scholarly journals Delineate Subsurface and Groundwater Investigation of Ongur Watershed, South India

2020 ◽  
Vol 2 (1) ◽  
pp. 17-33 ◽  
Author(s):  
Vinodh K ◽  
Senthilkumar S ◽  
Gowtham B ◽  
Srinivasamoorthy K
Keyword(s):  
Tamil Nadu ◽  
South India ◽  
Electrode Array ◽  
Geological Structure ◽  
Fresh Groundwater ◽  
Current Electrode ◽  
Potential Electrode ◽  
Electrical Sounding ◽  
Resistivity Meter ◽  
Schlumberger Array

The electrical resistivity technique is extremely supportive to investigate the nature of subsurface lithology by understand the variations in their electrical properties. The Vertical Electrical Sounding (VES) technique by Schlumberger electrode array applied in 77 Locations at Ongur River Sub Basin in Tamil Nadu, India. The Signal stacking Resistivity Meter Model SSR-MP-ATS has been applied to gather the VES data by employed a Schlumberger array, one end current electrode (AB/2) ranging from 1 to 100 m, other side placing potential electrode (MN) from 0.5 to 10 m. The concept of the VES data interpreting is the foundation of IPI2Win. It means for a VES data are treated as a unity representing the geological structure of the Ongur River watershed. The output Geo-electrical layers, iso- resistivities and thickness of this area were prepared in spatial maps by using ARCGIS software. Consequently, the following zones with different resistivity values are detected consequent to different formations: (1) identification of lithology Ongur River Sub Basin, (2) layer saturated with fresh groundwater, (3) determine saltwater horizon.

Assessment of Leachate Contamination of Groundwater at Some Waste Disposal Sites in the Southern Guinea Savannah Ecological Zone of Nigeria Using Geoelectric Processes

2021 ◽  
Vol 47 (2) ◽  
pp. 383-392
Author(s):  
M.E. Omale ◽  
E.E. Udensi ◽  
J.J. Musa
Keyword(s):  
Ionic Concentration ◽  
Contaminant Plume ◽  
High Concentration ◽  
Current Electrode ◽  
Contaminant Plumes ◽  
Active Structures ◽  
Electrode Separation ◽  
Profile Line ◽  
Potential Electrode ◽  
Electrical Sounding

This study aims at determining the leachate contamination of the groundwater resource at selected domestic wastes disposal sites in Minna, Nigeria for a population about 2.1 million, to locate aquifers and hydraulically active structures by tracing the movement of contaminant plumes and seepages in ground at the selected locations. Resistivity data was collected using a terrameter (SAS4000) while the Vertical Electrical Sounding (VES) mode was deployed using the Schlumberger array to enable investigation of the depth penetration of contaminant plume. The induced polarization (IP) was used to determine the level of contaminant plume. The VES readings measured at 50m intervals along each profile line and 100m inter-profile distance, with a maximum current electrode separation of 200m and potential electrode separation of 30m. There are equal numbers of three and four layers observed on the profile, which has ten VES points. The first layer has a resistivity range between 48.4 Ωm & 428 Ωm and thickness between 0.65m & 3.83m. However, isolated resistivity area such as VES; N5 (287Ωm), N6 (295Ωm) and N8 (428Ωm) also suggested sandy/soil rich in organic matter (humus material/soil). The second and third layer is the fractured basement which has very low resistivity values for most VES (N1–48.5Ωm, N2–38.7Ωm, N3–41.6Ωm, N5–61.5Ωm, N7–49.6Ωm, N8–60.7Ωm, N9–108Ωm and N10–97.6Ωm) that indicated leachate presence and contamination, which results from increased ionic concentration. In conclusion, it was discovered that the study area had high conductivity values for some of the locations using the resitivity determination method. This indicated the presence of water within the study area. It was also concluded that the IP which indicated high concentration of metals caused the lowering of the resisitivity values at some of the locations, thus indicating the presence of metals within the study area.

scholarly journals Groundwater Prospecting Using Combined Vertical Electrical Sounding and Borehole Performance

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
S.O Oyegoke ◽  
A.S Adebanjo ◽  
O.O Fayomi ◽  
O. Obot
Keyword(s):  
Specific Capacity ◽  
Electrode Array ◽  
Data Interpretation ◽  
Pumping Test ◽  
Vertical Electrical Sounding ◽  
Computer Assisted ◽  
Current Electrode ◽  
Top Soil ◽  
Weathered Layer ◽  
Electrical Sounding

This study aimed to determine the prospect of groundwater in Afe Babalola University, Ado-Ekiti(ABUAD); result of which will inform of the possibility of getting sufficient water underground. Geophysical survey was carried out in the study area and complemented with performance of an existing borehole. The survey involved 1-D Vertical Electrical Sounding (VES) utilizing the Schlumberger electrode array with half-current electrode separation (AB/2) that ranged from 1m to 50m. The VES data interpretation involved partial curve matching and computer assisted 1-D forward modeling using IPI 2 WIN software. The results showed the subsurface to have 3-layer earth strata comprising of sandy-clay top soil up to 3.26m deep, weathered/fractured basement in the next 9.06m depth and then, the fresh basement with the weathered layer constituting the main aquifer unit. The resistivity values of the weathered and fractured basement are 174 and 192 ohmm indicating relatively low potential for groundwater resource. Pumping test on a nearby borehole gave specific capacity of 7.95m2/day which depicts a low to intermediate transmissivity conforming to the VES.

scholarly journals Geoelectrical Investigation of Subsurface Structures for Mapping Groundwater Potential of Joseph Ayo Babalola University Campus Environment, Ikeji Arakeji, Osun State, Southwestern Nigeria

2019 ◽  
pp. 1-12
Author(s):  
O. E. Odeyemi ◽  
O. M. Odeyemi ◽  
S. A. Owolabi ◽  
E. A. Mamukuyomi ◽  
R. A. Salako
Keyword(s):  
Electrode Array ◽  
Groundwater Potential ◽  
Vertical Electrical Sounding ◽  
Electrode Spacing ◽  
Clayey Sand ◽  
Southwestern Nigeria ◽  
Current Electrode ◽  
Campus Environment ◽  
Lateritic Clay ◽  
Electrical Sounding

Owing to fast increase in number of staff and students of Joseph Ayo Babalola University, Ikeji Arakeji, Southwestern Nigeria, it is therefore very important to carry out this research in order to recommend the actual locations where boreholes can be sunk for good potential yields of groundwater when the time comes. The aim of this research is to carry out vertical electrical sounding geophysical survey at study area with a view to determining good aquifers that are good for the accumulation of groundwater. The study area is located between latitude 0820225 m to 0820345 m (UTM) Northings and longitude 717320 m to 717450 m (UTM) Eastings. Schlumberger electrode array was employed for the study using Ohmega Resistivity meter for the data acquisition. The geoelectric survey of the study area comprised of twelve vertical electrical soundings, with maximum current electrode spacing (AB) of 100 m. The modeled curves are mainly KH-type. The geoelectric sections generated from the sounding curves revealed 4 major layers earth models. The topsoil is made up of clay, clayey sand/lateritic sand with resistivity and thicknesses varying from 54.7 – 210.1ohm-m and 0.2 –0.8m respectively. The second layer is the lateritic clay with resistivities and thicknesses varying from 334 – 963ohm-m and 1.5 – 10.8m respectively. The third layer constitutes the clay / sandy fractured quartzite and it serves as the aquifer unit. The resistivity values lie between 71.7 and 498 ohm-m while the thicknesses vary from 2.1 – 76.3 m. The fourth layer is the fractured/presumably fresh basement bedrock with the resistivity varying from 1879 – 13991.8 ohm-m. Areas characterized with fractured basement of low resistivity with appreciable thickness are therefore recommended for the siting of boreholes. It is concluded that the vertical electrical sounding points of the study area are good aquifers for groundwater accumulation.

Geophysical Survey as a Surface Tool in Groundwater Exploration in Delta North District, Nigeria

2011 ◽  
Vol 367 ◽  
pp. 795-800
Author(s):  
F.O. Ezomo ◽  
C.N. Akujieze
Keyword(s):  
Research Work ◽  
Electrode Array ◽  
Water Shortage ◽  
Groundwater Exploration ◽  
Geophysical Survey ◽  
Vertical Electrical Sounding ◽  
Electrode Spacing ◽  
Current Electrode ◽  
Resistivity Method ◽  
Electrical Sounding

Geophysical survey based on electrical resistivity method employing the techniques of vertical electrical sounding (VES) was carried out in order to investigate Groundwater existence in Delta North District, of Nigeria. This research work became necessary in order to solve the problem of acute water shortage in the area by way of prospecting or searching for additional aquifers which would subsidize the existing one, domestically, industrially and agriculturally. Ten (10) vertical electrical sounding (VES) (uniformly distributed) tests were conducted in the area and its environs using “Schlumberger” electrode array. The VES were carried out with half current electrode spacing with the spread Im-928m at six (06) points per decade. The results of the interpretation identified wet sand/clean sand as perched aquifer which can deliver ground water to the bore-hole at perceptible rates between depths of 85m to 145m below sea level. The resistivity of the aquifer detected varied from 95.0 ohm-m to 110,000 ohm-m while the thickness ranged from 30.0m to 105.0m.

Synthetic electric sounding surveys over known oil fields

Geophysics ◽  
1984 ◽  
Vol 49 (11) ◽  
pp. 1959-1967 ◽  
Author(s):  
N. R. Garg ◽  
G. V. Keller
Keyword(s):  
Apparent Resistivity ◽  
Contrast Ratio ◽  
Electrode Array ◽  
Oil Field ◽  
Oil Fields ◽  
Current Electrode ◽  
Transverse Resistance ◽  
Order Of Magnitude ◽  
Electrical Sounding ◽  
Bearing Layer

The possibility of using various types of electrical methods to locate oil or gas fields has been proposed in recent years. In an effort to quantify the anomaly to be expected with electrical sounding methods, average geoelectrical parameters have been determined by studying electrical well logs from several oil fields characterized by different geoelectrical sections. The dc resistivity anomaly due to the presence of an oil‐bearing layer at depth depends upon the sequence of resistivities above and below and the electrode array employed. The radial dipole array gives the largest anomaly values, and is followed by other arrays such as the Schlumberger and Wenner arrays. The maximum anomaly in apparent resistivity is observed when the resistivity beneath the target zone is lower than that above; the relative anomaly in apparent resistivity is almost the same as the contrast ratio of the transverse resistance of the oil‐bearing layer to the overlying beds. When the radial dipole array is used, a limited areal extent of the oil‐bearing layer does not cause a significant change from the anomaly value due to a layer of infinite lateral extent. In that case the least dimension is about four times the depth. Use of one buried current electrode in the vicinity of the oil‐bearing layer increases the amplitude of the anomaly; the maximum anomaly appears at a separation comparable to the depth. Typical anomalies in apparent resistivity caused by these oil fields range from less than 0.1 percent to more than 10 percent. Such anomalies would be detectable only with an order of magnitude improvement in the capabilities of electrical sounding methods, or with considerably larger oil field targets.

scholarly journals Lecanicillium lecanii (Zimmermann) Zare & Gams, as an efficient biocontrol agent of tea thrips, Scirtothrips bispinosus Bagnall (Thysanoptera: Thripidae)

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Mariappan Sankara Rama Subramaniam ◽  
Azariah Babu ◽  
Bhabesh Deka
Keyword(s):  
Tamil Nadu ◽  
South India ◽  
Biocontrol Agent ◽  
Uv Light ◽  
Biological Control Agents ◽  
Optimum Conditions ◽  
Lecanicillium Lecanii ◽  
Wettable Powder ◽  
Label Claim ◽  
Yeast Powder

Abstract Background Continuous and non-judicial application of synthetic insecticides to control the tea thrips, Scirtothrips bispinosus (Bagnall), one of the major tea pests in South India has led to certain undesirable issues in the ecosystem besides the presence of the pesticide residues in manufactured tea. Biological control agents are of immense importance in tea cultivation. The present study was designed to isolate Lecanicillium lecanii (Zimmermann) Zare & Gama from the field-collected cadavers of the insects/mites infected by fungi of tea growing areas of Anamallais (Tamil Nadu, South India), and to evaluate their field bio-efficacy against the tea thrips. Results Lecanicillium lecanii isolated from the tea ecosystem had been formulated into a wettable powder (WP) formulation and evaluated against tea thrips under both laboratory and field conditions. Among the several media evaluated, the PDAY (Potato Dextrose Agar + 1% Yeast powder) was found to be the best suitable medium for the growth and germination of spores. Optimum conditions for the growth of L. lecanii were found in PDAY medium at the pH 6-7, temperature 25-30°C and 90-95% RH. Exposure to UV light for more than 30 min significantly inhibited the growth of the fungus. Lecanicillium lecanii at (1 × 107 spore/ha) was found significantly effective against thrips. Fungal development index (FDI) of L. lecanii + jaggery significantly differed than other treatments. Lecanicillium lecanii at 1500g (1×107 conidia/ml) mixed in 400 l of water was effective against the tea thrips. Addition of equal amount of jaggery with L. lecanii wettable powder in the tank mixture could increase the efficacy of the mycopesticide against tea thrips. Conclusion The powder formulation of L. lecanii was found safer to natural enemies present in the tea ecosystem. After fulfilling the requirements for its registration and label claim on tea, this strain of L. lecanii could be commercialized for the benefit of the tea industry for the management of tea thrips in an eco-friendly manner.

Representing Disasters and Long-term Recovery – Insights from Tamil Nadu

2021 ◽  
Author(s):  
Chandni Singh ◽  
Mark Tebboth ◽  
Jasmitha Arvind ◽  
Yashodara Udupa
Keyword(s):  
Tamil Nadu ◽  
Shape Recovery ◽  
South India ◽  
State Policies ◽  
Indian Ocean Tsunami ◽  
Recovery Processes ◽  
Disaster Impacts ◽  
Chennai City ◽  
Post Disaster

This study focuses on disaster impacts and recovery in Tamil Nadu, drawing on insights from Chennai city and Nagapattinam district. The research is part of a larger three-year project called “Recovery with Dignity”, which examines the experiences of recovery in post-disaster situations across three states in India – Odisha, Tamil Nadu, and Kerala – and explores how recovery processes represent vulnerable populations. In this report, we focus on three key disasters in Tamil Nadu: the 2004 Indian Ocean Tsunami, the 2015 South India flood, and the 2018 Cyclone Gaja. Through these events, we examine how the ways disasters and their losses are represented shape recovery outcomes. The study uses a range of data, from a review of state policies in Tamil Nadu (2005-2019), an analysis of media articles published in English and Tamil (2004-2019), to interviews with disaster-affected people and secondary stakeholders. The findings indicate that disaster responses and outcomes are highly differentiated based on how disaster-affected people and their needs and losses are represented. To enable inclusive recovery, it is necessary to recognising the heterogenous nature of disaster impacts and acknowledge different ideas of what recovery means.

Sign in / Sign up

Export Citation Format

Share Document