Landslide Dynamics of Trinity Ravine Ted Chwalk Elton Ham

Purpose l View Dynamics of Ravine and Gullies l Determine Depositional Environment l Hypothesis how depositional environment effects soil stability

Methods l Visual Observations –Ravine –Gullies –Landslide l Soil Pits –4 soil pits –Stratigraphic columns

Data: Gullies l 2/3 Gullies had active landslides l All had scarps ~1m high l All scarps had thick organic layer at surface

Data: Soil Pits

Data: Soil Pit Stratigraphic Column

Depositional Environment l Champlain Sea l Lake Vermont l Post Glacial

Discussion l Infiltration Rates in Sediments – Organic Topsoil 1-4mm/hr –Sand 4-8mm/hr –Silt 1-4 mm/hr –Heavy Clay 0-1mm/hr

Conclusions l Heavy Clays + Silt = Saturated Soil l Saturated Sand and Topsoil = Slope Failure –Liquification l Landslides are the primary processes effecting erosion l What do Landslides and Gullies Have in Common? –Landslide Erosion creates gullies –Landslide in Ravine = Possible Gully Formation

Things we would have done differently l Direct Study of Infiltration Rates l Quantitative Study of Local Landslide Dynamics, Gully formation, and how it relates to Sediment Transport

Questions ???