HomeMy WebLinkAboutSconset Sep-Dec 2017 Work Reports
PRINCIPALS
Theodore A Barten, PE
Margaret B Briggs
Michael E Guski, CCM
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
Samuel G. Mygatt, LLB
1943-2010
ASSOCIATES
Richard M. Lampeter, INCE
Maria B. Hartnett
Geoffrey Starsiak
3 Mill & Main Place, Suite 250
Maynard, MA 01754
www.epsilonassociates.com
January 15, 2018
Nantucket Conservation Commission
2 Bathing Beach Road
Nantucket, MA 02554
Subject: Submission of Work Logs (September-December 2017)
SE48-2824, Sconset Bluff Geotextile Tube Project
Dear Commissioners:
Special Condition 59 of the above-referenced Order of Conditions requires that “A
daily work log documenting all project activity shall be filed with the Commission
as part of each quarterly [shoreline monitoring] report.” As the quarterly shoreline
monitoring report was recently submitted to the Commission by the Woods Hole
Group, this letter is transmitting the work logs from September through December
2017.
The attached work logs include two template re-grading reports and one sand
delivery log.
Sincerely,
EPSILON ASSOCIATES, INC.
Maria B. Hartnett
Associate
1
Sand Template Work Report
Baxter Road and Sciasconset Bluff Stabilization Project
October 11, 2017
Author: Chris Humphrey
Proposed Template Action:
(Re-grade and/or Replenish)
Re-grade to restore template on face of geotubes.
Cause for Template Work:
(Storm, Periodic Maintenance,
etc.)
A minor winter storms exposed the face of the second tier
geotubes.
Pre-Work/Storm Template
Condition:
(Describe condition of ramps,
ends, and face of geotubes.
Prior to work, attach
photographs from the 6 photo
locations and template
measurements.)
The entire length of the second tier. Both ramps were
accessible.
Template Work Description:
(Provide dates of work, length
of template re-graded, volume
of sand added, etc. After
work is completed, attach
photographs from the 6 photo
locations and template
measurements.)
Template restoration work began at approximately 10:00 am
on 9/25/17 and was concluded at approximately 10:00 am on
9/27/17. All tubes were covered. Based on previous surveys, it
is estimated that approximately 1’ of the template depth on the
top tube structure was lost over a distance of approximately
925 LF as a result of grading (approximate pre-grading
elevation 35.5 ft. ± MLW).
If the template work is being done in response to a storm that does not require a separate
“Major Storm Report,” please fill out the following sections.
Storm Dates:
9/24/17 (The storm did not satisfy major storm criteria.)
Post-Storm Inspection
Date/Time:
9/25/17
Inspector(s): Chris Humphrey
2
Template loss: Using geometric calculations based on the dimensions of the
exposed geotubes, it is estimated that approximately 2.0
cy/linear ft. of sand was contributed from the sand template
during the storm. (925 LF x 2.0 cy= 1850 cy)
Adjacent Bluff Loss:
In the areas north and south of the project, approximately 1 ft.
of the toe of the bluff was lost.
Estimated Beach Level in
Front of the Seaward
Geotextile Tube:
Bottom of second geotube (approximately +7.5 MLW).
Location(s) of Exposed
Geotextile
The entire length of the second tier of the geotube structure.
Repairs to Tubes: None
Condition of Ends/
Observations of Flanking:
None
Proposed Template Action
(Re-grade and/or Replenish):
Regrade to restore template on the face of the geotubes.
Last Maintenance Performed: 5/23/17 (Annual sand delivery grading)
Last Storm Event: 4/24/17
Photograph Attachments:
Photographs shall be taken from the following locations with the date provided in the
caption:
• Northern return and access ramp
• North end looking south
• Mid-point looking south
• Mid-point looking north
• South end looking north
• Southern return and access ramp
• Clay Head
3
Template Measurements:
Pre-grading template width:
North end ramp: 15’ 700 ft.: 20’
North End: 27’ 800 ft.: 20’
100 ft.: 27’ 900 ft.: 22’
200 ft.: 28’ South end ramp: 15’
300 ft.: 20’
400 ft.: 22’
500 ft.: 19’
600 ft.: 22’
Seaward edge of template in front of Bench Mark #1 ─ Elev. = *35.0 ft. ± MLW
Seaward edge of template in front of Bench Mark #2 ─ Elev. = *36.0 ft. ± MLW
*Approximate measurements taken from the bench mark using a line level and rod after last
grading event. The benchmark height is Elev. 38± MLW based on Blackwell & Associate’s survey
dated 3/4/16.
Post-grading template width:
North end ramp: 14’ 700 ft.: 19’
North end: 25’ 800 ft.: 18’
100 ft.: 27’ 900 ft.: 18’
200 ft.: 27’ South end: 20’
300 ft.: 20’ South end ramp: 15’
400 ft.: 21’
500 ft.: 18’
600 ft.: 20’
Seaward edge of template in front of Bench Mark #1 ─ Elev. = *34.0 ft. ± MLW
Seaward edge of template in front of Bench Mark #2 ─ Elev. = *35.0 ft. ± MLW
*Approximate measurements taken from the bench mark using a line level and rod.
4
Photo Attachments:
9/25/17 Northern ramp & return 9/25/17 Northern end viewing south
9/25/17 Midpoint viewing north 9/25/17 Midpoint viewing south
5
9/25/17 Southern ramp & return 9/25/17 Southern end viewing north
9/25/17 Clay Head viewing south 9/25/17 Clay Head viewing north
6
Post-Grading Photos:
9/27/17 Clay Head viewing south 9/27/17 Clay Head viewing north
9/27/17 Northern return and ramp 9/27/17 Northern end viewing south
7
9/27/17 Midpoint viewing north 9/27/17 Midpoint viewing south
9/27/17 Southern end viewing north 9/27/17 Southern return and ramp
1
Sand Template Work Report
Baxter Road and Sciasconset Bluff Stabilization Project
November 28, 2017
Author: Chris Humphrey
Proposed Template Action:
(Re-grade and/or Replenish)
Fill a wash-out area in the center of the tube structure and grade
template to cover approximately 150’ of exposed tubes at the
northern end.
Cause for Template Work:
(Storm, Periodic Maintenance,
etc.)
Maintenance following a minor storm.
Pre-Work/Storm Template
Condition:
(Describe condition of ramps,
ends, and face of geotubes.
Prior to work, attach
photographs from the 6 photo
locations and template
measurements.)
Both ramps were accessible. Approximately 150’ of the face of
the second-tier tubes were exposed at the northern end of the
project and a gully approximately 15’ wide by 10’ long
exposed the 4th and 3rd tier tubes in the center of the sub
structure.
Template Work Description:
(Provide dates of work, length
of template re-graded, volume
of sand added, etc. After
work is completed, attach
photographs from the 6 photo
locations and template
measurements.)
Template restoration work began at approximately 8:00 am on
11/28/17 and was concluded at approximately 4:00 pm on
11/28/17. All tubes were covered. Based on previous surveys,
it is estimated that approximately 6” of the template depth on
the top tube structure was lost over a distance of
approximately 175 LF as a result of grading (approximate pre-
grading elevation 35.5 ft. ± MLW).
If the template work is being done in response to a storm that does not require a separate
“Major Storm Report,” please fill out the following sections.
Storm Dates:
11/22/17 (The storm did not satisfy major storm criteria.)
Post-Storm Inspection
Date/Time:
11/28/17
Inspector(s): Chris Humphrey
2
Template loss: Using geometric calculations based on the dimensions of the
exposed geotubes, it is estimated that approximately 2.0
cy/linear ft. of sand was contributed from the sand template
during the storm. (175 LF x 2.0 cy= 350 cy)
Adjacent Bluff Loss:
Approximately 1’ of bluff was lost north of the project.
Estimated Beach Level in
Front of the Seaward
Geotextile Tube:
Bottom of second geotube (approximately +7.5 MLW).
Location(s) of Exposed
Geotextile
Approximately 150’ of the face of the second-tier tubes were
exposed at the northern end of the project and a gully
approximately 15’ wide by 10’ long exposed the 4th and 3rd tier
tubes in the center of the sub structure.
Repairs to Tubes: None
Condition of Ends/
Observations of Flanking:
None
Proposed Template Action
(Re-grade and/or Replenish):
Regrade to restore template on the face of the geotubes and fill
in15’ x 10’ gully.
Last Maintenance Performed: 10/11/17
Last Storm Event: 9/25/17
Photograph Attachments:
Photographs shall be taken from the following locations with the date provided in the
caption:
• Northern return and access ramp
• North end looking south
• Mid-point looking south
• Mid-point looking north
• South end looking north
• Southern return and access ramp
• Clay Head
3
Template Measurements:
Pre-grading template width:
North end ramp: 14’ 700 ft.: 19’
North end: 25’ 800 ft.: 18’
100 ft.: 27’ 900 ft.: 18’
200 ft.: 27’ South end: 20’
300 ft.: 20’ South end ramp: 15’
400 ft.: 21’
500 ft.: 18’
600 ft.: 20’
Seaward edge of template in front of Bench Mark #1 ─ Elev. = *34.0 ft. ± MLW
Seaward edge of template in front of Bench Mark #2 ─ Elev. = *35.0 ft. ± MLW
*Approximate measurements taken from the bench mark using a line level and rod after last
grading event. The benchmark height is Elev. 38± MLW based on Blackwell & Associate’s survey
dated 3/4/16.
Post-grading template width:
North end ramp: 14’ 700 ft.: 19’
North end: 25’ 800 ft.: 18’
100 ft.: 27’ 900 ft.: 18’
200 ft.: 27’ South end: 20’
300 ft.: 20’ South end ramp: 15’
400 ft.: 21’
500 ft.: 18’
600 ft.: 20’
Seaward edge of template in front of Bench Mark #1 ─ Elev. = *33.5 ft. ± MLW
Seaward edge of template in front of Bench Mark #2 ─ Elev. = *34.5 ft. ± MLW
*Approximate measurements taken from the bench mark using a line level and rod.
4
Photo Attachments:
11/28/17 Northern ramp & return 11/28/17 Northern end viewing south
11/28/17 Midpoint viewing north 11/28/17 Midpoint viewing south
5
11/28/17 Southern ramp & return 11/28/17 Southern end viewing north
11/28/17 Clay Head viewing south 11/28/17 Clay Head viewing north
6
Post-Grading Photos:
12/5/17 Clay Head viewing south 12/5/17 Clay Head viewing north
11/28/17 Northern return and ramp 12/5/17 Northern end viewing south
7
12/5/17 Midpoint viewing north 12/5/17 Midpoint viewing south
12/5/17 Southern end viewing north 11/28/17 Southern return and ramp
8
11/28/17 Gully repair
Baxter Road and Sciasconset Bluff Stabilization Project
Sand Delivery Summary December 2017
On the following dates sand was delivered from the top of the bluff by dump truck:
12/17/17 – 560 CY
12/8/17 – 966 CY
12/11/17 – 564 CY