scholarly journals Ground-water levels near the top of the water-table mound, western Cape Cod, Massachusetts, 2002-04

2006 ◽  
Author(s):  
Andrew J. Massey ◽  
Carl S. Carlson ◽  
Denis R. LeBlanc
Keyword(s):  
Ground Water ◽  
Water Table ◽  
Water Levels ◽  
Cape Cod ◽  
Western Cape

scholarly journals Hydrogeology of Brahmaputra Basin, India

2003 ◽  
Vol 28 ◽  
Author(s):  
Barendra Purkait
Keyword(s):  
Ground Water ◽  
Water Table ◽  
Land Surface ◽  
Flood Plain ◽  
Water Levels ◽  
The South ◽  
Drainage Pattern ◽  
The North ◽  
The World ◽  
Brahmaputra Basin

The Ganga-Brahmaputra river system together forms one of the largest deltas in the world comprising some 59570 sq km. The waterpower resources of the Brahmaputra have been presumed to be the fourth biggest in the world being 19.83 x 103 m3s1. The entire lower portion of the Brahmaputra consists of a vast network of distributary channels, which are dry in the cold season but are inundated during monsoon. The catchment area of the entire river is about 580,000 sq km, out of which 195,000 sq km lies in India. The maximum discharge as measured at Pandu in 1962 was of the order of 72800 m3 s-1 while the minimum was 1750 m3 s-1 in 1968. The drainage pattern in the valley is of antecedent type while the yazoo drainage pattern is most significant over the composite flood plain to the south of the Brahmaputra. The Brahmaputra valley is covered by Recent alluvium throughout its stretch except a few isolated sedimentary hills in the upper Assam, inselbergs/bornhardt of gneissic hills in the Darrang, Kamrup and Goalpara districts and a few inlying patches of Older Alluvium in the Darrang and Goalpara districts. The basin is very unstable. The present configuration of the basin is the result of uplift and subsidence of the Precambrian crystalline landmasses. Four geotectonic provinces can be delineated in the N-E India through which the Brahmaputra flows. These are bounded by major tectonic lineaments such as the basement E-W trending Dauki fault, a NE-SW trending structural feature of imbricate thrusts known as 'belt of Schuppen' and the NW-SE trending Mishmi thrust. Hydrogeologically, the Brahmaputra basin can be divided into two distinct categories, viz(a) dissected alluvial plain and (b) the inselberg zone. The first category is rep resented in the flood plain extending from the south of Sub-Himalayan piedmont fan zone in the north to right upto the main rock promontory of Garo Hills and Shillong Plateau. The inselberg zone is characterized by fractured, jointed and weathered ancient crystalline rocks with interhill narrow valley plains, consisting of thin to occasionally thick piles of assorted sediments. From the subsurface lithological data, two broad groups of aquifers are identified. These are i) shallow water table and ii) deeper water table or confined ones, separated by a system of aquicludes. The shallow aquifer materials, in general, consist of white to greyish white, fine grained micaceous sand and the thickness ranges from 1.2 to 10.3 m. The sand and clay ratio varies from 1: 2.5 to 1:26. The bedrock occurs at depth ranges of 30.4 to 39.5 m. The materials of the deeper aquifers comprise grey to greyish white, fine to medium grained sand. The sand and clay ratio varies from 1:2 to 1:7. The effective size of the aquifer materials varies from 0.125 to 0.062 mm with uniformity co-efficient around 4.00, porosity 38 to 42%, co-efficient of permeability 304 to 390 galls per day/0.3m2. The ground water is mildly alkaline with pH value 6.5 to 8.5, chloride 10 to 40 ppm, bi-carbonate 50 to 350 ppm, iron content ranges from a fraction of a ppm to 50 ppm. Total dissolved solids are low, hardness as CaCo3 50 to 300 ppm, specific conductance at 25 °C 150 to 650 mhos/cm. The yield from shallow aquifers is 1440 litres to 33750 litres/hour and for deeper aquifers ~ 1700 litres/hour at a drawdown of 13.41 m, specific capacity 21 litres/minute. The temperatures of ground water are 23°-25° C during winter, 24°-26° C during pre-monsoon and 27°- 28° C during peak monsoon. The general hydraulic gradient in the north bank is 1:800 whereas in the south bank it is 1: 300-400 The Tertiary sediments yield a range of water from 200 to 300 l.p.m whereas the yield from the Older Alluvium is 500 to 700 1.p.m. The estimated transmissibility and co-efficient of storage is of the order of ~ 800 1.p.m/ m and 8.2 x 10-3 respectively. Depths to water levels range from 5.3 to 10m below land surface (b.l.s). In the Younger or Newer Alluvium, ground water occurs both under water table and confined conditions. Depths to water levels vary from ground level to 10 m b.l.s. Depth to water ranges from 6 m b.l.s. to 2 m above land surface. The yield of the deep tubewells ranges from 2 to 4 kl/minute for a drawdown of 3 m to 6 m. The transmissibility of the aquifers varies from 69 to 1600 l.p.m/m and the storage co-fficient is of the order of 3.52 x 10-2.

scholarly journals Water Level and the Potentials for Wetland Formation and Sustainability in Lower Ogun River Floodplain, Nigeria

2020 ◽  
Vol 24 (6) ◽  
pp. 1041-1044
Author(s):  
I.A. Ogunyemi ◽  
O. Oguntoke ◽  
C.O. Adeofun
Keyword(s):  
Surface Water ◽  
Ground Water ◽  
Water Table ◽  
Rainy Season ◽  
Soil Depth ◽  
Wetland Management ◽  
Water Levels ◽  
Groundwater Levels ◽  
One Year ◽  
Ogun River

Identification, delineation and monitoring of wetlands which requires the understanding and application of their ecological characteristics are critical factors in wetland management and conservation. This study assessed the potentials of wetland formation and sustainability in the lower Ogun river basin by determining the levels of surface and ground water. The study area was divided into 1 km2 grids of 67 units using 0.052 %  sampling intensity for the assessments in dry and wet seasons. Monthly water table levels were assessed in 50 cm soil pit while inundation levels were measured during the flooding event using staff gauge. Assessment was carried out for one year during which frequency and periodicity of water table and inundation events were recorded. Results revealed that low water table level ranged from 5 to 45cm of soil depth and occurred between August and September within 6 grids. Water table and surface water was recorded within a period of 2 – 10 weeks during the rainy season. The peak of water levels coincided with the peak of precipitation (> 200 mm) ranging from 30 to 280 cm between September and October while covering 28.75 km2. Conclusively, surface and groundwater levels were recorded during the rainy season having direct variation with the volume of  precipitation for a duration that is long enough to support the formation of wetland hydrophytes and hydric soil. Keywords: Wetlands; Hydrology; Ground water; Surface water; Inundation; Precipitation

scholarly journals ANALYSES OF WATER TABLE DEPTHS VARIATIONS IN AN OUTCROP AREA OF THE GUARANI AQUIFER SYSTEM IN BROTAS/SP-BRAZIL

Irriga ◽  
2015 ◽  
Vol 1 (1) ◽  
pp. 186-197
Author(s):  
Rodrigo Lilla Manzione ◽  
Bruna Camargo Soldera ◽  
Claudiane Otilia Paes ◽  
Edson Wendland
Keyword(s):  
Ground Water ◽  
Water Table ◽  
Sao Paulo ◽  
Water Levels ◽  
São Paulo ◽  
State University ◽  
Aquifer System ◽  
Paulo State ◽  
Guarani Aquifer ◽  
São Paulo State

ANALYSES OF WATER TABLE DEPTHS VARIATIONS IN AN OUTCROP AREA OF THE GUARANI AQUIFER SYSTEM IN BROTAS/SP-BRAZIL  RODRIGO LILLA MANZIONE 1; BRUNA CAMARGO SOLDERA 2; CLAUDIANE OTILIA PAES 3 E EDSON WENDLAND 4 1 UNESP/OURINHOS – São Paulo State University, Ourinhos, SP, Brazil. Email: [email protected] UNESP/FCA – São Paulo State University, Botucatu, SP, Brazil. Email: [email protected] UNESP/FCA – São Paulo State University, Botucatu, SP, Brazil. Email: [email protected] Department of Hydraulics and Sanitation – USP/EESC – University of São Paulo, São Carlos, SP, Brazil. Email: [email protected]  1 ABSTRACT Several factors may influence variations in ground water levels. Some of these factors present static behavior while others present dynamic changes over time. The differences in management operations in agricultural sites, plant development and agricultural practices have direct impact on the unsaturated zone, as the levels of recharge and water tables can respond differently due to local conditions.  Different information sources may be used and integrated in a statistical model to reveal the responses of ground water levels under certain conditions.  Understanding these processes involves meeting a way of representing correlated variables together to form a new and smaller set of derived variables with minimum loss of information, removing redundancy or duplication.  The objective of this study was to analyze the variations in water table depths using information from a groundwater monitoring network     in an outcrop area of the Guarani Aquifer System (GAS) in Brotas, São Paulo, Brazil, associated with soil, vegetation and  terrain variables,  which possibly influence the  groundwater dynamics.   A factorial analysis was applied to identify the underlying factors which would   explain    this pattern of correlation   within these sets of   study variables.  The main factors influencing the variations in   water table over the monitoring period were as follows:  sand particle size, terrain   attributes, soil texture, soil and crop management and vegetation. This methodology can be useful for groundwater management, policy making and regulation of soil use in watersheds, and regional studies, for example, maximizing information in data analysis. Keywords: factorial analysis, statistical modeling, recharge, Brazil  MANZIONE, R.L.; SOLDERA, B.C.; PAES, C.O.; WENDLAND, E.ANÁLISES DAS VARIAÇÕES DOS NÍVEIS FREÁTICOS EM UMA ÁREA DE AFLORAMENTO DO SISTEMA AQUÍFERO GUARANI EM BROTAS/SP-BRASIL  2 RESUMO Diversos fatores influenciam as variações de níveis freáticos. Alguns desses fatores apresentam comportamento estático enquanto outros apresentam mudanças dinâmicas ao longo do tempo. As diferenças nas operações de manejo do solo em áreas agrícolas, desenvolvimento de plantas e práticas agrícolas tem impactos diretos na zona não saturada uma vez que os níveis de recarga e lençóis freáticos podem responder a condições locais. Diferentes fontes de informação podem ser usadas e integradas em um modelo estatístico para revelar a resposta dos níveos de águas subterrâneas sob certas condições. Entender esses processos envolve encontrar uma maneira de representar variáveis correlacionadas juntas para formar um novo e menor conjunto de variáveis derivadas com uma perda mínima de informação, removendo redundâncias ou duplicações. O objetivo desse estudo foi analisar as variações dos níveis freáticos usando informações de uma rede de monitoramento de águas subterrâneas em uma área de afloramento do Sistema Aquífero Guarani (SAG) em Brotas, São Paulo, Brasil associadas a variáveis de solo, vegetação e terreno que possivelmente influenciem a dinâmica das águas subterrâneas. Foi aplicada a análise fatorial para identificar fatores que expliquem o padrão de correlação entre esse conjunto de variáveis observadas. Os principais fatores influenciando a variação dos níveis freáticos durante o período monitorado foi o tamanho da fração areia, atributos de terreno, textura do solo, manejo dos solos e culturas e vegetação. Essa metodologia pode ser útil para a gestão das águas subterrâneas, formulação de políticas e regulação do uso do solo em bacias hidrográficas e estudos regionais, por exemplo, maximizando as informações na análise de dados. Palavras-chave: análise fatorial, modelagem estatística, recarga, Brasil

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