Introduction
The Yom River is a tributary of Chao Phraya River [1]. It passes major urban areas such as
Phrae, Suko thai, and Bangrakam and has no large dams in the catchment [2]. This is because of the
major natural resources in the basin areas such as golden teak forests. As a result, water surface is
limited. General agriculture in the area is using water resource from rainfall, pond or groundwater
resource. Lower elevations within theYom basin uses the groundwater resource. Specifically ,the
lowland areas of Yom basin that includes Sukothai, Phrae, Pichit and Pichsanulok province. These
areas have high levels of groundwater usage. Therefore, we need to study the groundwater balance
in this area.
This case study involved simulation of the groundwater balance in the Yom groundwater basin.
Visual MODFLOW 4.2 mathematical groundwater flow model is applied in this case. There are two
sub-groundwater basin [3,4] that is Phrae and upper Chao Phraya groundwater basin. Therefore it
was necessary to simulate each of these sub-basins. The method and stepof model are setting and
correcting parameters of model.