may 2006 suncook river avulsion epsom, new hampshire · legend # erosional feature # high water...

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Epsom Traffic Circle Old Mill 0.75 Mile New Channel Scoured Area Abandoned Channel May 2006 Suncook River Avulsion Epsom, New Hampshire Digital Mapping by the New Hampshire Geological Survey, NHDES ® Data Sources 1. DOT Roads Coverage; New Hampshire Water Bodies Coverage 2. DOT Arieal Photography 3. Surficial Geologic Map of the Gossville Quadrangle, R. Goldsmith, New Hampshire Geological Survey Open-File Map; USGS 24K Digital Raster Graphic 4. USGS Digital Raster Graphics and Elevation Models Chad Wittkop, phone (603) 271-3915, e-mail: [email protected] Derek Bennett, phone (603) 271-4087, e-mail: [email protected] Rick Chormann, phone (603) 271-1975, e-mail: [email protected] David R. Wunsch, State Geologist, phone (603) 271-6482, e-mail: [email protected] Su n c o o k R iv e r Bear Island 1. Location Glacial Lake and Stream Sediments (Sand, Gravel, and Silt) 0.5 Miles 3. Surficial Geology Legend Glacial Till Shallow Bedrock Floodplain and Stream Terrace Wetlands 1 Mile 4. Topographic Map and Elevation Model of Avulsion Area 1967 Topographic Map Digital Elevation Model Saddle Between Sand Ridges Elevation 342 ft High Water Mark Approximate Elevation 335 ft River Elevation 324 ft River Elevation 300 ft # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # ! ! ! # ! # # Legend # Erosional Feature # High Water Mark # New Channel # Sand Sheet # Undisturbed Road 2. Differential GPS Surveys May 22 and 24, 2006 0.5 Mile Epsom Well House New Channel, Abaonded Channel, and Erosional Features Old Mill Gravel Pit 0 0.2 0.4 0.6 0.8 0.1 Miles Legend New Channel Scoured Area Abandoned Channel Length of New Channel: 0.44 miles (2,323 ft) Length of New Channel Plus Pre-existing Channel: 1.03 miles (5,483 ft) Length of Abandoned Channel (West): 1.52 miles (8,026 ft) Length of Abandoned Channel (East): 0.45 miles (2,376 ft) Total Length of Abandoned Channels: 1.97 miles (10,402 ft) Gradient of Abandoned Channel: 16 feet/mile Gradient of New Channel: 23 feet/mile Channel Statistics

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Page 1: May 2006 Suncook River Avulsion Epsom, New Hampshire · Legend # Erosional Feature # High Water Mark # New Channel # Sand Sheet # Undisturbed Road 2. Differential GPS Surveys May

Epsom Traffic Circle

Old Mill

0.75

Mile

New Channel

Scoured AreaAbandoned Channel

May 2006 Suncook River AvulsionEpsom, New Hampshire

Digital Mapping by the New Hampshire Geological Survey, NHDES

®

Data Sources1. DOT Roads Coverage; New Hampshire Water Bodies Coverage2. DOT Arieal Photography3. Surficial Geologic Map of the Gossville Quadrangle, R. Goldsmith, New Hampshire Geological Survey Open-File Map; USGS 24K Digital Raster Graphic4. USGS Digital Raster Graphics and Elevation Models

Chad Wittkop, phone (603) 271-3915, e-mail: [email protected] Bennett, phone (603) 271-4087, e-mail: [email protected] Chormann, phone (603) 271-1975, e-mail: [email protected] R. Wunsch, State Geologist, phone (603) 271-6482, e-mail: [email protected]

Suncook River

Bear Island

1. Location

Glacial Lake and Stream Sediments (Sand, Gravel, and Silt)

0.5

Miles

3. Surficial Geology

Legend

Glacial Till

Shallow BedrockFloodplain and Stream Terrace

Wetlands

1

Mile

4. Topographic Map and Elevation Model of Avulsion Area1967 Topographic Map Digital Elevation Model

Saddle Between Sand RidgesElevation 342 ft

High Water MarkApproximate Elevation 335 ft

River Elevation 324 ft

River Elevation300 ft

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Legend# Erosional Feature# High Water Mark# New Channel# Sand Sheet# Undisturbed Road

2. Differential GPS Surveys May 22 and 24, 2006

0.5

Mile

Epsom Well House

New Channel, Abaonded Channel, and Erosional Features

Old Mill

Gravel Pit

0 0.2 0.4 0.6 0.80.1

Miles

LegendNew Channel

Scoured AreaAbandoned Channel

Length of New Channel: 0.44 miles (2,323 ft)Length of New Channel Plus Pre-existing Channel: 1.03 miles (5,483 ft)Length of Abandoned Channel (West): 1.52 miles (8,026 ft)Length of Abandoned Channel (East): 0.45 miles (2,376 ft)Total Length of Abandoned Channels: 1.97 miles (10,402 ft)Gradient of Abandoned Channel: 16 feet/mileGradient of New Channel: 23 feet/mile

Channel Statistics