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.

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 Groundwater Flow Modeling in Chitwan Dun Valley (Between Narayani River and Lothar Khola), Nepal

2019 ◽  
Vol 24 (2) ◽  
pp. 30-38
Author(s):  
Rita Bhandari ◽  
Dinesh Pathak
Keyword(s):  
Numerical Model ◽  
Groundwater Flow ◽  
Groundwater Modeling ◽  
Flow Direction ◽  
Flow Modeling ◽  
Aquifer System ◽  
Flow Equations ◽  
Flow Models ◽  
Future Behavior ◽  
Fence Diagram

 Models are simplification of reality to investigate certain phenomena or to predict future behavior and always tries to generate scenario that is close to the real condition. Groundwater flow models are computer models generated through using established flow equations that simulate and predict aquifer conditions. The result of groundwater modeling is used for groundwater management and remediation. In the present study, hydrostratigraphic units were identified through interpreting the lithological logs of the drilled wells then fence diagram was prepared with three major aquifer horizons, namely unconfined, shallow confined and deep confined aquifers. In addition, hydrogeologic data were integrated to develop a conceptual hydrogeologic model of the aquifer system of the Chitwan Dun valley, which was the basis for the development of the numerical model. The aquifer system was modeled numerically using MODFLOW-2005 numerical modeling, which was further calibrated and an acceptable numerical model was obtained which showed different flow direction in each aquifer layer. The model was validated by comparing the observed and simulated heads. The result shows that in each of the aquifer layers, the general flow direction is towards west and south-west.

scholarly journals Predicted Climate Change Impact on Groundwater Flow for the Upper Zone of Iraqi Aquifers

2020 ◽  
Vol 55 (2) ◽  
Author(s):  
Thair Sharif Khayyun ◽  
Hasan Hadi Mahdi
Keyword(s):  
Climate Change ◽  
Groundwater Flow ◽  
Water Resource Management ◽  
Groundwater Modeling ◽  
Flow Direction ◽  
Flow Behavior ◽  
Climate Change Impacts ◽  
Groundwater Levels ◽  
Groundwater Movement ◽  
Aquifer Systems

A 3D groundwater steady-state flow conceptual model was built for all of Iraq using a MODFLOW package integrated with the Groundwater Modeling System to simulate the groundwater movement and flow direction for the upper zone of Iraq as well as to compute the water budget for all aquifer systems in Iraq. This model was run for seven scenarios of climate change conditions for the period of 2020–2050. A Representative Concentration Pathway model (RCP4.5) was used for the prediction of future rainfall over the next 31 years. The results showed that the decline in rainfall will be 6.247% due to climate change impacts. The decline in rainfall will cover two-thirds of the area of Iraq. Seven scenarios simulating groundwater flow behavior showed that decreased soil moisture content will significantly reduce groundwater recharge and increase runoff. A decline in groundwater levels by an average of 1.8–4.8 m will occur for the upper zone of Iraqi aquifers over the next 31 years. These results will help Iraqi decision-makers improve water resource management.

scholarly journals Groundwater Storage Changes in the Major North African Transboundary Aquifer Systems during the GRACE Era (2003–2016)

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2669 ◽  
Author(s):  
Frédéric Frappart
Keyword(s):  
Water Loss ◽  
North African ◽  
Groundwater Storage ◽  
Aquifer System ◽  
Water Abstraction ◽  
Nubian Sandstone ◽  
Sandstone Aquifer ◽  
Aquifer Systems ◽  
Terrestrial Water ◽  
Transboundary Aquifers

Groundwater is an essential component of the terrestrial water cycle and a key resource for supplying water to billions of people and for sustaining domestic and economic (agricultural and industrial) activities, especially in arid and semi-arid areas. The goal of this study is to analyze the recent groundwater changes which occurred in the major North African transboundary aquifers in the beginning of the 21st century. Groundwater storage anomalies were obtained by removing soil moisture in the root zone (and surface water in the case of the Nubian Sandstone Aquifer System) from the terrestrial water storage anomalies estimated using the Gravity Recovery and Climate Experiment (GRACE) over the 2003–2016 time period. Spatio-temporal changes in groundwater storage contrast significantly among the different transboundary aquifers. Low changes (lower than 10 km3) were observed in the Tindouf Aquifer System but they were found to be highly correlated (R = 0.74) to atmospheric fluxes (precipitation minus evapotranspiration, P − ET) at annual scale. The GRACE data revealed huge water loss in the North Western Sahara and the Nubian Sandstone Aquifer Systems, above 30 km3 and around 50 km3, respectively. In the former case, the aquifer depletion can be attributed to both climate (R = 0.67 against P − ET) and water abstraction, and only to water abstraction in the latter case. The increase in water abstraction results from an increase in irrigated areas and population growth. For these two aquifers, a deceleration in the water loss observed after 2013 is likely to be attributed either to an increase in rainfall favoring rain-fed agriculture or to measures taken to reduce the over-exploitation of the groundwater resources.

scholarly journals Groundwater flow in the Campaspe and Loddon Valleys of Northern Victoria: an enhanced role for the Shepparton Formation

2010 ◽  
Vol 122 (2) ◽  
pp. 43
Author(s):  
Phillip G. Macumber ◽  
Jennifer J. Macumber
Keyword(s):  
Saline Water ◽  
Groundwater Development ◽  
Vertical Flow ◽  
True Nature ◽  
Aquifer System ◽  
Aquifer Systems ◽  
Late Tertiary ◽  
Hydraulic Gradients ◽  
Sand Sheet ◽  
Regional Aquifer

Recent work on the fluvial aquifer systems of the Campaspe and Loddon Valleys in northern Victoria has shown that a two-aquifer conceptualisation and use of ‘typical’ hydraulic parameters for the Calivil Formation regional aquifer and its notional aquitard the Shepparton Formation, may mask the true nature of their interactions. In the highland tracts of the Loddon and Campaspe Valleys the regional aquifer system comprises the Calivil Formation and much of the Shepparton Formation. On the southern Loddon Plains, intensive groundwater development occurs from both the Calivil Formation and a Shepparton Formation ‘sand sheet’ aquifer, which follow separate paths across the plain, dictated by an evolving late Tertiary palaeogeography. Whatever the aquifer system invoked, the emphasis has been on horizontal down basin flow. At other times, upbasin flow of saline water under reversed hydraulic gradients into irrigation areas has been stressed, with the concerns for aquifer salinisation. Yet it is shown that in the Campaspe Valley, vertical flow from overlying or underlying aquifers poses a far more immediate salinity threat to the regional Calivil Formation aquifer than upbasin horizontal flow. Overall, the role of the Shepparton Formation as a significant aquifer system, and elsewhere as a conduit for salinisation via vertical flow, has been largely overlooked. More generally, the lithological variability of the Shepparton Formation across north central Victoria strongly influences the behaviour of the regional aquifer system, including groundwater throughflow and groundwater development. This is especially clear on the permeable Campaspe Fan, which is the principal recharge area in the Campaspe Valley, with recharge coming from direct precipitation, the Campaspe River, irrigation, and the Waranga-Western and Campaspe No 1 channels.

The Distribution of Volatile Organics in a Leachate Plume, Gloucester, Ontario

1987 ◽  
Vol 22 (1) ◽  
pp. 49-64 ◽  
Author(s):  
J.F. Devlin ◽  
W.A. Gorman
Keyword(s):  
Organic Contaminants ◽  
Source Area ◽  
Unconfined Aquifer ◽  
High Concentration ◽  
Organic Contamination ◽  
Aquifer System ◽  
Aquifer Systems ◽  
Volatile Organic ◽  
Volatile Organic Contaminants ◽  
Aquifer Sediments

Abstract The Gloucester Landfill is located near Ottawa, Ontario, on a northeast trending ridge of Quaternary age. The ridge comprises outwash sediments which make up two aquifer systems. A confined system exists next to bedrock, and is overlain by a silty-clayey stratum (the confining layer) which is, in turn, overlain by an unconfined aquifer system. Two independent volatile organic plumes have previously been identified at the landfill: the southeast plume, which has penetrated the confined aquifer system, and the northeast plume which is migrating in the unconfined aquifer. The distribution of volatile organic contaminants at the northeast plume site appears to be a function of two factors: (1) heterogeneities in the aquifer sediments are causing the channeling of contaminants through a narrow path; (2) the low fraction of organic carbon in the unconfined aquifer sediments at the northeast site is resulting in little retardation of the contaminants there, relative to those at the southeast site. Acetate was the only volatile fatty acid detected in the leachate. It was measurable only in areas where the volatile organic contamination was significant. Although methane was detected in the contaminated sediments, suggesting that microbial activity was present, the high concentration of acetate (>1000 ppm) which was detected down-gradient from the source area indicates that any biodegradation which is occurring is proceeding at a very slow rate.

The Migration Behaviour of Transuranium Elements in Gorleben Aquifer Systems: Colloid Generation and Retention Process

1988 ◽  
Vol 127 ◽  
Author(s):  
J. I. Kim ◽  
G. Buckau ◽  
H. Rommel ◽  
B. Sohnius
Keyword(s):  
Migration Process ◽  
Transuranium Elements ◽  
Aquifer System ◽  
Migration Behaviour ◽  
Aquifer Systems ◽  
Migration Study

ABSTRACTThe colloid generation as a part of the migration process of trans-uranic ions has been studied in the Gorlben aquifer system. From the migration study for the Gorleben repository site, typical examples are selected to demonstrate the influence of colloids. The quantification of colloid generation and its influence on the dissolution and geochemical sorption of transuranium elements are discussed.

scholarly journals Large-scale groundwater modeling using global datasets: a test case for the Rhine-Meuse basin

2011 ◽  
Vol 8 (2) ◽  
pp. 2555-2608 ◽  
Author(s):  
E. H. Sutanudjaja ◽  
L. P. H. van Beek ◽  
S. M. de Jong ◽  
F. C. van Geer ◽  
M. F. P. Bierkens
Keyword(s):  
Sensitivity Analysis ◽  
Land Surface ◽  
Large Scale ◽  
Groundwater Modeling ◽  
Land Surface Model ◽  
Water Levels ◽  
Surface Model ◽  
Groundwater Model ◽  
Model Output ◽  
Global Datasets

Abstract. Large-scale groundwater models involving aquifers and basins of multiple countries are still rare due to a lack of hydrogeological data which are usually only available in developed countries. In this study, we propose a novel approach to construct large-scale groundwater models by using global datasets that are readily available. As the test-bed, we use the combined Rhine-Meuse basin that contains groundwater head data used to verify the model output. We start by building a distributed land surface model (30 arc-second resolution) to estimate groundwater recharge and river discharge. Subsequently, a MODFLOW transient groundwater model is built and forced by the recharge and surface water levels calculated by the land surface model. Although the method that we used to couple the land surface and MODFLOW groundwater model is considered as an offline-coupling procedure (i.e. the simulations of both models were performed separately), results are promising. The simulated river discharges compare well to the observations. Moreover, based on our sensitivity analysis, in which we run several groundwater model scenarios with various hydrogeological parameter settings, we observe that the model can reproduce the observed groundwater head time series reasonably well. However, we note that there are still some limitations in the current approach, specifically because the current offline-coupling technique simplifies dynamic feedbacks between surface water levels and groundwater heads, and between soil moisture states and groundwater heads. Also the current sensitivity analysis ignores the uncertainty of the land surface model output. Despite these limitations, we argue that the results of the current model show a promise for large-scale groundwater modeling practices, including for data-poor environments and at the global scale.

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