Bedrock Aquifer Systems of Crawford County, Indiana &-21&- 22 23 &

Frank O'Bannon, Governor Department of Natural Resources Division of Water John Goss, Director Aquifer Systems Map 07-B BEDROCK AQUIFER SYSTEMS OF CRAWFORD COUNTY, INDIANA &-21&- 22 23 &- North Ridge Rd &- &- R. 1 W. R. 1 E. 28 27 26 R. 2 W. R. 1 W. R. 1 E. R. 2 E. R. 2 W. Crawford County Bedrock Aquifer Systems 25 &-Baylor Rd d F d V hillips R d R a P a r le R Patoka Lake g e n o n e e e l R R v l d o o d r G &- H The occurrence of bedrock aquifers depends on the original composition of the rocks and subsequent changes which influence the hydraulic properties. Post-depositional 32 33 34 35 36 31 32 33 34 &- 36 31 35 k 35 36 35 d B &-36 a 31 32 33 34 32 33 34 S R d &- processes which promote jointing, fracturing, and solution activity of exposed bedrock generally increase the hydraulic conductivity (permeability) of the upper portion of 31 S a O R P oo es R c u Z dig on a R d n bedrock aquifer systems. Because permeability in many places is greatest near the bedrock surface, bedrock units within the upper 100 feet are commonly the most productive 1 ae n to e d H H &- 4 k d ar u o 5 l a H t R l aquifers. In Crawford County, rock types exposed at the bedrock surface range from relatively unproductive shales to moderately productive limestones and sandstones. h o L i w " ll R T. 1 S. a R T. 1 S. k R d B Whi d r skey d e o T. 2 S. Bedrock aquifer systems in the county are overlain by unconsolidated deposits of varying thickness. Refer to the map for unconsolidated aquifer systems for more information. T. 2 S. w Marengo &- n ! s ! Most of the bedrock aquifers in the county are under confined conditions. In other words, the potentiometric surface (water level) in most wells completed in bedrock rises above t o Cave &- 6 5 4 3 w 2 1 Rd &- the top of the water-bearing zone. 2 1 n 6 5 4 3 ler 6 d 3 il 2 1 &-5 4 R &-3 6 5 4 o Rd R M 2 Jerich d Marengo w a School Rd ie Pedor V The yield of a bedrock aquifer depends on its hydraulic characteristics and the nature of the overlying deposits. Shale and glacial till act as aquitards, restricting recharge to y &- 164 rt &- SR k Rd e underlying bedrock aquifers. However, fracturing and/or jointing may occur in aquitards, which can increase recharge to the underlying aquifers. Hydraulic properties of the Cider For ib d L R B bedrock aquifers are highly variable. n e a l g c Tunnel R r h d o d M Deich Rd e W R u &- M r k l 12 il e z R 11 In general, the potential for encountering mineralized or saline ground water in Crawford County increases rapidly for bedrock wells deeper than about 300 feet. Mineralized lia re e H 9 10 11 12 r 7 8 d m C 4 s 6 Q water is noted in some springs and shallower wells, particularly in low-lying areas. Therefore, the discussion and evaluation of the ground-water potential of the bedrock aquifers 12 i o g R H &- 10 11 g n o 7 S 8 u 9 10 11 12 7 o 8 9 &- 10 D 9 h R D a g &- 7 8 A r to &-&- d k r e w is essentially limited to those geologic units lying above the expected limits of nonpotable water. F l e y p s e o n i t r R d R l o t d l t C d R H t A C g y llen R o d il Cr h eek d D r l Three bedrock aquifer systems are identified for Crawford County based on bedrock lithology. They are, from west to east, youngest to oldest: Raccoon Creek Group of Rd a a R Leaso p H d r Rd e Pennsylvanian age; Buffalo Wallow, Stephensport, and West Baden Groups of Mississippian age; and Blue River and Sanders Groups of Mississippian age. l Hu ghes W Rd &- 13 R d i l l i The bedrock aquifer systems extend across Crawford County generally as a series of bands trending north-northwest to south-southeast. In the county, the Mississippian age a T st Rd Milltown m Longe w 18 17 16 15 14 13 s L 13 o bedrock was truncated by thousands of years of erosion. Subsequent burial of the erosion surface by sediments during Pennsylvanian time created one of the most widespread 18 17 18 17 16 15 14 13 16 15 R 14 a C 15&- 17 16 n 18 i k h regional unconformities in the world, the Mississippian-Pennsylvanian unconformity. Younger Pennsylvanian age rocks overlap onto progressively older Mississippian age rocks d u d f g o r d c Temple Rd R e r d h R at increasing distances north of the Ohio River. d e R e R f S J e s e f r d l d c o o R i R eed b l h m p a n S k o d c b y e c o S a i s r l Bedrock aquifers are used much more than unconsolidated aquifers in most of the county. This is because unconsolidated materials are typically very thin, primarily consisting R d c R W s R R d d of weathered bedrock residuum. The exception is the Ohio River valley, where thick deposits of sand and gravel provide abundant ground water. d r SR 64 o nns Sto a n b e e C d S ipher R R e d H l o 19 20 r 21 M ho s 22 23 24 Beasley Rd c 24 o S 19 20 21 22 19 20 RiverBlue The susceptibility of bedrock aquifer systems to surface contamination is largely dependent on the type and thickness of the overlying sediments. Just as recharge for bedrock 23 23 24 21 22 i a n 21 22 k l l d 20 to 19 a R t P o aquifers cannot exceed that of overlying unconsolidated deposits, susceptibility to surface contamination will not exceed that of overlying deposits. However, because the bedrock R d w e l English l n aquifer systems have complex fracturing systems, once a contaminant has been introduced into a bedrock aquifer system, it will be difficult to track and remediate. i d d R v O T e R R v r d e c y e i r r h n e s e a o R d t l t 27 B l r e Tunnel Hill Rd Sl a i om id c g R k g C e D Rd d ric d nt d k R R o R d Pennsylvanian -- Raccoon Creek Group Aquifer System ek g &- re d Rd M 25 30 29 n 28 27 26 25 C roun ou 30 29 28 27 26 25 30 29 n pg 26 L &- 28 so 28 Cam 27 Y 29 r i 30 e v d S An m e i l th y 27 R Aquifers contained within the Pennsylvanian age bedrock have generally low yield potential. However, their value is most significant to the homes and farms using these sources. 1 d R 9 ell Rd d er Lasw In general, well depths are greater in the Pennsylvanian rocks than in other aquifer systems in the state, and depths over 200 feet are common. Well casing diameters are usually d rson Riv Balmer Rd 26 a Ande M d Pil o ot Knob Rd B o six inches or greater, indicating the low yield capabilities of these aquifers. Because of the low permeability of the bedrock, the abundance of shale confining zones both above unt R R S e d te Rd rli w &- n R n y r Rd g o e l t dau n R l and below aquifer systems, and the limitation in available drawdown, it is seldom possible to divert large volumes of water into any particular pumping center. Lin h u d l n o o a h o o G u over l nors Trace m a H h R o d C c 31 32 d 33 M C 36 34 35 36 r Mt S 31 32 33 a Lebanon Rd 35 34 35 36 &-31 32 33 The outcrop/subcrop area of the Raccoon Creek Group covers most of the uplands of western Crawford County. The group consists in ascending order of the Mansfield, Brazil, 34 i g &- 34 n 33 l o 32 l 35 o 31 B s and Staunton Formations. The Staunton Formation and the Brazil Formation are not present in the county. The Mansfield Formation rests unconformably on rocks of late R n M d itc h d h o Mississippian age. This erosional contact surface is quite irregular in elevation, resulting in quite a variable thickness of Mansfield rocks. e R J O ld ll C Felker Rd 36 ree p &- k S m R d T. 2 S. p d e T. 2 S. e R 1 K Total thickness of the group in the county ranges from 0 where the younger Mississippian rocks are exposed in the eastern half of the county to about 260 feet on ridge tops in e 7 T.

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