Groundwater in Bed Rock in Korea

Abstract

There are two types of groundwater in the Korea.One is the groundwater containedin the unconsolidated rock system, the other is the groundwater existing in the consolidated rock system.In this report only the latter type of groundwater is discussed.Geologically the Korean Peninsula is a part of Continental China.In terms of geogical time the ages concerned with the formation of sedimentary rocks range from the Pre-Cambrian Era to the Tertiary Epoch of the Cenozoic Era.In Palaeozoic deposits there are many limestone beds, and Mesozoic deposits oftentimes contain limy shales.Groundwater in sedimentary rocks is usually contained in limestones or limy rocks. Groundwater can also be found in igneous rocks and metamorphic rocks which are derived from old sedimentary rocks.Groundwater in the sedimentary rocks is fissure and stratum water, and in igneous rocks and metamorphicrocks only fissure type water exists.Results of the study made by drilling wells in various types of rocks, the following facts are made clear: In consolidated sedimentary rocks largest quantity of groundwater is found and next in quantity comes the groundwater from granite.On the contrary, the groundwater in metamorphic rocks is found in smaller quantity than in any other rocks.With respect to water quality, the groundwater in granite and metamorphic rocks isbetter than the groundwater in sedimentary rocks.The groundwater in dike rocks is also good.Anyway all the groundwater from these rock systems is good for agricultural use and drinking purpose.In the Korea the shallow groudwater is easily affected by the surface water and gets polluted.The deep groundwater on the contrary is not easily influenced by the surface water body and has the advantage of constant temperature.In developing the groundwater to meet the demand for water, unpolluted and with constant temperature, it is necessary to investigate carefully on these points.