Adjoint modeling to quantify stream flow changes due to aquifer pumping

November 2013.Includes bibliographical references.As populations grow and demand for water increases, new sources of water must be found. If groundwater resources are developed to meet these growing demands, the increased pumping of aquifers should not reduce flows in rivers to levels that would limit the availability of water for drinking water supply, irrigation, and riparian habitat. Stream depletion is the term for the change in the river flow rate due to pumping in an aquifer that is hydraulically connected to the river. In many regions of the U.S., a new well cannot be sited until it is shown that pumping the new well will not cause substantial stream depletion. Numerical simulations are typically used to quantify stream depletion. In the standard approach, two numerical simulations are run—one without pumping and one with pumping in a well at the proposed location. In both simulations, the water flux between the river and aquifer is calculated, and the difference between these fluxes is the stream depletion due to pumping at the proposed well location. If multiple well locations are considered, one addition simulation must be run for each additional potential well location; thus, this approach can be inefficient for siting new wells. The goal this research was to develop an adjoint-based modeling approach to efficiently quantify stream depletion due to aquifer pumping. In a single simulation of an adjoint model, stream depletion is calculated for a well at any location in the aquifer; thus, it is computationally efficient when the number of well locations or possible well locations is large. The adjoint approach was developed to be used with standard groundwater flow simulators, and therefore can be applied in practice. The research included rigorous development of the adjoint equation for calculating stream depletion in confined and unconfined aquifers with various models of groundwater/surface water interaction, along with numerical simulations to verify the adjoint equation. In addition, we used the adjoint method to investigate the sensitivity of stream depletion to the hydraulic conductivity of the stream channel, a parameter which is known to be uncertain

Heat conduction in the ground under natural conditions and with heat exchanger installed

The results of calculations of the heat transfer in a horizontal ground heat exchanger are presented. The applied model is based on a one-dimensional equation of the transient heat conduction with an internal heat source. The model was correctly verified by comparison of computational results and experimental measurements presented in literature. Thermal calculations concerning heat transfer in the ground under natural conditions are also presented

To What Extent Does Ericsson Adapt Their Organisational Culture When Opening A Branch in A New Culture?

Telefonaktiebolaget LM Ericsson (Ericsson) is a Swedish telecom company with branches all over the world. It is not a secret that a company with branches in several diverse cultures has to decide what extent the organization will go in adapting the host culture into the new branch. This essay will focus on Ericsson and a few cases on how well Ericsson decided to incorporate host cultures into their organization. The cases picked will mainly be in Asia due to the greater cultural difference between the Asian host culture and their European home culture

Use of groundwater lifetime expectancy for the performance assessment of a deep geologic waste repository: 1. Theory, illustrations, and implications

Long-term solutions for the disposal of toxic wastes usually involve isolation of the wastes in a deep subsurface geologic environment. In the case of spent nuclear fuel, if radionuclide leakage occurs from the engineered barrier, the geological medium represents the ultimate barrier that is relied upon to ensure safety. Consequently, an evaluation of radionuclide travel times from a repository to the biosphere is critically important in a performance assessment analysis. In this study, we develop a travel time framework based on the concept of groundwater lifetime expectancy as a safety indicator. Lifetime expectancy characterizes the time that radionuclides will spend in the subsurface after their release from the repository and prior to discharging into the biosphere. The probability density function of lifetime expectancy is computed throughout the host rock by solving the backward-in-time solute transport adjoint equation subject to a properly posed set of boundary conditions. It can then be used to define optimal repository locations. The risk associated with selected sites can be evaluated by simulating an appropriate contaminant release history. The utility of the method is illustrated by means of analytical and numerical examples, which focus on the effect of fracture networks on the uncertainty of evaluated lifetime expectancy.Comment: 11 pages, 8 figures; Water Resources Research, Vol. 44, 200

A geostatistical framework for incorporating transport information in estimating the distribution of a groundwater contaminant plume

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95253/1/wrcr10904.pd