NO, THIS ISN’T THE EDWARDS PLATEAU, BUT WE CAN DREAM!

HYDROGEOLOGY OF THE EASTERN EDWARDS PLATEAU

WELDON W. HAMMONDDIRECTORCENTER FOR WATER RESEARCH UNIVERSITY OF TEXAS AT SAN ANTONIO

AUGUST 29, 2012

Vasey’s Paradise, Grand Canyon

WATER MASSES AT THE EARTH’S SURFACE

 Reservoirs Volume (in millions of cubic Percent of Total

kilometers. One cubic kilometer equals 172,052,358 gallons)

Oceans 1,370 97.25 Ice Caps and Glaciers 29 2.05 Deep Groundwater (700- 4,000 5.3 0.38 meters)

Shallow groundwater 4.2 0.3 (less than 750 meters) Lakes 0.125 0.01 Soil Moisture 0.065 0.005 Atmosphere 0.013 0.001 Rivers 0.0017 0.0001 Biosphere 0.0005 0.00004 Total 1, 407.8 100

Interesting note…..as a comparison we have over 3,200 times more water that occurs as shallow groundwater than in all the rivers and lakes combined. FIGURE 2. WATER MASSES AT THE EARTH’S SURFACE

(Source: Encyclopedia Britannica) 

Population GrowthExample:

Kendall County Population Census 2010: 33,410 40.7Census 2000: 23,743 62.7Census 1990: 14,589 37.2Census 1980: 10,635 52.7Census 1970: 6,964` 18.3Census 1960: 5,889 8.6Census 1950: 5,423 6.8Census 1940: 5,080 -

Water resources may well be a limiting factor for future growth potential

FIGURE 3. KENDALL COUNTY POPULATION GROWTH

% Change from Previous Decade

Geology

FIGURE 4. SURFACE GEOLOGY (modified from TWDB Report 273)

Geologic Formations in the eastern Edwards Plateau that are capable of yielding groundwater (from oldest to youngest)

FIGURE 5. STRATIGRAPHY

FIGURE  6.  GEOLOGIC CROSS SECTION 

FIGURE 6.  GEOLOGIC CROSS SECTION

FIGURE 7. AREA STREAMS

FIGURE 8. STREAM HYDROGRAPH

FIGURE 9. USES OF GROUNDWATER IN TEXAS

FIGURE 10. UNDERGROUND WATER 

FIGURE 11. CONFINED AND UNCONFINED AQUIFERS

FIGURE 12. MAJOR AQUIFERS

FIGURE 13. MINOR AQUIFERS

FIGURE 14. WATER BEARING UNITS

Groundwater Flowpaths

FIGURE 16. WATER TABLE AND BASE FLOW TO STREAMS