HomeMy WebLinkAbout47 SE48_3115 SBPF Sconset Expanded Project recap 03_11_2019Notice of Intent
Expanded Baxter Road and Sconset Bluff
Storm Damage Prevention Project
March 11, 2019
Sept 2018
Existing
Project
Jute/Coir Envelopes
NOI Summary
4 geotextile tube tiers to provide continuous protection from 59 to 119
Baxter Road
▪North from Existing Project to 119 Baxter Road = 895 ft
▪South from Existing Project to 59 Baxter Road (plus returns) = 1,978 ft
▪Length of Proposed Extension = 2,873 feet
▪Extension of Existing Project
2
Existing Project
Proposed Project
Project Purpose and Need
3
Source: Correspondence from G. Berman to J. Carlson, 01 February 2019
4
Northern Cross-Sections
Summary of Closing Topics
5
▪Eligibility for a CES
▪Maintaining a Walkable Beach
▪Effects on Abutting Beach
▪Effects on Nearby Beaches
▪Proposed Mitigation
▪Comparison of Existing (Approved) Project and
Proposed Extension Project
▪Compliance with Performance Standards
Homes in Question
6
Review of Building Department materials submitted by Commissioner
Golding identified four home that we disagree on eligibility
▪83 Baxter Road
▪79 Baxter Road
▪77 Baxter Road
▪73 Baxter Road
83 Baxter Road
7
2001:Relocate one story 2,330 s.f.dwelling and place on a newfoundationonthesamelot.No dimensional changes occurred:0%change in habitable space.
1991:Addition to a one story 2,140 s.f.dwelling,Building Permit issuedfora200s.f.sunroom addition and replacement roof over diningroom:9.3%increase in floor area.
1982:Addition to a one story 2,041 s.f.dwelling.Building Permit issuedfora99s.f.kitchen extension:4.9%increase in floor area.
Structure dimension was determined to be 2,041 s.f.based onreviewofplotplansincludedinthe2001,1982 and 1991 BuildingPermitfiles.
Summary:Cumulative increase in habitable space from 1982 to 1991 was
299 s.f.divided by original floor area of 2,041 s.f.correlates to
14.2% increase in floor area, assumed to be habitable space.
83 Baxter Road
8
May 11, 1981
83 Baxter Road
9
April 10, 1993
83 Baxter Road
10
2001 House Move
79 Baxter Road
11
2013:Relocate single family house on the same lot.Building Permitreportsdwellingcontains3,738 s.f.total floor area.No dimensionalchangeswithbuildingrelocation:0%change in habitable area.
1999:Replace windows and redo roof walk.No dimensional changes:0%change in habitable area.
1997:Deck addition to dwelling.Building Permit issued for a 287 s.f.deckaddition:0%in habitable area
1989:Alteration and addition to single family 3,272 s.f.dwelling.BuildingPermitissuedfor466s.f.net addition,use undefined:14.2%increase in floor area.
Pre-addition total floor area was determined to be 3,272 s.f.as therearenootheradditionsrecordedinBuildingDepartmentfilesbetween1989and2013.
Summary:Cumulative increase in habitable space from 1989 to 2013 was466s.f.divided by original floor area of 3,272 s.f.correlates to14.2%increase in floor area,assumed to be habitable space.Therefore,this dwelling is eligible as a pre-1978 house becausethecumulativeincreaseinhabitablespaceislessthan20%.
77 Baxter Road
12
2006:Demolish 558 s.f.bunk house:558 s.f.reduction in habitable space.
2005:Relocate single family house on same lot and add 555 s.f.additionperCertificateofAppropriatenessNo.47427:555 s.f increaseinhabitablespace.
Summary:Net change is a 3 s.f.reduction in floor area.Therefore,thisdwellingiseligibleasapre-1978 house because the cumulativeincreaseinhabitablespaceislessthan20%.
2012:Relocate single family dwelling on same lot.Demolish 350 sf of 1st
floor,add 150 sf to first floor for kitchen,renovate baths,reside,and re-roof.Net change is a 200 s.f.reduction in floor area.
1989:Construct a 10 ft x 14 ft (140 s.f.)addition to garage for storage:0%increase in habitable space.
1989:Construct 253 s.f.addition for library.
1986:Addition of 2nd story bathroom no area provided.Bathroom is notconsideredhabitablespace–0%increase in habitable space.
Summary:No total square foot of floor area could be affirmed from therecords.Review of the 1989 permit application suggests theprinciplestructurehadafloorareaof1,534 s.f.Records show thatbetween1989and2013therewasanetincrease53sfinhabitablespace.This correlates to approximately a 3.5%increaseinfloorarea.
73 Baxter Road
Walkable Beach In Front
of Existing Array
13
Walkable Beach In Front
of Existing Array
14
Walkable Beach In Front
of Existing Array
15
Existing Array Not Damaging
Adjacent Beaches
16
Profile Starting Date & Position (feet)(1)
Ending Date & Position (feet)Total Change (feet)Annualize Rate of Change (feet / year)
92.1 10/2014 / -1.7 9/2018 / +5 6.7 ft Accretion 1.68 ft /yr Accretion
92(2)10/2014 / -55.7 9/2018 / -61.3 5.6 ft Retreat 1.4 ft /yr Retreat
Existing Geotube Systemt
90.85 10/2014 / -2.1 9/2018 / +4.9 7.0 ft Accretion 1.75 ft / yr Accretion
90.8 10/2014 / -1.3 9/2018 / +7.3 8.6 ft Accretion 2.15 ft/yr Accretion
Table 2.Review of Shoreline Change Adjacent to the Existing GeotubeSystem
(1)Position is feet from a previously established baseline point.(2)Approximate location of the clay head
At Profile 92 there was about a 10-foot retreat documented from October2014toOctober2015.Since October 2015 the shoreline has beenrelativelystabileatProfile92,with 4.4 feet of accretion observed fromOctober2105toOctober2018,and that correlates to an annualizedaccretionrateof1.47 feet per year.
Existing Array Not Damaging Nearby
Beaches
17
Existing Array Not Damaging Nearby
Beaches
18
Sand Mitigation Summary
Protocol Summary:
Complete construction placing 22 cy/lf of compatible sand on the template.
Periodically contribute sand to the littoral drift system by covering exposed
tubes after erosion events.
“What was Contributed from the Template?”Determine volume of sand
contributed to the littoral drift system during the winter storm season.
Replace sand on the template with the volume of sand contributed to the
littoral drift system the previous year or up to 22 cy/lf, whichever is greater, to
“top it off.”
In response to peer review comment SBPF proposes to place a
minimum of 8.8 cy/lf of sand –length weighted average annual
Coastal Bank contribution –or volume of sand contributed off the
template, whichever is greater.
19
Comparison of Existing Project to Extension Project
(Minor Changes based on “Lessons Learned”)
20
PROJECTELEMENT EXISTING PROJECT EXPANDED PROJECT
Project Purpose :
+/-950 feet
Protects 2 homes and public
infrastructure and 5 vacant
lots (to protect public
infrastructure or “gap lots”
per the state definition).
+/-2,900 feet
Protects 21 lots -16 homes
and 5 vacant lots (to protect
public infrastructure or “gap
lots” per the state
definition).
Comparison of Existing Project to Extension Project
(continued)
21
PROJECT ELEMENT EXISTING PROJECT EXPANDED PROJECT
Geotube System Design:
Geotube
Layout
Four tier geotube configuration
covered by sand template.
Same design. Difference is
lowest geotube set at elevation
-3 feet MLW instead of 0 feet
MLW
Geotube
Returns
Sloped returns that tie into
adjacent Coastal Bank at a
shallow angle.
Same design.
Return
Extensions
None originally –Coir rolls
approved November 28, 2018.
Add Special Condition to install
coir roll return extensions when
appropriate.
Comparison of Existing Project to Extension Project
(continued)
22
PROJECT
ELEMENT EXISTING PROJECT EXPANDED PROJECT
Sand
Template
Management
Place sand on template at a
rate of 22 cy/lf/yr and use that
sand stockpile to recover
exposed tubes after erosion
events.
Import sand during storm
season as needed to replenish
stockpile.
Fill template to 22 cy/lf before
each storm season and use
that sand stockpile to recover
exposed tubes after erosion
events.
Import sand during storm
season as needed to
replenish stockpile.
Minimum volume of 8.8 cy/lf
(average annual volume off
Coastal Bank) or volume to re-
establish 22 cy/l, whichever is
greater
Comparison of Existing Project to Extension Project
(continued)
23
PROJECT
ELEMENT EXISTING PROJECT EXPANDED PROJECT
Monitoring:
Extensive monitoring program:
▪Shoreline change quarterly;
▪Bathymetric Survey semi-
annually;
▪Underwater video semi-
annually;
▪Post-storm inspections;
▪Template survey annually.
Extensive program with minor
modifications2:
▪Shoreline change semi-
annually;
▪Bathymetric Survey
annually;
▪Underwater video once
every 3 year;
▪Post storm inspections;
▪Template survey annually;
▪Discontinue reporting on
Alternative Access
Agreement
Comparison of Existing Project to Extension Project
(continued)
24
PROJECT ELEMENT EXISTING PROJECT EXPANDED PROJECT
Reporting:Annual Report and interim
reports to the Commission Same
25
Notes:
1.Per the Nantucket Bylaw 14 homes are eligible as pre-1978 structures,2 are non-
eligible structures but can be protected as “gap lots”,and 5 are vacant lots eligible
for protection to protect public infrastructure from damage.
2.Correspondence from Greg Berman,Woods Hole Sea Grant |Cape Cod Cooperative
Extension to Jeff Carlson (Natural Resources Coordinator,Town of Nantucket)
dated April 7,2017 Regarding the Independent Review of the 2016 Annual Report,
noted the following:
▪Shoreline Monitoring –The requested reduction to 2 profiles per year is
reasonable based on the collected data so far as well as more consistent with
MassDEP guidance.(pg.4)
▪Wetland Well Monitoring –If the data from 2001-2007 shows similar dry levels as
this project the well monitoring could be discontinued.(pg.5)
▪Beach Invertebrate Monitoring –The invertebrate monitoring could be
discontinued as no impacts to the few species have been observed.(pg.5)
▪Underwater Video Monitoring –Video monitoring likely is not needed yearly.
(pg.6)
Comparison of Existing Project to Extension Project
(continued)
Expanded Project
Compliance to Performance Standards
Detailed review of compliance with the Regulations and Performance
standards was presented on October 1, 2018 Public Hearing
Comparing the Existing Project to the Expanded Project we observe:
1.Expanded Project is very similar in design with the Existing Project,
with minor changes based on “Lessons Learned;”
2.A robust sand mitigation is proposed for the Expanded Project, as was
provided for the Existing Project; and
3.Shoreline monitoring to date has not documented damage to nearby
Coastal Beaches
Therefore the Expanded Project meets the requirements of the Act and
Bylaw just as the Existing Project does. 26
27
Thank You