HomeMy WebLinkAboutSconset 2020 Sand Delivery and Contribution Report 3_16_20January 2020 - January 2021
Sand Delivery and Contribution Report
Baxter Road and Sconset Bluff
Stabilization Project Nantucket,
MA
March 2021
Submitted by:
Siasconset Beach Preservation Fund
PO Box 2279
Nantucket, MA 02584
Prepared by:
Epsilon Associates
3 Mill & Main Place, Suite 250
Maynard, MA 01754
In Association with :
Cottage + Castle, Inc.
37 Old South Road, Unit #6
Nantucket, MA 02554
PRINCIPALS
Theodore A Barten, PE
Margaret B Briggs
Dale T Raczynski, PE
Cindy Schlessinger
Lester B Smith, Jr
Robert D O’Neal, CCM, INCE
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
Richard M Lampeter, INCE
Geoff Starsiak, LEED AP BD+C
Marc Bergeron, PWS, CWS
ASSOCIATES
Alyssa Jacobs, PWS
Holly Carlson Johnston
Brian Lever
3 Mill & Main Place, Suite 250
Maynard, MA 01754
www.epsilonassociates.com
978 897 7100
FAX 978 897 0099
March 16, 2021
Nantucket Conservation Commission
2 Bathing Beach Road
Nantucket, MA 02554
Subject: Annual Sand Delivery and Contribution Report
File No. SE 48-2824, Sconset Bluff Geotextile Tube Project, Nantucket MA
Dear Commissioners:
On behalf of the Siasconset Beach Preservation Fund (“SBPF”), Epsilon Associates, Inc.
submits the attached Annual Sand Delivery and Contribution Report (prepared as
required in Special Condition 32.d).
If you have any questions regarding this transmittal, please contact me at 978-897-7100
or ddunk@epsilonassociates.com.
Sincerely,
EPSILON ASSOCIATES, INC.
Dwight R. Dunk, LPD, PWS, BCES
Principal
21597/Sconset 1 2020 Annual Sand Delivery Report
Epsilon Associates, Inc.
ANNUAL SAND DELIVERY REPORT
1.0 Introduction
The Baxter Road and Sconset Bluff Stabilization Project (the “Project”) was constructed in two
phases. The first phase was constructed in late December 2013 and January 2014 via an
Emergency Certification approval issued by the Nantucket Conservation Commission. The first
phase consisted of the installation of three stacked tiers of 45-foot circumference geotextile tubes
at the base of the eroding Sconset Bluff. The geotextile tube installation was approximately 852
feet long and extended along the toe of the bank from 87-105 Baxter Road. The second phase
was constructed in October 2015 through February 2016 and included the installation of a fourth
tier of geotextile tubes on lots 91-99, intermediate returns, end returns, and a surface runoff
drainage system. With the returns included, the total project length is now 947 feet.
The purpose of the annual sand delivery report is to present the sand mitigation volumes and
corresponding delivery tickets for each “Sand Year” initially from April 1 through March 31 of any
given year. SBPF has previously submitted detailed Sand Reports for the first six sand years
associated with the Project:
• November 2013 through March 31, 2014 (referred to as the “2014 Sand Year”)
• April 1, 2014 through March 31, 2015 (referred to as the “2015 Sand Year”)
• April 1, 2015 through March 31, 2016 (referred to as the “2016 Sand Year”)
• April 1, 2016 through January 31, 2018 (referred to as the “2017 Sand Year”)
• February 1, 2018 through April 30, 2018 (referred to as the “2018 Sand Year”)
• May 1, 2018 through December 31, 2019 (referred to as the “2019 Sand Year”)
This report presents information on sand deliveries during the period from January 1, 2020
through January 15, 2021 (referred to as the “2020 Sand Year”).
2.0 Sand Delivery Requirements
The Project incorporates a substantial mitigation volume of 22 cubic yards/linear
foot/year[cy/lf/yr]. Given the project’s length of 947 feet, the total annual mitigation volume
required is currently 20,834 cy. As required by the Project’s Order of Conditions (SE48-2824),
annually in Sept. – Nov. place sand to ensure a substantial volume of sand (10 – 15 cy/lf) is
available at the onset of the winter storm season, place additional sand as needed during the
winter and if the total volume is not placed before March 1, the balance shall be placed by March
31. Delivery tickets are to be provided annually to document the total volume of sand provided
on a yearly basis.
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3.0 Volume of Mitigation Sand Delivered
The following ten tables document the sand delivery amounts.
♦ Tables 1-2 present a summary of the volume of sand delivered and contributed from
December 2013 through January 15, 2021. Table 3 presents a comparison of the volume
of sand eroded from the bluff in adjacent unprotected areas from July 2013 – June 2020.
♦ Table 4 presents the volume of sand delivered during the period from December 2013 –
March 31, 2014, which includes construction of the initial Project.
♦ Table 5 presents the total volume of mitigation sand delivered during the period from
April 1, 2014 – March 31, 2015.
♦ Table 6 presents the total volume of sand delivered during the period from April 1, 2015
– March 31, 2016, which includes supplementary construction of the fourth tier and
returns.
♦ Table 7 presents the total volume of sand delivered during the period from April 1, 2016
– January 31, 2018.
♦ Table 8 presents the total volume of sand delivered during the period from February 1,
2018 – April 30, 2018.
♦ Table 9 presents the total volume of sand delivered during the period from May 1, 2018
– December 31, 2019.
♦ Table 10 presents the total volume of sand delivered during the period from January 1,
2020 through January 15, 2021.
Each of these tables is discussed in further detail below.
3.1 Table 1. Summary of Sand Delivery Volume
Lines 1-4 of Table 1 describe the total volume of sand delivered to the site, and separate this total
into the following categories: mitigation sand, sand used on the bluff face, and sand used for
construction (inside or behind the geotextile tubes). Neither sand placed on the bluff face nor
sand used for construction is counted towards the mitigation requirement. Lines 5-11 of Table 1
provide a summary of the required mitigation volume. The base mitigation volume is determined
by multiplying the 22 cy/lf/yr by the Project’s length (Line 5). This volume is then adjusted by
subtracting out the surplus sand from the previous year and the amount of sand eroded from the
bluff face. The surplus sand is calculated as that sand delivered the previous year that is in excess
of the base mitigation requirements and that is still in the sand template at the end of the sand
year (see Line 6-8). The bluff erosion volume accounts for that portion of the bluff face that
continued to erode and is discussed further in Section 5.0 below.
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Lines 13 and 14 of Table 1 presents the final calculation of whether the project’s mitigation
requirement was met. Any surplus of sand delivered during one year, up to but not in excess of
the amount remaining on the sand template on the beginning of the new sand year, is carried
forward and counted towards the following year’s requirement.
3.2 Table 2. Summary of Sand Contribution
Table 2 presents a summary of the volume on sand contribution for the period from December
2013 – December 31, 2020. Table 2 provides a breakdown of the sand contribution from the sand
template, bluff face, construction, and the total contribution. Line 9 of Table 2 provides the total
volume of sand contributed during the 2020 Sand Year. Line 10 provides the average of annual
sand contribution from December 2013 – January 15, 2021.
3.3 Table 3. Bluff Volume Loss in Unprotected Areas Adjacent to Geotextile Tubes
Tables 3a-c present a comparison of the volume of sand eroded from the bluff in adjacent
unprotected areas from July 2013 – June 2020. Table 3a provided the bluff volume change from
September 2019 – June 2020. During this period the unprotected bluffs to the north and the south
of the geotextile tubes eroded approximately 4,623 cy which is equivalent to a distance-weighted
average of 6.6 cy/lr/yr. Table 3b presents the bluff volume loss during the period of May 2013 –
September 2019. Table 3c presents the bluff volume loss in the unprotected areas adjacent to the
geotextile tubes from July 2013 – June 2020.
3.4 Table 4. Sand Delivery December 2013 – March 31, 2014
Table 4 presents the volume of sand delivered during the period from December 2013 – March
31, 2014, which includes construction of the initial Project. Table 4 provides a detailed breakdown
of that portion of sand placed within and behind the geotextile tubes and presents the total
volume of mitigation sand placed over, in front of, and at the ends of the geotextile tubes. All
delivery tickets for the total volume delivered of 39,204 cy were previously submitted to the
Conservation Commission, most recently as part of the 2015 Sand Report.
3.5 Table 5. Sand Delivery April 1, 2014 – March 31, 2015
Table 5 presents the total volume of mitigation sand delivered during the period from April 1,
2014 – March 31, 2015. Three separate deliveries were made over this period of time. All delivery
tickets for the total volume of 14,428 cy were submitted as part of the 2015 Sand Report.
3.6 Table 6. Sand Delivery April 1, 2015 – March 31, 2016
Table 6 presents the total volume of sand delivered during the period from April 1, 2015 – March
31, 2016. Table 6 provides a detailed breakdown of the sand delivered for construction, sand
delivered for mitigation, and sand delivered to the bluff face. All delivery tickets for the total
volume of 22,485 cy delivered during the 2016 Sand year were provided in the 2016 Sand Report,
including the 19,066.7cy delivered during the most recent construction period in November,
December, and January and the 3,418 cy delivered in April 2015.
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Epsilon Associates, Inc.
3.7 Table 7. Sand Delivery April 1, 2016 – January 31, 2018
Table 7 presents the total volume of sand delivered during the period from April 1, 2016 – January
18, 2018. Deliveries occurred in the latter half of 2016, in May and December 2017, and in January
2018. All delivery tickets for the total volume delivered of 15,138 cy were submitted as part of
the 2017 Sand Report.
3.8 Table 8. Sand Delivery February 1, 2018 – April 30, 2018
Table 8 presents the volume of mitigation sand delivered during the period from February 1, 2018
– April 30, 2018. Three separate deliveries were made over this period of time. All delivery tickets
for the total volume delivered of 8,152 cy were submitted as part of the 2018 Sand Report.
3.9 Table 9. Sand Delivery from May 1, 2018 – December 31, 2019
Table 9 presents the total volume of sand delivered during the period from May 1, 2018 –
December 31, 2019. Deliveries occurred between October 2018 to February 2019, and between
October 2019 to December 2019. A table of all deliveries for the total volume delivered of 23,335
cy were submitted as part of the 2019 Sand Report.
3.10 Table 10. Sand Delivery from January 1, 2020 – January 15, 2021
Table 10 presents the total volume of sand delivered during the period from January 1, 2020 –
January 15, 2021. Deliveries occurred in June, November, and December 2020, and in January
2021. A table of all deliveries for the total volume delivered of 10,656 cy are included in with this
report.
3.11 Summary
Table 1 shows that sand delivery requirements were met during the first three years of the
Project1, with a surplus of sand delivered in the Project’s first two years. At the end of the Project’s
fourth winter in 2017, SBPF proposed using an adaptive mitigation approach, whereby the sand
template was refilled to 22 cy/lf/yr. (This adaptive mitigation approach was discussed with the
Commission during the Project’s March 2018 Annual Review and is also described in the 2017
Sand Report).
The UAV survey in June 2020 indicated there was approximately 16,793 cy within the template at
the time of the survey. An additional 10,656 cy was delivered before January 15, 2021 bringing
the total volume delivered to the sand template to be approximately 27,449 cy which correlates
to approximately 29.0 cy/lf. There was an unknown amount of sand from the template used to
re-cover exposed geotubes after storms in the fall of 2020 which reduced the actual volume of
sand in the template to less than 27,449 cy.
1 As described in the 2017 Sand Report, a small deficit was apparent in spring 2016 after bluff erosion contribution
values were recalculated and slightly reduced.
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Epsilon Associates, Inc.
4.0 Annual Aerial Survey of Bluff
SBPF contracted AirShark to perform the annual aerial survey of the bluff in June 2020. AirShark
is the same firm that previously performed the 2017, 2018 and 2019 aerial surveys. A separate
report on the aerial survey is attached (the “Sconset Bluff June 2020 Aerial Survey Report” or the
“2020 Survey Report”).
5.0 Changes in Bluff Volume
Changes in Bluff Volume are also reported in the Sconset Bluff September 2019 Aerial Survey
Report. To understand changes in the bluff volume since Project construction, the results of the
2020 survey were compared to the previous aerial surveys of the Project area that were
conducted in September 2019, May 2018, August 2017, and July 2013. The July 2013 survey was
conducted about 6 months prior to the installation of the geotextile tubes.
5.1 Changes in Bluff Volume in Adjacent Unprotected Areas
The results of the 2020 aerial survey were used to calculate the changes in the bluff volume from
September 2019 to June 2020 for those unprotected areas immediately adjacent to the geotextile
tube project (Figure 1). During review of the topography generated from this survey and the
updated profile views, it was determined that the break in slope between beach and bluff (toe of
the slope) generally varies between elevation +10 and +11 feet North American Vertical Datum of
1988 (“NAVD 88”) but is best represented by using elevation +11 feet NAVD 882. This contour was
used to provide a constant toe elevation and for consistency across the survey area. Therefore,
the change in the bluff volume in these unprotected areas was calculated from the toe of the bluff
(elevation +11 feet NAVD 88) to the top of the bluff.
♦ For the north unprotected area, the section of the bluff within 802 feet immediately to
the north of the geotextile tubes was used.
♦ For the south unprotected area, the section of bluff within 138 feet immediately to the
south of the geotextile tubes was used. Areas farther south than this could not be used
because they had coir or jute terraces installed so were not representative of the
unprotected bluff.
♦ No areas with a bulge of sand from sand delivery activities at the accessway between 85
and 87 Baxter Road were used in the calculations. In particular, the size of the south
unprotected area was reduced in 2019 (i.e. the northern boundary was moved farther
south) to account for sand delivery activities and the associated accretion of sand on the
bluff face extending farther south in 2019 than in previous years.
2 The conversion from Mean Low Water 92 to NAVD 88 is -1.88 feet.
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Epsilon Associates, Inc.
As shown in Tables 3a-c, this analysis indicates that the unprotected areas immediately adjacent
to the geotextile tubes eroded at the following rates:
♦ For the most recent year (September 2019 – June 2020), the unprotected areas eroded
approximately 4,623 cy (Table 3a). This is equivalent to a distance-weighted average of
6.6 cy/lf/yr.
♦ For the period from geotextile tube installation to the previous reporting period (July
2013 – September 2019), the unprotected areas eroded approximately 41,000 cy (Table
3b). This is equivalent of a distance weighted average of 6.8 cy/lf/yr. As discussed in the
2019 Bluff Survey Report, the apparent accretion in the previous reporting period was
within the vertical accuracy range and likely represents no changes.
♦ For the period from geotextile tube installation to present (July 2013 – June 2020), the
unprotected areas eroded approximately 45,623 cy (Table 3c). This is equivalent to a
distance-weighted average of 6.6 cy/lf/yr.
The 2019-2020 estimate of the annual loss of sand from unprotected areas was calculated to be
6.6 cy/lf/yr. This annual loss from September 2019 to June 2020 is consistent with the less
energetic winter storm season than in previous years. This loss is greater than the annual loss of
the previous reporting period for reasons more thoroughly described in the 2019 Bluff Survey
Report. The 2019-2020 estimate is equal to the annualized loss of sand from the geotextile tube
installation in 2013 to the June 2020 survey of 6.6 cy/lf/yr.
5.2 Changes in Bluff Volume Above Geotextile Tubes
The 2020 aerial survey was also used to calculate the changes in the bluff volume above the
geotextile tubes for the period between September 2019 and June 2020. Based on this aerial
survey the bluff above the geotubes eroded approximately 267 cy. As described in the 2020 Bluff
Survey Report, the accuracy of the survey data was 2.3cm, which applied across this area
correlates to approximately ±181 cy, or a distance weighted average of ±0.19 cy/lf.3 With a net
loss of 267 cy, and an accuracy range of approximately ±181 cy, this suggests there was some loss
of sediment off the bluff face above the template.
Reviewing Figure 1, the locations of red are indicative of “gain” and represent maintenance
activities at the Project area, specifically rebuilding of the end returns that were washed away
during winter storms and general template maintenance to re-cover the geotubes. The template
maintenance can also be seen with the creation of the windrows, visible as the relatively north-
to-south narrow linear strips of “gain” shown along the westerly edge of the template.
3 The vertical accuracy was used to calculate the sand volume and presented as a volume rather than vertical
accuracy based on comments from Greg Berman on the 2019 Annual Report.
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Epsilon Associates, Inc.
6.0 Volume of Sand in Template
The volume of sand in the template was calculated by determining the total volume of the
template at the time of the 2020 aerial survey and subtracting out the known volume of sand
within the geotextile tubes and returns located above beach level. The total volume of sand above
the beach level was 28,506 cy and the total volume of sand in the geotubes is 11,713 cy. This
yields a sand cover volume in June 2020 of approximately 16,793. This was prior to the delivery
of an additional 10,656 cy between June 2020 and January 15, 2021. As described in Section 3.11,
this results in an estimate of approximately 27,449 cy of sand available for the 2020-2021 storm
season.
Calculations were also performed on that portion of the sand template that is located above the
fourth tier. Per the Project’s Order of Conditions, the sand on the top of the fourth tier is not
counted as mitigation sand. This volume is calculated as approximately 1,974 cubic yards. It is
anticipated that sand on top of the sand template, including san don top of the fourth tier, will
continue to be pushed down to re-cover the geotextile tubes as needed. Therefore, the volume
above the fourth tier will become available through time.
7.0 Volume of Sand Contributed to Littoral System
Table 2 presents the approximate volume of sand contributed to the littoral system. The amount
contributed is that portion of the sand delivered to the site that is no longer in place in the sand
template and therefore is deemed to have been contributed to the littoral system. As has been
previously notes, the mitigation sand is delivered to the top of the geotextile tubes and then is
pushed over to cover the face of the tubes. On an as-needed basis after erosion events, the sand
on top of the geotextile tubes is pushed from the top of the tubes to the face of the tubes
whenever needed to re-cover exposed geotextile tubes. Table 2 provides a reasonable estimate
of how much mitigation sand has been contributed off the template and into the littoral system
over the past seven years, which totals 91,279 cy.
For each of the seven sand years (Sand Year 2014, Sand Year 2015, Sand Year 2017, Sand Year
2018, Sand Year 2019, and Sand Year 2020), this estimate was calculated by the following steps
shown in Table 2:
1. Beginning with the volume of sand in the sand template at the start of each year (this
was estimated in Sand Years 2014 – 2016 and measured in Sand Years 2017 – 2020);
2. Adding the total amount of mitigation sand delivered each year (this is a known
amount for each Sand Year);
3. Subtracting the volume of sand in the sand template at the end of each sand year
(this was estimated in Sand Years 2014 – 2016 and measured in Sand Years 2017 –
2020);
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Epsilon Associates, Inc.
4. Adding the bluff volume eroded (this is a known total from 2013 through 2017 and
was apportioned to Sand Years 2015 and 2016 as described in Section 5.1 of the 2017
Sand Report);
5. Adding the volume of sand contributed during construction (this is known from 2013);
and
6. Determining the total volume of sand contributed (both as a total volume and as a
rate expressed in cy/lf/yr), including as an average rate from 2013 – 2020.
A review of Tables 2 and 3a-c indicates that the sand template has consistently contributed more
sand than the unprotected bluff to the north and south of the project:
♦ During the first six years, the unprotected bluff contributed an average of 6.8 cy/lf/yr,
while the sand template contributed an average of 13.8 cy/lf/yr.
♦ During the most recent year, the unprotected bluff contributed 6.6 cy/lf/yr, while the
sand template contributed 16.9 cy/lf/yr. While it was a calmer storm year, this volume
contributed by the template is the result of various Project activities associated with
the re-covering of the geotubes post-storm events, rebuilding the end returns, and to
push excess sand off the template to remove sand containing topsoil from the
template.
♦ Over the nearly seven years from July 2013 – January 2021, the unprotected bluff
contributed an average of 6.6 cy/lf/yr compared to 14.3 cy/lf/yr of sand contributed
an average off the template (although more than this has been delivered to the site).
Tables
Line Sand Amounts 12/13-3/31/14 4/1/14-3/31/15 4/1/15-3/31/16 4/1/16-1/31/18 2/1/18-4/30/18 5/15/18-12/31/19 1/1/20-1/15/21
1 Total Volume Delivered for Geotube Construction (See Line 5 in Table 4 and Line 5 in Table 6)12,653 0 2,931 0 0 0 0
2 Total Volume Delivered for Mitigation (see Tables 4-10)23,951 14,429 15,085 15,138 8,152 23,335 10,656
3 Total Volume Delivered to Bluff Face (Not Counted as Mitigation; See Ln 10 in Tbl 4 & Ln 12 in Tbl 6)2,600 0 4,469 0 0 0 0
4 Total Volume Delivered by Truck (Sum Lines 10-12)39,204 14,429 22,485 15,138 8,152 23,335 10,656
5 Required Mitigation Volume (22 cy/lf * Project Length of 852' for 3 tiers, 947' for 4 tiers w/ret.)18,744 18,744 20,834 20,834 20,834 20,834 20,834
Surplus Sand From Prior Year
6 Surplus Delivered in Prior Year (From Line 13 in Preceding Column)0 5,207 3,029 -583 -6,278 -18,960 -16,459
7 Volume on Template at Start of Sand Year 0 5,900 8,500 15,000 17,000 10,200 33,020
8 Countable Surplus Present in Sand Template (Line 6; Not to Exceed Line 7)0 5,207 3,029 -583 -6,278 -18,960 -16,459
9 Volume on Template at End of Sand Year 5,207 8,500 15,000 17,000 10,200 33,020 27,449
Bluff Erosion
10 Net Contribution from Erosion of Bluff Face (pre-veg & during 4th tier const.; see Table 6)0 2,138 2,138 0 0 0 0
11 Adjusted Required Mitigation Volume (Line 5 - Line 8 - Line 10)18,744 11,400 15,667 21,417 27,112 39,794 37,293
12 Total Volume Delivered for Mitigation (Line 2 above)23,951 14,429 15,085 15,138 8,152 23,335 10,656
13 Mitigation Surplus or Deficit (-) ( Line 12 - Line 11)5,207 3,029 -583 -6,278 -18,960 -16,459 -26,637
14 Mitigation Surplus or Deficit (-) to Refill Template to 22 CY/LF 755 -10,634 12,186 6,615
Table 2. Summary of Sand Contribution in Cubic Yards (CY), December 2013 - January 15, 2021
Line Sand Amounts 12/13-3/31/14 4/1/14-3/31/15 4/1/15-3/31/16 4/1/16-5/31/17 6/1/17-5/14/18 5/15/18-12/31/19 1/1/20-1/15/21
1 Volume on Template at Start of Sand Year (Line 7 in Table 1)0 5,900 8,500 15,000 17,000 10,200 33,020
2 Total Volume Delivered for Mitigation (Line 2 in Table 1; Lines 1 through 4 in Table 10)23,951 14,429 15,085 10,550 12,741 23,335 10,656
3 Volume on Template at End of Sand Year (Line 9 in Table 1)5,900 8,500 15,000 17,000 10,200 33,020 27,449
4 Total Volume Contributed from Sand Template (Line 1 + 2 - Line 3)18,051 11,829 8,585 8,550 19,541 515 16,227
5 Total Volume Contributed from Sand Template (cy/lf/yr)21.2 13.9 9.1 8.9 20.3 0.5 16.9
6 Net Contribution from Erosion of Bluff Face (Line 10 in Table 1)0 2,138 2,138 0 0 0 0Construction Contribution
7 Contribution from Construction (Line 8 in Table 4)3,707 0 0 0 0 0 0
Total Annual Sand Contribution
8 Total Volume Contributed 21,758 13,966 10,723 8,550 19,541 515 16,227
9 Total Volume Contributed in cy/lf/yr 25.5 16.4 11.3 8.9 20.3 0.5 16.9
10 Average of Annual Sand Contribution from 2013-2020 (cy/lf/yr)14.3
Template Sand Contribution
Bluff Face Contribution
Note: 2020 Sand Template was measured in June, 2020. Minor template maintenance was performed during Fall months following storms.
Mitigation Volume Summary
Sconset Bluff and Baxter Road Geotextile Tube Project, 87-105 Baxter Road, Nantucket, MA
Table 1. Summary of Sand Delivery in Cubic Yards (CY), December 2013 - January 2021
Sand Delivery Summary
Base Required Mitigation Volume
Mitigation Volume Adjustments
Page 1 of 5
Line Area Volume
Eroded (CY)Length (Feet)Duration
(Years)
Annual Change
(CY/LF/YR)
1 North Unprotected Area 4,418 802 0.75 7.3
2 South Unprotected Area 205 138 0.75 2.0
3
Total Bluff Erosion for Adjacent Unprotected Areas (Distance-weighted average)4,623 6.6
Line Area Volume Eroded (CY)Length (Feet)Duration (Years)Annual Change (CY/LF/YR)
1 North Unprotected Area 35,423 802 6.0 7.4
2 South Unprotected Area 5,577 192 6.0 4.8
3
Total Bluff Erosion for Adjacent Unprotected Areas (Distance-weighted average)41,000 6.8
Line Area Volume
Eroded (CY)Length (Feet)Duration
(Years)
Annual Change
(CY/LF/YR)
1 North Unprotected Area 39,841 802 7.0 7.1
2 South Unprotected Area 5,782 192 7.0 4.3
3
Total Bluff Erosion for Adjacent Unprotected Areas (Distance-weighted average)45,623 6.6
Table 3a. Bluff Volume Loss in Unprotected Areas Adjacent to Geotextile Tubes, September 2019 - June 2020
Table 3b. Bluff Volume Loss in Unprotected Areas Adjacent to Geotextile Tubes, July 2013 - September 2019
Table 3c. Bluff Volume Loss in Unprotected Areas Adjacent to Geotextile Tubes, July 2013 - June 2020
Note: As described in the 2019 Bluff Survey Report, the apparent accretion was within the vertical accuracy range and likely represent no net change ; therefore, a value of 0 was used for the
2019 Sand Year to calculate the 7-year annual rate of change.
Note: The volumes provided in the above table is a comparison of the unprotected areas from the September 2019 survey to the June 2020 survey
Note: As described in the 2019 Bluff Survey Report, the apparent accretion was within the vertical accuracy range and likely represents no change; therefore, a value of 0 was used for the 2019
Sand Year to calcualte the annual rate of change over the previous six years.
Page 2 of 5
Line Sand Delivery Amounts
Cubic Yard
(CY)/ Linear
Foot (LF)
Project Length
(LF)Total CY
1 Inside Tier 2 Geotube 5 852 3,834
2 Inside Tier 3 Geotube 5 835 3,758
3 Bench Behind Tier 2 Geotube 3 852 2,556
4 Bench Behind Tier 3 Geotube 3 835 2,505
5 Total Sand For Geotube Construction (Sum Lines 1-4)12,653
6 Template on Top 22 852 18,744
7 Template at Ends 1,500
8 Sand Contributed to Littoral System During Construction 3,707
9 Total Mitigation Volume (Sum Lines 6-8)23,951
10 Total Volume Delivered to Bluff Face (Not Counted as Mitigation)2,600
11 Total Sand Delivered (Sum Lines 5, 9, and 10)39,204
Line Sand Delivery Amounts Cubic Yard (CY)/ Linear Foot (LF)
Project Length (LF)Total CY
1 April 2014 7.1 852 6,015
2 Jan 2015 5.3 852 4,477
3 Feb 2015 4.6 852 3,936
4 Total Sand Delivered (Sum Lines 1-3)14,429
Mitigation Volume
Bluff Face Volume
Table 4. Sand Delivered December 2013 - March 31, 2014
Geotube Construction
Total Sand Delivered
Table 5. Sand Delivered April 1, 2014 - March 31, 2015
Mitigation Volume
Page 3 of 5
Line Sand Delivery Amounts
Cubic Yard
(CY)/ Linear
Foot (LF)
Project Length
(LF)Total CY
Fourth Tier (3) 120' long x 45' circumference tubes(1) 75' long x 45' circumference tubeTotal of 435 linear feetNorthern Returns
(4) 25' long x 30' circumference tubesTotal of 100 linear feet
Northern Intermediate Returns(1) 35' long x 30' circumference tube(1) 45' long x 30' circumference tubeTotal of 80 linear feet
Southern Returns
(1) 65' long x 30' circumference tube(1) 70' long x 30' circumference tube(1) 75' long x 30' circumference tube(1) 80' long x 30' circumference tubeTotal of 290 linear feet
Southern Intermediate Returns(1) 35' long x 30' circumference tube(1) 45' long x 30' circumference tubeTotal of 80 linear feet
6 Total Sand For Geotube 4th Tier and Returns Construction (Sum Lines 1-5)2,931
7 November and December 2015 (immediately post-construction)15,085
8 Total Mitigation Volume 15,085
9 Total Volume Delivered to Bluff for Vegetation (April 2015)3,418
10 Total Volume Delivered to Bluff to Fill Gully South of Viewing Area (Nov/Dec 2015)931
11 Total Volume Delivered to Bluff to Fill Gully at Viewing Area (Jan 2016)12012Total Volume Delivered to Bluff Face (Not Counted as Mitigation)4,469
13 Total Sand Delivered (Sum Lines 6, 8, and 12)22,485
Mitigation Volume
Bluff Face Volume (Not Counted as Mitigation)
Total Sand Delivered
5 2.0 80 160
3 2.0 80 160
4 2.0 290 580
Geotube Construction - 4th Tier and Returns
2 2.0 100 200
1 4.21 435 1831
Table 6. Sand Delivered April 1, 2015 - March 31, 2016
Page 4 of 5
Line Sand Delivery Amounts Cubic Yard (CY)/ Linear
Foot (LF)
Project Length
(LF)Total CY
1 August through December 2016 1,230
2 May 2017 9,320
3 December 2017 2,090
4 January 2018 2,499
5 Total Sand Delivered (Sum Lines 1-4)15,138
Line Sand Delivery Amounts Cubic Yard (CY)/ Linear
Foot (LF)
Project Length
(LF)Total CY
1 February 2018 40
2 March 2018 5,506
3 April 2018 2,606
5 Total Sand Delivered (Sum Lines 1-3)8,152
Line Sand Delivery Amounts Cubic Yard (CY)/ Linear Foot (LF)
Project Length (LF)Total CY
1 October 2018 2,204
2 November 2018 3,156
3 January 2019 4,120
4 February 2019 2,683
5 October 2019 5,400
6 November 2019 4,266
7 December 2019 1,506
8 Total Sand Delivered (Sum Lines 1-7)23,335
Line Sand Delivery Amounts Cubic Yard
(CY)/ Linear Foot (LF)
Project Length (LF)Total CY
1 June 2020 1,350
2 November 2020 1,800
3 December 2020 5,454
4 January 2021 2,052
5 Total Sand Delivered (Sum Lines 1-4)10,656
Table 9. Sand Delivered May 1, 2018 - December 31, 2019
Mitigation Volume
Table 7. Sand Delivered April 1, 2016 - January 31, 2018
Mitigation Volume
Table 8. Sand Delivered February 1, 2018 - April 30, 2018
Mitigation Volume
Table 10. Sand Delivered January 1, 2020 - January 15, 2021
Mitigation Volume
Page 5 of 5
Sand Delivery Table
Cottage + Castle Ventures, Inc.
Sconset Beach Preservation Trust2021-2021 Sand Season Delivery Schedule
Truck Delivery Date Loads Per Load CYD's Total CYD's Hours Amount Source Delivery Vendor Delivery Location AH Invoice Number Invoice Date Delivery Qtr
656 6/17/2020 18 18 324 1,800.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 361 7/29/2020 Q2, 2020
97 6/17/2020 7 18 126 675.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 361 7/29/2020 Q2, 2020
500 6/17/2020 19 18 342 1,950.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 361 7/29/2020 Q2, 2020
207 6/17/2020 11 18 198 1,125.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 361 7/29/2020 Q2, 2020
473 6/17/2020 20 18 360 2,100.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 361 7/29/2020 Q2, 2020
083 11/20/2021 12 18 216 8.00 1,200.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 2020
473 11/20/2021 11 18 198 7.50 1,125.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 2020
097 11/20/2020 11 18 198 7.00 1,050.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 2020
083 11/23/2021 13 18 234 8.50 1,275.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 2020
473 11/23/2020 11 18 198 7.50 1,125.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 2020
097 11/23/2020 9 18 162 6.50 975.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 2020
083 11/30/2020 13 18 234 8.50 1,275.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 202047311/30/2020 11 18 198 7.50 1,125.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 202009711/30/2020 9 18 162 6.50 975.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 202008312/3/2020 11 18 198 7.50 1,125.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 202047312/3/2020 12 18 216 8.00 1,200.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 202009712/3/2021 12 18 216 8.00 1,200.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 202008312/8/2020 9 18 162 6.50 975.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 202047312/8/2020 13 18 234 8.50 1,275.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 202009712/8/2020 11 18 198 7.50 1,125.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 202008312/12/2020 14 18 252 9.00 1,350.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 202047312/12/2020 10 18 180 7.50 1,125.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 202009712/12/2020 7 18 126 6.00 900.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 399 1/8/2021 Q4, 202047312/14/2020 12 18 216 8.50 1,275.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 402 1/12/2021 Q4, 202009712/14/2020 9 18 162 6.50 975.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 402 1/12/2021 Q4, 2020
473 12/16/2020 11 18 198 7.50 1,125.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 402 1/12/2021 Q4, 2020
097 12/16/2020 11 18 198 7.00 1,050.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 402 1/12/2021 Q4, 2020
473 12/17/2020 10 18 180 7.50 1,125.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 402 1/12/2021 Q4, 2020
097 12/17/2020 9 18 162 7.00 1,050.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 402 1/12/2021 Q4, 2020
473 12/18/2020 13 18 234 9.00 1,350.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 402 1/12/2021 Q4, 2020
097 12/18/2020 8 18 144 6.00 900.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 402 1/12/2021 Q4, 2020
473 12/19/2020 10 18 180 7.50 1,125.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 402 1/12/2021 Q4, 2020
097 12/19/2020 11 18 198 8.00 1,200.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 402 1/12/2021 Q4, 2020
473 12/21/2020 12 18 216 8.50 1,275.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 402 1/12/2021 Q4, 2020
097 12/21/2020 9 18 162 7.00 1,050.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 402 1/12/2021 Q4, 2020
473 12/22/2020 13 18 234 9.00 1,350.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 402 1/12/2021 Q4, 2020
097 12/22/2020 8 18 144 6.50 975.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 402 1/12/2021 Q4, 202047312/23/2020 12 18 216 8.50 1,275.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 402 1/12/2021 Q4, 202009712/23/2020 12 18 216 7.00 1,050.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 402 1/12/2021 Q4, 202047312/28/2020 7 18 126 6.00 900.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q4, 202009712/28/2020 10 18 180 7.50 1,125.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q4, 202047312/30/2020 9 18 162 7.00 1,050.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q4, 202009712/30/2020 8 18 144 6.50 975.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q4, 20204731/1/2021 7 18 126 6.00 900.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q1, 20210971/1/2021 9 18 162 7.00 1,050.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q1, 20214731/2/2021 10 18 180 7.50 1,125.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q1, 20210971/2/2021 8 18 144 6.50 975.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q1, 20214731/5/2021 9 18 162 7.00 1,050.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q1, 20210971/5/2021 10 18 180 7.50 1,125.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q1, 20214731/6/2021 8 18 144 6.50 975.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q1, 2021
097 1/6/2021 6 18 108 5.50 825.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q1, 2021
473 1/9/2021 9 18 162 7.00 1,050.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q1, 2021
097 1/9/2021 9 18 162 7.00 1,050.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q1, 2021
473 1/11/2021 6 18 108 5.50 825.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q1, 2021
097 1/11/2021 8 18 144 6.50 975.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q1, 2021
473 1/12/2021 8 18 144 6.50 975.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q1, 20210971/12/2021 7 18 126 6.00 900.00 Industrial Road/Purchased Town Sand AH Construction To Bluff 412 2/19/2021 Q1, 2021Total592 10,656 376.00 64,050.00 57