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.

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).

Methods for calculating the safe yield are evaluated in this paper using a high-quality and long historical data set of groundwater recharge, discharge, extraction, and precipitation in a karst aquifer. Consideration is given to the role that climatic variability has on the determination of a climatically representative period with which to evaluate the safe yield. The methods employed to estimate the safe yield are consistent with its definition as a long-term average extraction rate that avoids adverse impacts on groundwater. The safe yield is a useful baseline for groundwater planning; yet, it is herein shown that it is not an operational rule that works well under all climatic conditions. This paper shows that due to the nature of dynamic groundwater processes it may be most appropriate to use an adaptive groundwater management strategy that links groundwater extraction rates to groundwater discharge rates, thus achieving a safe yield that represents an estimated long-term sustainable yield. An example of the calculation of the safe yield of the Edwards Aquifer (Texas) demonstrates that it is about one-half of the average annual recharge.

© 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.

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.

Principles of sustainable ground-water exploitation are presented in this paper. The renewable and inappropriable nature of ground water is examined in light of the process of recharge. An example illustrates the interplay among ground-water extraction, recharge, natural recharge, and storage. It demonstrates the aquifer-specific characteristics of overdraft and replenishment, which are driven by climatic variability and the rate of ground-water mining. A second example uses game theoretic methodology to quantify the roles of cooperation and non-cooperation on ground-water extraction. The economic and environmental advantages of cooperative ground-water extraction are demonstrated with data from a coastal aquifer. © 2002 Taylor & Francis Group, LLC.