Geology and Ground-Water Resources of Southeastern New Hampshire By EDWARD BRADLEY GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1695 Prepared in cooperation with the New Hampshire Water Resources Board 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: Bradley, Edward, 1922- Geology and ground-water resources of southeastern New Hampshire. Washington, U.S. Govt. Print. Off., 1964. v, 80 p. maps (7 fold, in pocket) diagrs., tables. 24 cm. (U.S. Geological Survey. Water-supply paper 1695.) Prepared in cooperation with the New Hampshire Water Resources Board. Bibliography: p. 75-78. 1. Geology New Hampshire. 2. Water-supply New Hampshire. 3. Water, Underground New Hampshire. I. New Hampshire. Water Resources Board. (Series) For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 CONTENTS Page Abstract._______________________________________________________ 1 Introduction. ___________________________ _______-__._.___.__-_____ 2 Purpose and scope of the investigation.__________________________ 2 Location and extent of the area. ________________________________ 3 Methods of investigation.______________________________________ 4 Acknowledgments _____________________________________________ 5 Geography______________________________________________________ 7 Topography and drainage----____-__-_--________-____-----_____ 7 Climate._____________________________________________________ 8 Development _________________________________________________ 11 Population __ ____________________________________________ 11 Economy.___________ _ ___________________________________ 12 Water supply_________-_-___-_--_--_--_--__-_-___-_--_____ 13 Geology and the occurrence of ground water________________________ 13 Bedrock______________________________________ 16 Description and distribution._______________________________ 16 Water in the bedrock______________._______________________ 17 The bedrock surface.______________________________________ 18 Unconsolidated deposits________________________________________ 19 Summary of Pleistocene and Recent history_________________ 19 Till______________________________________________ 21 Ice-contact deposits______________________________________ 23 Marine deposits__________________________________________ 27 Outwash and shore deposits________________________________ 29 Swamp deposits___________________________________________ 30 Alluvium. _ _______________________________________________ 30 Beach deposits_________________________________.__________ 31 Eolian deposits__________________________________________ 31 Ground-water hydrology ___________________________________________ 32 Source and movement of ground water___________________________ 32 Recharge___________________________________________________ 33 Discharge ____________________________________________________ 33 Water-level fluctuations and changes in ground-water storage.______ 34 Utilization of ground water_________________________________________ 37 Quality of ground water______.____________________________________ 38 Mineral constituents in solution_________________________________ 42 Properties and characteristics of ground water___________________ 44 Quality of ground water in relation to rock types_________________ 46 Contamination of ground water_________________________________ 46 Recovery of ground water________________________________________ 47 Wells_________________________________________ 47 Springs_____________________________________________________ 50 m IV CONTENTS Aquifers in southeastern New Hampshire.-___________________________ 51 Rockingham County___________________________________________ 52 Atkinson _________________________________________________ 52 Brentwood___ ___________________________________________ 52 East Kingston ____________________________________________ 53 Epping.__________________________________________________ 53 Exeter ___________________________________________________ 54 Greenland ________________________________________________ 55 Hampton _________________________________________________ 55 Hampton Falls___________-________--___-_-____-_______-___ 56 Kensington._ _____________________________________________ 56 Kingston _________________________________________________ 56 Newcastle ________________________________________________ 57 Newfields. _ _______________________________________________ 57 Newington___________________________________ _____________ 57 Newmarket__ _ ____________________________________________ 58 Newton __________________________________________________ 59 North Hampton___________________________________________ 59 Plaistow________________________________________________ 60 Portsmouth_____________________________________________ 60 Rye____________-______.-____--_-_-_--__--_______ 60 Seabrook _________________________________________________ 61 South Hampton.. ___________________________ _____________ 61 Stratham_______________________________________________ 62 Strafford County._____________________________________________ 62 Barrington___ ___________________________________________ 62 Dover______________________________________________ 63 Durham____________________________________________ 66 Farmington.______________________________________________ 66 Lee_________________________________________________ 67 Madbury_______________________________________________ 68 Rochester ________________________________________________ 71 Rollinsford____________________________________ 72 Somersworth_ ___________________________________________ 73 Principal conclusions ______________________________________________ 75 Selected references _________________________________________________ 75 Index._______________________________________________ 79 ILLUSTKATIONS [Plates are in pocket] PLATE 1. Geologic map of part of Rockingham County, N.H. 2. Geologic map of part of Strafford County, N.H. 3-7. Geologic maps and sections of areas. 3. E. 4. D. 5. B. 6. C. 7. A. CONTENTS V Page FIGURE 1. Index map of New Hampshire..__________________________ 4 2. Sketch showing well-location system _______________________ 6 3. Annual precipitation at Durham, N.H_____________________ 9 4. Monthly precipitation at Durham, N.H ____________________ 10 5. Particle-size distribution curves.__________________________ 22 6. Ice-contact deposits in central part of Pudding Hill__________ 25 7. Unconsolidated deposits in the Johnson Creek area. _________ 26 8. Hydrographs of selected wells___________________-_-_______ 35 9. Diagrammatic cross section in the Coheco River valley_______ 67 TABLES Page TABLE 1. Population of towns in southeastern New Hampshire.-_______ 11 2. Geologic units in southeastern New Hampshire____________ 15 3. Particle-size analyses of selected samples of unconsolidated deposits in southeastern New Hampshire.________________ 23 4. Chemical analyses of water samples from selected wells and springs in southeastern New Hampshire._________________ 39 GEOLOGY AND GROUND-WATER RESOURCES OF SOUTH­ EASTERN NEW HAMPSHIRE By EDWARD BRADLEY ABSTRACT The continued growth and development of southeastern New Hampshire, an area of about 390 square miles adjacent to the Atlantic Ocean, will depend partly on effectively satisfying the demand for water, which has increased rapidly since World War II. The report identifies and describes the principal geologic units with respect to the occurrence of ground water. These units include bedrock and the various unconsolidated deposits that mantle the bedrock surface discontinuously through­ out the area. The bedrock formations, consisting of igneous and metamorphic rocks, chiefly of Paleozoic age, form a single water-bearing unit. Ground water is in joints and fractures. The fractures are small and scattered and therefore impart only a low permeability to the rocks. Wells in the bedrock commonly produce small but reliable supplies of ground water at depths of less than 150 feet. The yields of about 80 wells inventoried for this report ranged from l}{ to 100 gpm (gallons per minute) and the median was 9>£ gpm. Depths ranged from 45 to 600 feet. The unconsolidated deposits consist of glacial drift of Pleistocene age; swamp deposits, alluvium, and beach deposits of Recent age;, and eolian deposits of Pleistocene -and Recent age. For this report the glacial drift is divided into till, ice-contact deposits, marine deposits, and outwash and shore deposits. Glacial till forms a discontinuous blanket, commonly less than 15 but in some hills (drumlins) as much as about 200 feet thick. It has a low permeability but, because of its widespread outcrop area, it has been utilized as a source of water for numerous domestic supplies. Because most wells in till are shallow, many fail to meet modern demands during dry summers. Ice-contact deposits locally form kames, kame terraces, kame plains, and ice- channel fillings throughout the area. They overlie bedrock and till and range in thickness from less than 1 foot to as much as 190 feet. In general, the ice-contact deposits are coarse textured and permeable, but variations in the physical and hydrologic properties of a single deposit and from deposit to deposit are common. Ice-contact deposits are the source of the larger ground-water supplies in south­ eastern New Hampshire. Marine deposits underlie lowlands and valleys