Abstract
In the period 19711973, the hydrogeological studies were done in the area of the Koga basin, Shiga Prefecture. The conclusions are summarized as follows :
1) The geology of the Koga basin consists of the Kobiwako Group, The main confined aquifers are Katuragi sand bed and Aburahi sand bed.
2) The artesian wells in this basin are about 100 to 170 meters in depth and their discharge is about 5002, 000 m3/day.
3) The depth of the basement was presumed from the result of gravity survey. The maximum value in depth situated near Ueno is approximately 220 meters under the ground.
4) On the basis of the result of gravity survey and the interpretation of chemical characteristics of groundwater samples, the groundwater basin of this area was divided into the northern part (Konan area) and the southern part (Koga area).
5) The mineral springs of sodium chloride type are flowing out at about 1 km west of Konan Station. The chemical composition of artesian groundwater of the northern end of this basin is affected by the mineral water.
