The Effect of the Earth’s Rotation on Ground Water Motion

The average pore velocity of ground water according to Darcy's law is a function of the fluid pressure gradient and the gravitational force (per unit volume of ground water) and of aquifer properties. There is also an acceleration exerted on ground water that arises from the Earth's rotation. The magnitude and direction of this rotation-induced force are determined in exact mathematical form in this article. It is calculated that the gravitational force is at least 300 times larger than the largest rotation-induced force anywhere on Earth, the latter force being maximal along the equator and approximately equal to 34 N/m(3) there. This compares with a gravitational force of approximately 10(4) N/m(3)

Long-term climatic change and sustainable ground water resources management

Atmospheric concentrations of greenhouse gases (GHGs), prominently carbon dioxide (CO2), methane (CH4), nitrous oxide (N 2O), and halocarbons, have risen from fossil-fuel combustion, deforestation, agriculture, and industry. There is currently heated national and international debate about the consequences of such increasing concentrations of GHGs on the Earth's climate, and, ultimately, on life and society in the world as we know it. This paper reviews (i)long-term patterns of climate change, secular climatic variability, and predicted population growth and their relation to water resources management, and, specifically, to ground water resources management, (ii) means available for mitigating and adapting to trends of climatic change and climatic variability and their impacts on ground water resources. Long-term (that is, over hundreds of millions of years), global-scale, climatic fluctuations are compared with more recent (in the Holocene) patterns of the global and regional climates to shed light on the meaning of rising mean surface temperature over the last century or so, especially in regions whose historical hydroclimatic records exhibit large inter-annual variability. One example of regional ground water resources response to global warming and population growth is presented. © 2009 IOP Publishing Ltd

Solar Insolation on Uniformly Sloping Terrain in a Changing Climate

Equations for the solar radiation input and the duration of the daily insolation on surfaces of arbitrary slope and aspect are presented in this work. It is shown that the sunrise- and sunset-hour angles and the duration of daily insolation depend on the roots of the equation Acos + B sin + C = 0, in which is the hour angle and A, B, and C are coefficients that involve the slope of the surface, the aspect of the sloping surface, the solar declination, and the latitude of a point of interest on the sloping surface. The equation developed to calculate the duration of daily insolation can be applied to any sequence or combinations of days to obtain the total number of daylight hours over arbitrary periods. It is applicable to clear-sky conditions and, therefore, it produces the theoretical upper limit of the duration of daily insolation. Equations are also developed in this paper to calculate the input of solar radiation on a slope for arbitrary atmospheric transmissivity, and coupled with other radiatiative fluxes to quantify the energy budget on the surface of the earth. The effect of changing climate and variable atmospheric conditions on solar insolation are cited in this work. The paper identifies areas of application for the methods herein presented. © 2011 ASCE

Sediment Discharge Scaling in Large Rivers of the World

The variation of suspended sediment discharge with respect to changes in drainage area follows a series of scaling laws that express sediment discharge as a power function of drainage area. Four such scaling laws for sediment discharge were discovered for large rivers, with average annual runoff exceeding 10 km3. These scaling laws require that rivers be categorized in non-overlapping ranges of specific sediment yield. An analysis of the variation of sediment discharge with respect to runoff revealed four other scaling laws for sediment discharge as function of annual runoff categorized by sediment concentration. The applicability of scaling laws is highlighted. © 2011 ASCE

The Life Cycle of Vernal Pools: Hydrologic Principles

This paper reviews the hydrologic principles governing the life or flooding-drying cycle of vernal pools. A quantitative method for describing the ponding hydrograph in a vernal pool formed by rainfall or by artificial flooding is proposed. This method can be used for predicting the flooding-drying phases of a vernal pool, and also to achieve desired ponding hydrograph in vernal-pool restoration work. © 2006 ASCE

Probability Distributions in Groundwater Hydrology: Methods and Applications

© 2014 American Society of Civil Engineers. This paper presents the most frequently used probability-density functions in groundwater hydrology and practical ways to apply them. The paper provides several examples of probability-density functions dealing with (1) their application to various types of groundwater phenomena, (2) the estimation of their parameters by the method of moments, and (3) the implementation of goodness-of-fit tests in probabilistic groundwater hydrology. The versatility of the log-gamma probability-density function to fit highly skewed groundwater data is demonstrated. Important univariate probability-density functions are covered, and the multivariate lognormal probability-density function's applicability to goodness-of-fit testing and synthetic generation of random fields is elucidated

Aquifer storage capacity and maximum annual yield from long-term aquifer fluxes

Long-term time series data of aquifer recharge, groundwater extraction, and discharge are used to estimate aquifer storage capacity and maximum annual yield. Aquifer storage capacity is defined as the maximum volume of water that can be stored in an aquifer. It is estimated using a transient water-balance approach. The maximum annual yield is defined as the maximum combined groundwater extraction plus discharge that can be sustained in an aquifer judged by the historical record of recharge. It is determined according to a graphical mass-curve method. These two quantities are useful in aquifer characterization and groundwater management, the apportionment of groundwater rights and aquifer storage and recovery operations being two frequent applications. Time series data from the Edwards Aquifer, Texas, USA, illustrate the application of the methods presented. © Springer-Verlag 2007

CO2 Capture and Geologic Storage: The Possibilities

Carbon dioxide (CO(2)) capture and geologic storage has been postulated as one possible method to stabilize the atmospheric concentration of CO(2) by injecting and storing it in deep geologic formations. This issue paper analyzes the viability of capture and geologic storage of becoming an effective method to aid in stabilizing the atmospheric concentration of CO(2). It is herein shown that such viability is contingent on overcoming major obstacles that are hydrogeological, technical, and economic in nature. Our analysis indicates that capture and geologic storage is likely to have negligible success in reducing the atmospheric buildup of CO(2) in the coming decades. The magnitude of the anthropogenic emissions of CO(2) indicates that a transition of the world economy away from reliance on fossil fuels might be the only path to stabilize its atmospheric concentration