Development of a conceptual groundwater model for a complex basement aquifer system: The case OF OSUN drainage basin in southwestern Nigeria

2019 ◽  
Vol 159 ◽  
pp. 103574 ◽  
Author(s):  
A.S. Akinwumiju ◽  
M.O. Olorunfemi
Keyword(s):  
Drainage Basin ◽  
Groundwater Model ◽  
Southwestern Nigeria ◽  
Aquifer System

Groundwater budget deficit caused by drought and overexploitation

2019 ◽  
Vol 20 (2) ◽  
pp. 621-632
Author(s):  
Mahdi Soleimani-Motlagh ◽  
Hoda Ghasemieh ◽  
Ali Talebi ◽  
Khodayar Abdollahi ◽  
Walter Dragoni
Keyword(s):  
Budget Deficit ◽  
Unconfined Aquifer ◽  
Groundwater Model ◽  
Aquifer System ◽  
Relative Contribution ◽  
Model Predictions ◽  
The World ◽  
Groundwater Overexploitation ◽  
Groundwater Budget ◽  
Semi Arid

Abstract Groundwater is generally influenced by overexploitation and climatic stresses particularly in arid and semi-arid areas of the world. The present research was conducted to identify the relative contribution of drought and overexploitation to groundwater budget deficit in an unconfined aquifer system. In order to simulate groundwater, the simulated recharge from WetSpass-M model was applied in the MODFLOW model along with other required packages. Moreover, the groundwater budget deficit caused by stressors was quantified through the use of calibrated groundwater model predictions. In order to better understand how the stressors affect the groundwater deficit, the aquifer was divided into Clusters 1, 2, and 3. Locally, the results showed that the contribution of stressors to groundwater budget deficit was the highest in Cluster 1 due to the groundwater overexploitation and quick reaction of the groundwater level to the droughts. Overall, this research showed that both drought and overexploitation, with an average of 2.44 and 3.32 million cubic meters, respectively, played a significant role in groundwater storage deficit. Furthermore, the effect of groundwater overexploitation was approximately 36% more than droughts.

COASTAL AQUIFER GROUNDWATER MODELING IN THE SOUTHERN PART OF YOGYAKARTA AREA, INDONESIA

2015 ◽  
Vol 4 (1) ◽  
Author(s):  
Doung Rata ◽  
Doni Prakasa Eka Putra ◽  
Heru Hendrayana
Keyword(s):  
Coastal Aquifer ◽  
Groundwater Modeling ◽  
Groundwater Resources ◽  
Total Surface Area ◽  
Research Area ◽  
Unconfined Aquifer ◽  
Groundwater Table ◽  
Groundwater Model ◽  
The South ◽  
Aquifer System

Parangtritis beach, located in a coastal aquifer at the southern part of Yogyakarta Province, Indonesia is bounded by the Indian Ocean at the South, Opak River at the West, and Tertiary Limestone Rock to the East. Local land-use is predominantly agriculture, rice fields and settlements and the population is estimated to be 9,386 persons as per the 2012 census. The total surface area is estimated at 9.46 km2. The aims of this research were to understand the system of groundwater and to assess and predict saltwater intrusion by conducting a numerical groundwater model. Hydrological and hydrogeological data were collected directly from the field and from previous work for input into the model. The model simulates an unconfined aquifer system where the aquifer thickness varies from 30-40 meters. The material of the aquifer consists of sand varying from fine to coarse grain size and fine gravel with hydraulic conductivity values of 8.974 × 10−4, 1.794 × 10−3, and 1.337 × 10−3 m/s at the northern, central, and southern part of the research area, respectively. The maximum length of the saltwater interface was estimated at about 205.1 m laterally and 40 m vertically relative to the location of the groundwater table around 1m above sea level. Direction of groundwater flow is from north to south. Groundwater table elevation equals 5 m at the north and 0 m at the south with a hydraulic gradient estimated at about 2.45 × 10−3. As a result of a steady-state simulation as well as two cases of prediction for five and ten years in the future, it is determined that that the salinity of the surrounding environment is not potentially adverse to the groundwater quality in the study area. This is in part due to low population in this area and abundant groundwater resources, as well as the results of the groundwater model. Keywords: Coastal aquifer, numerical groundwater model, conceptual model, observed heads

scholarly journals Mapped Fractures and Sinkholes in the Coastal Plain of Florida and Georgia to Infer Environmental Impacts from Aquifer Storage and Recovery (ASR) and Supply Wells in the Regional Karst Floridan Aquifer System

2016 ◽  
Vol 8 (2) ◽  
pp. 76 ◽  
Author(s):  
Wenjing Xu ◽  
Sergio Bernardes ◽  
Sydney T. Bacchus ◽  
Marguerite Madden
Keyword(s):  
Ground Water ◽  
Environmental Impacts ◽  
Coastal Plain ◽  
Preferential Flow ◽  
River Basins ◽  
Groundwater Model ◽  
Aquifer System ◽  
Flow Through ◽  
Dougherty County ◽  
Regional Aquifer

The regional Floridan aquifer system (FAS) extends from the submerged carbonate platform of the Atlantic Ocean, Gulf of Mexico, and Straits of Florida in the southeastern United States (US), throughout Florida and the coastal plain of Alabama, Georgia, and South Carolina. This carbonate aquifer system is characterized by bedding planes, fractures, dissolution cavities, and other karst features that result in preferential flow of ground water, particularly in response to anthropogenic perturbations such as groundwater withdrawals and aquifer injections. The FAS was divided into six sub-regions for groundwater-modeling purposes in 1989, with results concluding that breaches of those groundwater divides had occurred and those breaches were attributed to large withdrawals of ground water in the US southeastern coastal plain. Those results suggest the model did not elucidate preferential flow conditions through fractures and other karst conduits. We hypothesized that incorporating fractures and sinkholes into groundwater models could improve results and predict adverse impacts to environmentally sensitive areas. We analyzed extensive fracture networks and sinkholes previously mapped throughout Florida and in Dougherty County, Georgia. Some of those fractures extend from one sub-region into an adjacent sub-region of the FAS and may be facilitating the breaching of groundwater divides described in the 1989 groundwater model for this regional aquifer system. The greater total fractures and fracture density in Dougherty County (1,225 and 141.3/100 km2, respectively) compared to 21 north-Florida counties (10-91fractures per county and 0.6-3.8/100 km2, respectively) presumably is due to the scale of fracture mapping and shorter mean lengths of mapped fractures in Dougherty County (1.2 km), compared to north Florida counties (26-118 km), rather than to orders of magnitude increases in fracture densities in that part of the FAS. The number of sinkholes identified in Dougherty County in a recent, unrelated project using 2011 Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images, was approximately an order of magnitude greater than the number of sinkholes mapped in analog form in that county and published in 1986. Extension of the dense network of those fractures that occurred within the boundaries of a Priority Amphibian and Reptile Conservation Area (PARCA) that encompassed Dougherty County covered the Elmodel Wildlife Management Area (WMA) and ASR demonstration well in Baker County, Georgia. Those extensions also passed through numerous agricultural areas with center-pivot irrigation wells in southwest Georgia; intersected other Georgia PARCAs near the Florida-Georgia state line; and clumped in two areas of dense sinkhole clusters in northwest Florida. No determination has been made regarding the contributions of pirated water from the Apalachicola-Chattahoochee-Flint (ACF) River Basins and Wakulla Springshed from the magnitude and extent of agricultural, municipal, and industrial groundwater withdrawals in Georgia’s coastal plain, that exceed groundwater withdrawals in Florida for that area of the FAS, to the increase in sinkholes in Dougherty County and the dense clusters of sinkholes in northwest Florida, via preferential flow through fractures. Similarly, the survival and recovery of at least 24 animal species in Georgia that are either federally listed or high-priority state species may be jeopardized by adverse direct, indirect, and cumulative impacts from preferential flow through fractures, sinkholes, and other karst conduits in response to aquifer injections and withdrawals that have not been evaluated. Currently no regional groundwater model has been constructed to evaluate such preferential groundwater flow in the FAS. A model incorporating preferential flow via mapped fractures and sinkholes is essential to determine the magnitude and extent of environmental impacts from ASR wells and other supply and disposal wells in this regional aquifer system, such as pirated water from the ACF and other river basins, alterations in submarine groundwater discharge to Apalachicola Bay and other coastal areas, saltwater intrusion, upconing of saline ground water and resulting impacts to federally endangered and threatened species and high-priority state species.

scholarly journals PENGELOLAAN AIR TANAH DAN INTRUSI AIR LAUT

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Arie Herlambang ◽  
Robertus Haryoto Indriatmoko
Keyword(s):  
Fresh Water ◽  
Sea Water ◽  
Model Simulation ◽  
Groundwater Resources ◽  
Three Dimensions ◽  
Three Dimension ◽  
Groundwater Model ◽  
Confined Aquifer ◽  
Aquifer System ◽  
Simulation And Optimization

Coastal Aquifer System of Jakarta consist of unconfined aquifer layers, confined aquifer I and  confined aquifer II.  Resources of  groundwater is very important for Jakarta City, for drinking water, industry, hotel, government offices and various other facility. Important considering of    groundwater resources of Jakarta hence needed an effort to preserve the groundwater and awake its continuity by conducting a system management of groundwater. Model used for the management of groundwater system of aquifer coastal referred as Groundwater Model Simulation and Optimization of Quasi Three Dimension ( OPT-Q3D). Model simulation and optimization represent computer model of quasi-three dimensions with method of finite difference used for the operation of infiltration of sea water. This model can conduct current simulation of groundwater flow, head of fresh water and brine, and describe the movement of interface fresh water and sea water. The model can also make optimization of system aquifer with single or multi layers.  Jakarta Groundwater Basin assumed consist three layers of aquifer separated by impermeable layer. Applying of groundwater simulation model in Jakarta can give information regarding balance of groundwater, head of freshwater, head of  brine, interface brine and freshwater, map of brine distribution and bargain in each; every aquifer. Herein after model optimization will yield various information able to wear upon which consideration to manage the amount of pumping of optimal ground water every area in each layer of aquifer, amount of optimal pumping, optimal freshwater head, head of optimal brine and map of infiltration.  Kata Kunci  : Air Tanah, Pengelolaan, Intrusi Air Laut, Modeling

scholarly journals Morphometric Analyses of Osun Drainage Basin, Southwestern Nigeria

2016 ◽  
Vol 8 (4) ◽  
pp. 9 ◽  
Author(s):  
Akinwumiju A. S. ◽  
Olorunfemi M. O.
Keyword(s):  
Overland Flow ◽  
Drainage Basin ◽  
Drainage Density ◽  
Main Stream ◽  
Stream Length ◽  
Southwestern Nigeria ◽  
Stream Frequency ◽  
Morphometric Analyses ◽  
Drainage Channels ◽  
Drainage Texture

This study evaluated some morphometric parameters with a view to assessing the infiltration potential of Osun Drainage Basin (ODB), Southwestern Nigeria. Input data were derived from SPOT DEM using ArcGIS 10.3 platform. ODB has an area extent of 2,208.18 km2, and is drained by 1,560 streams with total length of 2,487.7 km. The Relief Ratio (5.6) suggests that ODB is characterized by topographic high and topographic low. Thus, infiltration potential would be low as surface runoff would have less time to infiltrate before entering the drainage channels. The computed values of Drainage Texture (0.52), Stream Number (1,560), Total Stream Length (2,487.7 m) and Main Stream Length (119 m) indicate that larger percentage of annual rainwater would leave ODB as river discharge. Stream Frequency, Basin Perimeter, Length of Overland Flow and Drainage Density influence Infiltration Number across the basin. Infiltration Number increases with increasing Stream Frequency (r = 0.95) and Drainage Density (r = 0.78); and Length of Overland Flow increases with decreasing Drainage Density (r = -0.83), Stream Frequency (r = -0.51) and Infiltration Number (r = -0.45). The study concluded that basin’s infiltration potential is moderate as suggested by the mean Infiltration Number.

scholarly journals A groundwater model of the Nubian aquifer system

1989 ◽  
Vol 34 (4) ◽  
pp. 425-447 ◽  
Author(s):  
MANFRED HEINL ◽  
PAUL J. BRINKMANN
Keyword(s):  
Groundwater Model ◽  
Aquifer System ◽  
Nubian Aquifer ◽  
Nubian Aquifer System

scholarly journals Assessment of Gold Mining Impact on the Vegetation of Itagunmodi-Igun Drainage Basin, Southwestern Nigeria from 1972–2011: A Remote Sensing

2021 ◽  
Vol 4 ◽  
pp. 1-6
Author(s):  
Olawale Oluwafemi ◽  
Akinola Akinwumiju ◽  
Oluseyi Oladepo ◽  
Daniel Oladepo
Keyword(s):  
Remote Sensing ◽  
Vegetation Cover ◽  
Input Data ◽  
Gold Mining ◽  
Vegetation Index ◽  
Drainage Basin ◽  
Southwestern Nigeria ◽  
Artisanal Mining ◽  
Mining Impact ◽  
Landsat 7

Abstract. A GIS-based Normalized Differential Vegetation Index (NDVI) was analyzed using space-based data between 1972 and 2011 as Input data. The result of the NDVI using Landsat 7 ETM+ shows clearly that the values range from 0.19 to −0.31. Mountains and highlands of the Itagunmodi-Igun area revealed stressed vegetation cover between 0.11 to −0.31. The NDVI was also performed on Landsat imageries of four different epoch: 1972, 1986, 2000, and 2010. Results showed that vegetation index ranged from −0.105 to 0.033, −0.25 to 0.480, −0.313 to 0.19 and −0.29 to 0.5 in 1972, 1986, 2000 and 2010 respectively. The analysis revealed that the study area experienced an increase in biomass between 1972 and 1986 but with some areas experiencing outright disappearance of vegetation as indicated by the lower bands of index values in 1972 (−0.105) and 1986 (−0.25). The result showed that the Basin experienced a rapid and significant increase in biomass between 2000 and 2010, as indicated by the lower bands of index values in 2000 (−0.291) and 2010 (0.5). The results of the NDVI in 1972 ranged from −0.105 to 0.033 while NDVI in 1986 ranged from −0.25 to 0.480 which indicated a significant increase in the vegetation index. The results of the NDVI in 2000 ranged from 0.291 to 0.5 also indicated a significant increase in the vegetation index. The study concluded that artisanal mining could cause land and vegetation degradation with consequent loss of biodiversity, ecological modification.

scholarly journals Irrigation-Intensive Groundwater Modeling of Complex Aquifer Systems Through Integration of Big Geological Data

2021 ◽  
Vol 3 ◽  
Author(s):  
Hamid Vahdat-Aboueshagh ◽  
Frank T.-C. Tsai ◽  
Dependra Bhatta ◽  
Krishna P. Paudel
Keyword(s):  
Groundwater Modeling ◽  
Flow Direction ◽  
Well Log ◽  
Vertical Flow ◽  
Groundwater Model ◽  
Entire Region ◽  
Groundwater Storage ◽  
Aquifer System ◽  
Fine Grained ◽  
Aquifer Systems

This study identifies hydrogeologic characteristics of complex aquifers based on constructing stratigraphic structure with large, non-uniform well log data. The approach was validated through a modeling study of the irrigation-intensive Chicot aquifer system, which is an important Pleistocene-Holocene aquifer of the Coastal Lowlands aquifer system in the southwestern Louisiana. Various well log types were unified into the same data structure, prioritized based on data sources, and interpolated to generate a detailed stratigraphic structure. More than 29,000 well logs were integrated to construct a stratigraphy model of 56 model layers for the Chicot aquifer system. The stratigraphy model revealed interconnections of various sands in the system, where 90% of the model domain is covered by fine-grained sediments. Although the groundwater model estimated a slight groundwater storage gain during 2005–2014 for the entire region, groundwater storage in the agricultural area was depleted. Nevertheless, the quick groundwater storage recovery during the non-irrigation seasons suggests that the Chicot aquifer system is a prolific aquifer system. The groundwater modeling result shows that the gulfward groundwater flow direction prior to pumping has been reversed toward inland pumping areas. The large upward vertical flow from the deeper sands indicates potential saltwater migration from the base of the Chicot aquifer system.

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