DETERMINE THE FLOODED AREAS BY USING HEC 6 MODEL IN CALCULATING SENDIMENTATION AND RISING WATER IN THAC GIENG 1,2 HYDROPOWER PLAN RESEVOIR

Abstract

Thac Gieng Hydropower plant (TDTG 1&2) when operate will produce around 24 million KWh/year, a considerable increase in national power grid. Based on the scalec capacity of the plant and local natural conditions, this article utilize HEC 6 model to calculate sedimentation and determine the areas affected by rising water as the basis to carry out the compensation process and area clearance. The calculation show: (1) after 50 years the total amount of sedimentation at TDTG 1 resevoir is 1,317 million m³, 37,1% usable capacity; TDTG 2 is 0,242 million m³ which is 43,1%. (2) When designed and examination flood occur, TDTG 1 rising water flood 5 local houses and 1,163 ha of production forest and farming land. Rising water from 96,57 – 103,56m in height flood 14,31 ha of land, with 12,05 ha of production forest and 2,26ha of long time perennial forest.