introduction to groundwater, karst and the edwards aquifer
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Introduction to Groundwater, Karst and the Edwards Aquifer
Water color by Kathy Rottier
Groundwater Zones
Alternate image of groundwater zones
Porosity
Permeability
Types of groundwater flow
Aquifer Recharge and Discharge
Groundwater flow timescales
Artesian groundwater systems
Water: the great dissolver and precipitator
Dissolves: Precipitates:
Limestone, gypsum, salt (makes caves and landscapes these rocks)
Cave deposits (stalactites, travertine, etc)
Cements that hold sedimentary rocks together (calcareous, siliceous, and ferruginous)
Few minerals from sandstones, shales, and igneous and metamorphic rocks (does not make caves in these rocks)
Spring and geyser deposits
Concretions and geodes
Limestone Dissolution
H2O + CO2 = H2CO3
water + carbon dioxide = carbonic acid
H2CO3 + CaCO3 = Ca++ + 2 HCO3-
carbonic acid + calcium carbonate (limestone) = calcium ions + bicarbonate ions
Karst Development: Initial Stage
Karst Development: Intermediate Stage
Karst Development: Late Stage
Karst Terrain
Mike Warton
Geologic History of the Edwards Aquifer
Uplifting and Earthquakes
The Edwards Aquifer
Barton Springs Segment (map view)
Barton Springs Segment (cross-section view)
Inner Space Caverns
Photos by Marsha WillisPhotos by Marsha Willis
Longhorn CavernsLonghorn Caverns’’Photos by Larry JayroePhotos by Larry Jayroe
Photo Credit: City of Austin <http://www.ci.austin.tx.us/watershed/images/
bartonaerial.jpg>,accessed September 22, 2008
Barton Springs Pool
Example Hydrograph
Discharge at Barton Springs January 1980 – September 2008
Source: USGS <http://waterdata.usgs.gov/tx/nwis/uv/?site_no=08155500>,accessed September 19, 2008
Source: Source: http://media.point2.com/p2a/htmltext/d51f/3a57/e5a5/4d13a91fhttp://media.point2.com/p2a/htmltext/d51f/3a57/e5a5/4d13a91fbcd071034cf8/original.jpg, accessed September 22, 2008bcd071034cf8/original.jpg, accessed September 22, 2008
The EndThe End
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