THE STUDY ON SUITABLE RESERVOIR LOCATIONS. Case Study of Thung Song District, Nakhon Si Thammarat Province

Abstract

The objective of this research is to study the appropriated area for building water storage source that able to supply for both consumption and agricultural water usage demand in Thung Song district, Nakorn Si Thammarat province, Thailand. By combining both Geographic information system (GIS) and region potential analysis to simulated the catchment area. For this study 5 factors are used as following, rainfall, land use, soil drainage, topography and geological. The weight of each factor is 4, 4, 3, 2 and 2, respectively. After data collected, each factor will be overlaid by GIS to find the most appropriated part of the area. The most appropriated part of area is 125,280.155.52 m² (14.19% of total area), 567,449,443.56 m² (64.25% of total area) and 190,427,396.25 m² (21.56% of total area), respectively. According to the overlaid process, the first appropriated part of the area where water storage sources supposed to build is located at Na Luong sub-district (WGS84/Zone 47N E: 575728 N: 906188). Where able to store 109,837,759.45 m³ of water from Wang Heep canal. The second appropriated part of the area is located at Tum Yai sub-district (WGS84/Zone 47N E: 581171 N: 906188). Where able to store 66,584,757.92 m³ of water from Perk canal. The capacity of both storages is 176,422,517.37 m³ and the maximum monthly water requirement is 150,259,910.22 m³. As a result, 26,162,607.15 m³ of water will be remained. However, the amount of water that remained in the storage can be increased or decreased is depends on each season. Nevertheless, with full capacity of water storage is sufficient for water demand of the area.

Keywords: Geographic Information System, Analytic Hierarchy Process