The Pinger Newsletter, Volume 7 Number 1 - Quester Tangent

VOLUME 7 NO 1 JANUARY/APRIL 2012
New York City Subway Cars mapped
using Acoustic Seabed Classification
Nicole Raineault, Ph.D. Candidate
Dr Art Trembanis, Coastal Sediments, Hydrodynamics and Engineering Laboratory, University of Delaware
Dr. Doug Miller, College of Earth, Ocean, and Environment, University of Delaware
Vince Capone, Black Laser Learning
Mapping the Shifting Sands at the Redbird Artificial Reef
using QTC SWATHVIEW
The continental shelf off the east coast of the U.S. is often thought
of as a vast, sandy desert. While a blanket of sand covers the shelf
in this area, many states are creating oases in this desert in the ultimate
form of recycling: sinking unwanted objects, like ships, concrete
objects, and tire units to create valuable habitat for fish and other
creatures. The once bare seafloor becomes a vibrant, living reef due
to the addition of structure, which creates habitat space and may
cause an upwelling of nutrients. The reefs increase recreational fishing
and diving trips and are so successful that states now bid for the materials
that were once unwanted.
QTC IMPACT has been reborn.!
Quester Tangent introduces a New Era to classification of single beam data.
After more than 10 years of sterling service, we have
completely rewritten our QTC IMPACT classification
software from the ground-up to offer:
New suite of feature-algorithms incorporating the latest research
for more accurate, robust bottom classification
New Adaptive SEL depth compensation provides superior
performance across a wide range of depths and echo sample rates
New interactive Echogram display with novel QA tools assures
accurate results
New streamlined workflow makes the software simple and easy
to use, from echo to classification
We are now shipping the new QTC IMPACT—contact us for details or to upgrade your existing license.
www.questertangent.com
Figure 1: Artificial Reef Site
info@questertangent.com

VOLUME 7 NO 1
QTC SWATHVIEW and Redbird Reef continues
www.questertangent.com
JANUARY/APRIL 2012
The Redbird artificial reef site is located at 28 m depth on the inner continental shelf 16 miles from the coast of
Delaware (Fig. 1). Started in 1996, the Delaware Division of Fish and Wildlife has added new objects to the reef
through 2010. The reef is made up of over 900 NYC Redbird-line subway cars, decommissioned military track
vehicles, barges, tugs, and other objects covering a 1.3 square nautical mile area.
We surveyed the site using a towed 500 kHz Klein
side-scan sonar annually from 2008-2011. In addition
we obtained bathymetric data from a 500 kHz Geoswath
phase-measuring bathymetric sonar (PMBS) on a Gavia
autonomous underwater vehicle (AUV) platform in
October 2010. We have found that the subways cars are
very successful as reef objects. The subway cars added
to the reef in 2001 through 2002 appear to have remained
intact for the most part. The surfaces of the reef objects
have been colonized by encrusting organisms and there
is an abundance of fish.
While the reef objects serve to increase the abundance
and diversity of life, the addition of structure to the
seafloor has unintended consequences. Structures on
the seafloor alter hydrodynamic forcing by waves and
currents, causing scour, or a lowering of the seabed. The
extent of scour that occurs depends on many factors
including surface and subsurface sediment characteristics, Figure 2: Scour Motes and Gravel Patches on the reef site
size of the object, incident wave and current energy,
frequency of storms, and object orientation to the flow. By examining the effects of the reef object on the seafloor,
we can form hypotheses about the effect of other engineered structures like wind towers on seafloor sediment and
transport processes.
Bathymetry of the area shows the reef is set in a recessed, swale, area (Fig. 1). Since the reef is surrounded by two
raised ridges, it accumulates higher amounts of fine sediment (silt and clay) than the sandy ridges. However, there
is a local increase in turbulence around the objects, which removes fine sediment and creates a scour mote.
Individual motes can be 10-30 m in diameter and 0.5-1 m deep (Fig. 2a). The individual scour motes around
individual reef objects coalesce when multiple objects are clustered, creating whole-scale gravel patches over
large areas of the seafloor.
Figure 3: Reef classification with QTC SWATHVIEW
Backscatter mosaics characterized by ROV images
and Smith-MacIntyre grab samples show changing
sediment patterns. Scoured areas are composed of
sand and gravel, while the areas remote from the
objects are composed of sand with silt and clay. The
backscatter from annual side-scan surveys show that
the comet-shaped gravel patches grew in the WSW
direction between 2008-2011 (Fig. 2b).
QTC SWATHVIEW was used to compare site-scale
sediment change. QTC SWATHVIEW detected the
two dominant sediment classes and
the metal reef objects (Fig. 3).
Comparisons between areas common
to the 2008 and 2010 survey show
an increase in coarse sediment
around individual reef objects,
info@questertangent.com

VOLUME 7 NO 1 JANUARY/APRIL 2012
QTC SWATHVIEW and Redbird Reef continues
while boundaries between large
areas of gravel and fine sediment
remain largely unchanged.
The increased coarse sediment near
reef objects affects the biology at the
site. There is very low abundance
of organisms, like sea star and hermit
crab on the silty sand that covers most of the site. The coarse sediment supports
a higher abundance and diversity of organisms.
Using acoustic backscatter and bathymetric surveys in combination with
QTC SWATHVIEW helped examine inter-annual, large-scale sediment
change at the dynamic Redbird reef. Knowing the magnitude and frequency of
scour and sediment change around seafloor structures can help coastal zone
managers determine the likely impact of adding new structures to the seafloor.
For more information please see:
Raineault N.A., A.C. Trembanis, and D.C. Miller, 2011. Mapping Benthic Habitats in Delaware Bay and the
Coastal Atlantic: Acoustic Techniques Provide Greater Coverage and High Resolution in Complex, Shallow-Water
Environments, Estuaries and Coasts, DOI: 10.1007/s12237-011-9457-8.
Thanks to Steven Donohue and the US EPA Mid-Atlantic Region Dive Team.
www.questertangent.com
Farewell Jon………
Since December 1998 we at Quester Tangent have had the honour and pleasure of
working with Dr. Jon Preston. Time moves on, and Jon has reached a point where
he wants to slow things down a little.
Jon has been the backbone and inspiration of our Research and Development efforts.
With his R&D team, Jon fashioned the science embodied in our marine products—
especially the original QTC MULTIVIEW and QTC SIDEVIEW software now so
widely accepted by discerning scientists, researchers and surveyors wishing quality
bottom classification of swath sonar data.
More than this, Jon has unselfishly imparted his knowledge and experience to many people far and wide, presenting
tutorials, papers, seminars and training clients. Fortunately for many of us, Jon has always had the patience to
humour those who have little technical skill. He has set an example to be followed and cherished by those of us
who were fortunate enough to have experienced it. And let’s not forget...we at QTC are also all much more
knowledgeable about Jon’s other passion—Curling. Thank you Jon for introducing us to this unique sport!
However— the time has now come for Jon to lay down his sonar and move on to a new era—retirement. While
we envy you, and are somewhat jealous of your opportunity to have more time to enjoy the finer things in life, we
are also very pleased that retirement, for you, does not mean we will not see you in future, or have your skills and
experience available to us.
Jon will be continuing his association with Quester Tangent as a Consulting Scientist, so,
those of you out there who have met Jon through QTC—you will still hear from him from
time to time! Here’s wishing you happy times Jon—enjoy the years ahead.
Throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails.
Explore. Dream. Discover." ~ Mark Twain
Redbird Rail Car. Top image a 3-D model of
a car on the seabed (courtesy All City Style).
Lower image courtesy of Wikipedia
info@questertangent.com

VOLUME 7 NO 1
International Partner: focus on……..
Quester Tangent’s partner for Eastern Europe, Martin Volz of
emma technologies, provides technologies, solutions and services
designed for environmental + monitoring + measuring applications.
emma technologies GmbH offers premium equipment made by internationally
reputed manufacturers and supplies integrated systems and solutions finely
tuned to client specifications. Whether you start a new project or you have to
integrate new tasks into an existing project and its equipment pool, emma is
there to take over and address your needs.
Our emma innovations department has
designed a multi-purpose research boat on
which state-of-the-art survey techniques,
communication technology and sampling
methods can be employed to fulfill a
broad cross section of survey tasks in
shallow water in a more economical way.
This cost-effective and adaptive solution emma multipurpose research boat
is available through emma, as is our
NEW workclass unmanned surface vehicle for monitoring and inspection
applications, named BOSS (Biosphere Observing & Servicing System). Stable,
robust and flexible, the BOSS platform carries a wide range of custom sensors.
Our customers rely on emma for
a simple reason: To receive a
tailored solution by one reliable
partner who monitors all
requirements from the start to
the successful end of the project.
Quester Tangent
6582 Bryn Road
Saanichton, British Columbia
Canada, V8M 1X6
Tel: +1-250-656-6677
Email: info@questertangent.com
Web: www.questertangent.com
www.questertangent.com
BOSS – Biosphere Observing & Servicing System
simply ask emma - we'll see to the rest
For more details visit www.emma-technologies.com/ or contact Chris or Tony at
Quester Tangent.
JANUARY/APRIL 2012
TO CONTACT US
Chris Elliott
Director, Marine
Tel: 250-654 3301
Cell: 250-744 9968
celliott@questertangent.com
Tony Tipple
Senior Technical Sales
Tel: 250-654 3308
Cell: 250-516 1661
ttipple@questertangent.com
Jon Preston
Consulting Scientist
Tel: 250-654 3316
jpreston@questertangent.com
Tony Christney
Lead Developer
Tel: 250-654 3316
t@questertangent.com
Ben Biffard
Applications Scientist
Tel: 250-654 3316
bbiffard@questertangent.com
Compiled and edited by:
Martina Elliott—Elmar Studio
Tel: 250-891-5107
elltalk@shaw.ca
Tony’s Tips
So little space this time, that I simply want to comment on our new QTC IMPACT software for single
beam classification. This product is such a radical change from our old software, you simply MUST
try it! Our new software is called QTC IMPACT 12 to distinguish it from the “old” QTC IMPACT.
The only part of QTC IMPACT 12 not entirely new is ACE, the Autocluster function, which is
incorporated from the previous version. This is not a face-lift! It is new! Contact me to arrange a demo.
Do you have any articles of
interest you would like to
contribute to The Pinger?
Please contact Chris Elliott
info@questertangent.com