HomeMy WebLinkAbout2017-6-8Minutes for May 22 2017 adopted June 7
CONSERVATION COMMISSION N A ti T U C
SPECIAL MEETING T C �� � N C L E R _-
2 Bathing Beach Road
Nantucket, Massachusetts 02554
w 2011 JUN —8 QM 8� 2�
ww.nantucket- ma.gov
Monday, May 22, 2017
4 Fairgrounds Road, Community Room - 4:00 P.M.
Commissioners: Andrew Bennett (Chair), Ashley Erisman (Vice chair), Ernie Steinauer, David LaFleur,
Ben Champoux, Ian Golding, Joe Topham
Called to order at 4:01 p.m.
Staff in attendance: Jeff Carlson, Natural Resources Coordinator, Terry Norton, Town Minutes Taker
Attending Members: Bennett, Erisman, Steinauer, LaFleur, Champoux, Topham
Absent Members: Golding
Late Arrivals: None
Earlier Departure: None
Agenda adopted by unanimous consent
*Matter has not been heard
I. PUBLIC MEETING
A. Public Comment — None
B. Annual report
1. *Sconset Beach Preservation Fund — Baxter Road Area SE48 -2581
Sitting
Bennett, Erisman, Steinauer, LaFleur, Champoux, Topham
Documentation
2016 `Sconset Beach Geotube Project Annual Report; Nantucket Land Council Letter 04-10 -2017; SBPF
Annual Report Peer Review-, correspondence.
(documents available at - hnp://www.nantucket-ma.gov/542/Baxter-Road-Fihng-Information)
Applicant
Maria Hartnett, Epsilon Associates Inc.
Representatives
Steven Cohen, Cohen & Cohen Law P.C.
Jamie Feeley, Construction Manager Cottage and Castle Inc.
Josh Posner, 77 Baxter Road, Chairman 'Sconset Beach Preservation Fund
Public
Emily Molden, Nantucket Land Council (NCL)
Hugh Ruthven, III Applied Coastal Research and Engineering (ACRE)
Rick Atherton, Nantucket Coastal Conservancy (NCC)
Discussion
Hartnett — Presented the project annual report referring to PowerPoint® presentation. The tubes have been in
place four winters and are holding up well and the bluff has stabilized. Sand delivery: they have been tracking
mitigation sand, construction sand, and sand placed on the bluff face before revegetation; explained why sand
from bluff slump was counted as mitigation sand. Aerial bluff survey: the beach in front of the project has not
significantly changed or is different from the control areas; unprotected areas contributed 12.9 cubic yards
(CY) per linear foot (LF) per year of sand to system over the last three years while the geotube contributed 18.9
CY /LF per year. Shoreline monitoring. this is done quarterly at 46 transects over six miles; analysis of the
shoreline indicates a trend toward erosion; the shoreline is currently where it was about eight to ten years ago;
reviewed the trend lines at various profile points both within and outside the project area; recent accretion at
Cod Fish Park is probably associated with natural variability; explained the reason for using mean low water
rather than mean high. Wetland well monitoring: reviewed the location of catch basins and wetland wells along
Baxter Road. Beach invertebrate monitoring. noted locations of monitoring points; across all 12 locations, both
within and outside the project area, found eight species indicating low abundance and diversity; the low
abundance does not warrant further monitoring. Underwater video monitoring. collected out to about 1000
feet off shore within and outside the project area; overall what they found was that the cobble habitat area
continues to be in place with no indication of affect by the sand template; willing to look into use of side scan
sonar but video shows what is actual down there; don't think Soil Profile Imagery will be helpful. Annual
drainage system report: the system seems to be functioning as designed; will monitor the system for another
year before turning over to the Town. Recommended changes to monitoring. include plots of shoreline trends;
change shoreline monitoring frequency to twice a year; change bathymetry monitoring frequency to once a year
and reducing the profile points to 22; wading shots should be eliminated from the shoreline surveys due to
safety risks; beach invertebrate and wetland well monitoring should be discontinued; underwater video
monitoring reduced to once every three years or if the template contributes more sand than expected; monitor
the drainage system once a year. Recommended changes in mitigation: reviewed two options for a more
adaptive mitigation program; it is important that the geotubes remain covered. Reviewed responses to NLC
and ACRE comments. Will be submitting another sand report within the next month or two.
Bennett — Comparing slopes of banks, the northern bank has an erosion rate of 14 CY /LF which indicates a
stable bank. Steep banks tend to fail. There's no data on the top of bank; he'd be interested in seeing that on
the shallower slope of the northern bank.
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Minutes for May 22 2017 adopted Tune 7
Molden — NLC was concerned about the recommendation to eliminate or reduce a number of the monitoring
requirements outlined in the Order of Conditions, especially the recommendation to reduce the amount of
nourishment for mitigation.
Ruthven — One thing missing with the long -term data set is that two -year, post - construction period is not a
sufficient length of time to study the post project erosion rates. A project that stops a bluffs natural response
needs suitable mitigation to match that. A long -term data set going forward could be critical in evaluating
adverse affects of the project.
Steinauer — It seems to him most storms come out of the northwest and our main requests for armoring are in
the harbor; Madaket is very concerned about the possible loss of Millie's Bridge and the end of Madaket Road.
He wonders if that weather -pattern change is the reason for a low bank loss; he'd like to see a summary of
wind over several years both pre- and post - construction of the project This project came about because of a
year of three unusually destructive storms.
Hartnett — That is why there is merit to the Department of Environmental Protection's suggestion to
maintaining 22 CY /LF per year but allows a credit when sand doesn't go into the system.
Erisman — Asked how often the tubes were uncovered throughout the storm season.
Posner — That happened about five times since September. When the sand in front of the tubes washes away, a
bulldozer goes in and pushes sand from on top of the tubes down the front.
Steinauer — Asked the affect of the tube sand has on beach grass planted to stabilize the bank.
Feeley — Each time there is major nourishment, about five or six feet of grass is covered along the bottom of
the template; it is replanted as needed in the Spring.
Bennett — Asked how many cubic yards of sand are needed to cover the tubes and the returns.
Feeley — On average between 1 and 2 cubic yards. We push it over to create a consistent angle of repose for
the template.
Hartnett — Explained how they calculate the sand contributed to the system; they know how much is there and
how much was added with the difference being what was contributed to the system.
Erisman — In regards to when the tubes weren't covered, asked if there is a way to quantify how much sand
would have been lost if it had been available.
Hartnett — That's why the try to do the aerial survey once a year. They look at the north and south for a visual
estimation.
Atherton — Reviewed comments in a letter submitted from the NCC which address non - technical issues in the
Order of Conditions: assertion there is no erosion, maintenance of a walkable beach, lack of updates from the
Town of Nantucket on the relocation of Baxter Road and infrastructure, and failure criteria.
Posner — Since the installation of the tubes, erosion at the toe of the bluff where the geotubes are installed has
been stopped; there is still erosion at the toe of the bluff outside the project area. He thinks they are doing well
with the walkable beach; when there is a big storm with wave run up there might not be beach to walk on in
front of the tubes. They have been working with the Town on alternative access; there is an Alternative Access
Agreement in place. He believes they are doing a good job of monitoring the project and doubts any other
project in the State has the conditions and monitoring requirements of this project.
Cohen — There are two concepts that this was supposed to be temporary and that the mitigation is important
and shouldn't be rolled back. Both mis- characterize what is going on. The emergency and temporary aspect
was about how the problem was going to be dealt with but the project was always considered a long -term
project that could possibly be expanded. We are looking at how to improve the data in terms of mitigation and
assessment.
Ruthven — A good point was brought up that when the tubes are uncovered, sand isn't being contributed. A
way to get the nourishment in place during a storm event should be established. It is important to look at
future monitoring especially if this project might expand.
Hartnett — It is valid to look at recovering; where the template sits, the sand is not contributing on a normal
day. It is only contributing when a storm reaches it; we want to focus on ensuring it is recovered quickly
enough that it is not uncovered when another storm hits. There are times in smaller events when the geotubes
do contribute and the unprotected bluff does not.
Erisman — The beach would have contributed the sand if the tubes weren't there.
Feeley — The average elevation of the beach in the winter is around 8 to 9 feet; it drops a foot or more during
a storm but that returns within 24 to 48 hours.
Cohen — Thanked the commission. The follow up to this will be a filing to deal with technical issues.
Bennett — Asked Ms Hartnett `s thoughts on the 2007 invertebrate survey and the cobble habitat
Hartnett — There was comfort that the habitat is still there in the same percentages; that habitat is consistent
Staff Comments No changes can be made to the report at this time. If there are no changes, the annual report can be accepted.
Action Motion to Accept the Report. Lf (made by: LaFleur) (seconded by: Erisman)
Vote Carried unanimously
Motion to Adjourn: 5:59 p.m.
Submitted by:
Terry L. Norton
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