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SOILS
The DEIS scope section “Impact on Soils and Topography” calls for the DEIS to “identify the existing soil
type(s) on the subject property, based upon the Suffolk County Soil Survey and any available test hole
data,” (p.6) and for the DEIS to discuss “the types and tested physical characteristics of the soils on site
that will be subject to excavation, future load bearing, and installation of sanitary systems and
stormwater conveyance systems” (p.6). Page 19 of the DEIS scope also states that “Soil types will be
identified from soil boring logs and published data through the USDA Suffolk County Soil Survey”.
The DEIS has not properly or adequately characterized and discussed the soils in the Project area.
As detailed below, there are problems with both the portions of the DEIS dealing with soils and the
Project’s geotechnical report in DEIS Appendix H 1. As a result, the validity, accuracy and utility of the
information in the DEIS that relates to Project area soils is suspect.
Tm (Tidal marsh) soils
The DEIS includes information on existing soil types as mapped by the USDA Suffolk County Soil Survey
(DEIS pp.22-26, DEIS Appendix A Figure 6). According to USDA soil survey mapping as described in the
DEIS 2, Tm (Tidal marsh) soils are present in the southern portion of the Project’s Construction
Excavation Area (CEA) in the area that will be partially occupied by proposed Storage Building No.2. DEIS
Table 7 (Soil Engineering and Planning Limitations) notes that the USDA classifies Tm soils as having
“Severe” limitations for homesites because of high water. A note to DEIS Table 7 states that the DEIS
used the homesites evaluation to “determine potential limitations for the development of the proposed
action.”
The USDA description of Tm soils is quoted in the DEIS:
“Tidal marsh is made up of wet areas that are throughout the county around the
borders of calmer embayments and tidal creeks. These level areas are not inundated by
daily tide flow, but they are subject to flooding during abnormally high moon or storm
tides. The areas range from about 2 to several hundred acres. Tidal marsh has an
organic mat on the surface that ranges from a few inches to several feet in thickness.
The organic mat overlies pale-gray or white sand. In many places the profile for the
marsh is made up of alternating layers of sand and organic material as a result of sand
deposited on the organic mat during abnormally high storm tides. They are best suited
to use as habitat for certain types of wildlife” (DEIS p.25).
1 Geotechnical Engineering Memo Report, 5780 Mill Road, Mattituck NY, 11952, August 3, 2021, P.W. Grosser Consulting.
2 See COMMENT FIGURE SOILS-1. It should be noted that DEIS Appendix A Figure 6, which has a scale of 1:3740, includes a note
copied from the USDA Soil Survey Mapper that notes “Warning: Soil Map may not be valid at this scale. Enlargement of maps
beyond this scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The
maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale.”
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The Project geotechnical report (DEIS Appendix H) includes the log for boring B-11, located within the
area mapped as containing Tm soils. The soil profile description for B-11 corresponds with the USDA
description of Tm soils. The log describes the first two feet of soil (below several inches of topsoil), from
11 to 9 feet in elevation, as “Very loose, light brown and tan medium to fine grained SAND (SP), roots.”
The presence of roots is indicative that organic matter is a component of the soil.
The existing surface elevation of the area containing Tm soils is approximately 11 feet. The finished
floor elevation of proposed Storage Building No.2 is 10 feet. This raises a number of questions: Will
excavated Tm soils be treated differently from other soils types during excavation? Will excavation of
Tm soils below the 10 ft elevation be necessary because of their severe engineering limitations? If so, to
what depth? Will excavated Tm soils below 10 feet be replaced with fill suitable for construction?
No discussion of the significance of Tm soils is included in the DEIS or the geotechnical report prepared
for the Project (DEIS Appendix H).
“Fd” (fill land, dredged material)
The DEIS also states that the only portion of SYC property identified as having soils classified as “Fd” (fill
land, dredged material) (DEIS Appendix A, Figure 6) is a very small area along the west shore of
Mattituck Creek, east of the southernmost of the existing marina structures. Table 6 in the DEIS (Soil
Types Mapped on Subject Property) notes that Fd soils “are located outside of the area of disturbance
for the proposed action.” However, Figures C-100, C-101 and C-102 (COMMENT FIGURE SOILS-2) in the
Project geotechnical report label large areas in the southern and eastern portion of the Project area as
“Potential Dredge Spoils.”3 No explanation of how the boundaries of these areas were determined is
provided in the DEIS or DEIS Appendix H. Fd soils are the only soil type reported in the Project area for
which the DEIS does not include the corresponding USDA soil type description.4
According to the boring logs, borings B-9 (COMMENT FIGURE SOILS-3), B-10 and B-11 showed evidence
of “Potential Dredge Spoils.” However, the logs for borings B-6, B-7 and B-8, also located within areas of
“potential dredge spoils”, do not indicate the presence of dredge spoils. (The geotechnical report
designates dredge spoil as Stratum 3, and describes it as “grey sands includ[ing] trace to little amounts
of shells”).5
3 Presumably this seeming contradiction is based on the fact that the USDA survey is referring to near surface soils, while the
DEIS figures are referring to buried deposits. This needs to be clarified as it is a potential source of confusion.
4 The USDA description for Fd soils reads in part: “Fill lands, dredged material (Fd), is made up of areas that have been filled
with material from hydraulic or mechanical dredging operations. These operations are used mainly to widen or deepen boat
channels in salt water; however, some dredged material has been obtained from new channels cut into tidal marshes. Most of
the dredged material is pumped onto tidal marshes. . . . Areas are satisfactory for building sites where the fill is adequate and
if the highly compressible organic layers in the tidal marshes are removed prior to filling” (Warner et al, 1975, Soils Survey of
Suffolk County, New York).
5 The presence of small amounts of shell in sands at these elevations suggests that an alternate explanation for Stratum 3 in
some of the borings is that it consists of old, naturally occurring, beach deposits, possibly dating to the Pleistocene.
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The northeast portion of the Project site is also shown on Figures C-100, C-101 and C-102 as “Potential
Dredge Spoils.” Boring B-6, is shown mapped in the geotechnical report as being located in the center of
the “potential dredge spoils” area in the northeast part of the Construction Excavation Area, under the
proposed location for Storage Building No. 1. The log for Boring B-6 does not note the presence of
“Potential Dredge Spoils”. It is unclear why this area was identified as containing dredged material.
Borings B-7 and B-8 were located along the southern edge of the site of proposed Storage Building No.
2. Both of these are located within an area shown on Figure C-102 in the geotechnical report as being
the center of the southerly area labeled as “Potential Dredge Spoils.” Neither of these logs notes then
presence of “Potential Dredge Spoils.”6
If the areas surrounding borings B-6, B-7, and B-8 do, in fact, contain dredge spoils, why was this not
indicated on the logs for these borings? What is the depth to the top of these deposits? How thick are
they? Will any of this material be excavated as part of the Project? If so, in what quantities? The last
question is especially important because according to the “Soil Type Breakdown of Cut Volume” tables
in both the geotechnical report (Appendix H) and the DEIS (Table 10, p.37), dredge spoils are not part of
the 135,000 CY of material that will be excavated from the Construction Excavation Area.7
The interpretation of the materials recovered in some borings as dredge spoil is problematic. Possible
uncertainty as to the classification of sediment recovered from Borings B-9, B-10 and B-11 is reflected in
the decision to refer to them as “potential” and “possible” dredge spoil. (References to Stratum 3 in
Tables 5 and 6 of the geotechnical report, however, do not include either qualifier).
The geotechnical report states that “PWGC believes that this material was deposited onsite as dredge
spoils as it was found where the spoils were suspected of being.” This is circular reasoning. No
discussion of why dredge spoil was expected in this area is provided.8
6 In contrast, the logs for borings B-9, B-10, and B-11 all contain strata labeled “Potential Dredge Spoils”. However, in these
instances the top of the “Potential Dredge Spoil” strata is located respectively at elevations of 7, 6 and 3 feet. Since proposed
excavation will be to an elevation of 9± feet, any dredge spoils in these areas would not be exposed.
7 According to DEIS Table 10, the “Total Approx. Quantity” of “Stratum 3: Grey Sand w/Shells, Dredge Spoil” is “0”CY out of the
total of 135,000 CY.
8 The DEIS states that “Based on observations made during the walkover of the eastern edge of the proposed Construction
Excavation Area on March 25, 2021 by project archaeologist, Carol S. Weed, MA (RPA), dredge spoil appears to have been
emplaced atop the east side of the valley slope, effectively creating the top of the broken upland slope line. As noted in the
Phase 1A Archaeological Assessment, the origin of the spoil is unknown but historic documents indicate that dredge spoil was
deposited onsite and particularly on the west side of Mattituck” (p.31). It is possible that the “expectation” that dredged spoil
deposits would be found was based on questionable interpretations of historical data included in the archeological
assessment for the Project (see accompanying comments on archeological investigations at the Project site).
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The most significant basis for questioning whether the material observed in borings B-9, B-10, and B-11
is dredge spoil is the fact that the top of Stratum 3, in all three cases, is found at depths varying from
four to eight feet below ground surface. This begs the question: if Stratum 3 is in fact dredge spoil, what
is the material overlying it? Any such material could not have been deposited earlier than the late
nineteenth century when the first dredging of Mattituck Inlet occurred. If the overlying strata are
natural, then Stratum 3 cannot be dredge spoil.9
Stratum 3 is also described in the geotechnical report as “generally found between EL. 0’ and El. +8’
NAVD88.” This means that they would be found below the maximum depth of excavation within the
Construction Excavation Area. However, if they are, in fact, found in the areas identified as containing
“Potential Dredge Spoils” as shown on geotechnical report Figures C-100, C-101, and C-102, this could
be of concern. It would mean that dredged spoil is present under the proposed locations of proposed
Storage Building No. 1, proposed Storage Building No. 2, and possibly segments of the proposed
retaining wall. The DEIS and the Appendix H both point out that the Stratum 3 “material was classified
as “SP” in accordance with the USCS10. This material is considered unsuitable for foundation bearing
based on the loose blow counts” (emphasis added) (DEIS p.28).
The DEIS also contains a disingenuous statement about the significance of the presence of Stratum 3. It
states “Stratums 3 and 4 are mostly located at elevations and locations outside the soil cut” (p.35). If
the area mapped as “Possible Dredge Spoil” is accurate, Stratum 3 soils are “outside the soil cut” only if
one interprets that to mean they will not be excavated because they are found below the limits of
excavation11. They are, however, inside the horizontal limits of the Construction Excavation Area. In the
case of the northeast portion of the Construction Excavation Area (the area surrounding boring B-6)
“dredge spoils” may well be within the soil cut. However, as noted above, as the DEIS failed to include
information about the depth or thickness of possible dredge spoil in this area, it is impossible to
determine whether or not this is so.
Page 31 of the DEIS includes a section titled “Historic Environmental Context.” It begins:
9 The Phase IA archeological assessment report (DEIS Appendix T states that, “[O]verall, the soil layers above the dredge spoils
generally agree with the CpE texture description . . . and represent erosion sediments from upslope.” In fact, the USDA
description of CpE soils (Warner et al. 1975) included in the Phase IA report, describes them as “glaciofluvial deposits.” Such
deposits would result from a considerably different formative process than would be associated with “erosional sediments.
The idea that from 4 to 8 feet of sediment could have eroded downslope to cover the “dredged spoil” seems very unlikely.
10 Unified Soil Classification System
11 As noted above, according to the DEIS, dredge spoils are not part of the 135,000 CY of material that will be excavated from
the Construction Excavation Area.
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“As indicated in the Phase 1A Archaeological Assessment included in Appendix T, based
on aerial photography, the topography of the eastern third of the subject property has
been the subject of significant alteration episodes occurring between 1962 and 2006.
These affected the upland and valley slopes, and marina location. At least one of the
episodes was the result of dredge deposition in a now filled inlet. The filling was under
the direction of the USACOE as part of their larger program to maintain the Mattituck
Creek inlet and channel. Review of published records indicate [sic] maintenance
dredging conducted under USACOE commercial permits was done between 1921 and
the 1970s (Morgan et al. 2005, Batten and Kraus 2006).”
This statement misrepresents and/or misinterprets the archeological assessment. That assessment
never states that “the eastern third of the subject property has been the subject of significant alteration
episodes occurring between 1962 and 2006.” It states only that “aerial photographs dated 1962 and
1978 (Figures 14, 15) show the gradual filling of an inlet in SYC’s southeast quarter” (p.6, also p.11). This
area corresponds to the area identified on the soil survey map (Figure 6 in DEIS Appendix A, and Figure
19 in the archeological assessment) as “Tm” (tidal marsh) soils. As noted above, portions of proposed
Storage Building 2 will be located in an area of Tm soils.
There is also no evidence to support the statement that the “filling was under the direction of the
USACOE as part of their larger program to maintain the Mattituck Creek inlet and channel” (p.31)12 (see
also fn 13, 14 and 16, below).
In fact, the Batten and Kraus report cited in the DEIS (see above) states that the “earliest maintenance
dredging was performed in 1921 and again in 1923 (Ralston 1929)13. The disposal area for this dredging
is not known. Material was likely disposed offshore, to the east of the inlet” (emphasis added) (p.9)14.
The DEIS’ claim that large amounts of dredge spoil is present in the Project area is also used to support
an unprovable contention that some aspects of the Project are necessary to correct actions of the
Army Corps of Engineers. For example:
12 The 1985 report Analysis Of Dredging And Spoil Disposal Activity Conducted By Suffolk County--Historical Perspective And A
Look To The Future, prepared by the Suffolk County Planning Department, does state that in 1955 Suffolk County undertook
the dredging of Mattituck Creek and that “Although some upland disposal sites were used for the placement of spoil from
dredging activities that occurred back in the 1950s and 1960s, all of the Projects now maintained by Suffolk County, with the
exception of West Harbor, utilize dredged spoil for beach nourishment” (p.53).
13 Ralston, R. R. (1929). “Report on survey of Mattituck Harbor, NY,” in House of Representatives (1935) report from the Chief
of Engineers on preliminary examination and survey of Mattituck Harbor, NY, House Document No. 8, 71st Congress, 1st
Session, U.S. Government Printing Office, Washington, DC.
14 Table 4 in the Batten and Kraus report lists a total of 15 dredging episodes between 1907 and 2004. That table, labeled
“Mattituck Dredging History,” also indicates that the disposal sites for the six earliest (pre-1937) episodes are unknown, but
that the disposal site for all subsequent dredging episodes was the “Beach east of east jetty.” This is well outside the Project
area. Morgan et al (2005) contains an almost identical table (Table 2.4).
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“The proposed Evergreen concrete retaining wall would be constructed along the west
side of Buildings 9 and 10, the north side of Building 10, and southeast of Building 9, to
stabilize the area excavated to accommodate the proposed action and correct existing
stabilization issues to the west of Buildings 7 and 8, that have been caused by
unconsolidated dredge spoils deposited in the past by the USACOE” (emphasis added)
(pp. ii, 6)15.
“The intent and purpose of the retaining wall is to stabilize the slope to be disturbed by
the proposed action and to correct existing stabilization issues caused by former
deposited dredge spoils by the USACOE” (emphasis added) (p.12).
“Additionally, SYC intends to improve the existing facility with constructing new parking,
installing drainage, connecting to the public water supply, and correcting an area of the
site that has been susceptible to erosion due to dredge spoils placed on-site as part of
routine federal maintenance dredging projects” (emphasis added) (p.14).
The DEIS notes that that the small area of USDA-mapped dredged material/fill (Fd soil) located in the
southeast part of the existing marina, outside the area that will be affected by construction for the
proposed Project, “coincide with fill episodes that are documented between 1962 and 1984” (p.23).
There is no evidence to support the claim that the Army Corps of Engineers ever deposited dredge spoil
in the Construction Excavation Area or any other part of the marina property.16,17 The notion that there
15 Local residents believe that the existing slope stabilization issues were aggravated by the unpermitted mining of sand by
prior owners of the property. It may also have been exacerbated by the unpermitted clearing of trees at the top of the slope
by the Applicant. The latter is documented in the records of the Investigation Unit of the Office of the Southold Town
Attorney, CC# 2017-363, dated March 29, 2017 (see COMMENT FIGURE SOILS-4)
16 Cited documentation, including histories of dredging activity in Mattituck Creek and adjacent areas (Morgan et al. 2005)
(Geomorphic Analysis of Mattituck Inlet and Goldsmith Inlet, Long Island, New York), referenced in the archeological survey
report has been incorrectly quoted as indicating that “dredge spoil has been deposited on the floodplain and in valley
locations particularly on the west side of Mattituck Creek by the US Army Corps of Engineers” (emphasis added). No such
statement appears in Morgan et al. However, Batten and Kraus (2006), Evaluation of Downdrift Shore Erosion, Mattituck
Inlet, New York: Section 111 Study), a source listed in archeological survey report’s references cited, but which is never
mentioned in the text, states that “In total, approximately 391,000 cu yd of sediment was dredged from Mattituck Inlet
between 1921 and 2004. Condition surveys for the 1946, 1950, 1955, and 1965 dredging show that dredged material was
placed either on the subaerial beach or below the waterline directly to the east of the inlet. Records indicate that, after these
initial placements on the beach or in the nearshore, disposal of maintenance dredged sediment on the eastern beach
became standard practice” (2006:10) (emphasis added).
17 There is evidence to suggest that a very small area of dredge spoil or other fill may be present east of existing Building 7.
However, as an Army Corps of Engineers report notes “One is immediately inclined to attribute the poor foundation
conditions to the dredge spoil. This has limited validity. Settlement must also be attributed to the subsurface soils, which are
usually highly organic, wet, and compressible. Consequently, poor foundation conditions at spoil disposal areas must be
attributed to poor subsurface conditions as well as poor dredge spoil characteristics. (Boyd et al. 1972:64)(Disposal of Dredge
Spoil, Problem Identification and Assessment and Research Program Development, Technical Report H-72-8, U. S. Army
Engineer Waterways Experiment Station)
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was an unrecorded disposal of dredge spoil by the Army Corps of Engineers in an elevated upland area,
which would likely have required the spoil to be pumped 18, is not credible. Combined with the fact that
any such disposal would have required the consent of the land owner, and that the ACOE has a
documented history of depositing dredge spoil from Mattituck Creek in low lying areas on the east side
of Mattituck Inlet, is additional evidence that the ACOE did not deposit dredge spoil in the area west of
the existing marina buildings 19.
Anecdotal information from local residents suggests that the former inlet area was filled by a previous
owner—not the ACOE. This is supported by a 1957 land survey that identifies a roughly 200 ft x 600 ft
area corresponding to the location of the former inlet as “Sand Filled” (COMMENT FIGURE SOILS-5).
Soil borings B-10 and B-11 were located in this area. This would suggest that all of the soil above what
the Project geotechnical report identifies as possible dredge spoil (Stratum 3) in the southeast portion of
the Construction Excavation Area is, in fact, dredge spoil or another type of fill, and not, as the
geotechnical report implies, naturally occurring material.
Chemical Testing of Project Area Soils
The soil analytics section of DEIS Appendix H includes a report describing the results of chemical testing
of soils on the Project site. However, the testing was limited to two locations and included an
“Embankment Sample” and an “Embankment Grab” sample at each location. Both locations are clearly
identified on an accompanying aerial photograph, and indicate that all of the samples were collected
from the actively eroding steep slope west of the existing marina structures. This slope forms the
approximate eastern edge of the Project’s Construction Excavation Area. It is clear that no testing of
soils (sand) in the main body of the excavation area was undertaken. This is significant.
The DEIS has not addressed the significance of the possible presence of dredge spoil.
As discussed above, the DEIS had identified large parts of the southern and northeast portions of the
Construction Excavation Area as containing dredge spoil deposits. Dredge spoils are known to be of
concern because of the possibility that they may contain dangerous contaminants. The two locations
sampled and chemically tested were collected from west of the areas of “possible dredge spoil “as
shown on Figures C-100, C-101 and C-102in the geotechnical report (DEIS Appendix H). If these areas
18 According to an Army Corps of Engineers study, “pumping distance from dredge site to disposal site is a significant economic
consideration” (Boyd et al. 1972:74)
19 It is possible that some dredge spoil was deposited in the area east of the existing marina structures by parties other than
Corps of Engineers. According to “Dredged Material Management Plan and Programmatic Environmental Impact Statement
Long Island Sound Connecticut, New York, Rhode Island (2015), there “are a small number of maritime interests in the Suffolk
County Northeast Shore Area Dredging Center that periodically generate dredged material. Most of these are located at
Mattituck Harbor and consist of marinas, boat yards and yacht clubs”.
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are, in fact, dredge spoil, as the DEIS maintains, then samples from those areas should have been
included in the chemical testing protocol.
Additional Discrepancies and Misleading Information
The boundary between the Phase 1 and Phase 2 Excavation Areas as, shown on DEIS Appendix A Figure
6, is not consistent with the location of the boundary as shown on Site Development Plans (Appendix C,
Excavation Phasing Plan) (COMMENT FIGURE SOILS-6).
Figure 6 in Appendix A includes a table indicating the total acreage and percentage of each soil type in
the AOI (Area of Interest). However, the AOI used to calculate these figures is the entire tax parcel on
which the Project will be located—not the area that will be directly affected by construction activities
(the “Project Area” as defined in the DEIS) which will be confined almost entirely to the portion of the
parcel zoned M-II. The AOI as defined in Figure 6 includes the entire portion of the parcel zoned R-80 as
well as the M-II portion. The figures in the table included on Figure 6 are therefore inaccurate and
misleading as they do not reflect the actual Project Area.
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COMMENT FIGURE SOILS-1
DEIS Appendix A, Figure 6 (portion)
USDA Soil Survey Mapper, https://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx
(accessed 1-22-22)(Not in DEIS. Note the differences in the boundaries of the various soil types as a
result of a slight change in the map scale).
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COMMENT FIGURE SOILS-2
From DEIS Appendix H. Figures C-100 and C-101 show the same areas delineated as “Potential Dredge
Spoils.”
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COMMENT FIGURE SOILS-3
Log for Boring B-9 noting presence of “Potential Dredge Spoils”. The logs for borings B-10 and B-11 also
note the presence of “Potential Dredge Spoils”.
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COMMENT FIGURE SOILS--4
Photographs from the Southold Town Attorney’s report CC# 2017-363, dated March 29, 2017. The residence at
5106 West Mill Road, located immediately north of the Project’s Construction Excavation Area is visible in the
photo on the right.
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COMMENT FIGURE SOILS-5
1957 Ketcham Survey (reduced, scale shown is inaccurate)
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COMMENT FIGURE SOILS-6
DEIS Appendix C – Excavation Phasing Plan
DEIS Appendix A – Figure 6 – Soil Survey Map