Analysis of Flood Storage Area Operations in Huai River Using 1D and 2D River Simulation Models Coupled with Global Optimization Algorithms

Andreja Jonoski,Sun Zhe,Yuhan Mu,Ioana Popescu,Yiqing He

doi:10.3390/geosciences9120509

Abstract

This article addresses the issue of flood management using four flood storage areas in the middle section of Huai River in China which protect the important downstream city of Bengbu. The same areas are also used by the local population as residential and agricultural zones. An optimization problem is therefore posed, with two objectives of simultaneously minimizing the downstream flood risk in Bengbu city and the storage areas’ economic damages. The methodology involved development of river flood models using HEC-RAS, with varying complexity, such as 1-dimensional (1D) model with storage areas represented as lumped conceptual reservoirs, and 2-dimensional (2D) models with detailed representation of the terrain, land-use and hydrodynamics in the storage areas. Experiments of coupling these models with global optimization algorithms (NSGA-II, PESA-II and SPEA-II) were performed (using the HEC-RAS Controller), in which the two objective functions were minimized, while using stage differences between the river and the storage areas as decision variables for controlling the opening/closing of the gates at the lateral structures that link the river with the storage areas. The comparative analysis of the results indicate that more refined optimal operational strategies that spread the damages across all storage areas can be obtained only with the detailed flood simulation models, regardless of the optimization algorithm used.

Highlights

Flood Storage Areas (FSAs) have been used in many countries for flood protection of downstream areas during incoming floods
There are some small differences in the identified solutions, the same clustering is still present and the solutions are grouped depending on whether Shouxi FSA is used or not
When using the two new models, 1D-2D and 1D-2D, some new solutions are identified, located between the two clusters identified earlier. These solutions are indicating operational strategies with more partial usage of Shouxi FSA

Summary

Introduction

Flood Storage Areas (FSAs) have been used in many countries for flood protection of downstream areas during incoming floods. As floods are rare events, the FSAs are often used as agricultural and residential areas, with increased vulnerabilities and risks that need to be taken into account during their operation They have been identified as zones of environmental protection in integrated river basin management, acting as one of nature-based solutions for flood risk management [4,5]. Analyzing the conditions within the FSAs during their operation needs to be taken into account together with the main objective of reducing downstream flood risks, aiming at optimal operations that minimize the risks both within the FSAs and downstream. These kinds of problems have already been studied using

Results

Discussion

Conclusion