Landslides and Ground Water Permeability with Respect to theContact of Glacial Lake Vermont

and the Champlain SeaSediments at Town Line Brook,

Winooski, VT

Michala PeabodyLara Vowles

Location Map

Town Line Brook Timeline

• 13,000 years ago retreat of Laurentide Ice Sheet developed Glacial Lake Vermont

• 12,000-10,000 years ago continued retreat of Ice Sheet permitted formation of The Champlain Sea

• Land rebounded causing the formation of Lake Champlain

• Town Line Brook developed creating a v-shaped valley running into the Winooski River.

Objectives• Determine the Exact

contact between Lake VT and Champlain Sea

• Determine how different sediments affect groundwater permeability

• Determine how this affects landslides

Methods• Dig out trenches to

find contact• Use pocket vane tester

to determine shear strength of sediments

• Use level & rod to create a cross section of area

• Obtain a core sample of contact

Elevation (meters)

Distance (meters)

Vertical Exaggeration 1:2

EastWest

Top Hole

Middle Hole

Bottom Hole

Contact Point Town Line Brook

0

1

2

3

4

5

6

7

8

9

10

40 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0

Cross Section

Results...starting @ top

• Champlain Sea sediments: alternating fine sand and silt layers

Top Hole

Results...cont.

Middle Hole Bottom Hole

Results...Contact!

• Distinct layer of oozing slime consisting of fine silt and sand

• Situated above hard packed Glacial Lake VT sediments

The Core

Check it Out!!

Results...below contact

• Hard packed

• Thin varved layers

• Alternating red / gray

• Creation of mini-landslide developing at contact

Mini-LandslideCreated by Lara & Michala...oops

Aerial Photographs1962

Aerial Photographs1988

Aerial Photographs1999

“In landslides, as in life. It’s the little things that count.”

~S.P. “Slump or Slide, Density Decides”

Much Thanks to Stephen Wright!!