兵庫県灘地区の水理地質学的研究 : 予報

Most of the area dealt with in this study is situated on the coastal plain extending from the southern foot of the Rokko Mountain-range to east. The aquiferous strata are contained in the alluvial deposits, the Itami gravel beds and the Osaka formation hidden beneath the plain concerned. In particular, the superficial aquifer is believed to be recharged mainly from the mountainous background composed of granitic rocks. The stratum concerned is found to become broader in depth from north to east, while its upper part with depth of about 5 m is composed mainly of gravel and sand suitable for permeation of descending water and the lower part lying under the former is represented by impermeable bed composed of silt and sand, upon which ground water named the first aquifer is found flowing. The portion including the well-developed gravel bed with abundance of ground water has so far been provided for the source of brewing industry as so-called "Miyamizu" and others. Because of its situation near the landsurface along the coastal region, the aquifer concerned is liable to be affected through various kinds of external agencies.
The Itami gravel bed developed widely on the eastern side of the Rokko mountain-range is surely found to construct the terrace diminishing its height with distance from the mountain and immerging under the alluvial deposits appeared within the area under consideration. This bed seems to take part in recharge of huge amount of ground water from the northern region and thus is called the second aquifer.