Recentry, deeper aquifers,200 meters or more in depth, have beem developed in proportion to the increasing amount of water required for the public supplies and the industries. Thus, it becomes possible to collect much information on subsurface geology by means of the microfossil analysis, water temperature, and water quality by the hydrochemical interpretations. New valuable information will be of use to advanced studies of the regional hydrogeology.
An experimental study of groundwater recharge by means of recharge basin has been done in a dune area of Showamachi, Akita Prefecture. Raw water source was withdrawn from the Hachirogata regulating reservoir. The purpose of this study is to make certain of storage of recharge water and changes in water quality. The experimental equipments consist mainly of a recharge basin (area of 10× 20 m and 0.4 m deep), a pumping well (14 m deep) and six observation wells (each 8 m deep). Water was analyzed in laboratory. The structural phases of the equipments are explained in this paper. Results obtained are discussed in the following papers.
In the ground work for construction, it is very important to apply the sufficient preventive measures for the various accidents caused by groundwater. In practice, however, the groundwater surveys for planning these preventive measures have rarely been carried out with enough accuracy. The authors have been trying to establish the method of groundwater survey for the above purpose and have published some useful techniques for this establishment. The most important problem at present is the interpretation of fluctuation characteristics of groundwater levels observed in construction sites. In the present study, we report this using the data of SKP building site.
This paper presents some hydrogeological features of Ryomo area in Tochigi Prefecture, based on the investigation for an appropriate usage of groundwater (1975,1979,1981) and the integrated investigation of hydraulics and hydrogeology in Tokyo urban area (1974) which were carried out by Tokyo Regional Bureaw of International Trade and Industry. This paper is summarized as follows; 1. The investigated area consists of mountains, hills, plateaus and lowlands, which are put in order from surrounding mountainous area towards a center of Kanto-plane. 2. The mountains comprise consolidated hard rocks such as granitic rocks, volcanic rocks and Paleozoic formations. The area except the mountains is composed of unconsolidated formations such as Tertiary and Ouaternary system. 3. The above unconsolidated formations results unconformably upon the impervious basement comprising the consolidated rocks and are divided into six formations such as formation“F” to formation “A”. 4. A form of the impervious basement indicates existence of two waste-filled valleys at both sides of the Ota observation well. One of them was called “Kinugawa waste-filled valley” by Dr. Akio Suzuki. And it is estimated that a hill lies in the gound at the extention of the Utsunomiya hill. 5. The thermal gradient of groundwater is divided into three groups in the investigated area. The thermal gradient is 1°C/100 m in south of Tone river and is 3° C/100 m in north of Tone river. Further, it is 5°C/100 m in the Watarase basin. 6. Groundwater quality varies from CaSO4 type to Ca (HCO3) type on the Key-diagram correspondent with a depth of respective formations. And it is likely thet there is a higher concentration in sodium ion in the area where is affected by groundwater of the basement. Although above mentioned results were led from the study, further, a palaeogeographicai study is required on difference of the thermal gradient of groundwater and on a type of groundwater.
The project of Wadi al Bab and Wadi Ahmar in Libya aims to deveplop the available water resources, both surface and groundwater. The study area is approximately 2,000 km2, located on the south-western flank of Jebel Akhdar Mountains,30 to 80 km southeast of Benghazi. The climate of the study area is semi-arid and its mean annual precipitation is 100 to 200 mm high. With First Escarpment as a border, to the west is spread the Benghazi coastal plain, and to the east, a table land. Tertiary rocks and Quaternary deposits are distributed. Each formation of Tertiary period displays transgressive and regressive facies and are comprised mainly of marine carbonates. In this paper, some results of hydrogeological investigation, such as groundwater storage conditions, water quality, water balance and etc., will be discussed.
It is a fascinating subject in both fields of hydrology and history to study the origin and the subsequent development of wells. Little investigation, however, has been done into that subject. If the characteristics of ancient wells in the world are clarified, it will gratefully contribute to understanding the history of groundwater use From this point of view, the auther has been investigating groundwater facilities and methods of withdrawal in the Middle and Near East, Africa, Europe, etc. The purpose of this study is to present the historical background and the characteristics of Pozzo di San Patrizio, or St. Patrick Well, on the site of an ancient castle in Orvieto city in Italy, as a part of those investigations. Pozzo di San Patrizio was named after a cavern in Ireland where St. Patrick used to be lost in contemplation. The construction of the well was started by Antonio da Sangallo in 1527, who was entrusted the work by Pope Clement VII. Geological conditions around the well are as follows. The formation consists of weathered soil (regosols) for the top, volcanic tuff (tufa) for the middle and submarine sediment (pliocene) for the bottom. Of the last, the clay forms aquicludes and the sand forms groundwater aquifers. Because of those geological conditions, it was easy to dig a hole for the well with a chisel or an ax, but a lot of bricks were used for reinforcement and it is said that many people were mobilized for carting the bricks. The well, an architecture of Baroque style, has double spiral staircases with 248 steps respectively around its pit, which keep both a descending person and an ascending one from bumping against each other. There are dormer windows made on the boundery wall between the staircases and the pit in order that the steps can be lighten up by the sunlight coming through them. A few years after the construction was completed in 1537, the well got a great fame because of its unusual and complicated structure and has maintained its popularily with the visitors.