HomeMy WebLinkAbout45 SE48_3115 SBPF Response to 03_06_19 NCC Letter 03_08_19
PRINCIPALS
Theodore A Barten, PE
Margaret B Briggs
Dale T Raczynski, PE
Cindy Schlessinger
Lester B Smith, Jr
Robert D O’Neal, CCM, INCE
Andrew D Magee
Michael D Howard, PWS
Douglas J Kelleher
AJ Jablonowski, PE
Stephen H Slocomb, PE
David E Hewett, LEED AP
Dwight R Dunk, LPD
David C Klinch, PWS, PMP
Maria B Hartnett
ASSOCIATES
Richard M Lampeter, INCE
Geoff Starsiak, LEED AP BD+C
Marc Bergeron, PWS, CWS
3 Mill & Main Place, Suite 250
Maynard, MA 01754
www.epsilonassociates.com
978 897 7100
FAX 978 897 0099
21597/2018/Expanded Project/NOI/Public Hearing Comments
March 8, 2019
Nantucket Conservation Commission Via Electronic Mail and U.S. Mail
2 Bathing Beach Road
Nantucket, MA 02554
Subject: Response to Comments from the Nantucket Coastal Conservancy dated
March 6, 2019 on the Expanded Baxter Road and Sconset Bluff Storm
Damage Prevention Project (DEP File No. SE 48-3115)
Dear Commission Members:
On behalf of the Siasconset Beach Preservation Fund (“SBPF”), Epsilon Associates,
Inc. (“Epsilon”) submits this response to the correspondence submitted by the
Nantucket Coastal Conservancy (“Coastal Conservancy”) dated 06 March 2019
which provides their opinion on the project assessment prepared by Mr. Greg
Berman regarding the Expanded Baxter Road and Sconset Bluff Storm Damage
Prevention Project (“Expanded Project”). For the record, we note the Coastal
Conservancy correspondence was submitted after the 01 March 2019 deadline
established by the Nantucket Conservation Commission (“Commission”) for receipt
of matters discussed during the 11 February 2019 Public Hearing.
The Coastal Conservancy correspondence dated 06 March 2019 presents no new
information and of their correspondence is their interpretation of the Mr. Greg
Berman’s report, to which SBPF provided a response dated 07 February 2019.
Whereas we have provided a thorough response to Mr. Berman’s report, we will
respond to the threshold issues identify by the Coastal Conservancy on pages 1 and
5. Those are presented in italics typeface and our response is in normal typeface.
The SBPF projects will never be in stasis; the environment is too dynamic.
We agree that coastal environments, including the Siasconset Beach shoreline, is a
dynamic shoreline. The project purpose is to stabilize the Coastal Bank to protect
existing homes and public infrastructure from erosion in compliance with the state
Wetlands Protection Act and local Bylaw Wetlands regulations. The nature of the
Nantucket Conservation Commission 2
Re: DEP File No. SE 48-3115
March 8, 2019
proposed geotube system will require ongoing management to deliver and place
sand on the template and extend returns periodically as the adjacent unprotected
Coastal Bank continues to retreat.
Extension of the returns will be required repeatedly in a losing battle to prevent end
scour.
It is expected that the returns for the geotube system will need to be lengthened
periodically as the adjacent unprotected Coastal Bank adjacent to the system
naturally erodes over time. The Conservation Commission recently permitted SBPF
to do exactly this type of return extension to protect the existing pilot project
system, and something similar will be needed going forward for the extension
Project as well.
Therefore, the adjacent beaches are suffering and will continue to suffer.
The quarterly shoreline monitoring has demonstrated there is no evidence of
accelerated erosion post-geotube construction that exceed historic observations. As
for adjacent beaches, see Table 2 in our 04 January 2019 correspondence. That
shows that 3 of the 4 Profiles adjacent to the existing geotube system (2 north and 2
south) document accretion from October 2014 to September 2018. At Profile 92
there was about a 10-foot retreat documented from October 2014 to October 2015.
Since October 2015 the shoreline has been relatively stabile at Profile 92, with 4.4
feet of accretion observed from October 2105 to October 2018, and that correlates
to an annualized accretion rate of 1.47 feet per year.
It is not feasible to artificially provide the amount of beach nourishment that will be
necessary to prevent the need for such extensions.
The sand mitigation program is provided to supply sediment to the littoral system to
compensate for placing the geotube system in front to the Coastal Bank. The
purpose of the sand mitigation is not to prevent the need to extend returns.
Extending the project fourfold would accelerate the destruction of the returns and
the scouring process because of the greater reduction of natural sand replenishment
caused by the longer project.
The extended length of the system is not correlated to increased end scour or
damage. As described above returns will need to be managed and extended
periodically as the adjacent unprotected Coastal Bank retreats. The proposed sand
Nantucket Conservation Commission 3
Re: DEP File No. SE 48-3115
March 8, 2019
mitigation protocol is described in our correspondence dated 02November 2019
and the volumes associated with the relative to the unprotected Coastal Bank
contribution is described in response to item 7 in our 08 March 2019 submitted in
response the Applied Coastal Research and Engineering comments.
Whether this project is/will be destructive of the environment in a way that violates
legal protections, and …
Throughout this review process the applicant presented a consistent description of
the design and mitigation program, and how the Expanded Project meets the
regulations and performance standards for Coastal Bank and Coastal Beach.
Compliance with the regulations and performance standards has been presented in
Public Hearing presentations and documented in written submittals, e.g. see our
response to comments document dated 02 November 2018.
… whether feasible alternatives exist.
Alternatives have been evaluated in theory and practice and those were presented
to the Conservation Commission during the 01 October 2018 Public Hearing and in
our written response document dated 02 November 2018.
Sincerely,
EPSILON ASSOCIATES, INC.
Dwight R. Dunk, LPD, PWS, BCES
Principal
cc: MassDEP-SERO
J. Posner, SBPF
A. Gasbarro, Nantucket Eng. & Survey
S. Cohen, Cohen & Cohen Law, PC
G. Wood, Ruben and Rudman, LLP
G. Thomson, W.F. Baird & Assoc.
L. Smith, Epsilon
R. Hamilton, Woods Hole Group