การป้องกันพื้นที่น้ำท่วมในลุ่มน้ำลำพระเพลิงด้วยแบบจำลอง Hec Ras

Abstract

The Lam Phra Phloeng reservoir is a big reservoir in the Lam Phra Phloeng river basin.  If there are big storms in the upper area of reservoir, there is a water drainage to the downstream of reservoir.  Then, there is a flooding in Pak Thongchai district as a heavy flooding in 2010 and 2019.  The objective of this study are (1) to evaluate the flooding areas in the return period 2, 5, 10, 25, 50, 100 and 500 yrs., and (2) to analyze the guidelines for preventing and reducing flood damage in the Lam Phra Phloeng river basin by using Hec Ras modelling.  The Hec Ras modelling can simulate both 1D and 2D flow conditions.  The results can be concluded that the flooding area in the return period 2, 5, 10, 25, 50, 100 and 500 yrs. are 4.62, 25.53, 37.28, 48.42, 55.63, 61.83, and 73.74 km², respectively.  To protect and reduce a flooding, many projects has to be concerned that consists of (1) building a water barrier flap, (2) increasing the potential for water transmission and drainage, (3) study and design of the installation of flood alarm systems along the Lam Phra Phloeng river, (4) study, design and installation of runoff stations, (5) study and design of river network system and (6) database system for flood and drought prevention.