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GEOCHEMISTRY OF SURFACE AND SUBSURFACE WATER FLOW IN THE OTSEGO LAKE BASIN, OTSEGO COUNTY, NEW YORK Andrew R. Fetterman North South GeneraIize<i Geologic Cross Section of Otsgo Lake Basin Alt. (ft.) 2000­ 1800­ 1600­ 1400­ 1200 ­ 1000 ­ 800 {Modified from Sales and others, 1977·1 V.E.=-14X BIOLOGICAL FIELD STATION COOPERSTOWN,NEW YORK Occasional Paper No. 35 June 2001 STATE UNIVERSITY COLLEGE AT ONEONTA _--,I ABSTRACT Otsego Lake occupies a glacially modified valley within Paleozoic bedrock near the northern extent of the eastern Appalachian Plateau. Recognized as a Pleistocene glacial through-valley, Otsego Lake basin is a north-to-south trending, V-shaped valley underlain by gently southwest dipping Devonian limestones, siltstones, and shales. Late Pleistocene lacustrine clay overlying glacial sediments and bedrock serve as confining layers which retard and control vertical migration ofground water. Geochemical analyses of surface and ground water in the northern lake basin indicate water rich in dissolved calcite, dolomite, and gypsum. Water geochemistry profiles in Otsego Lake (TR4C) from August 1997 and August 1998 reflect a subtle chemocline where the epilimnion was supersaturated with respect to carbonate minerals while the hypolimnion was undersaturated. The subtle chemocline, defined by calcium, bicarbonate, and PCOz, mirrors the more pronounced thermal stratification. The distribution ofcarbonate-rich sediments on the lake floor is controlled by solubility relationships in the water column. Samples from tributaries to the lake including Cripple Creek., Hayden Creek, and Shadow Brook, were tested for dissolved ion concentrations, and mineral equilibria for common minerals (calcite, aragonite, dolomite, gypsum) were calculated. Local high concentrations of sulfate (SOl-) and calcium, and summer temperatures in the range of 80 C can be used as indicators for groundwater influx to surface streams. Point source, sulfate-rich springs, occur along Lake Cooperstown strandlines in Cripple Creek and Shadow Brook. Springs in Cripple Creek maintain a mean summer temperature of9.6° C with sol- concentrations exceeding 370 mgIL, whereas upstream concentrations average only 15 mgIL. Springs in Shadow Brook exceed 1000 mgIL sol-. Sulfate inputs to the system originate from a subsurface gypsum source as is recognized by positive ()34S values ranging from +4.2 to +47.2. Aqueous geochemical modeling of water samples indicates that springs in the Otsego Lake basin are fed by water that has encountered mixed carbonate-sulfate lithologies, and that dedolomitization has taken place within the groundwater system. By the common-ion effect, the solubility of calcite is depressed while the solutional capacity ofthe water for both dolomite and gypsum is greatly increased. Water supersaturated with respect to calcite and dolomite can continue to dissolve dolomite while precipitating calcite. Gypsum and carbonate-rich groundwater in Shadow Brook can dissolve five (5) times more dolomite than that ofgypsum-poor water by precipitating calcite. The process of dedolomitization is recognized as a source of early solutional porosity in certain carbonate terrains. " ii '- J TABLE OF CONTENTS Subject Page ABSTRACT 11 TABLE OF CONTENTS III LIST OF FIGURES v LIST OF PLATES V11 LIST OF TABLES V11 I. INTRODUCTION 1 II. NATURE OF STUDY AREA 3 A. PHYSIOGRAPHY 3 B. BEDROCK GEOLOGY 5 C. UNCONSOLIDATED SEDIMENTS 10 D. DRAINAGE PATTERNS 13 E. HYDROLOGY AND STREAM HYDROGRAPHS 14 III. METHODS 16 A. SAMPLING PROCEDURES 16 B. SAMPLE LOCATIONS 17 C. WESTERN TRIBUTARIES TO OTSEGO LAKE: GLIMMER GLEN CREEK, THREE MILE POINT CREEK, AND MOHICAN CANYON CREEK 20 D. WHITE CREEK (TROUT BROOK) 20 E. CRIPPLE CREEK 21 F. HAYDEN CREEK .. 21 G. SHADOW BROOK 22 H. WATERSAMPLING 23 I. ORIGINS OF DISSOLVED MINERALS 26 1. SULFUR ISOTOPES - GENERAL THEORY 27 IV. RESULTS 29 A. YEARLY AQUEOUS GEOCHEMICAL CYCLES 29 GLIMMER GLEN CREEK SITE 1 29 THREE MILE POINT CREEK SITE 1 30 MOICAN CANYON CREEK SITE 1 33 CRIPPLE CREEK 35 CRIPPLE CREEK SITE 1 35 CRIPPLE CREEK SITE 2a 37 CRIPPLE CREEK SITE 3 40 CRIPPLE CREEK SITE 4 41 HAYDEN CREEK 44 SUMMIT LAKE SPRING 44 HAYDEN CREEK SITE 2 47 HAYDEN CREEK SITE 3 48 HAYDEN CREEK SITE 4 2W HAYDEN CREEK SITE 5 52 HAYDEN CREEK SITE 6 53 HAYDEN CREEK SITE 7 54 HAYDEN CREEK SITE 9 57 111 TABLE OF CONTENTS (CONTINUED) Subject Page SHADOW BROOK 60 SHADOW BROOK SITE 2 60 SHADOW BROOK SITE 3 61 SHADOW BROOK SITE 4 64 SHADOW BROOK SITE 4a . 65 B. AQUEOUS GEOCHEMICAL VARIAnONS WITHIN SUB-DRAINAGE BASINS 68 CRIPPLE CREEK 68 HAYDEN CREEK 75 SHADOW BROOK 80 OTHER SITES: 84 NATTY BUMPPO'S SPRING 84 TR4C (OTSEGO LAKE WATER GEOCHEMISTRy) 84 C. SULFATE-RICH AND HYDROGEN-SULFIDE RICH WATER 91 D. DISCUSSION 97 GEOCHEMICAL SIGNATURES AND IONIC CONCENTRAnONS 97 GEOCHEMICAL MODELING 98 MIXING PHENOMENA 99 V. SUMMARY 102 ACKNOWLEDGMENTS 105 REFERENCES 106 App~ndix I Analytical Data Tables Appendix II Statistical Analyses IV LIST OF FIGURES (page 1 of 2) Page Figure 1 Physiographic Provinces of New York State 4 Figure 2 Bedrock Geology of Otsego Lake Basin 6 Figure 3 Bedrock Geology of Otsego Lake Basin in Cross-Section 7 Figure 4 Paleostand of Lake Cooperstown 12 Figure 5 ab USGS Stream Hydrographs of Susquehanna River at Conklin, NY 15 Figure 6 Sampling Locations on Otsego Lake Basin 18 Figure 7 Glimmer Glen Creek Site 1 (GG1) yearly geochemical cycle 32 Figure 8 Three Mile Point Creek Site 1 (TP1) yearly geochemical cycle 32 Figure 9 Mohican Canyon Creek Site 1 (MCl) yearly geochemical cycle 34 Figure 10 Cripple Creek Site 1 (CC1) yearly geochemical cycle 34 Figure 11 Cripple Creek Site 2a (CC2a) yearly geochemical cycle 39 Figure 12 Cripple Creek Site 3 (CC3) yearly geochemical cycle 39 Figure 13 Cripple Creek Site 4 (CC4) yearly geochemical cycle 43 Figure 14 Summit Lake Spring (SLSP) yearly geochemical cycle 43 Figure 15 Hayden Creek Site 2 (HC2) yearly geochemical cycle 46 Figure 16 Hayden Creek Site 3 (HC3) yearly geochemical cycle 46 Figure 17 Hayden Creek Site 4 (HC4) yearly geochemical cycle 51 Figure 18 Hayden Creek Site 5 (HC5) yearly geochemical cycle 51 Figure 19 Hayden Creek Site 6 (HC6) yearly geochemical cycle 56 Figure 20 Hayden Creek Site 7 (HC7) yearly geochemical cycle 56 Figure 21 Hayden Creek Site 9 (HC9) yearly geochemical cycle 59 Figure 22 Shadow Brook Site 2 (SB2) yearly geochemical cycle 59 Figure 23 Shadow Brook Site 3 (SB3) yearly geochemical cycle 63 Figure 24 Shadow Brook Site 4 (SB4) yearly geochemical cycle 63 Figure 25 Shadow Brook Site 4a (SB4a) yearly geochemical cycle 67 Figure 26 Cripple Creek geochemistry (SI and Peo2 values), August 1997 72 Figure 27 Cripple Creek geochemistry (SI and Peo2 values), March 1998 72 Figure 28 Cripple Creek geochemistry (concentrations and Peo2), August 1997 73 Figure 29 Cripple Creek geochemistry (concentrations and Peo2), March 1998 73 Figure 30 Cripple Creek geochemistry: Site CC2e, CC2eP, and CCDBW 74 Figure 31 Cripple Creek geochemistry: Site CC3a and CC3Ap 74 Figure 32 Hayden Creek geochemistry (concentrations and Peo2 values), August 1997 78 Figure 33 Hayden Creek geochemistry (concentrations and Peo2 values), March 1998 78 Figure 34 Hayden Creek geochemistry (SI values and Peo2 values), August 1997 79 Figure 35 Hayden Creek geochemistry (SI values and Peo2 values), March 1998 79 Figure 36 Shadow Brook geochemistry (concentrations and Peo2values), August 1997 82 Figure 37 Shadow Brook geochemistry (concentrations and Peo2 values), March 1998 82 Figure 38 Shadow Brook geochemistry (SI and Peo2 values), August 1997 83 Figure 39 Shadow Brook geochemistry (SI and Peo2 values), March 1998 83 Figure 40 Geochemistry of the Stocking Well (concentrations), August 1998 87 v List of Figures Continued (page 20f2) Page Figure 41 Geochemistry of the Stocking Well (SI values), August 1998 87 Figure 42 Geochemistry ofNatty Bumppo's Spring (concentrations), August 1998 88 Figure 43 Geochemistry ofNatty Bumppo's Spring (SI values), August 1998 88 Figure 44 Geochemical profile of Otsego Lake at site TR4C, August 1997 89 Figure 45 Geochemical profile of Ostego Lake at site TR4C, August 1998 89 Figure 46 Depth profile of Otsego Lake geochemistry, site TR4C, August 1997 90 Figure 47 Depth profile of Otsego Lake geochemistry, site TR4C, August 1998 90 Figure 48 Histogram of sulfate concentration and site elevation of sites in Otsego Lake basin 95 Figure 49 Sulfur isotope (o34S) fractionation analysis of selected sites in the Otsego Lake basin region 96 Figure 50 Geochemical model (SOLEQUIL) ofselected. spring water sites in the Otsego Lake basin region 101 VI LIST OF PLATES Page Plate 1 SEM of carbonate-rich material collected on Glass Slide 91 LIST OF TABLES Table 1 Site Location and Geologic Descriptions 19 Table 2 Geochemistry of GG1 30 Table 3 Geochemistry ofTPI 31 Table 4 Geochemistry ofMCI 35 Table 5 Geochemistry of CC 1 36 Table 6 Geochemistry of CC2a 38 Table 7 Geochemistry of CC3 41 Table 8 Geochemistry of CC4 42 Table 9 Geochemistry of SLSP 45 Table 10 Geochemistry of HC2 48 Table 11 Geochemistry of HC3 49 Table 12 Geochemistry of HC4 50 Table 13 Geochemistry ofHC5 53 Table 14 Geochemistry of HC6 54 Table 15 Geochemistry of HC7 55 Table 16 Geochemistry of HC9 58 Table 17 Geochemistry of SB2 61 Table 18 Geochemistry of SB3 62 Table 19 Geochemistry of SB4 65 Table 20 Geochemistry of SB4a 66 VII I. INTRODUCTION Otsego Lake basin is the headwaters for the Susquehanna River near the northern extent of the eastern Appalachian Plateau. The village of Cooperstown is situated on the southern shore ofthe lake and Springfield Center is rougWy 2 km north of the lake. The basin is unique in that the southern portion is underlain by Middle Devonian sandstone, siltstone, and shale, whereas the northern portion ofthe basin consists ofEarly Devonian and Late Silurian limestone bedrock.

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