Freequency and discharge design of diversion works according to TCXDVN 285-2002 should be revised

Abstract

     Frequency and discharge design of diversion works have been decided by TCXDVN 285- 2002 Construction Standard and the frequency design for diversion works could be applied with P = 10% of maximum discharge data for all projects classification if they are being constructed in one dry season. This is only changed to P =5% if main projects are set in the group I and II, and construction time is lager than 2 dry seasons. Other projects could be applied in P =10% and do not change through construction time. This leading to some problems for designer and contractors when they have to cope with diversion works in the end of construction time that the water level is high and the discharge design is kept constantly. This paper will analyse and discuss the problems which should be revised in design standards.