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MARINE TRAFFIC IMPACTS
Boat Wake Impacts
The DEIS Scope requires the DEIS to include an “assessment on the impacts from current and increase
boat traffic on low and high marsh areas within the creek [and for the DEIS to discuss] “the impact from
boat wakes, emissions and chemicals (bottom paints) on the ecosystem” (p.10).
The DEIS contains almost no information relating to how boat wakes that might be generated by the
increased marine traffic from the Project will affect the marsh areas or other shoreline areas in the
Project vicinity. The DEIS states that
“Construction and waterfront development actions may result in . . . erosion due to
increased vessel wakes. . . Long Island’s tidal wetlands are also adversely impacted by
other factors Including . . . erosion caused by recreational and commercial vessel wakes
. . . Mattituck Creek is subject to a 5-mph (no wake zone) enforced by the US Coast
Guard and Town of Southold Bay Constable to maintain safe navigational conditions. No
wake zones reduce the potential for the erosion of marsh edges due to vessel wakes.
The proposed action provides several mitigation measures and best management
practices to minimize the potential for adverse impacts to the 0.63-acre of on-site tidal
wetlands and the approximately 60 acres of tidal wetlands located in Mattituck Creek”
(p.142).
The DEIS apparently acknowledges that the vessel wakes associated with the increased marine traffic
the Project will generate will have an adverse impact, but it makes no attempt to characterize or
quantify the impact. Environmental damage from boat wakes is cumulative—any increase in vessel
traffic—no matter how small--will result in an increase in impacts. The DEIS never addresses this. The
DEIS notes that “no wake zones reduce the potential for the erosion of marsh edges due to vessel
wakes” (p.142). The DEIS is careful to use the word “reduce”—not eliminate. It goes on to note that
any reduction of potential impacts is dependent upon enforcement of a 5-mph (no wake zone) by the
USCG and the Town of Southold.
Contrary to the above quote from the DEIS, the DEIS contains no discussion of mitigation measures to
reduce the environmental impacts resulting from boat wakes. Instead, it merely cites §96-13 of
Southold Town Code which requires that vessels operate in accordance with posted 5-mph (no wake
zone) signage. Section 5.4 of DEIS Appendix M states that “Boat operators have a responsibility to abide
by posted speed limits. It would be expected user groups of SYC would maintain appropriate boat
speeds within waters of the Town of Southold and within Mattituck Inlet and Mattituck Creek. There are
ramifications such as speeding tickets, fines, and the revocation of license for failure to adhere to posted
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speed limit.” While true, the DEIS has not provided any information, such as violation records from the
Southold Town Police Department’s Marine Division 1, to evaluate the validity of their “expectation.”
Boat wake energy is influenced by vessel length, water depth, frequency of vessel passage, as well as
boat speed. “Wakes tend to be most harmful in shallow and narrow waterways where wake energy has
limited ability to dissipate with distance from the vessel. Published values of wave decay after boat
passage indicate that even small (16 ft) recreational vessels traveling within 150 m (~500 ft) of shore are
capable of producing erosion causing waves.”2 The DEIS has made no attempt to provide a
quantitative, or even qualitative, analysis of the degree to which Project-related boat wakes might
increase coastal erosion and damage to marsh areas even though models, such as the Army Corps of
Engineer’s Vessel Wake Prediction Tool, could have been employed to estimate potential damage.
Vessel Traffic and Vessel Characteristics
The DEIS scope requires the DEIS to provide “a comprehensive boat (vessel) traffic study analysis in the
DEIS of the potential moderate to large significant increase of boats to the Mattituck Inlet”. The scope
calls for the DEIS to include an existing conditions analysis and potential adverse impacts based on,
among other things, “Boat Characteristics – Includ[ing] the number of additional new boats added to
Mattituck Inlet, average size of these boats, average draft and maximum draft.”
The DEIS states that “It is estimated that approximately 547 boats are active in Mattituck Creek on a peak
season day” (p.142). However, the actual language in DEIS Appendix M is: “[A]s explained in the table below,
the maximum number of boats utilizing Mattituck Creek on a peak day is approximately 547” (emphasis
added) (p.13, Table 1). A footnote to Table 1 indicates that the 547 number is based on an assumption
that “all boats [that were estimated to be docked on Mattituck Creek] are in use.” Employing this assumption
results in an unsupported decrease in the percentage increase in marine traffic attributable to the Project. In
addition, as the DEIS itself notes, Project-related traffic will occur “at the close of boating season (i.e.,
October-November), . . . [and] in the beginning of the boating season (i.e., April-May)” (pp.278-279),
not during the summer peak.
It may be significant that the original December 2021 version of the DEIS, and the original version of
Boat Vessel Study (DEIS Appendix M,) state that
1 Even if no, or only a few violations have been recorded, this may only reflect a lack of enforcement due the limited resources
available to Southold PD’s Maritime Division.
2 Bilkovic, Donna Marie et al.(2019),Defining boat wake impacts on shoreline stability toward management and policy solutions,
Ocean & Coastal Management 18(2019)104945; Zabawa, C. and C Ostrom (1980), The Role of Boat Wakes in Shoreline Erosion
in Anne Arundel County, Maryland Coastal Resources Division, Maryland Department of Natural Resources, Annapolis.
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“given an eight-week timeframe for entry to storage in the fall and the same timeframe
to remove boats from storage in the spring, this equates to an average of approximately
11 boats per week or less than two boats per day. Averaged annually, the total 176 trips
(88 boat trips in the spring and 88 boat trips in the fall) equates to 0.48 boat trips per
day. It is estimated that approximately 547 boats are active in Mattituck Creek on a peak
season day. Therefore, the increase in vessel traffic of 0.48 boat trips per day is nominal
and the potential for increased erosion of tidal marshes due to vessel traffic is not
significant” (emphasis added) (DEIS 2021:138)”.
However, the revised November 2022 DEIS, and revised Boat Vessel Study, state that:
“given a 12-week timeframe for entry to storage in the fall and the same timeframe to
remove boats from storage in the spring, this equates to an average of approximately
seven (7) boats per week or one-to-two boats per day. It is estimated that
approximately 547 boats are active in Mattituck Creek on a peak season day, which
occurs in the summer season (i.e., July or August), when temperatures are higher. The
entry and return of boats to the water from storage would occur outside of this peak
season day. However, even if the increase of one-to-two boats per day were to occur on
a peak season day, this would equate to 0.18-to-0.36 percent increase in boat traffic,
which is nominal and would not impact tidal marshes due to vessel traffic” (emphasis
added) (DEIS p.142).
No explanation for these changes is provided.3 Why has the original text been revised to suggest a less
severe potential impact to Mattituck Creek? The Applicant presumably is well aware of when boats
arrive for storage and depart. Why has this period been expanded by 50 percent, resulting in a
reduction in the number of boats arriving and departing each week? Why has the unit of measure of
potential impact been changed from “boats per day” to “percent increase in boat traffic”?
The DEIS concludes that “The proposed action would not substantially increase vessel traffic within
Mattituck Creek” (p.142). However, this conclusion is based on three assumptions: first, that existing
traffic on any given day is always at peak levels; second, that Project-related traffic will add to existing
traffic volumes during the summer peak; and three, that the Project-related vessels adding to existing
traffic are similar in characteristics to the average vessel currently traveling on Mattituck Creek. None of
these assumptions is valid.
Any increase in large vessel traffic entering and exiting Mattituck Creek also creates an increased
potential for accidents. In 2022, a 96-foot yacht ran aground east of Bailie Beach in Mattituck
(COMMENT FIGURE MARINE-1). The vessel remained stuck for several hours until the tide flooded and
3 The Planning Board and its consultant (NPV), based their review of, and a lengthy comment on, the adequacy of the original
DEIS on the assumption that vessel trip generation estimates were for two eight-week periods.
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two boats were able to pull it free. It then “made its way back to Strong’s Marine in Mattituck to dock.”4
Reports from MarineTraffic, a publicly available vessel tracking service, showed the yacht drove bow
first into the beach at 6.8 knots (COMMENT FIGURE MARINE-2). A police reports was filed, as was a
New York State Boating Accident report to the New York State Office of Parks, Recreation and Historic
Preservation.5 The DEIS fails to note that the increase in vessel traffic generated by the Project will also
create an increased potential for accidents.
The DEIS’ analysis of existing traffic is also deficient in that it fails to take into account the fact that the
nature of the vessels accounting for the increase in boat traffic will be qualitatively and quantitatively
different from existing marine traffic. No quantified information on the sizes or types of vessels that
currently travel Mattituck Creek during different seasons is provided. The only data in the DEIS relating
to the types (size) of vessels that currently travel Mattituck Creek is limited to the 2020 yacht inventory
at SYC (DEIS Table 1, DEIS Appendix M Table 2).
According to the DEIS “Based upon an average yacht size of 60 feet in length, it is estimated that
approximately 88 yachts could be stored within the proposed buildings” (p. ii, also p. viii, xliii, 20, 99, 315
fn 57). The DEIS also states that the “proposed action [will provide] indoor winter storage of larger
yachts, up to 86 feet in length” (pp. ii, 19, also p. viii, xliii, 20, 99, 315 fn 57).6 Table 4 in both the DEIS
(p.20) and DEIS Appendix M (Typical Yachts to be Stored at SYC Under Proposed Action) lists only yachts
with lengths of 68, 77, and 86 feet in length. It is therefore unclear how the assumed average size of the
yachts which will be stored can be 60 feet. Similarly, the DEIS states that the average beam of boats to
stored will be 17± feet. However, according to DEIS Table 4, typical boats in storage will have a beam of
17 feet 3 inches, 19 feet 6 inches, or 21 feet 3 inches.
The DEIS states that SYC “support[s] winter storage for 96 yachts and boats. In addition to indoor
storage, SYC provides outdoor winter storage for 40 boats and yachts” (p.3). However, in the Executive
Summary it states that “In the winter months, SYC provides both indoor and outdoor storage for 96 and
40 boats and yachts, respectively” (p. i). DEIS Appendix M states that “SYC provides winter storage for
96 yachts and boats. In addition to indoor storage, SYC provides outdoor winter storage for 40 boats and
yachts” (p.20). These statements are confusing and seemingly inconsistent. Are the 40 vessels included
in the 96? Are 96 vessels stored outdoors and an additional 40 stored indoors? Are 96 of the vessels
“boats,” and 40 “yachts”?
4 The yacht, named In Too Deep, was being docked for the summer at Strong’s Marine on Mattituck Inlet (the Project site).
5 https://suffolktimes.timesreview.com/2022/06/yacht-named-in-too-deep-runs-aground-near-bailie-beach-in-mattituck/
6 The Applicant’s website ambiguously states that “We offer both indoor and outdoor storage at our three service locations in
Mattituck, accommodating boats and yachts up to 110 ft.” (emphasis added).
https://www.strongsmarine.com/winterization_storage (accessed May 12, 2023).
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The DEIS creates further confusion in that in some places it makes a distinction between “boats” and
“yachts.” For example, DEIS Table 1, SYC’s 2020 yacht inventory, lists vessels up to 39 feet as “boats.”
Larger vessels are classified as “yachts.”7
Adding still more confusion, the DEIS states that the “average yacht size during the 2020 season was 30±
feet to 49± feet, which made up 50 percent of the boats and yachts at SYC. Of the aforementioned boats
and yachts, approximately 45 were docked at SYC and the remaining were stored in the existing storage
buildings and dry docked on the marina property” (p. 3). This appears to be inconsistent with the
statement in DEIS Appendix M that the “marina accommodates boats and yachts 18-to-133± feet in
length with the majority between 40± feet to 60± feet. The typical yacht size is 50-to-86± feet in length”
(DEIS Appendix M p.14).
Figures 4a-4e in DEIS Appendix M are photographs of “Typical Boats and Yachts at SYC”. Two of the
three photos are of the same vessel which has been identified as the M/Y Le Reve - a 110-ft Lazzara
motor yacht. This vessel would not be able to utilize the proposed indoor storage facilities because the
existing 85-ton travelift at SYC cannot accommodate this “typical” vessel.8
Impacts on Unmotorized Water Sports (Kayakers and Paddleboarders)
The DEIS has not addressed how the Project would impact kayakers and paddleboarders
The DEIS scope required the DEIS to discuss “the impacts of the increased large vessel traffic in the inlet,
and its effects on small local vessels, kayaks, and paddle boarders attempting to navigate the narrow
creek”.
The DEIS concludes that as “the vessel traffic would be comparable to existing conditions, it is not
anticipated the proposed action would alter the ability of personal watercrafts and non-motorized
watersports, such as kayaks and SUPs, to navigate within Mattituck Harbor” (p. xxii, 236). The only
evidence offered in support of this conclusion is the statement that “Viewpoints 12 and 13 in Appendix
Q indicate navigability within Mattituck Harbor is not impacted by larger vessels as they were taken
from the perspective of a kayak with a 95-foot yacht present adjacent to the existing SYC operations”
(DEIS p. 236). This is not evidence of anything. The larger vessels shown in the referenced photographs
are motionless and docked. They provide no evidence of how yachts travelling, up and down, and
generating wakes, would affect kayakers and paddleboarders.
7 This appears to be inconsistent with generally accepted definitions of what constitutes a “yacht” as opposed to a “boat.”
Although there are no “official” definitions, an internet search indicates that yachts are vessels longer than 30 feet, or 10
meters (33 ft). Smaller vessels are boats.
8 The La Reve (Lazzara model 110) has a displacement of 110 metric tons (MT)(wet) and holds 4300 gallons of fuel and 600
gallons of water. She can accommodate up to 8 passengers and 4 crew. Subtracting the weight associated with these items
(approximately 17 MT) results in a dry weight (the weight that the travelift would have to accommodate) of approximately
93 MT. https://www.superyachttimes.com/yachts/le-reve.
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The DEIS states that “[B]ased on SYC data and publicly available data, approximately 2,000 boats, yachts,
commercial fishing vessels, government/public vessels, personal watercrafts, and kayaks and Stand-Up
Paddleboards (SUPs) are docked or use Mattituck Creek annually. It is estimated that approximately 547
boats are active in Mattituck Harbor on a peak season day” (pp. xxii, vii, 95, 236). DEIS Table 1 contains
no estimates of the number of personal watercraft, kayaks and Stand-Up Paddleboards (SUPs) that use
Mattituck Creek on a given day. Presumably, personal watercraft, kayaks, and SUPs constitute the
balance of the 2000 watercraft. However, neither the SYC nor the “publicly available data” are provided;
nor is the source(s) of the publicly available data.
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COMMENT FIGURE MARINE-1
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COMMENT FIGURE MARINE-2