Here are the movies from the sonars on our quadpods. I added two new ones with 2-axis pencil beam rotary sonar imagery overlaid on top of the sidescan data to show some actual elevations of the bedforms in a limited region under the frame.
Since there has been a bit of discussion about bedforms recently I thought would post a kmz of sidescan imagery from May 5th. This survey started at the end of flood tide and the bedforms in the dredged channel were asymmetrical in flood oriented direction, by the end of the survey, 2 hrs later at the beginning off ebb tide flow, they had reversed asymmetry to ebb oriented.
The bedforms are generally bigger in the dredged channel on the southwest side of the inlet. This is especially noticeable in the inner portions of the inlet.
Not sure how to make post the images big enough here to see what is going on. Either click & download the images here or the kmz to see more detail
Posting on behalf of Rocky Geyer: These are near-surface velocity vectors from the WHOI REMUS at max ebb on May 4th in the north channel. Maximum ebb currents are well over 1 m/s. Lots of bathymetric steering, but some interesting free lateral shear zones as well.
Yesterday (May 2nd) we deployed two quadpods in the old and new channel (near the outer most red can channel marker #4) at the locations in the linked kml
These are 7′ tall frames that have the upper ~2 exposed at low tide and are submerged by ~2′ at high tide. They have various downward aimed sensors to measure flow, turbulence, sediment transport and bed morphology.
They are marked with red 6′ tall poles, and additional poles with yellow flashing lights will be added tomorrow or the next day.
We will be conducting REMUS and shipboard ADCP surveys for the next several days.
Many Thanks to Steve Elgar and Danik Forsman for the help with the deployment
In preparation for our quadpod deployement I conducted a quick sidescan survey of the old channel out my pod1 site and the new channel out to my pod2 site. Here is one spot in the newly dredged channel near WHOI (Elgar&Raubenhiemer’s) site 07.
KMZ’s with the complete data set can be downloaded here: