HomeMy WebLinkAboutNorris Estates Water Supply Wastewater Treatment I
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ENGINEERING REPORT
WATER SUPPLY
AND
WASTEWATER TREATMENT
SYSTEMS
NORRISESTATES/WANAT DEVELOPMENT
MATT1TUCK, NEW YORK
MAY 1988
REVISED 8-2-88
Id ,, GROUP
HOLZMACHER, McLENDON 8, MURRELL, P.C.
CONSULTING ENGINEERS · ARCHITECTS · PLANNERS · SCIENTISTS · SURVEYORS
MELVILLE. N.Y. RI~rERHEAD, N.Y. FAIRFIELD, N,J.
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ENGINEERING REPORT
WATER SUPPLY
AND
WASTEWATER TREATMENT
SYSTEMS
NORRISESTATES/WANAT DEVELOPMENT
MATTITUCK, NEW YORK
MAY 1988
R E V I S E D 8-2-88
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I. SUMMARY
The water supply and wastewater collection and
treatment system facilities are described in this report for
two (2) plans of development. Neither plan will unduly
stress the underlying aquifers by having the consumptive use
exceed the permitted yield. Plan I is the original plan for
108 condominiums on a portion of the Norris Estate (Parcel
A) in Mattituck, plus up to 24 single family dwelling units
· on the balance (Parcel B) of the Norris property and plus 41
single family homes on a 107 acre Parcel C located about 2-
1/2 miles away in northwest Mattituck. This Plan I requires
a central water and sewerage system at Norris but not at
Parcel C.
Plan II is an alternate and the recommended plan to
construct 25 homes on Parcel A portion of the Norris Estate
instead of the 108 condos, plus the same potential 24 units
on Parcel B and plus 107 single family units on Parcel C.
This plan does not require central water and sewers at
Norris but will require central water at Parcel C (Wanat).
Private individual lot sewage disposal is recommended at all
parcels.
8-2-88
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Plan I is justified and workable and, based on test
wells for quality and quantity, a central water plant at
Norris could supply the 132 dwelling units and still have
spare capacity for some nearby existing homes who have
problems. The consumptive use at Norris (Parcels A & B) is
less than the calculated permissive yield and indicates that
a properly designed and operated water system would not
adversely impact groundwater quality and quantity beyond its
capacity. The Plan I wastewater treatment system will
provide centralized tertiary treatment prior to recharging
the treated effluent to the groundwater. Included in the
plan is the'construction of an above-grade building to house
the proposed wastewater treatment facilities. The building
would be equipped with an odor control system and designed
to blend in with the overall aesthetics of the project site.
Plan II obviously reduces the water use and consumptive
use at Norris Parcels (A&B) and increases the water use at
Parcel C where there is obviously much more water resource
available. This is the recommended plan.
Estimated costs for water and wastewater facilities
have been included and are summarized in Table VII for both
plans. The total capital cost for both plans are shown and
totaled on Appendix D - $1,800,000 for Plan I and $1,800,000
for Plan II, the recommended Plan.
II WATER RESOURCES AND SUPPLY
WATER RESOURCES
Various
prepared
Fork and
listing
provided
The
government agencies and consultants have
reports covering the Town of Southold, the North
the County water resources and information. A
of references and other related documents can be
upon request.
predominant
topographical features of the mainland
portion of the Town of Southold are the Harbor Hill moraine
which follows the shore of Long Island Sound and a glacial
outwash plain extending from the moraine to the bays. The
North Fork peninsula is divided into several components by
salt water ponds and inlets, almost creating islands. The
fresh groundwater is exposed to salt water interfaces on the
sides, as
closer to
areas, the
balance and
principle.
well as underneath, with the
the surface as you extend
salty groundwater and fresh
salt water generally
eastward. In some
water are in dynamic
appro×imate conformity with the Ghyben-Herzberg
This principle approximates the location of the
-3-
salt water/fresh water interface at 40 times the elevation
of the water table below sea level assuming a salt water
specific gravity of 1.025. In some of the westerly portion
of the Town, fresh water extends below an existing and
confining clay, but any appreciable pumpage can disturb this
equilibrium and cause salt water to extend upward or to
lower static water levels to a point
water may enter just above the clay.
The long shoreline exposure in
that a mat of salt
the Southold Town
peninsula in relation , to its total area causes low
groundwater levels and a low amount of long-term available
water storage. During the 1965 drought, the water levels
were reduced even in the higher level areas to about 3 feet
above mean sea level. In the CPU-24 water budget area
used to calculate the amount of recharge or available water
resources, the 2-foot contour was selected as it existed in
July 1959 for the western portion of the Town. Hashamomuck
Pond is the dividing line between the two portions. In the
eastern portion of the Town, and the insular areas the 1-
foot groundwater contour defines the water budget area.
-4-
As reported in the various data, there is a
considerable range of rainfall within the Town of Southold,
with the average precipitation at the Cutchogue rain gauge
at 45 inches. The estimated average for the Town is
between 43 and 44 inches. Previous estimates ranging from
1.4 percent to 10 percent of the rainfall has been
calculated to be lost as surface runoff in the Town of
Southold. CPWS-24 indicated a range of 5 to 7'percent loss
by surface runoff.
CPWS-24 shows a water budget area west of Hashamomuck
Pond of 21 square miles, with a mean annual precipitation of
43 million gallons per day, a loss by evapotranspiration of
22 million gallons per day, and a direct runoff of 3 million
gallons per day, providing a mean annual recharge of 18
million gallons per day. Approximately 25 percent of these
and 75 percent east of
the Town area east of
amounts are west of Mattituck Creek
Mattituck Creek. In the balance of
Hashamomuck Pond, the water budget area is 6 square miles,
with a mean precipitation of 12 million gallons per day, an
evapotranspirtation of 6 million gallons per day, and a
direct runoff of about 1 million gallons per day, providing
-5-
a mean
estimations show a recharge rate
budget area of almost nine-tenths of
day over the 27 square miles. Based on
of &7 square miles, the average recharge
0.5 million gallons per day.
The County test wells installed
CPWS-24 disclosed the location of the
annual recharge of 5 million gallons per day. These
in Aquebogue, Cutchogue and Southold.
in the Southold well at depths below
More recent data has shown some salty
the clay northeast of the Hamlet of
per square mile of water
a million gallons per
the total Town area
per square mile is
in conjunction with
salt water interface
Salty water was found
the clay at 180 feet.
water areas Just above
Southold and in east
Greenport. Between Cutchogue and Mattituck on Alvah's Lane,
the salt water was encountered at 320 feet below grade, but
pumping tests indicated that it is not feasible to withdraw
any appreciable quantity of water from below the clay which
extends from 120 to 220 feet below grade. In Aquebogue, on
Tuthill Road, the well is drilled to a depth of 700 feet,
with salt water encountered at a depth of 520 feet. A
permanent observation well was placed at 460 feet so that
future monitoring of the movement of salt water upward can
be observed at this location.
CPWS-24, The North Fork Study and the 1987 Suffolk
County Management Plan all project that all future pumpage
in the Town of Southold will be from the Glacial formation.
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With regard to recharge basins, they should be
encouraged for the accumulation of surface runoff and its
return to the water table. This becomes increasingly
important as the area develops, causing more widespread
areas of impervious material subject to a higher percentage
of runoff than now exists. Recharge basins are also more
economical than major drainage systems and, with tributary
impervious areas for runoff, can actually result in a
greater percentage recharge than results from non developed
pervious areas with water consuming vegetation.
CONSUMPTIVE WATER USE
The major consumptive water usage in the Southold area
is that used for irrigation, although it is decreasing
substantially on the average. Most agricultural irrigation
is consumptive water use unless irrigation is practiced
beyond what is needed.
The consumptive water usage in Southold as a percentage
of total water use was estimated in CPWS-24 (reference page
201) as ranging from 82.3 percent in 1967 and higher in
earlier years to 79.6Z as shown in the 1987 Suffolk County
Water Plan for 1980.
The significance of agriculture in consumptive water
use is also indicated in CPWS-2& (reference page 205) for
the period of 1960-67, and the Suffolk County 1987 plan on
page 10-19. The CPU 524 estimates of consumptive water
-7-
use of 71 to 473 gallons per capita per day included
agricultural usage, but not private domestic well usage, of
which probably 70 percent is returned to the groundwater.
When water recharge exceeds consumptive water use,
underflow takes place. The consumptive water use in the
Town of Southold was estimated at 7 million gallons per day
in 1980, 8 million gallons per day in the year 2000, and 10
million gallons per day in the year 2020, all without, a
major future sanitary sewer system.
WATER LEVELS AND SALT WATER INTRUSION
As noted in the CPWS-24, the Southold area in the North
Fork is one of the areas in Suffolk County most susceptible
to salt water intrusion, since the peninsula is narrow, is
indented with many salt water inlets, and has salt water
underneath at var~ing depths. The thick clay layer which
was found in the County test wells, S-32390 in Cutchogue and
S-33775 in Southold, forms a restrictive barrier against
vertical intrustion of salt water, but it also forms a
barrier for recharge of the water bearing formation below
the clay. It has been indicated that groundwater levels of
2 to 3 feet above sea level are sufficient to prevent the
salt water contamination of the coarse Glacial deposits
-8-
which overlie the clay. This corresponds to a theoretical
fresh water/salt water interface of 80 to 120 feet below
mean sea level, or a fresh water lens of approximately 82 to
123 feet. During the drought of the 1960's, decreased
recharge and increased consumptive use lowered the
groundwater levels to a point near the minimum recommended.
CPWS-24 indicates (Volume II, Table 3-37., Page 362)
data related to permissive sustained yield and shows its
comparison to the average net yield. Since water will not
be needed and not be usable st average conditions in the
Town of Southold because of the lack of sufficient
underground storage, the most pertinent appraisal of the
Town's water resources is permissive sustained yield
compared with dry year consumptive use. Table II indicates
permissive sustained and average net yields for the Town of
Southold.
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TABLE I
PERMISSIVE SUSTAINED SOUTHOLD TOWN AREA
PERMISSIVE
SUSTAINED
YIELD
.(M.G.D.)
Southold - Without
Mattituck Creek 2.0
PERMISSIVE
SUSTAINED YIELD
PER SQ. MI. OF
WATER BUDGET
~REA
0.40
Southold Between
Mattituck Creek and
Hashamomuck Pond
15.5
0.35
Southhold - Between
Hashomomuck Pond and
Orient Harbor
1.0
0.25
Southold - East of
Orient Harbor 0.5
TOTAL 9.0
* Suffolk County 1987 Management Plan
of above.
0.25
used values about 90%
WATER QUALITY
Most of the discussions heretofore have centered on
water quantity. It is obvious that the quality of the
available water supply ia equally as important as quantity.
Water quality is generally segregated into three general
areas; bacteriological, physical and chemical. The physical
-10-
and some of the chemical constituents generally relate more
to the appearance or aesthetics of the water, whereas the
bacteriological and the majority of the chemical
constituents relate to safety of the water quality. Water
quality is measured in terms of concentration of numerous
constituents. Standards of quality may vary with the
intended use of the water. The most widely known and
accepted standards of water quality are those developed by
the United States Environmental Protection Agency (USEPA)
for drinking water, which been in effect for many years and
are updated from time to time. New York State has also,
more recently, adopted drinking water standards which
closely relate to the USEPA standards as a minium but have
gone even further in adopting other low limits. As the
presence and knowledge of contaminants increases, there will
be further revisions in water quality standards to reflect
additional requirements. Adopted standards for volatile
organic compounds and pesticides are more restrictive than
existing guidelines.
The bacteriological standards use the coliform bacteria
group as indicators of bacteriological pollution. This is a
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and simple method, and provides a factor of
be
or
is
very convenient
safety since, generally speaking, coliform bacteria would
present in significant to large numbers whenever harmful
pathogenic organisms were present. The exception to this
that concentrations of viruses have not necessarily
correlated well with the presence of coliforms.
The physical characteristics of water include
turbidity, color and odor. Obviously, some of these are
further related to chemical constituents which may cause an
undesirable appearance. The physical characteristics may
not relate to contamination, but are usually related by most
people to indices of pollution. The presence
objectionable physical characteristics can, of
indicate the presence of pollutants.
Chemical constituents and their presence related to
toxicity, pollution and safety of the drinking water supply
must be reviewed with respect to the local surroundings,
such as whether the constituents are naturally present in
of the
course,
the supply or whether the source of the constituents is from
a known or suspected local artificial source. For many
years, the nitrogen group of constituents and chlorides have
-12-
served as a pollution indicator since they were related to
human excretion. Generally speaking, the less advanced the
oxidation of the nitrogen group, the more recent the
indicated pollution (i.e., the higher the ammonia in
relation to the nitrates, the more recent the pollution).
This type of interpretation would not be valid for much of
the Town of $outhold wherein both ammonia and nitrates and
apparently nitrates in particular, have been introduced into
the water supply by fertilization of the farmlands in the
Town.
Existing drinking water standards contain a limit of 10
mg/1 for nitrates as nitrogen. The toxic significance of
nitrates is related to the "blue baby" condition in infants,
if nitrate content is too high. Based on information and
studies with livestock, it appears that nitrites are much
more toxic than nitrates but, fortunately, are unstable and
have not been found in any appreciable amounts in Long
Island's drinking water supply.
Much of the water in the Town of Southold has a nitrate
content which approaches, and in many cases exceeds, the
nitrate standard of 10 mg/1.
Also related to agricultural land use, the presence of
pesticides is widespread over many areas of the Town. The
primary one is A!dicarb (Temik) but several others such as
carbofuran, etc. are also present. The limits for Aldicarb
and its derivations has been set at 7 mg/1 and carbonfuran
at 15 mg/1.
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Although not related to toxicity or safety, the
presence of iron or manganese in water supplies may impart
an unpalatable taste and cause complaints due to stained
plumbing fixtures, laundry, etc. In the Town of Southold,
the most likely locations for iron and manganese to occur
are in the shallow wells along and near the southerly shore.
Iron and manganese are frequently associated with organic
matter, decaying vegetation and sulfate reduction, yielding
hydrogen sulfide. Some of the wells in the ara of the
proposed development have reported high iron content.
The major potential sources of groundwater pollution in
the Town of Southold include ammonia and nitrogen from
fertilizers, primarily on farms; the use of pesticides and
fungicides, primarily from agricultural use; salt water
intrusion in local areas from potential overpumpage;
recharge of untreated sewage via cesspools; and other
chemical pollution from rain water leaching through sanitary
landfills.
Based on our previous experience in shoreline areas,
and one of the test wells, it is possible that iron may be a
problem in portions of the Norris Estate area. The more
recent northerly and southerly test wells and the previous
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easterly test wells do not indicate iron to be a problem at
the site for a community system. In the immediate area of
the Norris Estates development nitrates will be acceptable
at considerably less than the recommended limit of 10 mg/1
but they may be a problem in parcel C (Wanat). Private
wells with a 40 foot submergence would not be available with
acceptable nitrates in some areas of the site. A central
source supply with less submergence and acceptable treatment
is expected to have lower nitrates. Lastly, chlorides might
be a problem at Norris and, therefore, was further
investigated. Of the 6 test wells constructed only one had
an elevated chloride which appareatly was due to the screen
being right at the top of the clay. When pumped, the
chloride was reduced substantially. At Norris Estates
Condos project is it proposed to locate the water supply as
close to the northeastern portion of the property as
feasible and to recharge the groundwater reservoir with
renovated wastewater and surface drainage in the southerly
part of the property.
Analysis of water samples from a fire well on
side of Lake Marratooka and from test wells
Suffolk Avenue on the property, are shown as
this report.
the north
south of New
Appendix A on
-15-
PROPOSED DEVELOPMENT
The development project consists of three (3) basic
elements ia either of 2 Plans, I and II.
Plan I - Condos Plus Single Family.
A. A maximum of 108 condominium units to be built
with accessory uses on approximately 28.15 acres (Parcel
situated on the east side of Camp Mineola Avenue, south of
New Suffolk Avenue. Of the 108 units,
units will be three-bedroom units, and
units will be two-bedroom units~
75 percent or 81
25 percent or 27
B. In addition, up
existing residences may be
acres (Parcel B) east and
to 20 new single family plus 4
placed on the remaining 45.33
southeast of the coadominium
units. There currently exists on these 45.33
estate main house and three dwelling units.
single family units in Parcel B is 24.
The total
C. As part of this plan, but listed separately,
Parcel C could be developed as a yield based on current
zoning with 41 single family plots on 107 acres.
Individual private wells with possible waiver of the 40 foot
depth of submergence would supply each of the homes. Each
home or plot would also be served by a private septic and
leaching sewage treatment and disposal facility.
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For Norris (Parcels A & B) it is proposed to construct
a central water supply and distribution system and a central
wastewater collection and treatment system. The preliminary
plans show that the wells would
northeasterly section of the condo
in the water shed easement
permit, the proposed water
plant would be located near
be located in the
property (Parcel A) and
to the east. As final plans
treatment storage and pumping
the southeast corner of the
condo site, adjacent to the waste water treatment plant. The
wastewater treatment and recharge would be in the southeast
corner of Parcel A.
Plan II Single Family Only
(a) A single family subdivision of 25 plots would be
substituted for the 108 condominium nnits on the Norris
Condo Parcel A (28.15 acres). At least 66 of the 83
decrease in Norris units would be transferred to Parcel C
(Wanat) north of Bergen Avenue in northwest Mattituck.
(b) Parcel B would not be part of this plan but
presumably would remain as in Plan I with 24 ultimate single
family units projected on the 45.33 acres (4 of which are
existing).
(c) Parcel C (Wanat) would be developed into 107
single family plots on 107 acres with private individual
sewage treatment and disposal facilities on lots ranging in
size from 20,000 square feet and up with a large open space
resulting from a modified cluster arrangement. Water supply
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would be a central public system, supplied by at least two
(2) wells with storage tank, treatment, distribution system
and accessories.
III POPULATION AND WATER REQUIREMENTS
The 108 condominium units, as proposed, consist of 81
three-bedroom units and 27 two-bedroom units. We have
estimatated the average population of these units at 3.5 and
2.5 respectively for a subtotal of 351 people. For the 24
single-family homes (including existing homes), we have
estimated an average of 3.75 per home for a subtotal of 90.
The total Norris project population is estimated for
ultimate development at
Water use estimates for Plan I and Plan II are
described hereinafter and are based on the criteria stated.
For the condominium areas, water use is segregated between
domestic dwelling unit use and common ground irrigation.
For the 351 people in the condos, the daily average use per
person will be 70 gallons or 24,570 gallons per day. For
irrigation on the grounds on 65% of the area, and using 8
inches of irrigation per year would require an average of
10,444 gallons per day. In the single family lot portion,
we have assumed for each home, including normal irr'igation,
a use of 140 gallons per person per day for the 90 persons
or 12,600 gallons per day. Of this, 5,670 (45%) is
estimated for private irrigation. In the event the single
-18-
family area is clustered and much of the pasture maintained,
the estimated pasture irrigation will be accomplished using
the existing well, and is estimated at an average of either
(a) 2 inches on the 40 acres of pasture or (b) 8 inches on
10 acres of crops as an alternative. Either of these
allowances would result in an average of 5,951 gpd
consumptive water use, whereas much of the other uses are
returned to the ground water system after treatment in the
wastewater treatment plant.
The treated wastewater will be recharged beyond the
normal cone of influence of the public well field and will
provide fresh water needed for underflow and for maintaining
a fresh water piezometric head.
The estimated water uses for Parcels A & B
tabulated below:
TABLE II WATER USE UNDER PLAN I - PARCELS A & B
are
Non Consumptive Consumptive Total
Use Use Use
Condos 24,570 gpd 10,444 gpd 35,014 gpd
(70 gcpd) (28.8 gcpd) (99.8 gcpd)
Single
Family
6,930 gpd 5,670 12,600
(77 gcpd) (63 gcpd) (140 gcpd)
Pasture or
Crops --- 5,951
Total Average
Water Use
5,951
(13.86 gcpd)
31,500 gpd 22,065 gpd 53,565 gpd
(71.4 gcpd) (50.0 gcpd) (121.5 gcpd)
(gcpd = gallons per capita per day)
-19-
For Plan I the total average water used at Parcels A &
B is 53,565 gallons per day or 37 gallons per minute or
19,551,225 gallons per year. This calculated to an average
of 121.5 gallons per capita per day on the development
planned for the entire 74 acres. As noted, the total
consumptive water use for Plan I at Parcels A & B is
calculated at 22,065 which.is an average of about 15 gallons
per minute. The consumptive use of 22,065 gallons per day is
5,285 gpd less than the permissive yield on the northerly 50
acres and 12,550 gpd less than permissive yield on the
entire 74 acres of parcels A & B. Based on the above
numbers and 63 gcpd consumptive use in single family
occupancy, the planned water system could supply another 95
to 214 people. If those supplied' discharged their treated
wastewater outside the recharge area these numbers would be
reduced. The calculated safe yield is 24 to 57 percent
greater than the consumptive use.
As part of Plan I for Parcel C (Wanat) the estimated
water pumpage for 41 single family plots (154 population)
would be 21,560 gallons per day of which about 45% or 9,702
gallons per day would be consumptive use for irrigation.
The balance would be returned or recharged via the
septic/leaching systems as. partially treated wastewater.
-20- 8-2-88
The total water pumpage for Parcels A, B & C in Plan I
would be 7§,125 gallons per day with a total consumptive use
of 31,767 sallons per day.
WATER RESOURCES AVAILABLE
Based on previous water reports, we have calculated for
Parcels A & B, a permissive yield of 27,350 gallons per day,
based on 0.35 million gallons per day per square mile, or
547 gallons per day per acre on 50 acres of the 74 acres.
This equates to 9,983,000 gallons per year or 2& percent
more than the consumptive use, thereby providing a factor of
safety as it relates to permissive sustained yield. Of the
24 acres remaining, if 15 acres at 0.25 mgd/sq mile and 9
acres at O.1/mgd/ sq. mile were used, this would provide an
added excess of 7,265 (5859 + 1406) gpd to provide a 57
percent excess with 34,615 gpd.
Of particular concern at the site is the location of
the aquifer.
area near the
the salt water/fresh water interface within
Some of the forty to forty-five homes in the
bay have had reported salinity problems with
their well
water. At a location on Camp Mineola Road, approximately
2,000 feet south of the proposed development, salt water was
found at a depth of 40 feet. Most private wells in the area
are 20 to 35 feet deep, and installed under a Suffolk County
Department of Health Services waiver from 40 feet into
groundwater.
- 2 1- 8-2-88
Based upon the Ghyben-Herzberg relationship and
observed or estimated groundwater elevations, the location
of the salt water/fresh water interface can be estimated.The
1985 Suffolk County groundwater elevation map indicates
groundwater levels at the site to be less than 3 feet above
mean sea level. The same map for 1984 indicated groundwater
levels to be approximately 4 feet at the northern property
line with lower levels further south. These levels
indicate that a fresh water lense from 100 to 160 feet in
thickness may be found at the site. Water levels measured
near the proposed well field during this study showed an
elevation of 2.5 fee~ above sea level, an indication of a
100 ft depth of water to the interface. This falls within
the underlying clay. Reduced water level has been
indicated recently in other areas of Southold as well.
In order to be able to minimize drawdown and provide
flexibility for future segregation of screened inlet, a
longer than standard screen length is planned for the
dispersed bottom of the screen well will be approximately
40 feet below water surface and near the top of a combining
clay layer. The calculated salt water interface with a
fresh water elevation of +2.5 M.S.L. is at a depth of 100 ft
below the water table or a total depth of about 120 feet.
The final well depth is planned for about 70 feet.
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Test or monitoring wells
northerly portion of Parcels A &
south edge of Parcel A.
a test and pumping well,
the northwest portion of
constructed in the northwest portion
No 3 was constructed in the northeast
No. 4 was a monitoring well
during pumping tests on well 1.
were drilled along the
B and one (1) near the
Test well No. 1 was constructed as
both temporary and permanent, in
Parcel B. Test well No. 2 was
of Parcel A (Condo).
corner of Parcel B.
for observing water levels
Test well#5 was constructed
in the northeast section of Parcel A and test well#6 was
constructed in the southeast section of Parcel A. A summary
of the analyses of these wells is included as A-1 in the
Appendix.
The water quality in test well No. 3 was excellent and
would be the primary location of a permanent central supply.
Test well 1 was also good except the iron content at 0.9 to
1.0 mg/1 will require at least sequestering and perhaps
removal. The limited testing done (Nitrates, iron etc) on
wells 5 and 6 also show acceptable to good quality water in
the vicinity.
Water quality pumping tests were considered good.
Upconing of saltwater in the immediate area is unlikely
because of a thick formation of clay which extends from
about 70 feet to about 120 feet below grade (-50 to -100
-23-
MSL). This is confirmed by the use for the past 6 years or
more of a 70 foot deep irrigation
of about 375 gallons per minute
pumpage from this well has not
capacity in this area near salt
impervious
unless a relatively
well.
Static water levels
irrigation well and
taken at well No. 1
well which has a capacity
(gpm). The total annual
been great but a high
water would be prohibitive
barrier existed below the
were obtained in 3 test wells, the
in Lake Marratooka. Pumping levels were
and the nearby monitoring well No. 4, 5
feet away. With a pumping
hours, the drawdown in Well
The central well supply
dispensed along the area
rate of 90 gpm for 10 consecutive
No. 4 was only 0.14 feet.
would consist of multiple wells
from the northeast portion of
Parcel A through Parcel B to the northeast portion of Parcel
B. A deed restriction specifyin'g a 10 acre watershed and
well development area in the northerly portion of Parcel B
is included in the "Appendix B". The center of the proposed
well field is about 2,000 feet from the nearest salt water
creeks to east and southwest, 1600 feet to the west and
about 300 feet to the bay.
The hydrogeological evaluation of the Norris site is as
follows:
-24-
Field Data
While well loggings on site and within the area are not
plentiful, we believe that the geology of the site in
question consists of the glacial aquifer of approximately 50
feet of saturated depth, underlain by an impermeable clay
lense of varying thickness but at least 50 feet in the
eastern sector of the water plant area.
Various types of analyses have been performed ow most
of the test wells on site. Three of these wells, which are
screened at depths of sixty (60) feet, 10 feet above the
clay lense, have indicated levels of chloride which range
from 14 ppm to 137 ppm. The easterly of these wells was
pumped for eleven hours with the concentration of chlorides
monitored hourly. The concentration of chloride in this
well actually decreased from 137 ppm to 92 ppm over this
eleven hour period.
We have studied the possible causes of this occurrence
and feel it is possible that a plug of dissolved pasture
salt may have been present and was diluted on pumping. It
is also possible that over many,
chlorides at a slow rate through
concentration just above the clay.
many years, diffusion of
the clay increased the
In any event, we do not
forsee this as a problem to well development in the areas.
-25-
In an attempt to determine the thickness of the
clay, a test well was driven oa the north east portion of
land. The clay lense was encountered at a depth of 70 feet
and was continuous to a depth of 120 feet, where drilling
stopped. This is believed to be very near the bottom of the
thick clay. This well was later used to monitor the water
in the clay at this depth in hopes to indicate the location
of the fresh/salt water interface. This well was baled up
to 50 times and samples were collected for analysis at
various intervals. After approximately 2/3 of the casing
was dewatered (half of the water) samples were collected at
some 25 30 feet below the well water surface. Flow rate
through the clay with a head difference of 40 to 40 feet was
about 0.02 gpm.
The laboratory data indicates that the water in the
lower clay becomes more brackish with depth. The first
samples taken had chloride concentrations of 76-ppm and a
specific conductance reading of 310 micromhos. Once the
aquifer was allowed to recover, the chlorides increased to
205 ppm with a final reading of 900 ppm of chlorides, which
-26-
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is indicative of almost brackish water conditions. Through
this analysis it is assumed that the water in the clay
increases in salinity with depth because of diffusion from
below, where the high saline water is located underneath the
clay lense.
Modes of Salt Water Intrusion
After analyzing existing data it has been determined
that the possibility of salt water intrusion, caused by the
proposed supply welis is unlikely but might occur in two
ways.
If there exists already a fracture in the impermeable
clay lense, then increased pumpage by any mode near this
fracture may reverse the local gradient and draw upward the
Salt water whic~ underlies the clay. Another means by which
salt may be introduced is due to heavy increased pumpage,
which could pull the naturally occurring fresh/salt water
wedge, located above the clay layer, inland, resulting in
brackish water being extracted from a well.
The likelihood of a fracture is considered to be
remote. If in fact a fracture does exist in the clay lense,
undoubtedly there would already be reports of salt water
-27-
intrusion to private wells on or near the area at a
considerable distance from shore. With the proposal for the
wells to be placed as far north on the site as possible, and
recharge to the aquifer via an on-site wastewater treatment
plant, most of the water drawn from the aquifer will be
replenished, minimizing
the salt water wedge.
Mathematical Analysis
the likelihood of encroachment of
Various types of analysis have been performed on the
existing site, including a 2-D aquifer flow' model (Prickett
and Longquist), and a 2-D vertical salt water interface
conceptual model. Predictions as to the extent of the salt
wedge can be made by utilizing the Ghyden - Herzberg -
Dupuit approximation, as formulated by Jacob Besr.
The worst case scenario was incorporated into the
Prickett & Longquist 2-D aquifer model. Drought condition
recharge along with 24-hour pumping of proposed supply wells
and the irrigation well were run for a three month period.
The flow rates obtained from this model were incorporated
into the 2-D vertical model by Jacob Bear which resulted in
the toe of the salt water wedge located 85 feet inland.
Without the proposed wells, pumping the toe of the wedge was
modeled at 75 feet inland.
-28-
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WATER SYSTEM - FOR PLAN I AT NORRIS (PARCELS A & B)
The central water system may be organized as a private
company, a water district, a satellite system of the Suffolk
County Water Authority or the Village of Greenport, or a
cooperatively managed water utility. The most likely system
will probably be as a satellite plant of the Suffolk County
Water Authority. The system should be developed with a
water treatment plant and water mains sized to provide~ at
least the minimum required protection. As the system grows
or is integrated with others the fire flow may be readily
increased.
Plant at Norris
In order to provide low rates of pumpsge at reasonable
depths and provide a standby well, we recommend the
construction of three (3) six inch diameter wells to a depth
of about 60 feet with 6 inch diameter screen over with a
length of 20 feet, and with the bottom set at approximately
minus 40 foot elevation. Each well would be equipped with
an electrically operated low head submersible well pump and
a motor of about 2 H.P. and would pump through a new water
PVC pipeline to the water plant in the southeast
corner of
Plan A.
-29-
The placement of the proposed water supply wells for
the Norris Estates/Associates development has been carefully
planned to minimize the possibility of any salt water
encroachment. Ail existing information that we have
available indicates 'that while salt water is located
primary well,
and to pump it extensively at 3 or 4 times
production rate for a period of at least
monitoring quality and drawdown in an nearby well.
construction will include 6 inch casing to about 50
depth with 20 feet of screen between 50 and 70 feet.
underneath the clay lense, movement of a salt wedge above
the clay is most likely mechanism of intrusion. Proposed
placement on the northeast corner of the property, along
with small proposed flow, the proposed wells will avoid any
significant movement of the salt water interface. In
addition, the expected recharge via an on site wastewater
treatment plant reduces the possibility of intrusion even
further.
When construction begins, it is planned to build the
the easterly well, as a test/permanent well
the planned
10 hours,
Well
feet
This
will have a very small drawdown at 66 to 70 gpm (permanent
capacity). We expect to pump the well during development
and testing at rates from 70 to 200 gpm and observe drawdown
in the aquifer nearby.
-30-
NORRIS ESTATE
OPTIONAL WATER SUPPLY & TREATMENT SYSTEM
The Developer/Owner has committed to an optional water
supply and treatment system using reverse osmosis (RO) under
two (2) conditions.
(a) If it is required by the Town as a condition of
approval for the water supply for the 132 units at
Norris, or
(b) If it is determined at a future date that
consumptive water use is Greater than calculated and a
reduction in fresh water with drawn from the project
site is necessary.
The optional water system would consist of the
following.
Reverse osmosis has been a proven, even though
expensive, technology for many years. Additional demands
and research have resulted in improved membranes, including
those better designed to convert saline water to fresh.
The saline supply source is proposed to be two (2) 8"
wells (WSA1 and WSA2 on site plan) approximately 250 feet
deep with 8 inch casing and 6 inch diameter stainless steel
screen 20 feet lonG. The proposed capacity, depending on
30 (1)
final design of reverse osmosis components, will approximate
300 gallons per minute such that a 150 g-p-m product will be
available at a 50 percent rejection rate. The other 150
gpm, as waste water, will be disposed of either by injection
into the deeper aquifer at 300 feet or by piping to or near
Peconic Bay. Piping to the Bay would be more economical but
will be subject to the availability of easements for pumping
and dispersion system. Either method of disposal would be
subject to a discharge permit (SPDES) by the New York State
Department of Environmental Conservation.
The proposed deep wells for reject water injection
would consist of two (2) 300 feet deep wells, 8" in diameter
each with 40 feet of 6 inch screen. Under normal operation
one well will be used for recharge, with twice the screen
length as the supply well and with only one half the flow.
When the first well develops excessive back pressure due to
clogging, the second will be placed in service. The first
well would be then treated, restored to capacity and placed
in a standby mode. The standby wells and the injection wells
would be constructed by cable tool method or by rotary
30 (2)
method with a cement grout seal between the drilled hole and
the outside of the well casing to prevent any communication
or hydraulic conductivity between the saline to brackish
water below the clay and the reservoir of fresh water above
the clay.
A monitoring well will be installed just above.the ~lay
in the vicinity of each supply well and near each injection
well so that water levels and quality samples can be
collected to show there is no negative effect on water level
or quality in the fresh aquifer.
If easements can be obtained to direct the reverse
osmosis reject to Peconic Bay, the simplest method of
disposal would be through a pipe submerged at a bulkhead.
If this is not available, it may be necessary to construct a
dispersion pipe just below bay bottom. The quality of the
wastewater would be less saline than the bay water, only
twice that pumped from the brackish well.
Multistage units, probably'3 stage, with 6 module rated
at 30 gpm product water each will provide 150 gpm normal
plus one reserve 30 gpm unit. They will be designed for
saline well water anticipating about 50% the concentration
of sea water or some 10,000 mgl of sodium carbide and 14,000
mg®l total needs.
30(3)
The brackish well water will
provide pH adjustment and scale
through a 5 micron mesh prefilter.
be chemically treated to
control and then pass
High pressure pumps will
deliver water to the membranes at about 800 - 900 psi. The
schematic diagram of the treatment plant is attached.
Should higher solinities be experienced in the future,
higher pressures ~ould be required.
A typical RO membrane is designed and constructed with
a production rating measured by flux of water through it -
i.e. gal/day ft2. The flux of a membrane depends on
membrane physical characteristics and system condition
(temperature, differential pressure across the membrane and
salt concentration). The flux value will gradually decrease
during the lifetime of a membrane due to a slow
densification of the membrane structure, which results in a
decrease in the membrane pore diameters. This gradual flux
reduction occurs in all membranes and it is permanent, not
reversible. The membrane must be replaced when the flux has
reached a minimal acceptable value. The flux versus time
duration will plot as a straight line on log-log paper. The
life span of a membrane may range from two months to two
years, depending on flow and water conditions.
30 (4)
The most common membrane used is made of cellulose
acetate. These membranes have low water permeability and
can. reject over 99 percent of the salts. The water flux is
very low. The main types of mounting hardware employed in
reverse osmosis equipment modules are classified as 1)
tubular, 2) hollow fiber and 3) spiral wound. The most
common saltwater/brine membrane type are made in the spiral
would fashion. In the spiral-would mounting, a porous
hollow tube is spirally wrapped with a porous sheet for the
feed flow, and a membrane sheet and a porous sheet for the
product water flow to give a
The spiral module is encased
feed flow through the porous sheet
to the porous tube. As the feed
porous sheet, a portion of the
spiral sandwich type wrapping.
in a pressure vessel, and the
is in an axial direction
flow passes through the
flow passes through the
membrane into the porous sheet annular space for the product
water. From there the product water flows spirally to the
porous center tube and is discharged from the conduit in the
tube. The brine is discharged from the down stream end of
the porous sheet for the feed flow.
3O (5~
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The modular RO system will have a production capacity
of 150 Gpm (reject 150 ~pm) for a daily maximum flow
capacity of 216,000 Gallons (a sixth 30 Gpm unit will be in
reserve). In this way the unit will be able to produce the
required 171,000 Gpd of flow (0.9 Gpm per dwelling unit) in
roughly 19 hours of operation with 5 of the 6 modules, in
service. The units will be skid mounted for flexible
installation. Thirty (30) Gpm from each module will permit
one of these units to be held in reserve in order to
facilitate routine maintenance on one of the five
operational units and will act as a spare should one
operational unit break down. The flow through the units is
divided into stages. Each 30 Gpm unit has 8 permeators
which are staged 5-2-1. In each module or unit the first
stage has 60 Gpm of raw water flow to it and the membranes
allow 45 Gpm to pass while rejecting 15 GPm. The second
stage receives the 45 Gpm and allows 35 gpm to pass while
rejecting 10 Gpm. The third stage allows 30 Gpm of the 35
Gpm to pass while rejecting 5 gpm. In each stage the
product wate~ has less and less total solids and the reject
water has Greater solids concentrations. Approximately 50
30 (6)
percent of the flow will pass the series of membranes and 50
percent will be rejected. Both inlet and outlet water will
be equipped with a conductivity meter to indicate raw water
total solids but with an arrangement to alternately test the
reject water for increase in conductivity.
The product water will be pH adjusted then chlorinated,
using automatic chemical solution pumps to deliver caustic
or soda ash and sodium hypochlorite to the demineralized
water. After final treatment the water will flow to the
storage tanks.
30 (7)
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It is expected that three (3) wells, 6 inch diameter
with 6" to 4" diameter screens will be constructed, each
with a capacity of 66 to 70 gallons per minute. Peak or
maximum day usage is estimated at 0.8 to 1.0 gpm per
dwelling unit. At 1.0 gpm per unit the well capacity
required is 132 gpm such that 2 wells (plus 1 reserve or
spare) at 66 gallons per minute would be adequate.
The above water system description would be to serve
Parcels A & B. For Parcel C under Plan I, the 41 single
family homes on minimum 40,000 square foot lots would each
be supplied by individual wells. Based on test wells on the
site a waiver for 40 foot maximum submergence to about 30
foot submergence could provide nitrate levels below the
limit .of 10 rog/1 and Aldicarb levels below the limit of 7
rog/1. Forty one (4]) ~ homes requiring a consumptive use of
63 gdpc or 9,702 gallons per day is only a small percentage
of the permitted yield of 86,000 gallons per day (100 acres
at 860 gpd) or 0.55 mg/1 per square mile).
It is obvious that the extensive agricultural use of
land in the area has contributed many pounds of nitrates and
other chemicals to the land surface and these have
percolated with rainfall and irrigation to the ground water.
;31- 8-2-88
The change in agricultural uses
the recent contamination and in some
possible to develop more shallow
contaminants present.
At a specific glacial or shallow
available from a well on this site
influenced as follows:
in many areas has reduced
areas has made it
wells with less
well site, the water
will generally be
The water near ground water surface will be from recent
recharge and will reflect generally improved quality because
of less fertilizer and pesticides use at the surface. The
deeper the well depth and the farther the well is from the
greund water divide the older will be the quality effect.
The vertical quality profile obtained at the plant with
samples at 10 ft intervals beginning 15 to 20 feet below
water surface shows a trend of better quality water near the
surface reflecting less contamination in the more recent
recharge.
If Plan II is adopted as recommended, the water
resource requirement at Parcels A & B (Norris) is substanti-
ally reduced. The 25 single family units to be built on
Parcel A and the additional future development of 24 homes
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on Parcel B (49 homes with population of 184) at Norris
would require s pumpage of 25,760 gallons per day with a
consumptive use of 45% or 11,592 gpd. Assuming some cluster
and that pasture irrigation would use 5,951 gpd the
consumptive use would increase to 17,543 gpd. This is 20
percent less that Plan I and therefore
predicted permitted yield of 27,350.
Parcel C under recommended Plan II
obviously within the
would be served by a
central water
based on 107
system. The estimated pumpage will be 56,140
single family homes with 3.75 persons per home
or 401 population at a use of 140 gallons per person per
day. Of this total, some 45% (63 gcpd) or 25,263 gallons
per day would be consumptive use. This compares to a
pumpage of 56,!40 gallons per day and a permissive yield of
86,000 gallons per day based on 0.55 mgd per square mile.
The proposed water plant is situated adjacent to 3 of
the 4 fresh water wetlands on the 107 acre project site at
Parcel C. Even though the depth to ground water is 45 feet,
there is one pond and 3 sink hole wetland areas on the site.
These areas are caused by water which is perched by clay or
hardpan under a portion of the site. Three of the test
holes dug on site indicated water near the bottom of the
test holes.
-33-
Three (3) test wells were performed on the parcel and
these wells and an existing well were tested. The exact
elevations of the three test wells have not been determined
but based on the Suffolk County Department~ of Health
Services monitoring wells and annual map of ground water
contours, water table elevation should approximate 5 feet
above mean sea level. This indicates a salt water/fresh
water interface at a depth of about 250 feet (200 feet below
water table).
Two (2) test wells were constructed and pumped at
depths of 40 to 60 feet into ground water (105 and 110
depth) in the northeast and south central portions of the
site. These wells were pumped until clear and analyzed as
follows.
A vertical profile multi depth test well was drilled in
the central part of the site at a predetermined central
water plant location. Screens were set and pumped at 10
foot intervals starting at 65 - 70 foot (about 20 feet
submergence). Good quality was found down to at least 80
feet but nitrates averaged about 11 mg/1 from 85 to 110
feet.
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PLAN II WATER SYSTEM - PARCELS A & B
The recommended water supply for 25 proposed single
family homes on the 28 acres of Parcel A and 24 potential
homes (including 4 existing) is the construction of
individual private wells with individual pumps and hydro-
pneumatic tanks. Based on the test wells on site, each well
would be drilled to a depth of about 70 feet on a resid-
ential plot of 40,000 square feet. Reference is made to
Appendix A showing test well results.
PLAN II WATER SYSTEM - PARCEL C (WANAT)
The
single family
lots between
include three
to 30 feet of
will be
proposed and recommended water system for the 107
dwelling units on about 20,000 square foot
Bergen Avenue and Long Island Sound will
(3) wells approximately 80 feet deep with 25
screen. Each well will be 8 inch diameter and
developed and equipped with a 70 gallon per minute
submersible 3 H.P. motor driven pump with Iow head
characteristics. The design includes four (4) stage
treatment system for a 70 gpm capacity for two (2) stage
treatment system for 210 gpm. Treatment for potential
Aldicarb (and other organics if present) adsorption will be
by a pressure type granulated activated carbon (GAC)
adsorber/filter with 3,000 pounds contained in a 5 foot
diameter unit. Provision will be made to periodically
-35-
backwash the unit with final treated
backwash water delivered to on site
replacement would be anticipated at once per year.
will be provided for a second unit after 50
development if mixing of water is not acceptable.
system water with the
leaching pools. GAC
Space
percent
Treatment for potential nitrate levels above 10 mg/1
will be included at a design rate of 35 gallons per minute
which will be adequate until at least 50 percent of
development and perhaps for final development. Additional
equipment may be easily added if needed but we think it
remote. The propose4 unit will be a pressure type ion
exchange unit, 4 feet in diameter to contain 50 cubic feet
of ion exchange media. Assuming 7 kilograms per cubic foot
of exchange capacity the unit could remove about 50 pounds
of nitrates and sulfates and replace them with chlorides.
At an expected maximum of 100 mg/1 to remove, this unit
would treat 50 percent of the flow from 120,000 gallons per
day or 40 percent of the flow from 150,000 gallons per day,
the ultimate approximate maximum day use for 107 homes.
Regeneration would be no more frequent than once daily and
would be accomplished with a brine or supersaturated salt
solution. The regeneration brine and rinse water would be
discharged to a brine disposal system to consist of leaching
pools near the Long Island Sound where it would flow
subterranean into the Sound. With rinse water and brine in
about 2 to 1 ratio, the disposal liquid would have a salt
content of about 5 percent or about twice that of the Sound.
A small plastic pipe will be installed in the same trench as
the water main from the treatment plant toward the Sound and
from the most northerly street through common property to
the leaching pools. A meter will be installed on both ends
of the line to verify that no leakage from the line has
occurred. The final quantity of brine waste will be
optimized based on less than complete exhaustion of the ion
exchange media. It has been found that by regenerating
prior to exhaustion of bed will require less salt and less
cost. A saturated brine supply storage tank will be
installed in the plant. When it is determined that the
operation of the nitrate removal system is required, a
continuous nitrate measuring probe and alarm/shutoff system
will be installed on the treated water system.
The above described GAC and Ion Exchange systems for
pesticide and nitrate removal respectively will be operated
when needed, based on water quality. The other system
described below will be used or usable in all cases.
Since the pH of t~e water is to expect approximate 6.5
based on test well data, it is planned to add an alkali to
reduce the carbon dioxide and corrosiveness by increasing
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the pR to about 7.5 by the addition of an alkali. Bench
scale tests will be done on the water to confirm that sodium
carbonate will be appropriate. It would be preferable to
caustic soda since it is easier to handle and less dangerous
to operators. Lime is more difficult to handle and may not
be practical for small suppliers. Either soda ash or
-37-
caustic treatment would be accomplished by a positive
displacement chemical feed pump and each well pumping from a
storage tank containing predetermined strength of chemical
solution. Similar equipment will be provided for use of
sodium hypochloride to provide chlorination of each well - 3
pumps up to a dosage of 5 p.p.m.
Following treatment the water will discharge to a steel
ground storage tank about 30 feet in diameter and 15 feet
high with a capacity of about 80,000 gallons. This tank
would provide about 20,000 gallons for maximum day operating
storage and about 60,000 for fire protection or emergency
reserve. This would be equivalent to a 500 gallon per
minute fire flow for two hours.
From the storage tank, water would be pumped by one or
more booster pumps to the system via a 5,000 gallon
hydropneumatic tank which will be used to provide a pressure
range controlled between 40 and 65 psi. The expected
booster pump capacities will be two (2) at 100 gallons per
minute and one at 500 gpm.
-38-
An engine generator set will be included with a capa-
city of about 60 KW. It will be automatically started in
the event of power failure and will be able to operate the
largest booster pump, two (2) well pumps and the treatment
equipment and controls.
Ail of the treatment equipment booster pumps, engine
generator, motor control center and instruments and
miscellaneous equipment will be housed in a building about
25 x 35 feet. The wells will be equipped with pitless
adapter type discharges or standard with a drain and will be
remote from the pump house building. The wells and
treatment will be controlled from storage tank level and the
booster pumps will be controlled from pressure switches on
the hydropneumatic storage tank (system pressure).
Telemetering equipment will be dictated by the
responsible operator. As a minimum, the status of critical
items will be transmitted by telephone to a central point.
These items will indicate power status, system pressure
status,
limits.
system
records
plant temperature status, and storage tank level
There will be local recorded data for tank level,
pressure and system flow meter. Totallizer type
will be provided for well pumps, booster pumps,
brine flow, etc.
-39-
Distribution System
The proposed transmission/distributer
consist primarily of an 8 inch diameter pipe,
system will
either ductile
iron cement lined or C900 PVC, with 6 inch pipe planned for
short dead end cul de sacs and with 12 inch on Bergen Avenue
for future transmission main capacity not required for this
development. Hydrants and valves will be placed at
appropriate locations with hydrant locations to be approved
by the Mattituck Fire District. The distribution system may
be installed in stages depending on the nature of
development but at least one of the mains toward the Long
Island Sound would be installed prior to the need to dispose
of brine waste.
The cost of the control water system as described is
shown in Table IV and totals $1,100,000, which includes
about $275,000 for distribution, $300,000 for treatment and
$425,000 for ths wells and plant plus contingencies.
-40-
2.
3.
4.
5
6
7
8
9
10
11
12
13
14.
TABLE IV
WATER SYSTEM COSTS
PARCEL C - 107 UNITS
PLAN II
Wells Three (3) 8" x 8" x 100'
Pumps (3) - 6" Pumps - 70 gpm
Engine Generator (60 W)
Pump House
Treatment (Chlorine & pH)
Mechanical & Boosters
Site Piping
Site Drainage & Blowoff
Electrical Service & Distribution
Telemetering & Control
Distribution System
Nitrate Treatment
Pesticide Treatment (GAC)
Contingencies
Sub Total
Engineering
& Mechanical
$
The cost for individual wells in Parcels A & B
included above.
-41-
$ 75,000.
15,O00.
20000.
50 000.
24 000.
59 000.
39 000.
17 OO0.
49 000.
32 O00.
240,000.
175,000.
75,000.
1OO~000.
970,000
130~OOO.
$ 1,100,000.
is not
III. WATEWATER TREATMENT AND DISPOSAL ALTERNATIVES
INTRODUCTION
Various options are available for the treatment and
disposal of wastewater generated by residential
developments.
In Suffolk County the most common system is a
conventional on-site system which utilizes a septic tank and
leaching pool system for each dwelling unit. Where density,
clustering, or deep recharge zones exist, community
ccllection systems with community septic tank and leaching
system, or community collection systems with centralized
wastewater treatment are typically utilized for treatment of
multiple residential wastewater The type of system utilized
is subject to the approval of the Suffolk County Department
of Health Services (SCHDS), and is dependent upon the
location, density, and subsoil a. nd groundwater conditions of
the development.
The SCDHS requires residential development with other
than detached single-family residences (apartments and
condominiums) to have an equivalent density of a minimum of
one acre per unit (maximum sewage flow of 300 gallons per
day per acre) in Groundwater Management Zones III and VI;
and
gallons
density
one-half acre per unit (maximum sewage flow of
per day per acre) in all other areas. If
requirements are exceeded, a
which incorprates nitrogen removal
development with a design flow less
day. Developments exceeding the
generating in excess
a central collection
ESTIMATED WASTEWATER
PLAN I - CONDO & SINGLE FAMILY ffOMES DEVELOPMENT
community septic
can be utilized
than 15,000 gallons
density criteria,
60O
the
tank
for
per
and
of 15,000 gallons per day, must utilize
system and sewage treatment plant.
FLOWS
In accordance with the most recent SCDHS "Standards of
Subsurface Sewage Disposal Facilities for Other Than Single-
Family Residences", the following criteria were utilized to
determine the design waterwater flow for the proposed
development.
Type of BuildinK DesiEn Flow
2 bedroom Condominium
(2 BR less than 1200 sq.ft) 225 gallons per day
2 bedroom Condominium
(2 BR greater than 1200 sq.ft) 300 gallons per day
3 bedroom Condominium
(3 BR greater than 1200 sq.ft) 300 gallons per day
Single-family residence (SFR) 300 gallons per day
8-2-88
-43-
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Based on the
acre parcel and
indicated below:
28.15 Acre
81 (3 BR/C)
27 (2 BR/C)
above, the design flow from the 28.147
the remaining 45.33 acre parcel are
Parcel
x 300 gpd/unit = 24,300
x 300 gpd/unit = 87100
Total Estimated Flow
B. 45.33 Acre
= 32,400
2O
4
Parcel
(SFR) X 300 gpd/unit = 6,100
(Estate + 3 existing
dwelling units) x
300 gpd unit = 1,200
Contingency for estate 300
Total Estimated Flow 7,600
TOTAL DESIGN FLOW
C. 107 Acre Wanat Parcel
Under Plan I (as of right) based
would be developed acco'rding to a 2-acre zoning
imately 41 szngle family dwelling units. Each
serviced by a standard single family septic
private treatment and disposal system. The
flow would be approximately 12,300 gallons
per day on the 107 acres.
40,000 gpd
on zoning, this parcel
with approx-
plot would be
and leaching
total wastewater
(41 x 300 gpd)
-44- 8-2-88
The wastewater flow rates indicated above are based on
typical design values and are conservative for the proposed
project. Actual wastewater flows are anticipated to be
approximately 10 to 20 percent lower.
ALTERNATE WASTEWATER SYSTEM FOR PLAN I
Based on the SCDS standards previously outlined, the
proposed Condo development could not utilize a community
septic system, pince it exceeds the maximum flow requirement
of 15,000 gallons per day, and the maximum density limit of
600 gallons per day per acre. Therefore, the only viable
alternative for the proposed condo ~evelopment is a comm-
system with a centralized wastewater
unity collection
treatment facility~
Under this option, all wastewater generated within the
development would be collected and conveyed to a central
location for treatment and disposal. Each condominium or
cluster would be serviced by a 5-inch or 6-inch house
connection to a wye connection, on an 8-inch gravity sewer.
Preliminary plans indicate two (2) north-south collectors
extending through the unpaced areas to service the
condominiums. A single lift station will be needed at the
treatment plant, depending on final detail plans and cost
-45-
estimates. Manholes will be installed at 250 to 350 foot
spacing and at changes in sewer direction.
either ABS truss pipe or polyvinyl chloride.
system will be checked for exfiltration and
acceptance and before placing
of the system will be subject
topography, as well as any proposed
but it is anticipated that flow will
the treatment plan in ornear
A.
Sewers will be
The collection
alignment before
it into service. Final design
to field verification existing
changes in final grade,
be north to south with
the southeast corner of Parcel
The sewage lift station, will be located at or near the
sewage treatment plant, and will consist of two pumps, each
capable of the peak load, estimated at 120 gallons per
minute. Standby power will be provided for ~he lift station
and sewage treatment plant.
There are various types of package treatment plants
available for treatment of wastewater. The majority of
these plants incorporate biological wastewater, treatment
methods. Since the proposed treatment facility would
discharge the treated effluent to groundwater, it must be
capable of meeting the NYSDEC standards for discharge to
-46-
Class GA groundwaters, which require BOD-5 and suspended
solids effluent concentrations of less than or equal to 30
mgl, and total nitrogen (as N) less than or equal to 10
mg/1-N. This equates to requiring tertiary treatment for
notrogen removal.
In addition to the ability to meet discharge standards,
the selectiom of a particular treatment process for the
proposed development must consider the capital and
operational costs, ease of operation and maintenance, and
aesthetics. Based on these considerations, it is
recommended that a rotating biological disc 9RBDO system be
utilized.
An acceptable option would be extended aeration which
is an aerobic biological treatment process which employs an
aerated tank containing a mixture of wastewater and micro-
organisms. The process is a low rate modification of the
activated sludge process, typically operating with a 24-hour
detention time. Operation is based on a microbial
population ingesting and metabolizing the soluble organic
constituents of wastewater and converting them to more
stable end products.
-47-
The recommended system is a Carbon Oxidation and
Nitrification system utilizing Rotating Biological Discs
followed by a Denitrification Filter. Nitrification is the
conversion of ammonia nitrogen to nitrate nitrogen.
The rotating biological disc (RBD) is a fixed film
biological treatment system which consists of a series of
closely-spaced, large-diameter plastic discs mounted on a
horizontal shaft and placed in a tank. Approximately 40
percent of the disc surface area is submerged for contact
with the wastewater flow and rotated slowly through it. As
the discs rotate, a biological film develops on the disc
media.
The rotating biological disc system accomplishes treat-
ment by movement of the media through wastewater, as opposed
to movement of wastewater through the media as in a
trickling filter. The rotating of the disc alternately
contacts the biological film with the organic material in
the wastewater and the atmosphere for adsorption of oxygen.
The film metabolizes and stabilizes the organic matter
present in the wastewater. Excess solids are removed from
the discs by rotational' shear forces and the stripped solids
are maintained in suspension by the mixing action of the
rotating media. The excess biomass is eventually settled
out and removed.
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Multiple staging of RBDs increases treatment effici-
ency, eliminates short circuiting and dampens shock
loadings. Each state of the media essentially operates as a
completely mixed reactor, enabling the most efficient types
of microorganisms to be present at each state of treatment.
As wastewater flows from stage to stage, an increasing
degree of treatment is achieved. As the concentration of
organic matter decreases, nitrifying bacteria begin to
appear in the final stages. Soluble organic matter is
removed from the wastewater by diffusion into the biofilm,
where it is oxidized by the microorganisms present.
Baffling of the treatment tank creates a staging effect
which enables a high degree
The flow train for the
a).
of treatment to be obtained.
RBD process would be as follows:
Preliminary treatment consisting of a commin-
utor and aerated equilization chamber;
rotating biological discs in a multi-stage tank
where carbonaceous BOD removal and nitrifi-
cation take place;
c) final clarifier for suspended solids removal
d) denitification sand filter for removal of nit-
rates by conversation of nitrate to nitrogen gas;
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e) discharge ef renovated wastewater to below-grade
leaching or recharge pools. Sludge would be
removed periodically from the final clarifier
and stabilized in an aerobic digestion tank.
Final disposal of sludge will be periodically
trucking to an approved disposal site, usually
a large treatment plant or a scavenger waste
treatment plan such as the Town of Southold plant
at Greenport.
Leaching pools are recommemded for the final effluent
disposal. Although the initial cost and maintenance are
more expensive than open beds, the primary advantages are
aesthetics and the elimination of disinfection requirements.
The sewage treatment plant itself requires a small
amount of land for placement of actual treatment units. It
is estimated that approximately 1/3 acre of land would be
sufficient for the plant, excluding recharge. NYSDEC and
the Health Department require minimum buffer distances to be
provided around sewage treatment plans. A minimum radial
separation of 500 feet is required between an aeration tank
and habitation of areas of signficant use by the public,
unless special designs or considerations warrant reduction
in distance.
Considering the minimal land available within the
proposed site layout, and the NYSDEC buffer requirements for
various "out door" treatment units, the buffer distances can
be relieved or eliminated by housing the treatment plan in a
two-level building. In addition to minimizing land
requirements, this will improve the overall aesthetics of
the treatment plant area. An odor control system is also
recommended as a necessity ~to eliminate offensive odors.
The preliminary construction cost of the sewage
collection system and treatment plan to serve the 28.15 acre
parcel is estimated at $750,000, of which approximately
$550,000 is for the treatment plan and $200,000 is for the
collection system. The cost of the treatment plant is based
on having the plant in a two-level building as previously
discussed. If the plant could be located in an area with
more buffer distance, and not housed, a cost savings of
but we recommend
approximately $120,O00 would
an enclosed plant.
We have also estimated
be achieved,
the capital costs associated
with providing a collection system and additional capacity
at the proposed sewage treatment plant to service the re-
maining 46-acre parcel. If this parcel is ultimately
developed, it would be developed at no more than 20
additional residences to complement the existing estate and
three dwelling units. The capital costs, as a result, would
increase from $750,000 to $980,000 for wastewater collection
and treatment.
The capital costs for wastewater collection and
treatment facilities are summarized in Table V.
Parcel C would have individual lot private sewage
treatment and disposal systems under both places I or II.
Parcel B could either be incorporated with the Parcel A
central system or have private systems under Plan I but
would be private systems under Plan II.
Drainage for each parcel amd plan will contain local
leaching pools at low points but at the condo site
additional piping and below ground leaching pools will
direct as much of the drainage runoff to a series of pools
along the southeast edge of the 28 acre Parcel A. This will
provide for return of the drainage water to the ground water
reservoir just upstream of the renovated wastewater.
No specific plans for drainage area included with this
report but would be available when needed.
-52-
PLAN II SINGLE FAMILY HOME DEVELOPMENT
(a). The alternate Plan II presented and recommended is
to develop the Norris 28 acre site (Parcel A) with single
family homesites each with a minimum lot area of 40,000 sq.
ft. (unless clustered). This would provide 25 plots which
would be served by a septic tank and leaching pool as a
private sewage treatment and disposal system on each lot.
The soils on the site are sandy and provide for good
drainage of subsurface liquids. Depth to water will range
from about 14 feet on the southern portion of parcel A to
about 25 feet on the north.
Each septic tank would have a minimum design capacity
of 900 gallons and a leaching system of at least 300 gallons
per day and would also conform to the current Suffolk County
Department of Health Services rules and regulations for
sewage disposal for single family homes. Test holes have
been dug on the site and most of the area has sand and
gravel.
b). The 20 additional (total 24) single family units
would be served by similar units to (a).
-53- (revised 6/29/88)
c). As part of the Plan II alternate plan for a single
family 25 lot subdivision at Norris, instead of condos there
would be included as part of the overall development plan
II, a subdivision of 107 single family units on 107 acre
known as the Wanat parcel C. north of Bergen Avenue in
northwest Mattituck. This property is presently zoned for 2
acres. Use of the 2 parcels (Parcel A of Norris and 28
acres plus Parcel C) involves a recommended transfer of 60
(maximum of 83) dwelling units from Parcel A to the 107
Parcel C. The minimize lot size on the Wanat Parcel C would
be 20,000 sq. ft.
All dwelling units in Plan II will be serviced with
private waste water disposal system as in (a) all in
conformance with the Suffolk County Department of Health
Services rules and regulations.
-54-
TABLE V
ESTIMATED WASTEWATER TREATMENT FACILITY CAPITAL
COSTS
STP Construction
Collection System
SUBTOTAL
Additional Reserve
Cost
Additional Collection
Cost
SUBTOTAL
(27.7-acre parcel)
(27.7-acre parcel)
Capacity (46.3-acre parcel)
System (46.3-acre parcel)
TOTAL CAPITAL COST ESTIMATE (WASTEWATER
COLLECTION AND TREATMENT) - PARCELS A & B
-55-
$550,000
· 200,000
$750,0O0
$110,000
100,000.
$210,000.
$960,000.
~PPENDI% A
TEST WELL ANALYSES
~ORRIS ESTATES AREA
,Well Numbers 1
2 3
Locations North North Nor:h
Central West East
Depth 61 60 70
Size 6 2
Nitrate N 2.7 0.1
Nitrite -- None None
Iron 0.9-1.0 8.4 0.04
Manganese 0.04 5.6 0.02
Chloride 14. 24. '92-134
Sc 180 230 610
Aldicarb None __ None
Ammonia 0.2 4.5 0.2
pH 6.5 6.6 6.4
Calcium -- 7.6 22.0
Magnesium
--- 4.2 13.1
Hardness --- 36.2 I09.
Sodium
--- 18. 79.
Pesticides __
--- None
*lowest value after pumping.
~' a shallower setting had 1.32
iron and
**North South
87
2
6.1 6.1
None -_
0.07
None
none none
23. 95.
250. 460.
none none
0.2 0.2
6.1 5.7
13.1 38.4
none
0.09 Mn.
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SITE
SoC.
I Lab #
Depth 105 110
ICi ....
IN03 13.7 6.4
Iron 0.04 0.08
I
pH
I Hardness
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Mg
ISOx
Aldicarb
lug/1
IAldicarb
Lab #
Results are ug/1
APPENDIX C
TEST WELL DATA
PARCEL C (WANAT)
PLANT SITE
805515 516 718 719 720
70' 80' 90' 100' 110'
12. 16. 19. 20. 26.
7.2 3.6 11.2 10.4 11.5
0.09 0.17 0.17 0.24 0.16
188. 300. 330. 330. 360.
6.2 6.4 6.4 6.2 6.5
55. 118. 124. 117. 138.
13.6 34. 36. 35. 36.
5.2 8.1 8.3 7.5 11.7
32 58 59 61 68
122'
24.
9.2
0.16
404.
6.9
149
44.
9.5
95
EXISTING
WANAT
805- 721
5 25
combined combined
855 737 855 852 855 962
except for Aldicarb which is mg/1.
-57-
65'
17.
6.3
0.93
290.
6.4
109
29
8.3
74
none
855 854
II.
APPENDIX D
CAPITAL COST ESTIMATES - ALTERNATIVE PLANS
CONDOS & SINGLE
A.
FAMILY
NORRIS ESTATES Area (108 Condos
Single Family 74 acres)
1. Water Supply & Distribution
2. Wastewater Collection &
Treatment
WANAT Parcel C 107 acres 47
1. Private Well Facilities
47 @ Approx $3,000
2. Wastewater Septic & Leaching
Facilities
47 @ Approx $3,200
TOTAL PLAN I
& 24
$550,000.
960,000.
plots)
140,000.
150,000.
$1,800,000.
SINGLE FAMILY ALTERNATE PLAN
A. NORRIS ESTATES Area (25 + 24
Family - 74 acres)
1. Private Well Facilities
49 @ Approx $2,600
2. Wastewater Septic Reading
49 @ Approx $3,200
(Parcel C 107 acres
WANAT
1.
2.
Single
$129,000.
Testing & Preliminary
157,000.
107 Plots)
$ 72,000.
Water Supply & Distribution
Facilities
Wastewater Sseptic
Facilities
107 @ 3200 Approx.
TOTAL
$1,100,000.
& Leaching
3~2,000.
ALTERNATE PLAN II $i,800,000.
-58-
0
"REEVE
AVENUE
olso known os "CAMP MINEOLA ROAD,,
WS-/
/:
]1
NOTE: FOR ALTERNATE (PHASE II) 26 PLOT SINGLE FAMILY
SUBDIVISION, SEE YOUNG ~ YOUNG DW6. No. 66-tO69(9/i2fS?)
80M WATR 66-I~ ,'NORRIS GO,
~"'~"""': "":,,,=,oo, PROPOSED WATER SUPPLY
SEP~ 1986 , ' ' ...... ' '
~,~ ,.:,;,..o..: lAND SEWERAGE SYSTEMS FOR
MAY 2 , 1988 - '
OC,~ 7, 1988 I ~ NORRIS ~ONDO AREA~
I , '
I I r &, ConsultingEngineers
~~. I r '~ ,, v, Environmental Scientists ,.:,.:,,,o
F~{ I Holzmacher, McLendon & Murrell, P.C.
SITE
LOCATION MAP
0
J
WETiLANDS'
BRINE DISCF
WEEL
NO, 2-
PL
~VIA
EASEMENT
SED
· TREA1
PL
....... ~WELL
~o. 1
HOUSE'
POND
'NON PO)LLUTION EAS~T
/
WIET~LANDS,
NOTE:
LEGEND
I °r""~J' I°"''"' "°=
PROPOSED 6,' WATER MAIN , '
AP iL 198 ;,'
PROPOSED ,2iWATER MA,. ,'--~pO.SED WATER SYSTEM
h Mcrendon & Murrell
DATA FROM PLAN BY : ;...',~,~,. , < ,
' AR~I~C~ · P~NERS · ~S~ · ~Y~,
ROAD (~ EASEMENT LOCATION qUBJECT TO CH(ANGE.
RIVERHEAD, N.Y. FAIRFiELD, N.J.
:I , , Sheet
~h~IH~A,N II,PR~qPelED WA?ES L&YOU~r