Mitigation of flash floods in arid regions using adjoint sensitivity analysis

Hossam Elhanafy, Graham J.M. Copeland

Research output: Contribution to conferencePaper

Abstract

This paper presents an analysis of the sensitivities of flood wave propagation to variations in certain control variables and boundary conditions by means of the adjoint method. This uses a variational technique to find the relationships between changes in predicted flood water levels and changes in control variables such as the inflow hydrograph, bed roughness, and bed elevation. The sensitivities can be used for optimal control of hydraulic structures, for data assimilation, for decision makers' procedures, for the analysis of the effects of uncertainties in control variables on the predictions of floods water levels, and for investigating both the sensitivities of model flood forecasts to model parameters, boundary and initial conditions. Example of the last application of the sensitivity analysis is presented and discussed These methods are developed and implemented through a numerical hydraulic model of channel flow based on the Shallow Water Equations (SWEs) and the corresponding adjoint model. The equations are integrated using finite difference methods and a new modified method of characteristics is used to define the open boundaries. Results of validation tests on both the forward hydraulic model and on the adjoint model are presented.
LanguageEnglish
Number of pages16
Publication statusPublished - 15 Mar 2007
EventEleventh International Water Technology Conference 2007 - Sharm el Sheijk, Egypt
Duration: 15 Mar 200718 Mar 2007

Conference

ConferenceEleventh International Water Technology Conference 2007
CitySharm el Sheijk, Egypt
Period15/03/0718/03/07

Fingerprint

Arid regions
Sensitivity analysis
Hydraulic models
Water levels
Variational techniques
Hydraulic structures
Channel flow
Finite difference method
Wave propagation
Surface roughness
Boundary conditions
Water

Keywords

  • floods
  • wave propagation
  • adjoint method
  • civil engineering
  • water equations
  • hydraulics

Cite this

Elhanafy, H., & Copeland, G. J. M. (2007). Mitigation of flash floods in arid regions using adjoint sensitivity analysis. Paper presented at Eleventh International Water Technology Conference 2007, Sharm el Sheijk, Egypt, .
Elhanafy, Hossam ; Copeland, Graham J.M. / Mitigation of flash floods in arid regions using adjoint sensitivity analysis. Paper presented at Eleventh International Water Technology Conference 2007, Sharm el Sheijk, Egypt, .16 p.
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Elhanafy, H & Copeland, GJM 2007, 'Mitigation of flash floods in arid regions using adjoint sensitivity analysis' Paper presented at Eleventh International Water Technology Conference 2007, Sharm el Sheijk, Egypt, 15/03/07 - 18/03/07, .

Mitigation of flash floods in arid regions using adjoint sensitivity analysis. / Elhanafy, Hossam; Copeland, Graham J.M.

2007. Paper presented at Eleventh International Water Technology Conference 2007, Sharm el Sheijk, Egypt, .

Research output: Contribution to conferencePaper

TY - CONF

T1 - Mitigation of flash floods in arid regions using adjoint sensitivity analysis

AU - Elhanafy, Hossam

AU - Copeland, Graham J.M.

PY - 2007/3/15

Y1 - 2007/3/15

N2 - This paper presents an analysis of the sensitivities of flood wave propagation to variations in certain control variables and boundary conditions by means of the adjoint method. This uses a variational technique to find the relationships between changes in predicted flood water levels and changes in control variables such as the inflow hydrograph, bed roughness, and bed elevation. The sensitivities can be used for optimal control of hydraulic structures, for data assimilation, for decision makers' procedures, for the analysis of the effects of uncertainties in control variables on the predictions of floods water levels, and for investigating both the sensitivities of model flood forecasts to model parameters, boundary and initial conditions. Example of the last application of the sensitivity analysis is presented and discussed These methods are developed and implemented through a numerical hydraulic model of channel flow based on the Shallow Water Equations (SWEs) and the corresponding adjoint model. The equations are integrated using finite difference methods and a new modified method of characteristics is used to define the open boundaries. Results of validation tests on both the forward hydraulic model and on the adjoint model are presented.

AB - This paper presents an analysis of the sensitivities of flood wave propagation to variations in certain control variables and boundary conditions by means of the adjoint method. This uses a variational technique to find the relationships between changes in predicted flood water levels and changes in control variables such as the inflow hydrograph, bed roughness, and bed elevation. The sensitivities can be used for optimal control of hydraulic structures, for data assimilation, for decision makers' procedures, for the analysis of the effects of uncertainties in control variables on the predictions of floods water levels, and for investigating both the sensitivities of model flood forecasts to model parameters, boundary and initial conditions. Example of the last application of the sensitivity analysis is presented and discussed These methods are developed and implemented through a numerical hydraulic model of channel flow based on the Shallow Water Equations (SWEs) and the corresponding adjoint model. The equations are integrated using finite difference methods and a new modified method of characteristics is used to define the open boundaries. Results of validation tests on both the forward hydraulic model and on the adjoint model are presented.

KW - floods

KW - wave propagation

KW - adjoint method

KW - civil engineering

KW - water equations

KW - hydraulics

UR - http://iwtc.info/archive/iwtc-2007/

M3 - Paper

ER -

Elhanafy H, Copeland GJM. Mitigation of flash floods in arid regions using adjoint sensitivity analysis. 2007. Paper presented at Eleventh International Water Technology Conference 2007, Sharm el Sheijk, Egypt, .