EGAT, the largest power producer in Thailand, currently owns and operates 15 reservoirs, which generate 10.5% of overall electricity in the country. A pilot project was conducted to develop a system that can support planning, problem solving, and decision making, especially against boundary and trespassing disputes.
EGAT presently builds, owns and operates several types and sizes of power plants across the country with a combined installed capacity accounting for about 45.6% of the country”s generating capacity. There are 15 reservoirs under EGAT’s control which generate 10.5% of overall electricity, second largest after natural gas power plant.
EGAT’s reservoirsare not only used for electricity generating, but also act as a water resource to the surrounding community.It is used for many purposes such as agriculture, fishery, transportation, tourist attraction, etc.All the activities that happened along the reservoir coast lead to trespassing problems, which will lead to complaints and compensation claims when the water level reached its maximum height and flooding occurred.
A geographic information system will providethe Authority with precise information in solving such legal disputes and other management purposes. A pilot project to generate ready-to-use database to build up the system was conducted in Bhumibol reservoir area, located at KhaoKaeo, Sam Ngao district, in Tak province.
GIS to support project planning, problem solving and decision making
Before the system was developed, reservoir field operators have to request maps and other geographic information from the sub-department of survey division, which based in EGAT’s headquarter. The procedure took a lot of time and delayed the operation that requires offhand decision. The objective of the pilot project is to find the best solution to support project planning, problem solving, and decision making in the work operations of EGAT’s fieldwork operators.
Orthophotoswere used as a base map, overlaid with high resolution satellite images for change detection, and to detect the activities that happen around reservoir boundary.Maximum high water level vectors were obtained by using 3 methods: digitisation from topographic map; digital elevation model (DEM) from orthophotos; and direct collection from field by 3rdorder direct levelling method.
Web GIS for reservoir and trespass area information
The pilot project output is a web GISthat allows EGAT officials to access geographical information directly in order to plan, solve problem and make decision in field. It also serves as a communication channel between the headquarters and fieldwork operators. The web GIS consist of base map, vector layers and swipe tool to display the changes that occurred in selected areas in certain period.
Web GIS available on EGAT”s intranet, provides reservoir and trespass area information
Prior to the system, delivery of geo-information data from information center in Bangkok to the reservoir site takes a lot of time. By having the system, operation time is now reduced. Web-based technology, with proper database structure, enable users to connect to database anytime and anywhere,and gain access to most updated geographic information. The system is only made accessible through intranet due to the highly sensitive information made for EGAT’s authority. The system can also be accessed through VPN from distance.