The calibration of the model parameter of Phrae groundwater basin has a minimum error average
head of 17.97 meter in rainy season and 13.71 meter in drought season and 6.30 meter in rainy
season and 5.14 meter in drought season of deviation error (Fig.2). For upper Chao Phraya
groundwater basin simulation the minimum error average head is 6.25meter in the rainy season and
15.06 meter in the drought season (Fig.3).