scholarly journals Assesment of Frequency-Magnitude of Extreme Rainfall Events-Case Study of the MeKong River Delta

Author(s):  
Pham Hai An ◽  
Tran Anh Tu ◽  
Tran Dinh Lan ◽  
Nguyen Ngoc Tien
2019 ◽  
Vol 80 (8) ◽  
pp. 1538-1548
Author(s):  
Lei Liao ◽  
Ruidong An ◽  
Jia Li ◽  
Wenmin Yi ◽  
Xiaofan Liu ◽  
...  

Abstract Cities in southwestern China experience urban drainage and overflow pollution after extreme rainfall events, which are major problems. In this study, a type of stepped spillway dropshaft suitable for drainage by deep tunnels in Chengdu was proposed and the hydraulic characteristics were investigated experimentally. The results showed that the nappe flow and strong turbulent deflected jet flow in the stepped spillway allowed the dropshaft to greatly dissipate energy. According to the distribution of the time-averaged pressure on the steps, the flow on the steps could be divided into a recirculating region, a wall-impinging region and a mixing region. The time-averaged pressure on the outside of the step was higher than that on the inside due to the centrifugal force effect of the water. The fluctuating pressure distribution of the step approximated the normal distribution. It was acceptable to calculate the minimum pressure with 3 times the root mean square (RMS). The vibration of the flow on the stepped spillway did not resonate with the step. When the outflow tunnel was under submerged outflow conditions, the aeration in the stepped spillway was exhausted through air holes and only a small amount of air entered the outflow tunnel, thereby avoiding an air explosion.


2002 ◽  
Vol 2 (1/2) ◽  
pp. 109-117 ◽  
Author(s):  
J. Burguete ◽  
P. García-Navarro ◽  
R. Aliod

Abstract. A numerical model for unsteady shallow water flow over initially dry areas is applied to a case study in a small drainage area at the Spanish Ebro River basin. Several flood mitigation measures (reforestation, construction of a small reservoir and channelization) are simulated in the model in order to compare different extreme rainfall-runoff scenarios.


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