scholarly journals Why continuous simulation? The role of antecedent moisture in design flood estimation

2012 ◽  
Vol 48 (6) ◽  
Author(s):  
S. Pathiraja ◽  
S. Westra ◽  
A. Sharma
Keyword(s):  
Design Flood ◽  
Continuous Simulation ◽  
Antecedent Moisture ◽  
Flood Estimation

scholarly journals An assessment of scale issues related to the configuration of the ACRU model for design flood estimation

2011 ◽  
Vol 42 (5) ◽  
pp. 401-412
Author(s):  
K. Chetty ◽  
J. C. Smithers
Keyword(s):  
Daily Rainfall ◽  
Simulation Modelling ◽  
Research Unit ◽  
Physical Parameters ◽  
Design Flood ◽  
Critical Question ◽  
Continuous Simulation ◽  
Agricultural Catchments ◽  
Flood Estimation ◽  
Modelling Process

A continuous simulation modelling approach to design flood estimation has many advantages and overcomes many limitations of commonly used design event approaches. A major concern with continuous simulation using a hydrological model is the scale at which modelling should take place. According to researchers, the level of representation that will preserve the physical chain of hydrological processes, both in terms of scale of representation and level of description of the physical parameters for the modelling process, is a critical question which must be addressed. Objectives of this research were to determine the optimum levels of catchment discretization and soil and land cover information and to assess the optimum use of daily rainfall stations for the configuration of the Agricultural Catchments Research Unit (ACRU) agrohydrological model when used for design flood estimation. Results obtained for selected quaternary catchments in the Thukela catchment and Lions River catchment indicated that modelling at the level of hydrological response units (HRUs), using area-weighted soils information and more than one driver rainfall station where possible, produced the most realistic streamflow volume results when compared with observed streamflows. Design flood estimates from simulated peak flows did not compare well with observed data.

scholarly journals Review: Continuous simulation modelling for design flood estimation – a South African perspective and recommendations

Water SA ◽  
2018 ◽  
Vol 44 (4 October) ◽  
Author(s):  
TJ Rowe ◽  
JC Smithers
Keyword(s):  
South Africa ◽  
Rainfall Variability ◽  
Simulation Modelling ◽  
Economic Losses ◽  
Design Flood ◽  
National Scale ◽  
Extreme Rainfall Events ◽  
Continuous Simulation ◽  
Flood Estimation ◽  
Further Development

A number of severe flooding events have occurred both in South Africa and internationally in recent years. Furthermore, changes in both the intensity and frequency of extreme rainfall events have been documented, both locally and internationally, associated with climate change. The recent loss of life, destruction of infrastructure, and associated economic losses caused by flooding, compounded by the probability of increased rainfall variability in the future, highlight that design flood estimation (DFE) techniques within South Africa are outdated and in need of revision. A National Flood Studies Programme (NFSP) has recently been initiated to overhaul DFE procedures in South Africa. One of the recommendations in the NFSP is the further development of a continuous simulation modelling (CSM) system for DFE in South Africa. The focus of this paper is a review of CSM techniques for DFE, to guide further development for application in South Africa. An introduction to DFE, and particularly the CSM approach, is presented, followed by a brief overview of DFE techniques used in South Africa, leading into a more detailed summary of CSM for DFE within South Africa to date. This is followed by a review of the development and application of CSM methods for DFE internationally, with a focus on the United Kingdom and Australia, where methods have been developed with the intention of national scale implementation. It is important to highlight that there is a plethora of CSM methods available internationally and this review is not exhaustive; it focuses on and identifies some of the strengths and weaknesses of several popular methods, particularly those intended for national scale application, as the intended outcome from this review is to identify a path towards the development of a usable national scale CSM system for DFE in South Africa. Emphasis on a usable method is important, considering the reality that, despite promising results, numerous benefits, and national scale methods being developed, it appears that the CSM method for DFE is rarely used in practice.

scholarly journals An Investigation of Modelling Accuracy Needs for Urban Design Flood Estimation

2020 ◽  
Author(s):  
James E. Ball
Keyword(s):  
Peak Flow ◽  
Continuous Model ◽  
Flood Management ◽  
Urban Environments ◽  
Flood Frequency ◽  
Flood Frequency Analysis ◽  
Design Flood ◽  
Continuous Simulation ◽  
Flood Estimation ◽  
Quantile Estimates

Flood Management remains a major problem in many urban environments. Commonly, catchment models are used to generate the data needed for estimation of flood risk; event-based and continuous-based models have been used for this purpose. Use of catchment models requires calibration and validation with a calibration metric used to assess the predicted catchment response against the recorded catchment response. In this study, a continuous model based on SWMM using the Powells Creek catchment as a case study is investigated. Calibration of the model was obtained using 25 selected events from the monitored data for the catchment. Assessment of the calibration used a normalised peak flow error. Using alternative sets of parameter values to obtain estimates of the peak flow for each of the selected events and different accuracy criteria, the best datasets for each of the accuracy criteria were identified. These datasets were used with SWMM in a continuous simulation mode to predict flow sequences for extraction of Annual Maxima Series for an At-Site Flood Frequency Analysis. From analysis of these At-Site Flood Frequency Analyses, it was concluded that the normalised peak flow error needed to be less than 10% if reliable design flood quantile estimates were to be obtained.

Revisiting design flood estimation of Nam River Dam basin considering climate change

2016 ◽  
Vol 49 (8) ◽  
pp. 719-729
Author(s):  
Hyunseung Lee ◽  
Taesam Lee ◽  
Taewoong Park ◽  
Chanyoung Son
Keyword(s):  
Climate Change ◽  
Design Flood ◽  
Flood Estimation

The Role of Computer Modeling in Combined Sewer Overflow Abatement Planning

1992 ◽  
Vol 26 (7-8) ◽  
pp. 1831-1840 ◽  
Author(s):  
L. A. Roesner ◽  
E. H. Burgess
Keyword(s):  
System Modeling ◽  
Cost Effective ◽  
Combined Sewer Overflows ◽  
Sewer System ◽  
New Techniques ◽  
Hydraulic Simulation ◽  
Continuous Simulation ◽  
Combined Sewer ◽  
The U.S

Increased concern regarding water quality impacts from combined sewer overflows (CSOs) in the U.S. and elsewhere has emphasized the role of computermodeling in analyzing CSO impacts and in planning abatement measures. These measures often involve the construction of very large and costly facilities, and computer simulation during plan development is essential to cost-effective facility sizing. An effective approach to CSO system modeling focuses on detailed hydraulic simulation of the interceptor sewers in conjunction with continuous simulation of the combined sewer system to characterize CSOs and explore storage-treatment tradeoffs in planning abatement facilities. Recent advances in microcomputer hardware and software have made possible a number of new techniques which facilitate the use of computer models in CSO abatement planning.

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