Aquifer Properties & Heterogeneities

		Aquifer Storage Mechanisms Beginner to Intermediate - Watch videos and respond. 1. Explain the difference in storage mechanisms in confined and unconfined aquifer. What are the key factors that dictate the magnitude of the two different storage coefficients? 2. Watch the following videos and comment on the dramatic difference between confined and unconfined aquifer dynamics. (Aquifer Properties & Heterogeneities- 14)

		Storage Coefficients and Mechanisms The property which expresses the capacity of an aquifer to take water into and release water from storage is called “storativity” for a confined aquifer and “specific yield” for an unconfined aquifer. Watch the related MAGNET videos and answer the short questions that follow. (Aquifer Properties & Heterogeneities- 14)

		Subsurface Heterogeneity Lesson (under development). Background: Groundwater occurs in the geological formations of the subsurface. An understanding of how geological materials are distributed, how they formed, and the changes they have undergone is therefore of key importance to hydrogeologists, groundwater hydrologists, etc. In this exercise, we review the different processes that generate different geologic features/patterns, and explore ways for qualitatively and quantitatively characterizing the heterogeneity of the subsurface. (Aquifer Properties & Heterogeneities- 14)

		Layered Heterogeneity Beginner to Intermediate - Theoretical application. Background: At regional scales, sedimentary rocks and unconsolidated lacustrine and marine deposits often exhibit a vertically-layered heterogeneity, with each individual bed (or layer) in the formation having a homogenous conductivity value K1, K2, etc (see Figure 1). Such layered heterogeneity can result in significant contrast in hydraulic conductivity within a layer sequence (i.e., several orders of magnitude). (Aquifer Properties & Heterogeneities- 14)

		Hydraulic Conductivity Heterogeneity Hydraulic conductivity can vary by orders of magnitude in the subsurface, depending on the size, shape and interconnectedness of the pores or open spaces between solid materials. Calculate the effective vertical hydraulic conductivity of the stratified formation between a lake and an aquifer. Also compute the vertical seepage flux from the lake to the aquifer using the Darcy's law based on the effective conductivity. Verify the results using MAGNET. (Aquifer Properties & Heterogeneities- 14)

		Effective Stress, Porosity, Compressibility, and Compaction Subsidence is a global problem and, in the United States, more than 17,000 square miles in 45 States, an area roughly the size of New Hampshire and Vermont combined, have been directly affected by subsidence. Analyzing subsidence for the a specific situation. (Aquifer Properties & Heterogeneities- 14)

		Statistical analysis of K and n data Perform a statistical analysis for a core of aquifer material, sectioned and tested on a permeameter. Consider frequency distributions, autocorrelations, and crosscorrelations. (Aquifer Properties & Heterogeneities- 14)

		An “Odd” Phenomenon Zeke, the well driller with a healthy curiosity, has a question for you. He had installed a set of wells in an aquifer he knows (accurately) to be confined. One of the wells was turned on and pumped continuously. Head measurements were taken at the surrounding wells. Playing around with Darcy’s law, he noticed an “odd” phenomenon: based on his calculations from the heads of surrounding wells, the amount of water flowing toward the well appeared to increase over time. Yet the pumping rate at the well was constant. Explain to the well-driller what was happening. (Aquifer Properties & Heterogeneities- 14)