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Geodesy at the Water’s Edge: The newsletter of the NGS ECO Team
Summer Double Issue
May - August, 2015
In this issue:
1. New ECO video highlights role of geospatial infrastructure in informing adaptation to sea
level rise
2. Updates from our partners in the field
3. Are wetland elevations biased by the observer?
4. Minimum time required for an SET study
5. In case you missed it
6. Coming up
Editor’s note: We have combined our May - June and July - August material to provide you
with a “double-issue” highlighting all our summer activities. We plan to resume the regular
bimonthly schedule in our September - October issue.
1. New ECO video highlights the role of geospatial infrastructure in
informing adaptation to sea level rise
NGS, in cooperation with The COMET® Program, developed a video that explains how using
geospatial information already available through NOAA, combined with strategic local
investments in infrastructure can provide communities with the data needed to confidently
plan for future sea-level changes. The video, aimed at community planners, emergency
managers, and other coastal zone decision-makers, is part of a larger effort to create an
NGS Video Library of educational materials for a broad range of audiences. Also, take a look
at the larger offerings of geospatial and mapping videos from the COMET site MetEd!
2. Updates from our partners in the field
Updated heights for Blackwater National Wildlife Refuge
Blackwater National Wildlife Refuge on Maryland’s Eastern Shore, home to one third of the
tidal wetlands in the state of Maryland, has witnessed dramatic wetland loss over the past
decades. One phenomenon suspected of being linked to this wetland loss is a localized
subsidence hot spot, whose presence has been the topic of much speculation. In the second
week of June, U.S. Fish & Wildlife Service (FWS), U.S. Geological Survey, and NGS ECO
partnered for a 72-hour GPS campaign at five selected bench marks around the refuge,
three of which had previously acquired high precision coordinates through a 2005 Height
Modernization project. These three marks are used as positional control for FWS’ intensive
Real Time Kinematic (RTK) GPS surveying of marsh elevation across the Refuge’s fire
management units. The new 2015 data are being analyzed through NGS’ On-Line Position
User Service “Projects” software (OPUS Projects), and the new coordinates will be
compared to those derived from the earlier height mod survey, after the earlier data have
been re-processed to ensure consistent reference frames. We hope that the comparison
between the two epochs (2005 and 2015) may yield useful insights into the stability of
bench marks, and whether there is any systematic change consistent with subsidence.
GPS surveying at the Wolf Pit site in Blackwater
Project Contacts:
Matthew Whitbeck ([email protected])
Philippe Hensel ([email protected])
3. Are wetland elevations biased by the observer?
ECO collaborated this summer with the Jug Bay Wetlands Sanctuary (Lothian, MD) and one of
their undergraduate summer interns on a project studying the correlation of tidal freshwater plant
communities with elevation and local tidal datums. Erika Loudermilk, a rising junior at the
University of Delaware, learned how to use a digital barcode level to transfer heights from local
control marks to wetland surfaces within identified vegetation communities along the intertidal
gradient at numerous locations within the Jug Bay tidal freshwater wetlands. As part of the
study, she also tested the effect that the observer may have had on the wetland surface that was
being measured. To test this, Erika took a series of repeated height measurements at flagged
points on the marsh either while standing on boardwalks/catwalks or standing directly on the
marsh next to the flags. This procedure was repeated with Real Time Kinematic (RTK) GPS
(thanks to the kind assistance of the Chesapeake Bay National Estuarine Research Reserve in
Virginia). Erika found that the tidal freshwater plant communities at Jug Bay could be separated
into four elevation bands based on locally estimated tidal datums (using the NOAA datum
transformation tool VDatum). She also found that the observer had minimal influence on the
elevation of the marsh surface (although a significant 2 mm effect was observed, about 1 mm of
that was due to soil compression from the repeated measurements). The correlation of
vegetation communities to tidal datums will help managers evaluate potential responses of tidal
freshwater plants to sustained sea level rise. The observer error results provide empirical support
for the validity of numerous wetland surveys using surveying techniques such as leveling and
RTK GPS.
Left panel: Erika Loudermilk surveying Jug Bay wetlands with a Real-Time Kinematic (RTK) GPS
Right panel: Summary table of the four vegetation community assemblages
4. Minimum time required for an SET study
ECO was thrilled to have Pathways Scholar Jay Howard back for another summer at NGS.
This year, Jay focused his efforts on completing and publishing a study he began back in
2013 on the “time to stability” in wetland surface elevation trends (using the Surface
Elevation Table, or SET, technology). For a number of years, the ever expanding
community of SET users has been eager for guidance on the minimum number of years
required to compute elevation change rates that would be representative of more than just
the short-term trend. Jay analyzed about 60 individual SET sample station plots with
decadal data sets, and applied two different computational/statistical methods to
determine the point at which the rates stabilized to the final, decadal trend. Jay then went
on to use modeling approaches to do sensitivity testing on the effect of sampling interval,
sampling intensity, and elevation change variability, in the time required to reach a stable
trend. Jay is hoping to publish a manuscript this fall. These results will provide very useful
information to the community of SET users, especially as more and more of them are being
used to monitor coastal wetland elevation change.
Left panel: Jay Howard displaying his Maryland Pride!
Right panel: Example of sensitivity analysis on the total number of intervals on the “time to
stability” in modeled linear rates of wetland elevation change.
5. In case you missed it!
● 2014 NOAA Hollings Scholar Molly Cain was accepted to the prestigious Fulbright
Scholarship program for the 2015-2016 academic year. Molly will be heading to the
Netherlands in August, where she will work with Professor H.H.G. Savenije,
department chair of the Water Management department at TU Delft. She will study
how the Dutch use natural and constructed wetlands to mitigate coastal flooding.
Upon her return state-side in 2016, Molly will begin her doctoral studies at the
University of Indiana, with Dr. Adam Ward, in the Environmental Science group of
the School of Public and Environmental Affairs. In the meantime, Molly has
continued to collaborate with ECO on the publication of the study she conducted last
summer with us, comparing an inexpensive digital barcode leveling technique to the
Surface Elevation Table. We hope to have the manuscript published this fall, and we
wish Molly a fun and productive time in her exciting new endeavors.
● 2014 NOAA Hollings Scholar Heather Nicholson has been accepted into the
prestigious doctoral program of geomatics at the University of New Brunswick.
Heather will be moving up to New Brunswick with her family this summer. We are
all very excited for her, and hope to hear more from her as she pursues her
advanced degree in geomatics.
● The Chesapeake Bay Sentinel Site Cooperative has a new coordinator! Sarah
Wilkins recently completed a full year in Silver Spring at NOAA Headquarters as a
Knauss Marine Policy fellow at the National Ocean Service’s Policy & Constituent
Affairs Division. She will be heading up the Cooperative for a two-year period
effective immediately. Sarah has a Master of Science in Conservation Biology &
Sustainable Development from the University of Wisconsin-Madison and a Bachelor
of Science from the University of Vermont in Environmental Science, and has
worked all over the country on coastal and estuarine projects for nonprofit,
academia and governmental agencies. Sarah takes over from acting coordinator
Andrew Larkin, from NOAA Fisheries (Chesapeake Bay Office, Virginia Outreach
Coordinator). Many thanks to Andrew for keeping the momentum on a number of
cooperative initiatives as the Cooperative searched for a full-time coordinator. If you
are interested in participating in or learning more about the Cooperative, please
drop Sarah a line at: [email protected]
● ECO presented at the August NGS Webinar Series on August 13. The new NGS
Webinar Series is a continuation of the highly successful Height Modernization
Monthly Meeting, but focused more broadly on all of NGS products and services. The
aim is to enhance the communication and outreach to all NGS stakeholders as NGS
continues to modernize and advance towards the new reference frames in the year
2022. Striving to reach a broader audience, ECO gave a presentation on its history,
what it does, and how it helps support our ecosystems & climate partners while
advancing the missions of both NGS and more broadly, NOAA. The webinar was
very well attended, reaching a broad and diverse audience that was mostly new to
ECO. The webinar was recorded, and can be found here.
● Nicole (“Nic”) Kinsman, an ECO partner from the Alaska Department of Natural
Resources, has joined NGS as the Alaska Regional Advisor. We all look forward to
working more closely with our Alaskan partners on coastal vulnerability in the face
of a changing climate.
6. Coming Up…
● Update on guidelines documents and SOPs:
○ The guidelines for the establishment and use of geospatial infrastructure for
sea level change sentinel sites has had to clear additional administrative
hurdles prior to being released as an official numbered NOAA technical
report. In the meantime, a non-numbered version will be made available on
the ECO web page in September..
○ The first complete manuscript of the Surface Elevation Table (SET) and
Marker Horizon Protocols, written in collaboration with the National Park
Service and the USGS, has been sent out for external Department of Interior
review. We are currently incorporating reviewer comments, and anticipate
an eventual public release date by sometime in Fall 2015.
Please share this Newsletter with friends and colleagues interested in Geodesy at the
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If you would like to contribute an update to a future newsletter, please feel free to contact
us at NGS ECO. We are eager to hear back from you and how you maybe using/adapting
geodesy and survey science in your coastal work. Also, feel free to contact NGS ECO if you
have any questions or concerns. Thank you!
