Ground-Water Resources of North-Central Connecticut
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MA' J964 Ground-Water Resources of North-Central Connecticut GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1752 Prepared in cooperation with the Connecticut ff^ater Resources Commission Ground-Water Resources of North-Central Connecticut By ROBERT V. CUSHMAN GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1752 Prepared in cooperation with the Connecticut Water Resources Commission UNITED STATES GOVERNMENT PRINTING-OFFICE, WASHINGTON : 1964 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director The U.S. Geological Survey Library has cataloged this publication as follows; Cushman, Robert Vittum, 1916- Ground-water resources of north-central Connecticut. Washington, U.S. Govt. Print. Off., 1963. v, 97 p. maps (part col.) diagrs., tables. 24 cm. (U.S. Geological Survey. Water-supply paper 1752) Part of illustrative matter fold, in pocket. Prepared in cooperation with the Connecticut Water1 Resources Commission. Bibliography: p. 91-93. (Continued on next card) Cushman, Robert Vittum, 1916- Ground-water resources of north-central Connecticut. 1963. (Card 2) 1. Water, Underground Connecticut. 2. Water-supply Connecti cut. 3. Geology Connecticut. 4. Water Composition. I. Connecti cut. Water Resources Commission. (Series) For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.G. 20402 CONTENTS Pag* Abstract_____________________________________________________ 1 Introduction..____________________________________________________ 3 Location and general features of the area...______________________ 3 Purpose of the investigation____________________________________ 4 Methods of study and scope of investigation ______________________ 5 Previous ground-water and geologic investigations _________________ 6 Acknowledgments. __________________________________________ 8 Well-numbering system ________________________________________ 10 Topography ______________________________________________________ 11 Streams-_______________________________________________________ 12 Climate-_________________________________________________________ 14 Physiographic development_________________________________________ 16 Pre-Pleistocene history.________________________________________ 17 Pleistocene glaciation__________________________________________ 18 Post-Pleistocene history ______________________________________ 21 Geology.__ _ ____________________________________________________ 21 Descriptions and water-bearing properties of the geologic formations. 21 Consolidated rocks_______________________________________ 22 Crystalline rocks of pre-Triassic age____________________ 22 General character and extent______________________ 22 Water-bearing properties ___________________________ 26 Yields of wells. __ ______________________ 27 Sedimentary rocks of Triassic age______________________ 28 General character and extent___________________ 28 Water-bearing properties___-___-__-___--__-______ 31 Factors causing areal variation in yield_____________ 35 Igneous rocks of Triassic age__________________________ 37 General character and extent_____________________ 37 Water-bearing properties.________________________ 38 Well construction________________________________ 39 Unconsolidated deposits____________________________________ 40 Ground-moraine deposits_________________________-___-_ 40 General character and extent______________________ 40 Water-bearing properties____-____________-_______ 43 Ice-contact deposits__________________________________ 44 General character and extent___________________ 44 Water-bearing properties____--_-____-------__-__-_- 46 Ice-contact deposits in Glastonbury, Manchester, and Vernon_________________________________________ 47 Ice-contact deposits in South Windsor and East Wind sor_____________________________ 48 Ice-contact deposits in Ellington and Somers______-- 49 in IV CONTENTS Geology Continued Descriptions and water-bearing properties of the geologic formations Con tinued Unconsolidated deposits Continued Page Outwash-plain, valley-train, and undifferentiated outwash deposits..--.-______________________________________ 50 General character and extent______________________ 51 Water-bearing properties___________________________ 53 Buried outwash deposits in the preglacial channel of the Connecticut River_____-_-_-_-_--_-_-_-_-_---___-___- 54 General character and extent______________________ 54 Water-bearing properties___________________________ 55 Glaciolacustrine and associated delta deposits_____________ 56 General character and extent of the glaciolacustrine deposits______________________________________ 56 Water-bearing properties of the glaciolacustrine deposits, 58 General character and extent of the deltaic deposits 5$ Water-bearing properties of the deltaic deposits_______ 60 Flood-plain deposits----------------------------------- 60 Dune deposits_______________________________________ 6^ Swamp deposits.-__-----_------_-------------------_-- 6l Ground water____________________________________________________ 62 General principles__-_______-_______--___-_-__---__---_-_---_-_ 62 Ground water in upland areas_______--_______-_____-_-__---___ 64 Till-mantled bedrock______________________.-._ 64 Shape and slope of the water table. ______-______--_-_-_ 64 Depth to water_____________________________________ 64 Recharge, movement, and discharge.____________________ 65 Ground water in lowland and valley areas. _______-----_-___-- _ 66 Tracts of outwash deposits_ ____________________________ 66 Shape and slope of the water table___-__--_-------------_ 66 Depth to water_____________________________________ 67 Recharge, movement, and discharge _____________________ 67 Buried outwash deposits in the preglacial channel of the Con necticut River____________________-___-_-_--_-_---_-__-- 68 Hydrostatic head________________-_-_-____-_-----_-__ 68 Recharge, movement, and discharge--------------------- 69 Glaciolacustrine and associated delta deposits_-___--_---_-__-_ 69 Shape and slope of the water table ___________________ 70 Depth to water___________________- ____--___-_---_- 70 Recharge, movement, and discharge.____-____----_-_____ 70 Fluctuations and trends of water levels---____-___-_-----_-------- 71 Quality of water___________________________ ________________ 73 Chemical constituents in relation to use..____________________ 78 Dissolved solids--------------------------------- --- 78 Hardness-____-________--__---_----------------------- 79 Iron. _____---____-________-_------_---------------_ 80 Chloride -_-.___------------------------------ 80 Hydrogen-ion concentration (pH) ___________________ 80 Minor constituents------------------------------------ 81 Water for irrigation__-_-___--_----__-------__---------- 81 CONTENTS Ground water Continued Quality of water Continued Types of water_____________.______________________________ 81 Quality in relation to water-bearing formations.____---__----__ 82" Pre-Triassic crystalline rocks__________________________ 82 Triassic sedimentary rocks____________________________ 82 Triassic basalt_-_----_-_-_-------__--_-_-------------- 83 Ground-moraine deposits.____________________________ 84 Ice-contact, valley-train, and outwash-plain deposits. ______ 84 Lacustrine and associated delta deposits.____-___-_-_---__ 84 Buried outwash deposits________________________ _____ 84 Utilization of ground water____-__--_-___-_______-__-_-_-------- 85 Public water supplies._____________________________________ 85 Industrial supplies.---.------------------------------------ 86 Domestic and stock supplies-------------------------------- 87 Irrigation supplies._____-______---__-__-__-_-___-__-_----__ 87 Future development of ground water_______________________________ 87 References cited.__________________________________________________ 91 ndex____________________________________________________________ 95 ILLUSTRATIONS [Plates are in pocket] PLATE 1. Map of north-central Connecticut showing generalized geology and well locations. 2. Map of north-central Connecticut showing contours on the bedrock surface. 3. Geologic sections. Page FIGURE 1. Index map of Connecticut showing area of report.___________ 3 2. Cumulative frequency curves of yield of wells___-___________ 34 3. Hydrographs of water levels. ________________ _______ 72 4. Graph showing typical chemical character of water__________ 74 5. Water-analysis diagram showing chemical character of water__ 75 TABLES Page TABLE 1. Summary of streamflow data in north-central Connecticut...- 13 2. Summary of meteorological data at Hartford ___________ 15 3. Stratigraphic units in north-central Connecticut and their water-bearing properties______________________________ 24 4. Chemical analyses of water from typical wells -__-___---__ 76 GROUND-WATER RESOURCES OF NORTH-CENTRAL CONNECTICUT By EGBERT V. CUSHMAN ABSTRACT The term "north-central Connecticut" in this report refers to an area of ahout 640 square miles within the central lowland of the Connecticut River basin north of Middletown. The area is mostly a broad valley floor underlain by unconsolidated deposits of Pleistocene and Recent age which mantle an erosional surface formed on consolidated rocks of pre-Triassic and Triassic age. The mean annual precipitation at Hartford, near the center of the area, is 42.83 inches and is uniformly distributed throughout the year. .The average annual stream- flow from the area is about 22 inches or about half the precipitation. The consolidated water-bearing formations are crystalline rocks of pre-