez Rosson
Keyword(s):  
Charged Particle ◽  
High Resolution ◽  
Geomagnetic Storm ◽  
Energetic Particle ◽  
High Energy ◽  
Radiation Belts ◽  
Radiation Environment ◽  
Storm Event ◽  
Storm Events ◽  
Particle Radiation

Abstract. With the energetic particle telescope (EPT) performing with direct electron and proton discrimination on board the ESA satellite PROBA-V, we analyze the high-resolution measurements of the charged particle radiation environment at an altitude of 820 km for the year 2015. On 17 March 2015, a big geomagnetic storm event injected unusual fluxes up to low radial distances in the radiation belts. EPT electron measurements show a deep dropout at L > 4 starting during the main phase of the storm, associated to the penetration of high energy fluxes at L < 2 completely filling the slot region. After 10 days, the formation of a new slot around L = 2.8 for electrons of 500–600 keV separates the outer belt from the belt extending at other longitudes than the South Atlantic Anomaly. Two other major events appeared in January and June 2015, again with injections of electrons in the inner belt, contrary to what was observed in 2013 and 2014. These observations open many perspectives to better understand the source and loss mechanisms, and particularly concerning the formation of three belts.

scholarly journals Development of Temporal Rainfall Pattern for Southern Region of Sarawak

2012 ◽  
Vol 3 ◽  
pp. 17-23 ◽  
Author(s):  
Rosmina A. Bustami ◽  
Nor Azalina Rosli ◽  
Jethro Henry Adam ◽  
Kuan Pei Li
Keyword(s):  
Temporal Pattern ◽  
Rainfall Intensity ◽  
Peninsular Malaysia ◽  
Southern Region ◽  
Rainfall Pattern ◽  
Rainfall Duration ◽  
Design Rainfall ◽  
Average Rainfall ◽  
Urban Storm ◽  
Australian Rainfall

 In the process of a design rainfall, information on rainfall duration, average rainfall intensity and temporal rainfall pattern is important. This study focuses on developing a temporal rainfall pattern for the Southern region of Sarawak since temporal pattern for Sarawak is yet to be available in the Malaysian Urban Storm Water Management Manual (MSMA), which publishes temporal pattern for design storms only for Peninsular Malaysia. The recommended technique by the Australian Rainfall and Runoff (AR&R) known as the ‘Average Variability Method’ and method in Hydrological Procedure No.1-1982 are used to derive design rainfall temporal pattern for the study. Rainfall data of 5 minutes interval from year 1998 to year 2006 for 7 selected rainfall stations in the selected region is obtained from Department of Irrigation and Drainage (DID). The temporal rainfall patterns developed are for 10 minutes,15 minutes, 30 minutes, 60 minutes, 120 minutes, 180 minutes and 360 minutes duration. The results show that Southern region of Sarawak has an exclusive rainfall pattern, which is different from the pattern developed for Peninsular Malaysia.

scholarly journals Fine Sediment Modeling During Storm-Based Events in the River Bandon, Ireland

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1523 ◽  
Author(s):  
Juan T. García ◽  
Joseph R. Harrington
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Fine Sediment ◽  
Storm Event ◽  
Storm Events ◽  
Event Scale ◽  
Model Based ◽  
Sediment Volume ◽  
Bed Erosion

The River Bandon located in County Cork (Ireland) has been time-continuously monitored by turbidity probes, as well as automatic and manual suspended sediment sampling. The current work evaluates three different models used to estimate the fine sediment concentration during storm-based events over a period of one year. The modeled suspended sediment concentration is compared with that measured at an event scale. Uncertainty indices are calculated and compared with those presented in the bibliography. An empirically-based model was used as a reference, as this model has been previously applied to evaluate sediment behavior over the same time period in the River Bandon. Three other models have been applied to the gathered data. First is an empirically-based storm events model, based on an exponential function for calculation of the sediment output from the bed. A statistically-based approach first developed for sewers was also evaluated. The third model evaluated was a shear stress erosion-based model based on one parameter. The importance of considering the fine sediment volume stored in the bed and its consolidation to predict the suspended sediment concentration during storm events is clearly evident. Taking into account dry weather periods and the bed erosion in previous events, knowledge on the eroded volume for each storm event is necessary to adjust the parameters for each model.

Assessing the health implications of turbidity and suspended particles in protected catchments

2004 ◽  
Vol 50 (1) ◽  
pp. 205-210 ◽  
Author(s):  
K. Cinque ◽  
M.A. Stevens ◽  
D.J. Roser ◽  
N.J. Ashbolt ◽  
R. Leeming
Keyword(s):  
Public Health ◽  
Water Quality ◽  
Suspended Particle ◽  
Supply System ◽  
Water Harvesting ◽  
Source Water ◽  
Storm Events ◽  
Australian Water ◽  
Microbial Indicators ◽  
High Turbidity

The supply of unfiltered disinfected drinking water from Melbourne's fully protected catchments means that the water-quality managers must ensure that the source water poses no public health risk. High turbidity is currently used as a surrogate of pathogens, and harvesting of water is based on its measurement. The work presented here summarises suspended particle and associated pathogen, microbial indicator and faecal biomarker concentrations collected to (a) quantify turbidity in an Australian water supply system and (b) assess the possibility of increasing water harvesting from selected tributaries. Pathogens and microbial indicators were present in low numbers in these source waters; increased turbidity during storm events was not associated with an increase in pathogen concentration. The results confirmed that protected catchments, along with good management, were effective barriers to pathogen contamination. Aesthetic issues still need to be addressed, but no measurable increase in microbiological risk was associated with storm-generated particles.

scholarly journals Geospatial Modelling of Watershed Peak Flood Discharge in Selangor, Malaysia

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2490 ◽  
Author(s):  
Ryan Cheah ◽  
Lawal Billa ◽  
Andy Chan ◽  
Fang Yenn Teo ◽  
Biswajeet Pradhan ◽  
...  
Keyword(s):  
Hydrological Modeling ◽  
Estimation Methods ◽  
Coefficient Of Determination ◽  
Storm Event ◽  
Storm Events ◽  
Unit Hydrograph ◽  
Runoff Simulation ◽  
Flood Discharge ◽  
Geospatial Modelling ◽  
Peak Flood

Conservative peak flood discharge estimation methods such as the rational method do not take into account the soil infiltration of the precipitation, thus leading to inaccurate estimations of peak discharges during storm events. The accuracy of estimated peak flood discharge is crucial in designing a drainage system that has the capacity to channel runoffs during a storm event, especially cloudbursts and in the analysis of flood prevention and mitigation. The aim of this study was to model the peak flood discharges of each sub-watershed in Selangor using a geographic information system (GIS). The geospatial modelling integrated the watershed terrain model, the developed Soil Conservation Service Curve Cumber (SCS-CN) and precipitation to develop an equation for estimation of peak flood discharge. Hydrological Engineering Center-Hydrological Modeling System (HEC-HMS) was used again to simulate the rainfall-runoff based on the Clark-unit hydrograph to validate the modelled estimation of peak flood discharge. The estimated peak flood discharge showed a coefficient of determination, r2 of 0.9445, when compared with the runoff simulation of the Clark-unit hydrograph. Both the results of the geospatial modelling and the developed equation suggest that the peak flood discharge of a sub-watershed during a storm event has a positive relationship with the watershed area, precipitation and Curve Number (CN), which takes into account the soil bulk density and land-use of the studied area, Selangor in Malaysia. The findings of the study present a comparable and holistic approach to the estimation of peak flood discharge in a watershed which can be in the absence of a hydrodynamic simulation model.

Water quality improvement in a small stormwater detention pond

1998 ◽  
Vol 38 (10) ◽  
pp. 115-122 ◽  
Author(s):  
Thomas J. R. Pettersson
Keyword(s):  
Water Quality ◽  
Quality Improvement ◽  
Specific Surface ◽  
Pollutant Removal ◽  
Storm Event ◽  
Storm Events ◽  
Small Particles ◽  
Water Quality Improvement ◽  
Linear Profiles ◽  
Detention Pond

The aim of this study was to investigate a small open detention pond predominantly receiving stormwater drainage from a highway. The results showed a difference in pollutant removal characteristics. Particle-associated pollutants were effectively removed during storm events as indicated by EMC (Event Mean Concentrations) while dissolved pollutants were not effectively removed. Outflow pollutant loads followed linear profiles when seven consecutive storm events were represented as cumulative graphs. PEMC's (Partial EMC's) during a storm event showed an association between the specific surface area of small particles and lead content. A detention pond should be designed according to capacity to detain the complete storm volume, thus avoiding short-circuiting of the pond by pollutants.

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