A Studyon the Movment of Ground Water of Banayweol Formation

반야월층(半夜月層)의 지하수운동(地下水運動)에 관(關)한 연구(硏究)

This study deals with the flow of bed rock ground water of Banyaweol Formation, which is presently cleared up as a laminar flow. The result obtained may be summarized as the following. 1) The Banyaweol Formation consists mainly of thin-bedded, green to blackish green shale, mudstone, and marl. The marl and mudstone alternatively occur with shale. The marl and mudstone form a aquifer of Banyaweol Formation. In this study, a group of aquifer is in convenience named as a aquifer zone. The aquifer occurs in lenticular form. The aquifer seems to be a type of artesian aquifer because it is covered with aquicludes, but it actually forms a unconfined aquifer because its piezometric surface stays under the lower aquiclude. The lowering of piezometric level is formed because of leakage of the ground water to the lower aquifer undersaturated. 2) The coefficient of permeability of Banyaweol Formation's ground water body (K) is derived by using Dupuit's equation as the following ${\log}K=\frac{CK^2-dK+f}{aK-b}\;\(M=1.365(2H-s)s\\M={\log}1.956s{\sqrt{H}}r\)$ here, $$a=\sum_{1}M_iG_i$$ $$b={\frac{1}{2}log{\sum_{i}}Q_i{^2}$$ $$c=2{\sum_{i}}M_i{^2}$$ $$d=loge{\sum_{i}}M_{i}Q_{i}+2{{\sum_{i}}N_{i}Q_{i}$$ $$f=loge{\sum_{i}}Q_i{^2}N_i$$ If the measured values substituted for the above equation, the coefficient of permeability of the aquifer is 4.1m/day. The coefficient of storge of the aquifer is $2.8{\times}10^{-4}$ if the measured values substituted for Theis's equation. Using the above constants, the filtration velocity of the aquifer is $2.1{\times}1O^{-1}m/day$and the daily flow quantity of the ground water is $847.38m^{3}/day$. 3) In order to understand the time necessary for a circulation of ground water body, the contents of tritum contained in the ground water are measured as 2.3 T.U. at the Korea Atomic Energy Research Institute. Before 1952, the average concentration of tritium per year in groundwater was reported as 10T. u., taking it as the standard, the groundwater of the present study 26.25 years old. Therofore, the groundwater of the Banyaweol Formation is judged as an relatively old groundwater. It is characteristic that the ground water of Banyawol Formation is laminar flow as well as unconfined aquifer and ground water flow of relatively long time. 4) The nature, means of flow, and circulation of Banyaweol Formation's ground water body make it possible set up this ground water body as a ground water system.