Mixing of Sea Water with Calcium Carbonate Ground Water

Author(s):  
L. N. Plummer
1978 ◽  
Vol 42 (322) ◽  
pp. 209-220 ◽  
Author(s):  
Stefán Arnórsson

SummaryHigh-temperature geothermal fields in Iceland represent localized anomalies of hot, altered rock in the uppermost part of the crust, which coincide with points of maximum tectonic/magmatic activity. These points correspond to the intersection of oblique fault swarms to the plate boundaries. Geothermal activity under mid-ocean ridges follows probably similar tectonic/magmatic anomalies.Due to high permeability sea-water invades the bed-rock of the Reykjanes Peninsula, Iceland, and is overlain by a variably thick lens of dilute ground water of meteoric origin. The variable degree of salinity of geothermal waters in the Reykjanes Peninsula has resulted from different degree of mixing of fresh ground water with the underlying sea-water-ground-water in the downflow zones around the geothermal fields. At Reykjanes the geothermal water represents heated sea-water without any freshwater mixing. The difference in the composition of sea-water or sea-water/fresh water mixtures and the geothermal waters is due to basalt/water interaction at elevated temperatures. The major-element chemistry of the geothermal water represents an equilibrium composition at the relevant aquifer temperatures. The activities of silica, calcium, sulphate, and carbonate are thus limited by the solubilities of quartz, anhydrite, and calcite. Fluoride activity is thought to be controlled by an ionic exchange reaction where it substitutes for hydroxyl groups in phyllosilicates. The ratios of individual cations and hydrogen ion are governed by ionic exchange equilibria with hydrothermal minerals, probably smectite and chlorite. The equilibrium pH for the Reykjanes and Svartsengi geothermal waters is 5·5 and 5·1 respectively. Sea-water will become somewhat acid upon heating to more than about 300 °C and equilibration with basalt, the acidity increasing with temperature.


2017 ◽  
Vol 20 (1) ◽  
pp. 35 ◽  
Author(s):  
Sugeng Widada ◽  
Alfi Satriadi ◽  
Baskoro Rochaddi

Coastal Region of Kangkung, Kendal Regency, Central Java Province is one of the areas that experiencing water in the dry season. Groundwater exploitation is one way solution to meet the water needs for people in the area, especially in the dry season. Therefore it is necessary to study potency of ground water in coastal area of Kangkung. The research was  conducted to determine the potential of ground water in the confined aquifer in the Coastal Region of Kangkung, Kendal District which is expected to be utilized as a source of water to meet the needs of local communities. The method used in this research is  descriptive analysis to describe the condition of aquifer, however some things are delivered quantitatively. The aquifer condition was obtained from the interpretation of geoelectricity (resistivity) data supported by geological and hydrogeological observation data and pumping test data as secondary data. Groundwater quality analysis and simple hydrochemical analysis is with Chlorida - Bicarbonat Ratio (CBR) method to know the possibility of sea water intrusion. The results showed that the aquifer in the coastal area of Kangkung has the potential of 29.13 lt / sec ground water discharge which can be utilized to meet the needs of clean water 18,800 people. Although it is adjacent to the sea, the groundwater in the study area does not undergo sea water intrusion. Groundwater quality in this location is qualified as raw drinking water according to SK Menkes No, 492/Menkes/Per/IV2010 tentang Persyaratan Kualitas Air Minum. Keywords: ground water, geoelectric, intrusion  Wilayah Pesisir Kangkung, Kabupaten Kendal Provinsi Jawa Tengah merupakan salah satu daerah yang pada musim kemarau mengalami kekeringan. Pemanfaatan air tanah merupakan salah satu cara untuk memenuhi kebutuhan air bagi masyarakat di daerah tersebut, terutama pada musim kemarau. Oleh karena itu perlu dilakukan kajian potensi air tanah di daerah Pesisir Kangkung tersebut. Penelitian ini bertujuan untuk mengetahui potensi air tanah pada akuifer dalam (tertekan) di Wilayah Pesisir Kangkung, Kabupaten Kendal yang diharapkan dapat dimanfaatkan sebagai sumber air bersih untuk memenuhi kebutuhan masyarakat setempat. Metode penelitian yang digunakan dalam penelitian ini adalah diskriptis analisis untuk menggambarkan kondisi akuifer, namun demikian beberapa hal disampaikan secara kuantitatif. Kondisi akuifer diperoleh dari hasil interpretasi data geolistrik resistiviti dengan didukung data hasil pengamatan geologi dan hidrogeologi serta data sekunder berupa hasil pumping test. Analisa kualitas air tanah dan analisis hidrokimia secara sederhana dengan metode Chlorida – Bicarbonat Ratio (CBR) dilakukan untuk mengetahui kemungkinan terjadinya intrui air laut. Hasil penelitian menujukan bahwa akuifer di daerah Pesisir Kangkung mempunyai potensi debit air tanah 29,13 lt/det yang dapat dimanfaatkan untuk memenuhi kebutuhan air bersih 18.800 orang. Meskipun berbatasan dengan laut, namun air tanah di daerah kajian tidak mengalami  terintrusi air laut. Kualitas air tanah di lokasi ini memenuhi syarat sebagai bahan baku air minum sesuai SK Menkes No, 492/Menkes/Per/IV2010 tentang Persyaratan Kualitas Air Minum. Kata Kunci : air tanah, geolistrik, intrusi


Author(s):  
D. M. Reid

SUMMARYIn the foregoing work it was found that: Arenicola marina was repelled and could not burrow in sand containing 20% of ferric oxide in the amorphous state.That 0·021% ferric oxide in suspension in sea-water was lethal owing to its forming with the mucus of the organism an envelope which prevented contact with the surrounding air-carrying water.That calcium carbonate, magnesium carbonate, Stourbridge clay, kaolin, and kieselguhr had the same effect as the ferric oxide in suspension.That although able to live for a short time in water of salinity 3·10%‰, Arenicola marina tended to become so turgid in water of 14·32%‰ as to be unable to burrow.


1922 ◽  
Vol s5-4 (22) ◽  
pp. 274-294 ◽  
Author(s):  
J. S. Brown
Keyword(s):  

2013 ◽  
Vol 29 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Takuya OKAZAKI ◽  
Wenjing WANG ◽  
Hideki KURAMITZ ◽  
Noriko HATA ◽  
Shigeru TAGUCHI

Author(s):  
Mohamed A. Ashour ◽  
Tawab E. Aly ◽  
Yousra A. Eldegwee

AbstractIn such problematic water situation in Egypt, control and saving of the available limited quantity takes great importance from both technical and national points of view. In addition to all the well-known traditional reasons of the problem such as pollution, over usage, and bad traditions of dealing with water, a new very important reason is added nowadays, called “Climate Changes” which has a direct impact on sea water rising, that causes a serious attack of the salt water to the fresh water especially in River Deltas., Not only the surface water, but also the ground water. Since that process proved some acceleration, several investigations have recently considered the worst impacts of climate change and sea water level rise on sea water intrusion. Most of them have revealed the severity of such problem, and the significance of the land movement of the dispersion zone under the sea water level rise situation. In this paper, we try to introduce a technical review and study for the most popular studies concerning our topic, and its most important conclusions, as an approach for preparing the Ph.D. thesis about the Nile Delta water equilibrium in the light of the expected Mediterranean Sea water level rise. Nile Delta, which located between Damietta Branch on the East, and Rosetta Branch on the west, occupies about 20000 square kilometers of the most rich, productive land in Egypt. About 50% of Egyptian population live in that area, agriculture is the main human activities on them, so water is the prime factor in their life, and their agriculture investments. The great amount of this investment depends on the ground water, which faces a serious challenge due to, two reasons, first, is the overuse, and over pumping, while the second is the attack of the salt water due to the Mediterranean Seawater level rise, because of the climate changes. These two reasons must be overcome, if the first reason can be controlled by law, and technical roles, the second reason needs intensive studies and investigations concerning the interaction between seawater and fresh ground water.


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