DEEP GROUNDWATER DRILLING CENTRAL TEXAS BY WILLIAM FEATHERGAIL WILSON, PG #21 STRATA GEOLOGICAL SERVICES GSA - 2008

TEXAS HILL COUNTRY

Regional Cross-Section

KERR COUNTY

RESEARCH WELLS (12) 8 4 9 6 5 7 11 3 2 This slide depicts all of the Headwaters monitor and research wells that have been drilled over the past few years. Additional drilling is scheduled for 2008. 1

RESEARCH WELLS (12) Drilled through the entire Cretaceous System Depths ranges: 610’-1330’ (~ 11,000’) Lithologic logs – stereo microscope @ 10’ intervals Geophysical logs Drilled 12 wells – 8 years – HGCD Conservation district

RESEARCH WELL RESULTS MAPS CROSS-SECTIONS ANALYTICAL MODELING ISOPACH FACIES ISOTOPE AGES FLOW DIRECTIONS RECHARGE CONCEPTS CROSS-SECTIONS ANALYTICAL MODELING AQUIFER AGE DATES – ISOTOPES PUMP TESTS DEMAND –SUPPLY PREDICTIONS

Cretaceous Stratigraphy Fm/Group Members Trinity Period Age 99 Edwards Albian Upper Lower Upper Glen Rose 112 Hensel Bexar Cow Creek Hammett Cretaceous Middle Pearsall Aptian This is a depiction of the aquifers and aquitards present within the county. The blue designates the major and minor aquifers. The great preponderance of groundwater in the county is derived from the Hensel and Cow Creek units. Often the Hensel and Cow Creek are interconnected into one aquifer. The two major aquitards are the Upper Glen Rose and the Hammett clays. 121 Sligo Neocomian Lower Hosston 144 Strata Geological Services, Inc

Kerr Co Geology

HENSEL FACIES TIME SLICE

HENSEL FLOW DIRECTIONS

CROSS-SECTION -SE-NNE

CROSS-SECTION – S-N

CROSS-SECTION – W-E

CROSS-SECTION 5-12

EDWARDS FLOW DIRECTIONS

C-14 Aquifer Age Dates (uncorrected) 1000-40,000 years <10,000 >20,000

% Modern Carbon High Low

RECHARGE & ISOPACH MAP This interesting map depicts a combination of Hensel thickness data across a large area of the Texas Hill Country. It introduces some of the recharge issues that move groundwater into all of the confined units in the county. Note the stippled yellow areas depicting the Hensel Sand outcrop and the recharge arrows. Rainfall recharges the Hensel outcrop and moves SE beneath the Upper Glen Rose aquitard into Kerr County. Another component of groundwater is derived from the Hensel sands that lie below the Edwards Plateau in the unconfined portion of the Edwards-Trinity aquifer. One implication is that dewatering of the Hensel sands in Kimble and Gillespie Counties will occur before they reach Kerr County over the next 50-years.

GROUNDWATER STORAGE The Hammett clay wedge separates the Hensel South from the Hensel North via facies change 11,986 ac ft recoverable sans annual recharge 15,981 ac ft using 20% recovery This computer generated map depicts the thickness of the Hensel Sands both north and south of the Hammett clay limit. The equation depicts and estimate of the water in storage at any one given moment in time. The factors that go into the equation can be changed either increasing or decreasing the water in storage. This equation represents mean value parameters. Note the thick areas in various shades of brown and the thin areas in shades of green. Mean aquifer thickness

PALEOZOIC SUBCROP

Structural Elements

SUMMARY REPRESENTS A SNAPSHOT OF DEEP GROUNDWATER DRILLING IN CENTRAL TEXAS ADDITIONAL PRIVATE AND PUBLIC DEEP DRILLING HAS BEEN CARRIED OUT ACROSS THE TEXAS HILL COUNTRY UTILIZING THE SAME TECHNIQUES RESEARCH CONTINUES IN COOPERATION WITH WATER DISTRICTS, DEVELOPERS, AND PUBLIC WATER SYSTEMS

SUMMARY KERR COUNTY DETAILED REPORT (BOOK) BEING PREPARED (~120 PAGES), MAPS, CROSS-SECTIONS, ETC. RESEARCH WILL BE EXPANDED TO INCORPORATE DEEP GROUNDWATER DRILLING DATA AND INTERPRETATION ACROSS ADJACENT COUNTIES

CONTACT INFORMATION WILLIAM FEATHERGAIL WILSON, PG #21 Strata Geological Services 13505 FM 462 Bandera (Tarpley), Texas 78003 E-mail <featherg@hctc.net> Office – 830-562-3680 Thank You!