Assessing impact of sluice gate operation on salinity intrusion in Ho Chi Minh City

Abstract

This study aims to evaluate salinity intrusion propagation in Ho Chi Minh City under the operation of six tidal sluice gates, namely, Ben Nghe, Tan Thuan, Phu Xuan, Muong Chuoi, Cay Kho, and Phu Dinh by utilizing the HEC-RAS model. The outcomes during calibration and validation procedures underscore the high performance of the HEC-RAS model in simulating salinity intrusion over the study area. In particular, R2 and NSE values were higher than satisfactory thresholds of 0.80 for water level and discharge simulations and 0.50 for salinity concentration simulations. Based on the calibrated HEC-RAS model, this study examined the potential influences of sluice gate operations on salinity distribution under different scenarios. Results indicate that salinity concentration would exhibit increasing trends when operating Ben Nghe and Tan Thuan sluices, while the closure of the Phu Xuan and Muong Chuoi sluices would cause a reduction in the salinity concentration within the areas enclosed by these sluices. In addition, the operations of the Cay Kho and Phu Dinh sluices would lead to decreases and increases in salinity concentration in the upstream and downstream areas of each corresponding sluice gate, respectively. Moreover, when closing six sluice gates simultaneously, the salinity concentration inside and outside the sluice gates would decrease and increase, respectively. In general, these findings indicate that salinity concentration and spatial distribution are significantly influenced by the location and structure of each tidal sluice gate.