Monuments shall be placed at all block corners,
angle points, points of curvature in streets and points of tangency
or horizontal curves and at intermediate points as shall be required
by the engineer; however, in no case shall there be less than four
permanent monuments per block. The monuments shall be of such material,
size and length as may be approved by the engineer.
Utility and street improvements shall be provided
in each new subdivision in accordance with the following:
A. Water supply and fire hydrants.
(1) Public or central water supply available. If public
or approved water supply is utilized, the system shall be designed
with adequate main sizes and fire hydrant water supply to meet the
Association of Fire Underwriters specifications for a protected area.
Such system shall be approved by the Village agency or authority operating
the central water system.
(2) No public water.
(a)
In general. A project water system with a central
well, adequately planned and protected, is often less expensive to
install than an individual well serving each lot. It is also easier
to protect against contamination. If contamination does occur, it
is simpler and more efficient to purify the water from a central well
than from numerous individual wells.
(b)
Project system. If a project system is planned,
it shall be approved by the New York State Department of Health and
the central well drilled, tested and approved prior to filing the
application for the subdivision. All land within 100 feet of a project
well shall be suitably protected and restricted from development.
All lines shall be of the size specified by the Village Board in its
regulations and standards of the Village supply system.
(c)
Individual wells. If the water supply is to
be from an individual well, the developer shall provide at least one
test well for each unit of 10 or fewer lots in the subdivision, location
of such well to be approved by the Planning Board. Test wells shall
be drilled, cased and grout sealed into bedrock, shall be not less
than 25 feet deep and shall have a production capacity of not less
than five gallons per minute of safe drinking water as certified by
the New York State Department of Health on the basis of bailer test.
B. Sanitary sewer facilities.
(1) Public sewer available. No stormwater shall be allowed
to enter sanitary sewers. Proof shall be submitted showing that all
plans of sewer extensions have been approved by the New York State
Health Department. Where required by Village policy, an offer to dedicate
sewers shall be prepared in form suitable to the Village Attorney.
(2) On-the-lot sewage disposal systems are generally unsatisfactory
even when carefully designed and constructed and given the best of
maintenance. Poor design, inadequate construction or poor maintenance
can result in conditions dangerous to health and generally obnoxious
to the senses. In view of the above, individual lot on-site sewage
disposal systems will not be approved within the limits of the Village
of Delhi unless the distance from the nearest point on the lot line
exceeds 500 feet.
(3) Project systems. Project systems shall be designed
by a licensed engineer, shall provide a six-inch-minimum-size connection
to each lot and shall have an adequate sewage disposal plant with
suitable arrangements for the operation thereof. Plans shall be approved
by the New York State Department of Health.
C. Storm drainage.
(1) Capacity.
(a)
Storm drainage facilities shall provide a clear
and protected channel fully adequate to handle runoff from a five-year
storm. The developer should keep in mind that more severe storms occur
at less frequent intervals and, where feasible, so design subdivisions
that especially heavy runoff exceeding the capacity of the required
channels can be handled with the least possible damage to improvements
and structures.
(b)
The rational method shall ordinarily be used
in computing runoff, using the formula Q=CIA wherein:
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Q
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=
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Water reaching channel, culvert bridge or storm
sewer in cubic feet per second
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I
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=
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Rainfall in inches per hour
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C
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=
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Coefficient of runoff suggested as follows:
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|
|
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Areas primarily paved or in building (such as
shopping centers): 0.85
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|
|
|
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Primarily residential area with lots smaller
than 7,500 square feet or apartment areas: 0.55
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|
|
|
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Primarily residential areas with lots 7,500
square feet to 1/2 acre: 0.40
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|
|
|
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Primarily residential areas with lots 20,000
square feet or over: 0.35
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|
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|
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Cemeteries, parkland and other permanent open
areas: 0.30
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A
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=
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Area in acres
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(c)
Minimum culvert shall be 15 inches.
(d)
Bridges or culverts, serving a drainage area
of more than one square mile, shall be approved by the New York State
Department of Public Works.
(e)
In small drainage areas intended for residential
development, the following rule of thumb may, if desired, be substituted
where applicable.
[1]
For drainage areas less than one acre in area:
twelve-inch pipe.
[2]
For drainage areas one to two acres in area:
fifteen-inch pipe.
[3]
For drainage areas two to four acres in area:
eighteen-inch pipe.
(2) General design.
(a)
Preferred runoff pattern. Preferred design of
streets and grading in relation to storm drainage shall be such that
runoff from roofs, driveways and other impervious surfaces will be
collected in the ditches and/or gutters along the street in short
runs (300 or 400 feet), and will be diverted from the street surface
into storm sewers or natural watercourses. Streets should be located
away from watercourses unless storm sewers are to be installed.
(b)
Downstream disposal. Subdivision and development
of an area increases and concentrates on the runoff of stormwater
from the area. Subdividers are warned that such increase may cause
flood or erosion damage to undeveloped properties lying downstream.
Storm drainage channels opening on an unimproved land shall empty
into natural watercourses unless suitable agreement is reached with
the owner of the downstream property for another method of handling.
In any instance, the disposal of storm drainage downstream shall be
satisfactory to the Planning Board as advised by the engineer.
(3) Open watercourses. The use of open watercourses for
drainage may involve problems relating to safety, erosion control,
stagnant water, protection of capacity and appearance, all of which
shall be given adequate attention by the developer as follows:
(a)
Safety. Broad, shallow courses shall be created
wherever necessary to increase capacity or eliminate steep banks.
Ditches shall, wherever feasible, be in the shape of a wide-top V
with rounded or squared invert.
(b)
Erosion control. There shall be required seeding
to prevent erosion. The Planning Board shall require seeding, sodding,
planting, riprap, or other such measures as may be necessary to prevent
scouring.
(c)
Drainage. The developer shall guard against
the creation or continuation of swampy areas or stagnant pools. The
Planning Board shall require fill and/or channel improvements in order
to forestall such problems.
(d)
Protection of capacity. The developer shall
provide adequate measures for the protection of open drainage channels
by establishing drainage easements sufficiently wide (generally 20
feet) to enable the working of the channel by motorized equipment
or, alternately, where authorized by the Planning Board, a center
block part of a minimum width of 50 feet. All easements shall prohibit
the erection of structures, the dumping of fill or the alteration
or obstruction of the watercourses without the written permission
of the Village Board. Property lines shall be so designed as to allow
drainage easements, except that drainage easements may be allowed
to cross lots larger than one acre.
(e)
Appearance. The developer should keep in mind
that natural watercourses can be an attractive asset to the subdivision
as well as to the community and, where possible, should improve and
beautify the watercourses to this end.
(4) Design of storm sewers.
(a)
Size and grade. Storm sewers shall have a minimum
diameter of 15 inches and a minimum grade of 0.5%.
(b)
Manholes. Manholes shall not be more than 300
feet apart where pipe sizes of 24 inches or less are used and not
more than 540 feet apart where larger sizes are installed.
(c)
Change in direction. Special sections of radii
of 10 to 15 feet shall be installed where abrupt changes are made
in alignment.
(5) Design of ditches and gutters.
(a)
Length of flow. Subdivisions should be so designed
that length of flow or water in gutter or roadside ditch does not
exceed 400 feet, except that in exceptional cases, runs up to 800
feet in length may be permitted by the Planning Board. Runs exceeding
the maximum shall be put in storm sewers or diverted to natural drainageways.
(b)
Minimum grade. All enclosed drainage courses
shall be designed with sufficient grade to create a cleansing velocity
of three feet per second. A lesser grade may be permitted by the Planning
Board where a greater grade cannot be achieved.
(c)
Street crossing. Water in gutters and ditches
shall not be allowed to flow over intersecting streets but shall be
placed in adequate culverts.
(d)
Depth and shape of ditches.
[1]
Where roadside ditches are permitted for runs
of more than 300 feet or where subgrade drainage is necessary, the
bottom of such ditch should be below the subgrade and, at a minimum,
should be approximately 18 inches below the crown of the road.
[2]
Ditches shall be V-shaped or parabolic with
sides sloping at approximately one-inch vertical to three inches horizontal
except where other cross section plan is authorized.
(e)
Erosion control. Suitable headwalls, endwalls,
ditch seeding or sodding and other procedures or devices to prevent
erosion shall be used.