Initial design of urban drainage systems for extreme rainfall events using intensity–duration–area (IDA) curves and Chicago design storms (CDS)

Assessing the functioning and the performance of urban drainage systems on both rainfall event and yearly time scales is usually based on online measurements of flow rates and on samples of influent and effluent for some rainfall events per year. In order to draw pertinent scientific and operational conclusions from the measurement results, it is absolutely necessary to use appropriate methods and techniques in order to i) calibrate sensors and analytical methods, ii) validate raw data, iii) evaluate measurement uncertainties, iv) evaluate the number of rainfall events to sample per year in order to determine performance indicator with a given uncertainty. Based on previous work, the paper gives a synthetic review of required methods and techniques, and illustrates their application to storage and settling tanks. Experiments show that, despite controlled and careful experimental conditions, relative uncertainties are about 20% for flow rates in sewer pipes, 6-10% for volumes, 25-35% for TSS concentrations and loads, and 18-276% for TSS removal rates. In order to evaluate the annual pollutant interception efficiency of storage and settling tanks with a given uncertainty, efforts should first be devoted to decrease the sampling uncertainty by increasing the number of sampled events.

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Hydraulic characteristics of stepped spillway dropshafts for urban deep tunnel drainage systems: the case study of Chengdu city

Water Science & Technology ◽

10.2166/wst.2019.405 ◽

2019 ◽

Vol 80 (8) ◽

pp. 1538-1548

Author(s):

Lei Liao ◽

Ruidong An ◽

Jia Li ◽

Wenmin Yi ◽

Xiaofan Liu ◽

...

Keyword(s):

Extreme Rainfall ◽

Stepped Spillway ◽

Urban Drainage ◽

Deep Tunnel ◽

Hydraulic Characteristics ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Fluctuating Pressure ◽

Air Explosion

Abstract Cities in southwestern China experience urban drainage and overflow pollution after extreme rainfall events, which are major problems. In this study, a type of stepped spillway dropshaft suitable for drainage by deep tunnels in Chengdu was proposed and the hydraulic characteristics were investigated experimentally. The results showed that the nappe flow and strong turbulent deflected jet flow in the stepped spillway allowed the dropshaft to greatly dissipate energy. According to the distribution of the time-averaged pressure on the steps, the flow on the steps could be divided into a recirculating region, a wall-impinging region and a mixing region. The time-averaged pressure on the outside of the step was higher than that on the inside due to the centrifugal force effect of the water. The fluctuating pressure distribution of the step approximated the normal distribution. It was acceptable to calculate the minimum pressure with 3 times the root mean square (RMS). The vibration of the flow on the stepped spillway did not resonate with the step. When the outflow tunnel was under submerged outflow conditions, the aeration in the stepped spillway was exhausted through air holes and only a small amount of air entered the outflow tunnel, thereby avoiding an air explosion.

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A Semi Risk-Based Approach for Managing Urban Drainage Systems under Extreme Rainfall

Water ◽

10.3390/w10040384 ◽

2018 ◽

Vol 10 (4) ◽

pp. 384 ◽

Cited By ~ 4

Author(s):

Carlos Salinas-Rodriguez ◽

Berry Gersonius ◽

Chris Zevenbergen ◽

David Serrano ◽

Richard Ashley

Keyword(s):

Extreme Rainfall ◽

Urban Drainage ◽

Drainage Systems ◽

Urban Drainage Systems

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Sediment and pollutant load modelling using an integrated urban drainage modelling toolbox: an application of City Drain

Water Science & Technology ◽

10.2166/wst.2010.139 ◽

2010 ◽

Vol 61 (9) ◽

pp. 2273-2282 ◽

Cited By ~ 8

Author(s):

J. P. Rodríguez ◽

S. Achleitner ◽

M. Möderl ◽

W. Rauch ◽

Č. Maksimović ◽

...

Keyword(s):

Computational Modelling ◽

Integrated Modelling ◽

Research Centre ◽

Urban Drainage ◽

Rainfall Events ◽

Drainage Systems ◽

Engineering Research ◽

Planning And Design ◽

Urban Drainage Systems ◽

Accumulation Of Pollutants

Numerical and computational modelling of flow and pollutant dynamics in urban drainage systems is becoming more and more integral to planning and design. The main aim of integrated flow and pollutant models is to quantify the efficiency of different measures at reducing the amount of pollutants discharged into receiving water bodies and minimise the consequent negative water quality impact. The open source toolbox CITY DRAIN developed in the Matlab/Simulink© environment, which was designed for integrated modelling of urban drainage systems, is used in this work. The goal in this study was to implement and test computational routines for representing sediment and pollutant loads in order to evaluate catchment surface pollution. Tested models estimate the accumulation, erosion and transport of pollutants—aggregately—on urban surfaces and in sewers. The toolbox now includes mathematical formulations for accumulation of pollutants during dry weather period and their wash-off during rainfall events. The experimental data acquired in a previous research project carried out by the Environmental Engineering Research Centre (CIIA) at the Universidad de los Andes in Bogotá (Colombia) was used for the calibration of the models. Different numerical approaches were tested for their ability to calibrate to the sediment transport conditions. Initial results indicate, when there is more than one peak during the rainfall event duration, wash-off processes probably can be better represented using a model based on the flow instead of the rainfall intensity. Additionally, it was observed that using more detailed models (compared with an instantaneous approach) for representing pollutant accumulation do not necessarily lead to better results.

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Impact of Extreme Rainfall Events on the Response of Shallow Land Drainage Systems

Journal of Irrigation and Drainage Engineering ◽

10.1061/(asce)ir.1943-4774.0001619 ◽

2021 ◽

Vol 147 (10) ◽

pp. 06021010

Author(s):

P. Tuohy ◽

J. O’Loughlin ◽

O. Fenton

Keyword(s):

Extreme Rainfall ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Drainage Systems ◽

Land Drainage

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Probabilistic Modelling of Sustainable Urban Drainage Systems

10.21203/rs.3.rs-979580/v1 ◽

2022 ◽

Author(s):

Anita Raimondi ◽

Maria Gloria Di Chiano ◽

Mariana Marchioni ◽

Umberto Sanfilippo ◽

Gianfranco Becciu

Keyword(s):

Control Systems ◽

Probabilistic Approach ◽

Urban Drainage ◽

Rainfall Events ◽

Drainage Systems ◽

Effective Strategies ◽

Urban Drainage Systems ◽

Rainwater Management ◽

A Chain ◽

And Control

Abstract Sustainable Urban Drainage Systems (SuDS) gatherer effective strategies and control systems for stormwater management especially in highly urbanized areas characterized by large impervious surfaces that increase runoff peak flow and volume. The main goal is to restore the natural water balance by increasing infiltration, evapotranspiration and promoting rainwater reuse. This paper proposes an analytical probabilistic approach for the modelling SuDS applicable to different structures and goals. Developed equations allow to estimate the probability of overflow and the probability of pre-filling at the end of dry periods, to evaluate the efficiency of the storage in rainwater management and its ability to empty between consecutive events. A great advantage of the proposed method is that it allows to consider a chain of rainfall events; this aspect is particularly important for control systems SuDS characterized by low outflow rates which storage capacity is often not completely available at the end of a dry period because pre-filled by previous events. Suggested formulas were tested to two cases studies in Milan and Genoa, Italy.

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The Influence of Geographical Factors on Extreme Rainfalls in Lampung Province

Journal of Engineering and Scientific Research ◽

10.23960/jesr.v1i1.7 ◽

2019 ◽

Vol 1 (1) ◽

pp. 33

Author(s):

M Welly

Keyword(s):

Geographical Location ◽

Daily Rainfall ◽

Extreme Rainfall ◽

Design Flood ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Ungauged Basin ◽

Flood Discharge ◽

Design Rainfall ◽

Geographical Factors

Many people in Indonesia calculate design rainfall before calculating the design flooddischarge. The design rainfall with a certain return period will eventually be convertedinto a design flood discharge by combining it with the characteristics of the watershed.However, the lack of a network of rainfall recording stations makes many areas that arenot hydrologically measured (ungauged basin), so it is quite difficult to know thecharacteristics of rain in the area concerned. This study aims to analyze thecharacteristics of design rainfall in Lampung Province. The focus of the analysis is toinvestigate whether geographical factors influence the design rainfall that occurs in theparticular area. The data used in this study is daily rainfall data from 15 rainfallrecording stations spread in Lampung Province. The method of frequency analysis usedin this study is the Gumbel method. The research shows that the geographical location ofan area does not have significant effect on extreme rainfall events. The effect of risingearth temperatures due to natural exploitation by humans tends to be stronger as a causeof extreme events such as extreme rainfall.Keywords: Influence, geographical, factors, extreme, rainfall.

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CLIMATOLOGY OF EXTREME RAINFALL EVENTS IN EASTERN AND NORTHERN SANTA CATARINA STATE, BRAZIL: PRESENT AND FUTURE CLIMATE

Brazilian Journal of Geophysics ◽

10.22564/rbgf.v31i3.314 ◽

2013 ◽

Vol 31 (3) ◽

pp. 413 ◽

Cited By ~ 3

Author(s):

André Becker Nunes ◽

Gilson Carlos Da Silva

Keyword(s):

Climate Model ◽

Climate Modeling ◽

Linear Trend ◽

Extreme Rainfall ◽

Eastern Region ◽

Santa Catarina ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

History Of ◽

Santa Catarina State

ABSTRACT. The eastern region of Santa Catarina State (Brazil) has an important history of natural disasters due to extreme rainfall events. Floods and landslides are enhancedby local features such as orography and urbanization: the replacement of natural surface coverage causing more surface runoff and, hence, ﬂooding. Thus, studies of this type of events – which directly inﬂuence life in the towns – take on increasing importance. This work makes a quantitative analysis of occurrences of extreme rainfall events in the eastern and northern regions of Santa Catarina State in the last 60 years, through individual analysis, considering the history of ﬂoods ineach selected town, as well as an estimate through to the end of century following regional climate modeling. A positive linear trend, in most of the towns studied, was observed in the results, indicating greater frequency of these events in recent decades, and the HadRM3P climate model shows a heterogeneous increase of events for all towns in the period from 2071 to 2100.Keywords: ﬂoods, climate modeling, linear trend. RESUMO. A região leste do Estado de Santa Catarina tem um importante histórico de desastres naturais ocasionados por eventos extremos de precipitação. Inundações e deslizamentos de terra são potencializados pelo relevo acidentado e pela urbanização das cidades da região: a vegetação nativa vem sendo removida acarretando um maior escoamento superﬁcial e, consequentemente, em inundações. Desta forma, torna-se de suma importância os estudos acerca deste tipo de evento que inﬂuencia diretamente a sociedade em geral. Neste trabalho é realizada uma análise quantitativa do número de eventos severos de precipitação ocorridos nas regiões leste e norte de Santa Catarina dos últimos 60 anos, por meio de uma análise pontual, considerandoo histórico de inundações de cada cidade selecionada, além de uma projeção para o ﬁm do século de acordo com modelagem climática regional. Na análise dos resultados observou-se uma tendência linear positiva na maioria das cidades, indicando uma maior frequência deste tipo de evento nas últimas décadas, e o modelo climático HadRM3P mostra um aumento heterogêneo no número de eventos para todas as cidades no período de 2071 a 2100.Palavras-chave: inundações, modelagem climática, tendência linear.

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