scholarly journals The saline Interface of a Shallow Unconfined Aquifer, Rangitikei Delta

2021 ◽  
Author(s):  
◽  
Desiree S A Craig
Keyword(s):  
Salt Marsh ◽  
River Estuary ◽  
Shallow Groundwater ◽  
Cumulative Effect ◽  
High Volume ◽  
Unconfined Aquifer ◽  
Saline Intrusion ◽  
Groundwater System ◽  
The North ◽  
Groundwater Aquifer

<p>The coastal communities of Tangimoana and Scott's Ferry have a long history of using shallow groundwater bores. The cumulative effect of pumping over decades could influence the saline interface given the close proximity of the communities to the seashore and river estuary. It is important to quantify the effects of pumping on both the shallow groundwater system and the dynamics of the saline interface. This is necessary to protect the groundwater system against saline intrusion especially given the increasing number of high volume groundwater consents to support dairying. Resistivity soundings and traverses, coupled with chemical analyses of groundwater samples, were found to be an effective method for defining the saline interface of the shallow groundwater aquifer under the Rangitikei delta. The saline interface extends from the salt marsh to beneath the farmland north of Tangimoana. The interface is a zone of diffusion with freshwater and brackish water mixing from the estuary. The interface is currently located on the outskirts of Tangimoana, and it is likely to extend beneath the township. The infiltration of brackish surface waters into sediments of the salt marsh form a surficial mixing zone that decreases with distance from the salt marsh. There is no indication of salinity in the area to the north of the Rangitikei delta. This area is most at risk of contamination from saline intrusion because of high volume groundwater abstractions, even though these abstractions are from deeper aquifers. The shallow groundwater beneath Tangimoana showed high concentrations of Ca and HCO3 ions. This may be a result of carbonate dissolution, which can occur when saline and freshwater mix. This creates groundwater that is under-saturated with calcium. The mixing water dissolves carbonates and increases the concentrations of Ca and HCO3. The major source of sodium and chloride was likely rainwater with evaporated solutes from seawater. The saline interface near Tangimoana appears to be relatively static, but the estuary and salt marsh are areas of low relief. There are preferential flows paths across the salt marsh to the farmland. These factors make the shallow groundwater in the Rangitikei delta vulnerable to saline intrusion.</p>

scholarly journals The saline Interface of a Shallow Unconfined Aquifer, Rangitikei Delta

2021 ◽  
Author(s):  
◽  
Desiree S A Craig
Keyword(s):  
Salt Marsh ◽  
River Estuary ◽  
Shallow Groundwater ◽  
Cumulative Effect ◽  
High Volume ◽  
Unconfined Aquifer ◽  
Saline Intrusion ◽  
Groundwater System ◽  
The North ◽  
Groundwater Aquifer

<p>The coastal communities of Tangimoana and Scott's Ferry have a long history of using shallow groundwater bores. The cumulative effect of pumping over decades could influence the saline interface given the close proximity of the communities to the seashore and river estuary. It is important to quantify the effects of pumping on both the shallow groundwater system and the dynamics of the saline interface. This is necessary to protect the groundwater system against saline intrusion especially given the increasing number of high volume groundwater consents to support dairying. Resistivity soundings and traverses, coupled with chemical analyses of groundwater samples, were found to be an effective method for defining the saline interface of the shallow groundwater aquifer under the Rangitikei delta. The saline interface extends from the salt marsh to beneath the farmland north of Tangimoana. The interface is a zone of diffusion with freshwater and brackish water mixing from the estuary. The interface is currently located on the outskirts of Tangimoana, and it is likely to extend beneath the township. The infiltration of brackish surface waters into sediments of the salt marsh form a surficial mixing zone that decreases with distance from the salt marsh. There is no indication of salinity in the area to the north of the Rangitikei delta. This area is most at risk of contamination from saline intrusion because of high volume groundwater abstractions, even though these abstractions are from deeper aquifers. The shallow groundwater beneath Tangimoana showed high concentrations of Ca and HCO3 ions. This may be a result of carbonate dissolution, which can occur when saline and freshwater mix. This creates groundwater that is under-saturated with calcium. The mixing water dissolves carbonates and increases the concentrations of Ca and HCO3. The major source of sodium and chloride was likely rainwater with evaporated solutes from seawater. The saline interface near Tangimoana appears to be relatively static, but the estuary and salt marsh are areas of low relief. There are preferential flows paths across the salt marsh to the farmland. These factors make the shallow groundwater in the Rangitikei delta vulnerable to saline intrusion.</p>

scholarly journals Identification Of Unconfined Aquifer Using 3D Resistivity Analysis At Simpang 5 Area, Semarang, Central Java, Indonesia

Warta Geologi ◽  
2020 ◽  
Vol 46 (3) ◽  
pp. 199-203
Author(s):  
Supriyadi Supriyadi ◽  
◽  
Fianti Fianti ◽  
Dwi Rizki R ◽  
Agus Setyawan ◽  
...  
Keyword(s):  
Survey Design ◽  
Living Organism ◽  
Unconfined Aquifer ◽  
The North ◽  
Resistivity Method ◽  
Central Java ◽  
Groundwater Aquifer ◽  
Groundwater Condition ◽  
On Line ◽  
2D And 3D

Water is a unique property of the Earth and very important to every living organism. The existence of groundwater is only 0.61% of the total water on earth (oceans, rivers, lakes, polar ice, rain). The purpose of this research is to determine the location and depth of the aquifer by using 2D and 3D modeling. The method of research is resistivity method using Schlumberger configuration, where data is collected according to the survey design with coordinate ranging from X:436100, Y:9226880 to X:436680, Y:9227640, and covered by 7 lines. The modeling results indicate that the present groundwater aquifer potential has low resistivity distribution in this area. The spreading of unconfined aquifer is estimated on the north side to the east of Simpang 5 area. This can be seen from syncing the data of line one to six. But the data on line seven is of different patterns with other lines. The existence of groundwater basin is not easily identified on this line. This may be due to the location of Line Seven being located in the area of Ciputra Mall, Horison Hotel and Tlogorejo Hospital with higher consumption of water, thus the decrease in groundwater condition. This may cause conditions such as land subsidence. The results of interpretation based on the modeling show the possibility of an unconfined aquifer with groundwater level at 10-15 m depth with varied end of border groundwater depth.

scholarly journals Studi Kerentanan Air Tanah Terhadap Kontaminan Menggunakan Metode Drastic di Kota Pekalongan

Teknik ◽  
2016 ◽  
Vol 37 (1) ◽  
pp. 26
Author(s):  
Thomas Triadi Putranto ◽  
Dian Agus Widiarso ◽  
Fatir Yuslihanu
Keyword(s):  
Hydraulic Conductivity ◽  
Total Population ◽  
Shallow Groundwater ◽  
Groundwater Vulnerability ◽  
Unconfined Aquifer ◽  
Shallow Aquifer ◽  
The North ◽  
Drastic Method ◽  
Dug Wells ◽  
Aquifer Type

Kota Pekalongan berada di Pulau Jawa bagian Utara. Jumlah penduduk kota pekalongan setiap tahunnya mengalami peningkatan. Tahun 2008 jumlah penduduk Kota Pekalongan sebanyak 271.990 jiwa kemudian menjadi 290.347 di Tahun 2012.. Untuk memenuhi kebutuhan air, peduduk Kota Pekalongan menggunakan sumur gali yang menyadap air dari akuifer bebas atau akuifer dangkal. Air tanah bebas sangat rentan terhadap pencemaran akibat pengaruh letaknya yang dangkal dan aktivitas manusia. Oleh sebab itu diperlukan suatu kajian mengenai kerentanan air tanah terhadap kontaminan. Analisis dilakukan denganmenggunakan metode DRASTIC. Metode ini merupakan metode pombobotan berdasarkan beberapa parameter, yaitu: kedalaman muka air tanah (D), jumlah area recharge (R), litologi akuifer (A), jenis media tanah (S), topografi (T), jenis media zona tak jenuh air (I), dan konduktivitas hidrolika (C). Berdasarkan hasil analisis DRASTIC, terdapat tiga tingkat kerentanan yaitu: daerah tingkat kerentanan sedang dengan nilai DRASTIC Indeks (DI) 101-140, daerah tingkat kerentanan tinggi dengan nilai DI 141-180, dan daerah tingkat kerentanan sangat tinggi dengan nilai DI >180.[An Assessment of Groundwater Vulnerability of Contaminant Using DRASTIC Method in Pekalongan City] Pekalongan city which located on the north of Java Island is growing fast, in particular in the population growth. In 2008, total population in Pekalongan city was 271.990 inhabitants increased then up to 290.347 inhabitants in 2012. To fill the water necessary, people in Pekalongan city are using dug wells which are abstracted groundwater from the unconfined aquifer or shallow aquifer. Shallow groundwater can be vulnerabe which are influenced by surface and human activities. Thus, it requires an assessment of the groundwater vulnerability and risk of contaminant. It was analyzed by DRASTIC method. The DRASTIC method is applied by using weighted of some parameters, i.e.: groundwater Depth (D), amount of Recharge (R), Aquifer type (A), Soil type (S), topography (T), Impact of unsatuated zone (I), and hydraulic Conductivity (C). DRASTIC Index (DI) results in three vulnerability levels which are medium with DI 101-140, high with DI around 141-180 and above 180 for high vulnerable of contaminant.

scholarly journals The effect of coal stockpile on shallow groundwater aquifer: Study case Tarahan

2021 ◽  
Vol 882 (1) ◽  
pp. 012034
Author(s):  
M Iqbal ◽  
B A Farishi ◽  
M A A Hassan ◽  
H C Natalia ◽  
D Radityo ◽  
...  
Keyword(s):  
Content Analysis ◽  
Shallow Groundwater ◽  
Quality Standard ◽  
Research Area ◽  
Nitrate Contamination ◽  
Groundwater Levels ◽  
The North ◽  
Groundwater Aquifer ◽  
Chemical Content ◽  
The Impact

Abstract This paper aims to determine the existence of groundwater contamination due to coal stockpile activity in shallow groundwater. The research area is located in a stockpile that has been operating since 1986. We conducted chemical content analysis at several points around the coal stockpile and outside the stockpile area to see the impact of pollution on the surrounding residents’ areas. This study also uses geoelectric methods and direct observations to identify shallow groundwater levels (water table). The research area has a groundwater depth of about 2 m from the surface, and groundwater flows from northeast to southwest (sea). The chemical content analysis results show that each sample taken around the stockpile is below the water quality standard threshold, so it can be concluded that coal stockpile activity does not contaminate the shallow groundwater. However, there is nitrate contamination from shallow groundwater located outside the stockpile area taken from dug wells and drilling wells with a depth of 8 m shows a value of 14.08-23.67 ppm (>10 ppm threshold). We suspect that this pollution is caused by the large number of mining activities carried out in the north of the study area.

Sources of Chlorophenolic Compounds to the Fraser River Estuary

1988 ◽  
Vol 23 (1) ◽  
pp. 55-68 ◽  
Author(s):  
J. H. Carey ◽  
J. H. Hart
Keyword(s):  
River Flow ◽  
River Estuary ◽  
Low Flow ◽  
Fraser River ◽  
Pulp Mills ◽  
Flow Conditions ◽  
Downstream Site ◽  
Upstream Site ◽  
The North ◽  
Main River

Abstract The identity and concentrations of chlorophenolic compounds in the Fraser River estuary were determined under conditions of high and low river flow at three sites: a site upstream from the trifurcation and at downstream sites for each main river arm. Major chlorophenolics present under both flow regimes were 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP), pentachlorophenol (PCP), tetrachloroguaiacol (TeCG) and a compound tentatively identified as 3,4,5-trichloroguaiacol (3,4,5-TCG). Under high flow conditions, concentrations of the guaiacols were higher than any of the Chlorophenols and concentrations of all five chlorophenolics appeared to correlate. Under low flow conditions, concentrations of chloroguaiacols were higher than Chlorophenols at the upstream site and at the downstream site on the Main Arm, whereas at the downstream site on the North Arm, concentrations of 2,3,4,6-TeCP and PCP were higher than the chloroguaiacols in some samples. Overall, the results indicate that pulp mills upstream from the estuary are important sources of chlorophenolics to the estuary under all flow conditions. Additional episodic inputs of 2,3,4,6-TeCP and PCP from lumber mills occur along the North Arm. When these inputs occur, they can cause the concentrations of Chlorophenols in the North Arm to exceed provisional objectives. If chloroguaiacols are included as part of the objective, concentrations of total chlorophenolics in water entering the estuary can approach and exceed these objectives, especially under low flow conditions.

Evolution of groundwater chemistry on shallow aquifer of Yogyakarta City urban area

2015 ◽  
Vol 3 (2) ◽  
Author(s):  
Doni Prakasa Eka Putra
Keyword(s):  
Shallow Groundwater ◽  
Unconfined Aquifer ◽  
Groundwater Chemistry ◽  
Shallow Aquifer ◽  
Nitrate Content ◽  
New Business ◽  
Urban Settlements ◽  
A Minor ◽  
New Settlements ◽  
Yogyakarta City

Since 1980s, accelerated by urbanization, Yogyakarta City was shifting to many directions defined by main road networks and service centres. Urbanization has transformed rural dwellings to become urban settlements and generated urban agglomeration area. Until now, new business centres, education centres and tourism centres are growing hand in hand with new settlements (formal or informal) without proper provision of water supply and sanitation system. This condition increase the possibility of groundwater contamination from urban wastewater and a change of major chemistry of groundwater as shallow unconfined aquifer is lying under Yogyakarta City. To prove the evolution of groundwater chemistry, old data taken on 1980s were comparing with the recent groundwater chemistry data. The evaluation shows that nitrate content of groundwater in 1980s was a minor anion, but nowadays become a major anion, especially in the shallow groundwater in the centre of Yogyakarta City. This evidence shows that there is an evolution of groundwater chemistry in shallow groundwater below Yogyakarta City due to contamination from un-proper on-site sanitation system. Keywords: Urbanization, Yogyakarta city, rural dwellings, settlements, agglomeration, contamination, groundwater

scholarly journals Development of a Practical Model for Predicting Soil Salinity in a Salt Marsh in the Arakawa River Estuary

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2054
Author(s):  
Naoki Kuroda ◽  
Katsuhide Yokoyama ◽  
Tadaharu Ishikawa
Keyword(s):  
Salt Marsh ◽  
Hydraulic Conductivity ◽  
Shallow Water ◽  
Soil Salinity ◽  
River Estuary ◽  
Flow Simulation ◽  
Design Tool ◽  
Water Model ◽  
Shallow Water Model ◽  
Practical Model

Our group has studied the spatiotemporal variation of soil and water salinity in an artificial salt marsh along the Arakawa River estuary and developed a practical model for predicting soil salinity. The salinity of the salt marsh and the water level of a nearby channel were measured once a month for 13 consecutive months. The vertical profile of the soil salinity in the salt marsh was measured once monthly over the same period. A numerical flow simulation adopting the shallow water model faithfully reproduced the salinity variation in the salt marsh. Further, we developed a soil salinity model to estimate the soil salinity in a salt marsh in Arakawa River. The vertical distribution of the soil salinity in the salt marsh was uniform and changed at almost the same time. The hydraulic conductivity of the soil, moreover, was high. The uniform distribution of salinity and high hydraulic conductivity could be explained by the vertical and horizontal transport of salinity through channels burrowed in the soil by organisms. By combining the shallow water model and the soil salinity model, the soil salinity of the salt marsh was well reproduced. The above results suggest that a stable brackish ecotone can be created in an artificial salt marsh using our numerical model as a design tool.

The Origin of Chemical Variations in Groundwaters from a Small Watershed in Southwestern Ontario

1974 ◽  
Vol 11 (7) ◽  
pp. 893-904 ◽  
Author(s):  
Franklin W. Schwartz
Keyword(s):  
Porous Medium ◽  
Cation Exchange ◽  
Unique Feature ◽  
Shallow Groundwater ◽  
Ionic Species ◽  
Small Watershed ◽  
Gas Generation ◽  
Groundwater System ◽  
Creek Watershed ◽  
Pass Through

A very striking and unique feature of the groundwater system within the Upper Kettle Creek watershed is the marked concentration decrease of nearly all ionic species in the direction of flow. The conceptual model proposed here attributes this decrease to selective ion filtration by the Port Stanley till. Ionic constituents generated in the shallow groundwater zone by dissolution of the porous medium either pass through the till or accumulate depending upon their relative mobilities. Other important processes that influence the composition of the groundwaters are cation exchange within the Port Stanley till, CO2 gas generation within the soil zones of recharge areas, and the upward leakage of H2S gas from deeper in the Paleozoic section.

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