On the Groundwater of Nishinomiya District, Kinki, Japan: with Special Reference to the Characteristics of Permeability of the Aquifer and Chemical Composition of the Miyamizu

The geological structure and constituents of aquifer and chemical composition of the groundwater of Nishinomiya city, Kinki, Japan were investigated. The Miyamizu, a brewing water of the city has long been known as a most suitable water for brewing purpose of japanese Sake. The district is composed of Alluvial sediments and the aquifer of the district is restricted to the Alluvial sediments which can be divided into several zones according to its permeability. The Miyamizu aquifer corresponds to the first aquifer (higher than 5 X10-2 cm/sec) and with increasing the depth, permeability decreases gradually. The basement of the sediments is consisted of the aquiclude with permeability smaller than 5 X 10-4 cm/sec.
Based on the analysis of the groundwater levels, it is clarified that the groundwater flowing into the Miyamizu aquifer comes from several underflows of the old rivers, and each old river has its own chemical characteristics. Chemical composition of the Miyamizu is characterized by high contents of phosphorous, potassium and calcium and very low content of iron. Variation of the chemical composition of the Miyamizu for long years, seasonal and monthly variations are clarified. Concerning the formation process of the chemical characteristic of the Miyamizu; it is concluded that the present composition is formed under the great influence of Paleo-environment of about 1,000 years ago, i.e., so-called the Jōmon transgression, especially in relation to the development of shallow sea.