In the past, watershed management in both overall watershed and irrigation
project were focused on water storage development. They were allocating water to
supply the water demands and reducing flood opportunity. However, in practice, they
had many limits in engineering and economic hence unexpected success. In recent
time, the approach has been changed. It has been focused on land managements for
adjusting water demand to equal with water supply, controlling soil stability, and
reducing flood damages. Integration of data and mathematic models are necessary for
this approach. Unfortunately available spatial data and attribute data are in various
formats or standards and lack of collecting or grouping. Besides, mathematics models
are complicated. They led real-time managements in each seasonal water situation to
difficulty. One of these resolution problems is information system that well-managed
data, both spatial data and attribute data, and well-cooperates with mathematics
models. This study is applying geo-informatics that consisted of remote sensing (RS),
geographic information system (GIS), and global positioning system (GPS) with
hydrologic model to develop geo-informatics for watershed management. Case study
is MAE CHAN watershed that sub-basin of MEKHONG basin in northern Thailand.