Hydrogeologic Framework and Geochemistry of the Intermediate Aquifer System in Parts of Charlotte, De Soto, and Sarasota Counties, Florida Water-Resources Investigations Report 01-4015 Prepared in cooperation with the SOUTHWEST FLORIDA WATER MANAGEMENT DISTRICT SARASOTA CO. MANATEE CO. HARDEE CO. GULF OF MEXICO Sarasota Myakka City DE SOTO CO. ROMP 26 ROMP 17 ROMP 9.5 STUDY Venice ROMP 9 AREA ROMP 13 ROMP 12 Port Charlotte Englewood ROMP 5 Punta Gorda Charlotte 0 5 10 MILES Harbor CHARLOTTE CO. 0 5 10 KILOMETERS U.S. Department of the Interior U.S. Geological Survey Hydrogeologic Framework and Geochemistry of the Intermediate Aquifer System in Parts of Charlotte, De Soto, and Sarasota Counties, Florida By A.E. Torres, L.A. Sacks, D.K. Yobbi, L.A. Knochenmus, and B.G. Katz U.S. Geological Survey Water-Resources Investigations Report 01–4015 Prepared in cooperation with the SOUTHWEST FLORIDA WATER MANAGEMENT DISTRICT Tallahassee, Florida 2001 U.S. DEPARTMENT OF THE INTERIOR GALE A. NORTON, Secretary U.S. GEOLOGICAL SURVEY CHARLES G. GROAT, Director Use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Geological Survey. For additional information Copies of this report can be write to: purchased from: District Chief U.S. Geological Survey U.S. Geological Survey Branch of Information Services Suite 3015 Box 25286 227 N. Bronough Street Denver, CO 80225 Tallahassee, FL 32301 888-ASK-USGS Additional information about water resources in Florida is available on the World Wide Web at http://fl.water.usgs.gov CONTENTS Abstract.................................................................................................................................................................................. 1 Introduction ........................................................................................................................................................................... 3 Purpose and Scope....................................................................................................................................................... 3 Description of the Study Area ..................................................................................................................................... 4 Previous Investigations................................................................................................................................................ 4 Acknowledgments ....................................................................................................................................................... 5 Methods of Study................................................................................................................................................................... 5 Hydrogeology .............................................................................................................................................................. 5 Geochemistry............................................................................................................................................................... 6 Water Sampling ................................................................................................................................................. 6 Rock Sampling .................................................................................................................................................. 6 Geochemical Modeling...................................................................................................................................... 7 Geologic Framework ............................................................................................................................................................. 7 Depositional History.................................................................................................................................................... 8 Stratigraphy Underlying the Study Area ..................................................................................................................... 9 Avon Park Formation, Ocala Limestone, and Suwanne Limestone.................................................................. 9 Hawthorn Group................................................................................................................................................ 9 Arcadia Formation................................................................................................................................... 10 Nocatee and Tampa Members .......................................................................................................11 Peace River Formation ............................................................................................................................ 11 Bone Valley Member of the Peace River Formation..................................................................... 11 Tamiami Formation ........................................................................................................................................... 11 Surficial Deposits .............................................................................................................................................. 12 Hydrogeologic Units and Hydraulic Properties..................................................................................................................... 12 Surficial Aquifer System ............................................................................................................................................. 12 Intermediate Aquifer System....................................................................................................................................... 14 Upper Floridan Aquifer ............................................................................................................................................... 17 Confining Units ........................................................................................................................................................... 18 Ground-Water Flow Patterns ....................................................................................................................................... 18 Hydraulic Connection Between Hydrogeologic Units ................................................................................................ 23 Hydraulic Characteristics at the ROMP 9.5 Site ................................................................................................................... 25 Core Analysis .............................................................................................................................................................. 25 Specific-Capacity Tests ............................................................................................................................................... 25 Aquifer Tests................................................................................................................................................................ 26 Test Design and Implementation ....................................................................................................................... 26 Analytical Analysis of Aquifer Tests................................................................................................................. 31 Hantush (1960) Modified Leaky Method................................................................................................ 31 Jacob (1946) Leaky Artesian Method ..................................................................................................... 31 Neuman and Witherspoon (1972) Ratio Method..................................................................................... 33 Numerical Analysis of Aquifer Tests ................................................................................................................ 33 Limitations of Aquifer Test Analysis ................................................................................................................ 39 Geochemistry of Aquifer Systems......................................................................................................................................... 39 Chemical Composition of Ground Water .................................................................................................................... 39 Vertical Profiles of Chloride and Sulfate........................................................................................................... 43 Saturation State of Ground Water...................................................................................................................... 45 Isotopic Composition of Ground Water....................................................................................................................... 46 Stable Isotopes................................................................................................................................................... 46 Age of Ground Waters....................................................................................................................................... 48 Mineralogical and Isotopic Composition of Aquifer System Material ....................................................................... 50 Geochemical Evolution of Ground Water Along Flow Paths ....................................................................................