Friday, September 6, 2013

Sandy Pond II

Earlier this week I went back to Sandy Pond on an undergrad sedimentology field trip. Last year I was an observer, this year I am the TA for the class. The instructor for the class does most of the teaching on the field trip, although I'm still responsible for their lab write-ups and helping with some of the sampling etc.

This year, instead of going to Sandy Island Beach State Park first, we went straight to the marina and onto the boat to the barrier. It took two boat trips to get the big class over (I have 20 students) to the dunes, which imposed some logistical and time constraints on us, but it was still a good afternoon.

It was a sunny day, but very windy on Lake Ontario. There was less beach than I remember--not sure if that's because of the wind on the day, or if the lake really is higher than last year (time of year is the same). Still, we saw some great sand structures (interference ripples!!) and were able to walk up to the inlet to see how its migration is changing the barrier.

Ripples on the shore of Lake Ontario

Just a bit windy today...

Looking south along the beach. Those trees are growing on dunes.

Looking north to the inlet and the bird sanctuary

Something spooked the birds

Interference ripples...

... with a scalecard this time

Stormy skies in the north

Shell debris covering the "dune" This is probably where they dumped the sand when they dredged the inlet

Wind sculpted sand?

The inlet. It's been dredged since last year so that charter fishing boats can get to Lake Ontario from the pond

The inlet is moving north. You can see how it's incising the dunes on the other side.

A spot of sunlight on Lake Ontario


One of the most fascinating things I noticed was the wind blowing a fine single-grained sheet of sand across the beach, part of the process that minimizes the existing ripples. It's hard to see in this video, but the speckles are not noise, they're many individual grains of sand blowing across the surface (this video has no sound):

video

For a slightly higher quality version of the video, check out Vimeo.