-1 r r n CONFIDENTIAL REVIEW AND EVALUATION r OF GROUND-WATER CONTAMINATION AND PROPOSED REMEDIATION AT THE REILLY TAR SITE, ST. LOUIS PARK, MINNESOTA r. c Prepared by L Dr. James W. Mercer GeoTrans, inc. 209 Elden Street Herndon, Virginia 22070 [ Report to L U.S. Environmental Protection Agency Region V, Remedial Response Branch (5HR-13) Chicago, Illinois 60604 December 1984 L ieoT L GEOTRANS, INC. lrran« s P.O. Box 2550 Reston.Virginia 22090 USA (703)435-4400 EPA Region 5 Recorcte Ctr. i inn minium iflBiniiiiiiiw L 234542 r. CONFIDENTIAL REVIEW AND EVALUATION OF GROUND-WATER CONTAMINATION AND PROPOSED REMEDIATION AT THE REILLY TAR SITE, ST. LOUIS PARK, MINNESOTA Prepared By Dr. James W. Mercer GeoTrans, Inc. 209 El den Street Herndon, Virginia 22070 Report To U.S. Environmental Protection Agency Region V, Remedial Response Branch (5HR-13) Chicago, Illinois 60604 December 1984 TABLE OF CONTENTS Page LIST OF FIGURES v LIST OF TABLES vii 1.0 INTRODUCTION 1 1.1 PURPOSE AND SCOPE 1 1.2 SITE HISTORY 2 2.0 CONCLUSIONS AND RECOMMENDATIONS 4 2.1 CONCLUSIONS 4 2.2 RECOMMENDATIONS 6 3.0 SITE HYDROGEOLOGY 7 3.1 GEOLOGY 7 3.1.1 Stratigraphy 7 3.1.2 Geomorphic Features 14 3.2 GROUND-WATER HYDROLOGY 17 3.2.1 Flow Directions 17 3.2.1.1 Mount Simon-Hinckley Aquifer 17 3.2.1.2 Ironton-Galesville Aquifer 25 3.2.1.3 Prairie du Chien-Jordan Aquifer 25 3.2.1.4 St. Peter Aquifer 29 3.2.1.5 Drift-Platteville Aquifers 33 3.2.1.6 Vertical Gradients 35 3.2.2 Flow Properties 35 3.3 CHEMISTRY 39 4.0 GROUND-WATER MODELING 42 4.1 CODE SELECTED 42 4.2 GEOMETRY 43 4.2.1 Layering 43 4.2.2 Boundary Conditions 47 TABLE OF CONTENTS Page 4.3 HISTORY MATCHING 47 4.3.1 Wells 48 4.3.2 Flow Parameters 49 4.3.3 Results 49 4.4 PREDICTIVE SIMULATION WITH REMEDIATION 57 5.0 REMEDIAL ACTIONS 60 5.1 MULTIAQUIFER WELLS 60 5.1.1 Investigation 60 5.1.2 Remedy 61 5.2 NEAR-SURFACE CONTAMINATION 61 5.2.1 Deed Restrictions 61 5.2.2 Louisiana Avenue/Highway 7 61 Intersection Construction 5.3 DRIFT AQUIFER 62 5.3.1 Source Control 62 5.3.2 Gradient Control 62 5.3.3 Monitoring 62 5.3.4 Contingencies 63 5.3.5 Mitigated Impacts 63 5.4 PLATTEVILLE AQUIFER 63 5.4.1 Source Control 63 5.4.2 Gradient Control 63 5.4.3 Monitoring 64 5.4.4 Contingencies 64 5.4.5 Mitigated Impacts 64 5.5 ST. PETER AQUIFER 64 5.5.1 Source Control 64 5.5.2 Gradient Control 64 5.5.3 Monitoring 65 5.5.4 Contingencies 65 5.5.5 Mitigated Impacts 65 TABLE OF CONTENTS 5.6 PRAIRIE DU CHIEN-JORDAN AQUIFER 65 5.6.1 Source Control 65 5.6.2 Gradient Control 66 5.6.3 Monitoring 66 5.6.4 Drinking Water 66 5.6.5 Contingencies 67 5.6.6 Mitigated Impacts 67 5.7 IRONTON-GALESVILLE AQUIFER 67 5.7.1 Source Control 67 5.7.2 Gradient Control 68 5.7.3 Monitoring 68 5.7.4 Contingencies 68 5.7.5 Mitigated Impacts 68 5.8 MOUNT SIMON-HINCKLEY AQUIFER 68 5.8.1 Source Control 68 5.8.2 Gradient Control 68 5.8.3 Monitoring 69 5.8.4 Contingencies 69 5.8.5 Mitigated Impacts 69 6.0 REFERENCES 70 7.0 GLOSSARY OF TERMS 72 LIST OF FIGURES Number Legend Page 1.1 Location of former plant, St. Louis Park, Minnesota 3 (from Hult and Schoenberg, 1984). 3.1 Preliminary structural contours at the top of the 11 Mount Simon-Hinckley aquifer, where contour interval is 40 feet and datum is National Geodetic Vertical Datum of 1929 (from Hult and Schoenberg, 1984). 3.2 Preliminary structural contours at the top of the 12 Ironton-Galesville aquifer, where contour interval is 40 feet and datum is National Geodetic Vertical Datum of 1929 (from Hult and Schoenberg, 1984). 3.3 Preliminary structure contours at the top of the 13 Prairie du Chien-Jordan aquifer, where contour interval is 40 feet and datum is National Geodetic Vertical Datum of 1929 (from Hult and Schoenberg, 1984). 3.4 Preliminary structure contours at the top of bedrock, 15 where contour interval is 100 feet and datum is National Geodetic Vertical Datum of 1929 (from Hult and Schoenberg, 1984). 3.5 Preliminary bedrock geology, Minneapolis South and 16 Hopkin's quadrangles (from Hult and Schoenberg, 1984). 3.6 Hydrogeologic section through Minneapolis and St. Paul 18 (from Horn, 1983). Section trace not shown, but lies in an approximate east-west direction. 3.7 Potentiometric surface for the Mount Simon-Hinckley 19 aquifer based on water levels measured during January- March 1971 (from Schoenberg, 1984). 3.8 Potentiometric surface for the Mount Simon-Hinckley 20 aquifer based on water levels measured during January- February 1980 (from Schoenberg, 1984). 3.9 Potentiometric surface for the Mount Simon-Hinckley 21 aquifer based on water levels measured during August 1980 (from Schoenberg, 1984). 3.10 Hydrograph showing water level changes in the 24 Mount Simon-Hinckley aquifer in well number 117N21W32DAD01 in Edina, MN (from Schoenberg, 1984). Well location shown in Figures 3.7 to 3.9. LIST OF FIGURES I \ ' Number Legend Page f 3.11 Potentiometric surface for the Prairie du Chien- 26 i Jordan aquifer based on water levels measured during January-March 1971 (from Schoenberg, 1984). , 3.12 Potentiometric surface for the Prairie du Chien- 27 ! Jordan aquifer based on water levels measured during January-February 1980 (from Schoenberg, 1984). 1 3.13 Potentiometric surface for the Prairie du Chien- 28 Jordan aquifer based on water levels measured during j August 1980 (from Schoenberg, 1984). 3.14 Hydrograph showing water level changes in the Prairie 31 , du Chien-Jordan aquifer in well number 117N21W16CCA01 in east-central Hennepin County, MN (from Schoenberg, ' 1984). Well location shown in Figures 3.11 to 3.13. 3.15 Potentiometric surface for the St. Peter aquifer based 32 ; on water levels measured during the winter of 1970-1971 (from Norvitch et al., 1974). 3.16 Generalized potentiometric surface for the drift 34 aquifer based on water levels measured on June 5, 1979 (from Ehrlich et al., 1982). Contours are in meters. 4.1 Map showing boundaries used by ERT and U.S.G.S. 44 (after ERT, 1983). i 4.2 Comparison of calibrated ERT model results with observed 54 data for the Prairie du Chien-Jordan aquifer (from ERT, 1983). 4.3 Map showing the location of private and industrial wells 56 in the vicinity of the Reilly Tar site (from Hult and Schoenberg, 1984). VI LIST OF TABLES Number Legend Page 3.1 Stratigraphic Section Underlying Reilly Tar Site 8 (From Hult and Schoenberg, 1984) 3.2 Average Daily Pumpage From the Mount Simon-Hinckley 23 Aquifer, 1970-1979 (From Schoenberg, 1984) 3.3 Annual Daily Pumpage From the Prairie du Chien-Jordan 30 Aquifer, 1970-1979 (From Schoenberg, 1984) 3.4 Flow Properties of the Various Units Beneath the 36 Reilly Tar Site 4.1 Vertical Aquifer Geometry Used in the ERT Model 45 4.2 Vertical Aquifer Geometry Used in the U.S.G.S. Model 46 4.3 Values of U.S.G.S. Hydrologic Properties "50 (After Stark and Hult, 1984) 4.4 Values of ERT Model Hydrologic Properties 51 (After ERT, 1983) 4.5 Values Used by ERT to Compute Travel Times 52 4.6 Withdrawal Rates for Remedial Action Simulation 58 (From Stark and Hult, 1984) VII 1 REVIEW AND EVALUATION OF GROUND-WATER CONTAMINATION AND PROPOSED REMEDIATION AT THE REILLY'TAR SITE, I ST. LOUIS PARK, MINNESOTA ii | 1.0 INTRODUCTION r This section outlines the purpose and scope of work. In addition, ' for completeness and to help highlight the problem, a brief site history ! is provided. \!. 1.1 PURPOSE AND SCOPE In November 1984, GeoTrans, Inc. began an investigation of the ' Reilly Tar site in St. Louis Park, Minnesota, for purposes of trial preparation. The work was funded by the U.S. Environmental Protection Agency through a subcontract with PRC Engineering. The work was ) performed in conjunction with the U.S. Department of Justice, Minnesota Pollution Control Agency, and the Minnesota Attorney General's Office. The objectives of this investigation were, in part, to (1) review site « and basin-wide hydrogeologic data, (2) develop a conceptualization of site hydrology, (3) evaluate ground-water modeling performed at the site \ using the conceptualization of site hydrology as a basis, and (4) use all of the above to evaluate proposed site remediation. | The purpose of this report is to concisely summarize findings relevant to the objectives stated above. The report includes conclusions and recommendations, a review of site hydrogeology, and a i review of ground-water modeling, including proposed site remediation. L Where possible, conclusions have been summarized with supporting facts/ assumptions and data/reference sources. Comments have been restricted to those that concern hydrogeology. 1.2 SITE HISTORY Between 1917 and 1972, a coal-tar distillation and wood-preserving plant was operated by Reilly Tar & Chemical Corporation (RT&CC) on an | 80-acre site in St. Louis Park, Minnesota, as shown in Figure 1.1. Note the location of the former plant site, as it will be used for reference ir 1 in later figures. Coal-tar derivatives from this operation have j contaminated glacial drift and bedrock aquifers in this area (Hult and Schoenberg, 1984).