Geohydrology, Yield, and Water Quality of Stratified-Drift Aquifers in the Pemigewasset River Basin, Central New Hampshire By JOHN E. COTTON and JOSEPH R. OLIMPIO U.S. Geological Survey Water-Resources Investigations Report 94-4083 Prepared in cooperation with the NEW HAMPSHIRE DEPARTMENT OF ENVIRONMENTAL SERVICES, WATER RESOURCES DIVISION Pembroke, New Hampshire 1996 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Gordon P. Eaton, Director For additional information write to: Copies of this report can be purchased from: Chief, New Hampshire-Vermont District U.S. Geological Survey U.S. Geological Survey Branch of Information Services Water Resources Division Box 25286 361 Commerce Way Denver, CO 80225-0286 Pembroke, NH 03275 CONTENTS Abstract............................................................................................................^^ 1 Introduction.............................................................................................^^ 2 Purpose and Scope ................................................................................................................................................... 2 Study Area................................................................................................................................................................ 2 Previous Studies....................................................................................................................................................... 4 Numbering System for Wells, Borings, and Springs................................................................................................ 4 Methods and Approach............................................................................................................................................ 4 Acknowledgments.................................................................................................^ 5 Geohydrologic Setting........................................................................................................................................................ 6 Geohydrologic Units................................................................................................................................................ 6 Stratified Drift................................................................................................................................................ 6 Glaciofluvial Deposits.......................................................................................................................... 6 Glaciolacustrine Deposits..................................................................................................................... 7 Till.................................................................................................................................................................. 8 Bedrock.......................................................................................................................................................... 9 Redistribution of Earth Sediments ........................................................................................................................... 9 Geohydrology of Stratified-Drift Aquifers......................................................................................................................... 10 Delineation of Aquifer Boundaries and Water Table............................................................................................... 10 Areal Extent of Stratified-Drift Aquifers ....................................................................................................... 10 Stratigraphic Boundaries and Altitude of Water Tables................................................................................. 10 Well and Boring Data........................................................................................................................... 12 Seismic-Refraction Data...................................................................................................................... 12 Test Borings.......................................................................................................................................... 12 Ground Water........................................................................................................................................................... 13 Recharge, Discharge, and Direction of Row................................................................................................. 13 Water Levels................................................................................................................................................... 14 Aquifer Characteristics............................................................................................................................................. 14 Saturated Thickness and Storage.................................................................................................................... 14 Transmissivity and Hydraulic Conductivity................................................................................................... 16 Locations and Descriptions of Selected Stratified-Drift Aquifers ........................................................................... 19 Lower Pemigewasset River Basin.................................................................................................................. 19 Bagoon Brook Valley........................................................................................................................... 19 New Hampton Town Center................................................................................................................. 20 Newfound River Valley........................................................................................................................ 20 Confluence of the Smith and Pemigewasset Rivers............................................................................. 20 Needle Shop Brook Valley................................................................................................................... 20 Pemigewasset River Valley in Hill and Franklin ................................................................................. 20 Salmon Brook Valley ........................................................................................................................... 20 Middle Pemigewasset River Basin................................................................................................................. 20 Ashland, Bridgewater, and New Hampton........................................................................................... 20 Ashland, Holderness, and Plymouth.................................................................................................... 21 Campton and Southern Thornton......................................................................................................... 26 Upper Pemigewasset River Basin.................................................................................................................. 26 Pemigewasset River Valley in Southern Thornton to Lincoln............................................................. 26 Mad River Valley at Waterville Valley................................................................................................ 27 Contents III Geohydrology of Stratified-Drift Aquifers Continued Locations and Descriptions of Selected Stratified-Drift Aquifers Continued Smith River and Newfound Lake Basin......................................................................................................... 28 Smith River Valley in Eastern Danbury, Alexandria, and Bristol........................................................ 28 Smith River Valley in Grafton and Danbury ........................................................................................ 28 Fowler River Valley (Newfound Lake Basin) in Alexandria............................................................... 29 Cockermouth River Valley (Newfound Lake Basin) in Groton and Hebron........................................ 30 Baker River Basin........................................................................................................................................... 30 Lower Baker River Valley in Rumney and Plymouth.......................................................................... 30 Upper Baker River Valley in Wentworth and Warren .......................................................................... 30 Evaluation of Aquifer Yield................................................................................................................................................ 34 Ground-Water Yield of the Pemigewasset River Basin............................................................................................ 34 Simulation of Ground-Water Flow in the Stratified-Drift Aquifer at the Town of Woodstock................................ 36 Assumptions................................................................................................................................................... 37 Grid and Boundary Conditions....................................................................................................................... 39 Aquifer Parameters......................................................................................................................................... 40 Recharge and Discharge................................................................................................................................