Estimation of the G2P Design Storm from a Rainfall Convectivity Index

The two-parameter gamma function (G2P) design storm is a recent methodology used to obtain synthetic hyetographs especially developed for urban hydrology applications. Further analytical developments on the G2P design storm are presented herein, linking the rainfall convectivity n-index with the shape parameter of the design storm. This step can provide a useful basis for future easy-to-handle rainfall inputs in the context of regional urban drainage studies. A practical application is presented herein for the case of Valencia (Spain), based on high-resolution time series of rainfall intensity. The resulting design storm captures certain internal statistics and features observed in the fine-scale rainfall intensity historical records. On the other hand, a direct, simple method is formulated to derivate the design storm from the intensity–duration–frequency (IDF) curves, making use of the analytical relationship with the n-index.

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Modelling and assessment of urban flood hazards based on rainfall intensity-duration-frequency curves reformation

10.5194/nhess-2016-304 ◽

2016 ◽

Author(s):

Reza Ghazavi ◽

Ali Moafi Rabori ◽

Mohsen Ahadnejad Reveshty

Keyword(s):

Return Period ◽

Urban Areas ◽

Rainfall Intensity ◽

Flood Hazards ◽

Return Periods ◽

Urban Flood ◽

Design Storm ◽

Hourly Rainfall ◽

Idf Curves ◽

Intensity Duration Frequency

Abstract. Estimate design storm based on rainfall intensity–duration–frequency (IDF) curves is an important parameter for hydrologic planning of urban areas. The main aim of this study was to estimate rainfall intensities of Zanjan city watershed based on overall relationship of rainfall IDF curves and appropriate model of hourly rainfall estimation (Sherman method, Ghahreman and Abkhezr method). Hydrologic and hydraulic impacts of rainfall IDF curves change in flood properties was evaluated via Stormwater Management Model (SWMM). The accuracy of model simulations was confirmed based on the results of calibration. Design hyetographs in different return periods show that estimated rainfall depth via Sherman method are greater than other method except for 2-year return period. According to Ghahreman and Abkhezr method, decrease of runoff peak was 30, 39, 41 and 42 percent for 5-10-20 and 50-year return periods respectively, while runoff peak for 2-year return period was increased by 20 percent.

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A two-parameter design storm for Mediterranean convective rainfall

Hydrology and Earth System Sciences ◽

10.5194/hess-21-2377-2017 ◽

2017 ◽

Vol 21 (5) ◽

pp. 2377-2387 ◽

Cited By ~ 7

Author(s):

Rafael García-Bartual ◽

Ignacio Andrés-Doménech

Keyword(s):

Return Period ◽

Geographic Location ◽

Auxiliary Variable ◽

Rainfall Regime ◽

High Temporal Resolution ◽

Design Storm ◽

Starting Point ◽

Intensity Duration Frequency ◽

Two Parameters ◽

Two Parameter

Abstract. The following research explores the feasibility of building effective design storms for extreme hydrological regimes, such as the one which characterizes the rainfall regime of the east and south-east of the Iberian Peninsula, without employing intensity–duration–frequency (IDF) curves as a starting point. Nowadays, after decades of functioning hydrological automatic networks, there is an abundance of high-resolution rainfall data with a reasonable statistic representation, which enable the direct research of temporal patterns and inner structures of rainfall events at a given geographic location, with the aim of establishing a statistical synthesis directly based on those observed patterns. The authors propose a temporal design storm defined in analytical terms, through a two-parameter gamma-type function. The two parameters are directly estimated from 73 independent storms identified from rainfall records of high temporal resolution in Valencia (Spain). All the relevant analytical properties derived from that function are developed in order to use this storm in real applications. In particular, in order to assign a probability to the design storm (return period), an auxiliary variable combining maximum intensity and total cumulated rainfall is introduced. As a result, for a given return period, a set of three storms with different duration, depth and peak intensity are defined. The consistency of the results is verified by means of comparison with the classic method of alternating blocks based on an IDF curve, for the above mentioned study case.

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Does nonstationarity in rainfall require nonstationary intensity–duration–frequency curves?

Hydrology and Earth System Sciences ◽

10.5194/hess-21-6461-2017 ◽

2017 ◽

Vol 21 (12) ◽

pp. 6461-6483 ◽

Cited By ~ 26

Author(s):

Poulomi Ganguli ◽

Paulin Coulibaly

Keyword(s):

Precipitation Extremes ◽

Urban Drainage ◽

Design Standards ◽

Climate Change Projections ◽

Design Storm ◽

Drainage Design ◽

Current Design ◽

Recurrence Intervals ◽

Intensity Duration Frequency ◽

Frequency Curves

Abstract. In Canada, risk of flooding due to heavy rainfall has risen in recent decades; the most notable recent examples include the July 2013 storm in the Greater Toronto region and the May 2017 flood of the Toronto Islands. We investigate nonstationarity and trends in the short-duration precipitation extremes in selected urbanized locations in Southern Ontario, Canada, and evaluate the potential of nonstationary intensity–duration–frequency (IDF) curves, which form an input to civil infrastructural design. Despite apparent signals of nonstationarity in precipitation extremes in all locations, the stationary vs. nonstationary models do not exhibit any significant differences in the design storm intensity, especially for short recurrence intervals (up to 10 years). The signatures of nonstationarity in rainfall extremes do not necessarily imply the use of nonstationary IDFs for design considerations. When comparing the proposed IDFs with current design standards, for return periods (10 years or less) typical for urban drainage design, current design standards require an update of up to 7 %, whereas for longer recurrence intervals (50–100 years), ideal for critical civil infrastructural design, updates ranging between ∼ 2 and 44 % are suggested. We further emphasize that the above findings need re-evaluation in the light of climate change projections since the intensity and frequency of extreme precipitation are expected to intensify due to global warming.

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Generation of Synthetic Design Storm Hyetograph and Hydrologic Modeling under HEC HMS for Ziz Watershed

International Journal of Innovative Technology and Exploring Engineering - Special Issue ◽

10.35940/ijitee.j1214.0881019 ◽

2018 ◽

Vol 8 (10) ◽

pp. 3308-3319 ◽

Cited By ~ 1

Keyword(s):

Rainfall Intensity ◽

Hydrological Model ◽

Daily Rainfall ◽

Distributed Hydrological Model ◽

Flood Risks ◽

Design Storm ◽

Hourly Rainfall ◽

Intensity Duration Frequency ◽

Management Issues ◽

Frequency Curves

This article proposes a methodology for generating hourly rainfall from daily rainfall data. It was evolved as a tool for managing flood risks on Ziz catchment, by means of Intensity-duration-frequency curves (IDF) and designed hyetograph of Chicago. The study area is located in the south-eastern part of Morocco, and did not have a monitoring station for hourly rain measure, the methodomogy consist of determinating the rainfall intensity for 24 h using IDF, then estimating the hourly rainfall using Chicago formula, in order to assess the accuracy of the method the resulting hyetographs was introduced into the semi-distributed hydrological model HEC HMS to simulate hourly flow, which was compared to the observed one. The obtaining results exhibit that the observed value is positively correlated with those obtained by the above method, as shown by the correlation coefficient and the Nash-Sutcliffe. This approach can deal with instantaneous water management issues by tackling flood risks and providing an appropriate range of data for the dam’s management.

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Modifications of rainfall runoff and decision finding models for on-line simulation in real time control

Water Science & Technology ◽

10.2166/wst.1999.0477 ◽

1999 ◽

Vol 39 (9) ◽

pp. 201-207

Author(s):

Andreas Cassar ◽

Hans-Reinhard Verworn

Keyword(s):

Real Time ◽

Urban Drainage ◽

Rain Event ◽

Rainfall Runoff ◽

Real Time Control ◽

Design Storm ◽

Time Control ◽

Timing Data ◽

On Line ◽

Rainfall Runoff Model

Most of the existing rainfall runoff models for urban drainage systems have been designed for off-line calculations. With a design storm or a historical rain event and the model system the rainfall runoff processes are simulated, the faster the better. Since very recently, hydrodynamic models have been considered to be much too slow for real time applications. However, with the computing power of today - and even more so of tomorrow - very complex and detailed models may be run on-line and in real time. While the algorithms basically remain the same as for off-line simulations, problems concerning timing, data management and inter process communication have to be identified and solved. This paper describes the upgrading of the existing hydrodynamic rainfall runoff model HYSTEM/EXTRAN and the decision finding model INTL for real time performance, their implementation on a network of UNIX stations and the experiences from running them within an urban drainage real time control project. The main focus is not on what the models do but how they are put into action and made to run smoothly embedded in all the processes necessary in operational real time control.

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