Influence of flood control facilities on water level in downstream of river system Sai Gon -Dong Nai

Ho Chi Minh City, Vietnam's largest city, located on the lower reaches of the Sai Gon-Dong Nai (SG-DN) river system, is facing increasingly severe flooding due to changes in river flow and water levels. This article presents the results of a study to assess the impact of hydraulic structures located in the upper reaches on the water level in the lower reaches of the SG-DN River. As part of a study to assess the impact of upstream reservoirs and flood control structures on the water level in the lower reaches of the SG-DN River, hydrological data of the river network were collected. A hydraulic model was developed based on a digital elevation model (DEM) using the software package Mike 11, Mike 21 and Mike Flood. The water level of the Sai Gon River from the upper reaches to the Thu Dau Mot measuring station depends on the Dau Tieng reservoir, and the Tri An reservoir directly affects the water level in the river section from behind the Tri An dam to the Dong Nai section in the Tam An - Long Phuoc area. In the sections of the Sai Gon and Dong Nai rivers, which are less affected by the two overlying reservoirs, it is necessary to develop preventive measures to supply sufficient fresh water to meet the population's and industries' needs. In areas prone to flooding and underflooding due to the operation of anti-flood locks, it is also necessary to reconstruct hydraulic structures (raise the elevations of foundations, expand drainage systems, build reservoirs for collecting flood water, etc.)