[Adopted 10-20-1971]
This article shall be known as the "Town of
Henrietta Drainage Control Law."
The provisions herein contained are for the
purpose of achieving and maintaining an adequate, efficient and balanced
drainage and flood prevention system coordinated with existing and
projected land uses and in compliance with minimum protection levels
to be integrated with all public works planning, open land uses, conservation
objectives, watershed management and any community-inspired proposals
designed to promote the public welfare but not prejudicial to or inconsistent
with the primary purpose of adequate drainage and flood hazard prevention
requirements.
Certain terms used herein shall be defined as
follows:
The average interval in years between peak stream flows or
rainfall intensity of a given magnitude, determined statistically
or measured hydrologically over a base period of time.
Monroe County.
The actual owner or owners of the land and/or a person, firm
or corporation who or which shall develop or use land within the Town
in such a manner that in any way affects the storm- or surface water
drainage characteristics of the property developed or used. The term
"developer" shall include municipal, charitable and educational corporations,
institutions or associations.
Any improved land use, including residential, commercial,
industrial, institutional or recreational.
A network consisting of any combination or type of open channels,
holding basins and enclosed facilities employed to convey the runoff
of natural waters.
[Amended 9-7-1977]
A network of artificial conduits and pipe constructed to
convey the runoff of natural waters.
The boundary of a maintenanceway easement adjacent to a drainage
channel within which no building or structure shall be erected or
trees, bushes or other plantings planted which shall interfere with
the maintenance of the drainage channel.
Overflow water having sufficient velocity to transport debris,
to scour the surface soil or to dislodge or damage structures or contents.
It also indicates erosion of the banks of watercourses.
Standing water or water in motion of sufficient depth to
damage property due to the mere presence of or momentary contact with
water, or to the deposition of silt.
A network of natural streams, constructed channels, ditches
and detention/retention areas employed to convey and control the runoff
of natural waters.
[Amended 9-7-1977]
The Town of Henrietta.
The Town of Henrietta Director of Engineering and Planning,
or his consultant.
A report titled "Primary Requirements for Drainage Planning
- Drainage Study, Stage Two" by the Monroe County Planning Council.
A.
Developments shall be protected from flood hazard
and inundation by stormwater, springs and other surface waters. The
design and construction of drainage systems shall be such that watercourses
traversing the development and natural water emanating from within
the development will be carried through and off the development without
injury to improvements, building sites or buildings existing or to
be installed within or adjacent to the tract. Drainage water entering
the development shall be received and discharged at preapproved locations
and at a slower rate than which existed prior to construction of the
drainage facilities within the development. The design of drainage
facilities within the development shall be such that they will conform
to the ultimate drainage requirements of the land uses within the
development watershed. The discharged flow at the downstream area
of the development shall be conducted in drainage facilities such
that the flow effects shall be restored as near to predevelopment
conditions as possible prior to leaving the development area or reasonably
distant therefrom.
[Amended 6-20-2001 by L.L. No. 3-2001]
C.
Drainage easements and additional areas as dedicated
under these provisions need not be fenced but shall be identified
by monuments, acceptable to the Town Director of Engineering and Planning,
set at an angle point and at such other locations which allow intervisibility.
A.
Hydrologic.
(1)
The drainage channels for watercourses numerically
identified in the Town drainage report shall be provided to accommodate
not less than the minimum flows indicated in the drainage report.
These values shall be independently verified by their users using
hydrologic technology recommended herein, and the hydrologic analysis
thereof shall become a part of the supporting data of the proposed
drainage plans. The minimum flow requirements for the ultimate channel
of the watercourses shall be determined in accordance with not less
than the following frequencies:
(a)
Major watercourses. Major watercourses are defined
as those with a tributary drainage area between 20 square miles and
four square miles. Such watercourses shall be designed for an average
recurrence interval of 50 years in the determination of the ultimate
channel.
(b)
Secondary watercourses. Secondary watercourses
are defined as those with a tributary drainage area of between one
and four square miles. Such secondary watercourses shall be designed
for an average recurrence interval of 25 years in the determination
of the ultimate channel.
(c)
Minor watercourses. Minor watercourses and drainage
systems are defined as those with one square mile or less of tributary
drainage area. Such watercourses and drainage systems shall be designed
for an average recurrence interval of 10 years in the determination
of the ultimate channel.
(2)
The capacity of the channel that will occupy the ultimate drainage easement within the development shall be based upon both the existing degree and anticipated rate of urbanization within the development watershed and the type of development possible under Chapter 295, Zoning, as the same may be modified from time to time. Wherever a development may be located within a watershed undergoing initial stages of urban development, the proposed drainage system shall adequately pass the flows that would develop from continued urbanization within the useful life of the proposed channel improvement or system. Proposed drainage systems within developments located in watersheds that may be in the advanced stages of urbanization shall be designed and constructed to pass the project design flows determined for the ultimate urbanization of the tributary watershed.
(3)
For undeveloped areas of the tributary watershed,
the percentage of surface classifications shall be based upon the
Town of Henrietta's land use zoning, correlated with projected land
uses developed by the Town Planning Board. Wherever a development
watershed contains extensive permanent open land uses such as railroads,
public parks, cemeteries and parkways, such factors may additionally
be considered in determining an appropriate coefficient of runoff.
(4)
The technology for developing design flows for major
watercourses is offered in United States Geological Survey Circular
No. 451 and in United States Bureau of Public Roads Hydraulic Engineering
Circular No. 4 (New York). The results of such available hydrologic
techniques should be correlated and a suitable urbanization factor
be applied to the end result. Design flows for minor and secondary
drainage systems may be determined by the developer's engineer by
use of the Rational Method or an accepted modification thereof:
[Amended 9-7-1977]
|
Q = C i A
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|---|---|---|
|
Wherein:
| ||
|
Q = project design flow in cubic feet per second.
| ||
|
C = design coefficient of runoff.
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|
i = intensity of rainfall in inches per hour.
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A = tributary drainage area in acres.
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(a)
Rainfall-intensity-duration frequency charts
are included in the Henrietta drainage report. Copies may be obtained
from the Town Director of Engineering and Planning.
(b)
The determination of values for C may generally
conform to the following equation:
|
C = (%) CI + (%) CN
| ||||
|---|---|---|---|---|
|
wherein:
| ||||
|
CI
|
=
|
coefficient of runoff for impervious surfaces
representing roofs, driveways, patios, sidewalks, pavements and parking
areas.
| ||
|
CN
|
=
|
coefficient of runoff for natural surfaces representing
grading lawn areas, garden, etc.
| ||
|
(%)
|
=
|
the percent of the area for the surface classification.
The total of the percentages of surface classifications shall equal
100% of the watershed tributary to the development.
| ||
(5)
Drainage systems classed as minor and secondary shall
be tested by engineering computations to pass the flow requirements
of the next higher design level. If engineering computations indicate
that only minor inundation of grounds around buildings results, then
the system could be considered adequate.
B.
Hydraulic.
(1)
The hydraulic design of development drainage systems
shall be in accordance with modern standard procedures endorsed by
the American Society of Civil Engineers (ASCE).
(2)
Hydraulic design shall conform to the latest professional
manuals dealing with the many facets which constitute a comprehensive
drainage system. Reference to manual sources herein are for only the
principal features of drainage systems. These do not imply any limitations
in the use of such references, but rather should be supplemental with
all essential detailed references to assure sound design.
(3)
The hydraulic design of closed drainage systems shall
conform in basic details to ASCE Manual of Engineering Practice No.
37 and such applicable manuals that would supplement or integrate
advanced and proved hydraulic principles and basic assumptions. Enclosed
drainage systems shall be designed to provide complete drainage for
all elements within the development and shall include all appurtenances
essential for the adequate performance thereof. The size of conduits
shall be selected at grades which produce a minimum velocity of three
feet per second when flowing full.
(4)
The hydraulic design of open drainage systems shall
conform in principle and basic details to the United States Bureau
of Public Roads Hydraulic Design, Series Nos. 1, 3, 5 and 6, and such
commercially published modern open-channel hydraulic references that
would in the public interests assure sound design. A development grading
plan, similar to the Federal Housing Administration Grading Plan,
indicating a contour interval suitable for the map scale shall be
provided to show detailed comprehensive and efficient surface drainage
for all lots within and immediately adjacent to the development.
C.
Structural. Catch basins, manholes, inlet structures
and other appurtenances placed within the development shall conform
to standards approved by the Town Board. The structural design of
all drainage appurtenances shall be subject to the approval of the
Town Director of Engineering and Planning and shall conform to standard
specifications adopted by the Town Board as the same may from time
to time be amended.
(1)
Channels. The minimum center-line radius of constructed
curved channels shall be at least three times the bottom width of
the channel for subcritical flow. The creation of excessive numbers
of curves in open channels shall be avoided by reason of the increase
in friction loss and the potential erosion due to spiral flow. Outer
bank protection, especially at the downstream end of the curve and
to a lesser degree on the inner bank at the beginning of the curve,
may be required by the Town Director of Engineering and Planning.
Earth channels constructed within the development shall have side
slopes of one on four or flatter, unless otherwise approved by the
Town Director of Engineering and Planning. If and when paved channels
are required by the Town, the design of such channels shall be approved
by the Town Director of Engineering and Planning.
[Amended 9-7-1977]
(2)
Enclosed conduits. Except for adequate natural watercourses,
all storm drainage within the development which is capable of being
transmitted in a thirty-six-inch-diameter pipe shall be carried in
an enclosed conduit. This size may be varied, either increased or
decreased, according to topographic conditions or an economic analysis
of the cost of the conduit against an equivalent open channel, including
the occupied land value, provided that the ultimate selection is in
the public interest. The minimum conduit size shall be 12 inches in
diameter. Manholes shall be provided at all changes in grade and direction.
Spacing of manholes and minimum cover of conduit shall conform to
standard practice endorsed by the American Society of Civil Engineers.
Inverted siphons shall not be permitted except for temporary structures.
[Added 2-18-2015 by L.L.
No. 1-2015]
A.
Easement for enclosed conduits and appurtenances.
An easement not less than 20 feet in width, sufficient to contain
the enclosed conduit and appurtenances thereof and to provide working
space for personnel and equipment for the servicing thereof, shall
be indicated on the map of the development and designated as follows:
"Drainage Easement to Town of Henrietta." Drainage easements for enclosed
conduits shall, insofar as possible, be placed along or adjacent to
lot boundary lines in a parallel and straight alignment.
B.
Easement for natural watercourses.
(1)
Natural major watercourses which traverse a development
shall be preserved by an easement of sufficient width, including overbanks,
which will adequately pass the project design flow. The gross allowable
depth of flow shall not create a flood hazard to existing or proposed
developments and improvements. The channel and overbank widths, together
with a minimum twenty-foot continuous maintenanceway on each side,
shall constitute the floodway encroachment limits with a minimum width
of 100 feet. Wherever such natural watercourses are endowed with significant
natural beauty and have adequate capacity or have been determined
to have value for fish and wildlife, the developer may dedicate widths
in addition to those required above on the map of the development
with the following designation: "Easement to Town of Henrietta."
(2)
In natural minor and secondary watercourses which
contain insufficient waterway area to convey the flow from the ultimate
development, but which may prove deficient only at infrequent intervals
and locations, and where minor improvements could provide an adequate
channel and still preserve in the main the natural channel beauty
or fish and wildlife values, the developer may make such minor channel
improvements as are required to provide a channel which would otherwise
meet the conditions of these regulations. However, the developer shall
dedicate the full width required to contain the ultimate channel,
together with a minimum twenty-foot-wide continuous maintenanceway
on one side of the ultimate channel. When the water surface exceeds
20 feet in width, the continuous maintenanceway shall be 20 feet wide
at each side. The outside of the continuous maintenanceway shall constitute
encroachment limits. Additional widths of scenic areas and areas of
natural wetlands, which for economic reasons or limited suitability
would not warrant improving for urban development, may be dedicated
by the developer in addition to those above. Areas offered for dedication
to the Town as drainage easements, if considered of special interest
to the Town by the Planning Board, may be considered by the Planning
Board as dedication for municipal purposes for the purpose of § 278
of the Town Law and its authority thereunder.
[Amended 6-20-2001 by L.L. No. 3-2001]
C.
Easement for constructed channels and appurtenances.
Earth channels constructed within the development shall have sufficient
easement dedicated to contain the top width of the channel plus a
minimum twenty-foot continuous maintenanceway on one side thereof
for channels less than 20 feet in width at the water surface. A twenty-foot
continuous maintenanceway shall be provided on both sides of channels
with a water surface width greater than 20 feet. The ultimate channel
shall meet the flow requirements for the development of the tributary
drainage area. The allowable depth of flow to pass the project design
flow shall not create a flood hazard to existing and proposed developments
and improvements. A minimum of one foot freeboard above the design
hydraulic gradient shall be provided to contain the effects of flow
transmission factors. The outside of the continuous maintenanceway
shall constitute encroachment limits. The easement for constructed
channels shall be indicated on the map of the development and designated
as follows: "Easement to Town of Henrietta."
D.
Mutual benefit drainage easements. Whenever the installation
or construction of drainage swales shall be necessary so as to provide
adequate drainage in a development or subdivision, the course of which
shall affect or traverse one or more lots, the Town Director of Engineering
and Planning may require the developer to reserve easements appropriate
in size and location for the mutual benefit of the owners of the other
lots of the development or subdivision. Such easements shall be specified
in the deeds of conveyance by the developer to the purchasers of all
lots affected thereby and shall be designated on all the plans for
the development or subdivision as follows: "Drainage Easement for
the Mutual Benefit of the Owners of the Other Lots of the Subdivision."
[Added 9-7-1977]
Before final Planning Board approval of a development
plan, the developer shall submit drainage plans with a report containing
sufficient data for the Town Director of Engineering and Planning
to check the feasibility of the drainage system as proposed by the
developer. The following data shall be included:
B.
Hydraulic.
(1)
The plan and profile of all drainage systems.
(2)
Sizes and types of drainage improvements, including
special structures, typical sections, easements, width and fencing.
(3)
When required, supporting calculations for upstream
and downstream channel capacities as they affect water surface levels
and backwater within the development. Such calculations shall be supported
by such additional survey information as may be required to determine
profile and cross section of the upstream and downstream channel reaches
of the development under consideration.
(4)
A development grading plan prepared to suitable contour
intervals with grading details to indicate proposed street grades
and elevations, building site elevations and surface elevations at
critical points throughout the development (similar to the Federal
Housing Administration - type grading plan).
A.
The final construction plans for drainage disposal
within the development shall conform to the provisions of these regulations,
subsequent amendments thereto and any particular conditions as required
by the Town Director of Engineering and Planning in approving the
proposed plans and supporting data thereof. The construction plans
for the drainage requirements shall be approved by the Town Director
of Engineering and Planning prior to the construction of any drainage
facilities within the development.
B.
The plans shall bear the certification of a professional
engineer as evidence of the professional responsibility for the drainage
planning within the development.
C.
All drainage construction shall be subject to adequate
inspection. Any field changes which affect the intent of these provisions
shall have the prior approval of the Town Director of Engineering
and Planning.
[Added 2-18-2015 by L.L.
No. 1-2015]
A.
The property
owner shall be responsible for any maintenance or repair of that portion
of the storm lateral that he/she owns.
B.
The portion
that the property owner is responsible for shall be any drainage infrastructure
not otherwise located in a Town easement and/or any Town, county or
New York State right-of-way, including drainage infrastructure located
between any structure on private property and the right-of-way or
easement.
C.
In the
event of a blocked storm lateral and the absence of an existing cleanout,
the property owner shall be required to have a cleanout installed
prior to any repair work by the Town. The cleanout shall be located
at the junction of the existing easement or Town right-of-way and
the homeowner's property.
D.
All repairs
to any storm laterals in the Town of Henrietta must be made with PVC
SDR-21.
In order to ensure the proper performance of the work to be completed under plans as approved under § 84-16 above, the Town may require a cash deposit, a letter of credit or a performance bond issued by an acceptable bonding or surety company.
The approval of plans for proposed drainage
systems and flood hazard prevention requirements shall not constitute
a representation, guaranty or warranty of any kind or nature by the
Town of Henrietta or by an officer or employee thereof of the safety,
operation, adequacy or intent of the proposed facilities and shall
create no liability upon or cause for action against such public body,
officer or employee for any damage that may result from construction
pursuant thereto.
[Added 6-20-2001 by L.L. No. 3-2001;
amended 9-27-2023 by L.L. No. 9-2023]
Failure to comply with this article shall constitute
a violation, and, upon conviction thereof, shall be subject to a fine
in the minimum amount of $100, up to a maximum amount of $250. Each
week's continued violation shall constitute a separate additional
violation.
