Fractal scaling analysis of groundwater dynamics in confined aquifers

Download
2017-10-01
Tu, Tongbi
Ercan, Ali
Kavvas, M. Levent
Groundwater closely interacts with surface water and even climate systems in most hydroclimatic settings. Fractal scaling analysis of groundwater dynamics is of significance in modeling hydrological processes by considering potential temporal long-range dependence and scaling crossovers in the groundwater level fluctuations. In this study, it is demonstrated that the groundwater level fluctuations in confined aquifer wells with long observations exhibit site-specific fractal scaling behavior. Detrended fluctuation analysis (DFA) was utilized to quantify the monofractality, and multifractal detrended fluctuation analysis (MF-DFA) and multiscale multifractal analysis (MMA) were employed to examine the multifractal behavior. The DFA results indicated that fractals exist in groundwater level time series, and it was shown that the estimated Hurst exponent is closely dependent on the length and specific time interval of the time series. The MF-DFA and MMA analyses showed that different levels of multifractality exist, which may be partially due to a broad probability density distribution with infinite moments. Furthermore, it is demonstrated that the underlying distribution of groundwater level fluctuations exhibits either non-Gaussian characteristics, which may be fitted by the Levy stable distribution, or Gaussian characteristics depending on the site characteristics. However, fractional Brownian motion (fBm), which has been identified as an appropriate model to characterize groundwater level fluctuation, is Gaussian with finite moments. Therefore, fBm may be inadequate for the description of physical processes with infinite moments, such as the groundwater level fluctuations in this study. It is concluded that there is a need for generalized governing equations of groundwater flow processes that can model both the long-memory behavior and the Brownian finite-memory behavior.
EARTH SYSTEM DYNAMICS

Suggestions

Numerical reservoir simulation of Alaşehir geothermal field
Aydın, Hakkı; Akın, Serhat (null; 2020-02-10)
Use of a comprehensive reservoir simulation is essential for an effective geothermal reservoir management. TOUGH2 has become a widely used simulator for this purpose. In this study, one of the most exploited geothermal fields in Turkey, Alaşehir geothermal field has been modeled by using TOUGH2 reservoir simulator. The study includes more than 100 wells, which are operated by 7 different developers. The total installed capacity of geothermal power plants in the field is 212 MWe, but additional capacity (98 ...
Quantifying the effects of climate change on hydrological regime and stream biota in a groundwater-dominated catchment: A modelling approach combining SWAT-MODFLOW with flow-biota empirical models
Liu, Wei; Bailey, Ryan T.; Andersen, Hans Estrup; Jeppesen, Erik; Nielsen, Anders; Peng, Kai; Molina-Navarro, Eugenio; Park, Seonggyu; Thodsen, Hans; Trolle, Dennis (Elsevier BV, 2020-11-01)
Climate change may affect stream ecosystems through flow regime alterations, which can be particularly complex in streams with a significant groundwater contribution. To quantify the impacts of climate change on hydrological regime and subsequently the stream biota, we linked SWAT-MODFLOW (A model coupling the Soil and Water Assessment Tool and the Modular Finite-difference Flow Model) with flow-biota empirical models that included indices for three key biological taxonomic identities (fish, macroinvertebra...
Physical control of the spatial and temporal diversity of microbial mats at a shallow water hydrothermal vent
Giovannelli, Donato; Foustoukos, Dionysis; Le Bris, Nadine; Sievert, Stefan; Yücel, Mustafa; Dalessandro, Valerio; Ricci, Renato; Vetriani, Costantino (null; 2016-07-01)
Shallow-water hydrothermal vents are ubiquitous but poorly studied geothermal environments. The active hydrothermal emissions of the Milos hydrothermal system support complex microbial mats, which are fundamental in engineering the environmental niche in which extremophiles thrive. Because of the shallow depth, the mat community is wiped out during every major storm, when swell and wave action increase, and then it reconstitutes itself over a brief period of time (days). Here we report the results of a join...
Numerical modeling of Edremit geothermal field
Günay, Emre; Karahanoğlu, Nurkan; Department of Geological Engineering (2012)
The purpose of this study is to examine the geothermal potential, sustainability, and reinjection possibility of Edremit geothermal field. In order to investigate this, a numerical model consisting of a hot and cold water aquifer system is established. A two dimensional cross sectional model is set to simulate this geothermal system. Different pressure and temperature values are applied to the nodes at the boundaries to perform a steady state calibration which minimizes the computed results and observed val...
Numerical methodology for feasibility analysis of ground source heat pumps
Gamage, Kumudu Janani; Uzgören, Eray; Sustainable Environment and Energy Systems (2014-8)
Ground source heat pump (GSHP) systems provide an alternative energy source for residential and commercial space heating and cooling applications by utilizing the favorable temperature profile at a certain depth under the ground surface. GSHP’s aftereffects on the ground temperature profile need to be considered for estimating the economical breakeven point. The present study develops a new semi-analytical model to analyze the short term response of the ground heat exchangers by accounting the depth depende...
Citation Formats
T. Tu, A. Ercan, and M. L. Kavvas, “Fractal scaling analysis of groundwater dynamics in confined aquifers,” EARTH SYSTEM DYNAMICS, vol. 8, no. 4, pp. 931–949, 2017, Accessed: 00, 2022. [Online]. Available: https://hdl.handle.net/11511/101029.