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Unformatted text preview: 1 GY 111: Physical Geology GY 111: Physical Geology UNIVERSITY OF SOUTH ALABAMA Lecture 18: Geological Time Lecture 18: Geological Time Last Time Groundwater 1. The hydrosphere and the hydrological cycle 2. Groundwater concepts 3. Groundwater topography (Karst) Hydrological Cycle Water in the hydrosphere is circulated within the hydrological cycle ht p:/ www.coloradocol ege.edu/dept/ev/courses/EV211WWW/hydrological%20cycle.jpg Water Table ht p:/ myweb.cwpost.liu.edu/vdivener/notes/water_table.gif Undersaturated zone (Vadose) Straight down water movement Saturated zone (Phreatic) Lateral? water movement The water table is a planar surface that separates the saturated and undersaturated zones Types of Aquifers Potentiometric Surface: elevation to which the pressurized water in a confined aquifer will rise Artesian Well: water rises to an elevation above the aquifer Flowing Artesian Well/Spring: potentiometric surface is above the ground surface ht p:/ www.douglas.co.us/water/images/Denver_Basin_Aquifers_clip_image004.jpg Anthropogenic Effects z Excessive pumping can severely lower the elevation of the local water table ( cone of depression ) ht p:/ myweb.cwpost.liu.edu/vdivener/notes 2 Other Groundwater Issues z Ground subsidence and collapse Sinkholes Hydrothermal Systems z Groundwater heated by magmatic sources Karst Topography z Like meandering rivers, the degree of karstification can be related to age Groundwater Flow (Hydrogeology) z Darcys Law: governs the volume of groundwater produced at a well head Q= A(K x h ) z Q is volume z A is cross sectional area of aquifer z K is permeability z h is hydraulic head z l is map distance l i.e., you can determine groundwater flow rates Todays Agenda Web notes 18 A) How long is long?...
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- Fall '11