[1]
Editor's Note: The name of this district was changed from
“Station Avenue Overlay District” to “Town Center
Overlay District” by Planning Board amendment of 2-18-2016.
[Adopted 1-3-2008]
[Amended 2-18-2016]
Low-impact development (LID) techniques must
be incorporated into redevelopment projects in the Town Center Overlay
District. Applicants must use decentralized systems that involve the
placement of a number of small treatment and infiltration devices
located close to the various impervious surfaces that generate stormwater
runoff in place of a centralized system comprised of closed pipes
that direct all drainage from the entire site into one large detention
basin. The following standards must be followed in the design of LID
techniques.
A.
Stormwater recharge.
(1)
The volume of water to be recharged shall be calculated
using existing site conditions and the infiltration rates set forth
below:
|
Hydrologic Soil Group
|
Quantity to Recharge
(inches of runoff)
| |
|---|---|---|
|
A
|
0.6
| |
|
B
|
0.35
| |
|
C
|
0.25
| |
|
D
|
0.10
|
(2)
The volume of runoff to be recharged shall be calculated
as follows:
|
Recharge Volume (ft3) = Impervious Area (ft2) X Quantity to
Recharge (inches)/12
|
(3)
The following criteria also apply:
(a)
Initial exfiltration during the design storm
shall not be accounted for during the unit/device sizing, with the
exception of roof runoff devices, which may account for exfiltration
in sizing calculations.
(b)
All units/devices shall be designed to drain
completely with no standing water within 72 hours from the end of
the storm.
(c)
Recharge shall not be concentrated to one area.
It shall be distributed to multiple areas throughout the site.
(d)
The recharge volume criteria does not apply
to any portion of a site designated as a stormwater hotspot. Hotspots
are defined in the Massachusetts Department of Environmental Protection
Volume One: Stormwater Policy Handbook as sites with higher potential
pollutant loads, including:
[1]
Auto salvage yards (auto recycler facilities).
[2]
Auto fueling facilities (gas stations).
[3]
Fleet storage areas (cars, buses, trucks, public
works).
[4]
Vehicle service and maintenance areas.
[5]
Vehicle and equipment cleaning facilities.
[6]
Commercial parking lots with average trip generation
rates of 1,000 or greater per day, such as fast-food restaurants,
convenience stores, high-turnover (chain) restaurants, shopping centers,
and supermarkets.
[7]
Road salt storage and loading areas (if exposed
to rainfall).
[8]
Commercial nurseries.
[9]
Flat metal (galvanized metal or copper) rooftops
of industrial facilities.
[10]
Outdoor storage and loading/unloading areas
of hazardous substances.
[11]
SARA 312 generators (if materials or containers
are exposed to rainfall).
[12]
Marinas (service, repainting, and hull maintenance
areas).
B.
Pretreatment.
(1)
To prevent premature failure, the design of stormwater
treatment devices shall include a pretreatment device or method that
will trap sand and sediments to avoid clogging the treatment mechanism.
Infiltration of stormwater from the treatment device into underlying
soils and eventually groundwater aquifers is an important beneficial
component of the device. Pretreatment basins must be designed and
located to be easily inspected and accessible to facilitate maintenance.
Pretreatment devices must also be sized to accommodate a minimum of
one year's worth of sediment and debris.
(2)
The following standards shall be followed to ensure
that the device will permit sufficient treatment to treat stormwater
and allow for a reasonable required maintenance frequency for the
best management practice (BMP):
(a)
Pretreatment devices shall be provided for each
structural BMP; and
(b)
Pretreatment devices for bioretention areas
should include a grass buffer or transition zone between pavement
and bioretention (e.g., crushed stone entrance, cobbles) that allows
sediment to drop out before entering the treatment device; and
(c)
Pretreatment devices shall be designed to capture
anticipated pollutants, such as oil and grease; and
(d)
Pretreatment devices shall be designed and located
to be easily accessible to facilitate inspection and maintenance;
and
(e)
The Revised Universal Soil Loss Equation (RUSLE)
(Note: developed by the Natural Resources Conservation Service, USDA
to predict soil erosion to due water) shall be used to calculate sediment
deposits that would occur from pervious areas adjacent to the BMP;
and
(f)
Pretreatment structures shall be sized to hold
an annual sediment loading. An annual sediment load shall be calculated
using a sand application rate of 500 pounds/acre for sanding of roadways,
parking areas and access drives within the subcatchment area, a sand
density of 90 pounds per cubic foot and assuming a minimum frequency
of 10 sandings per year. To obtain an annual sediment volume, perform
the following calculation:
|
Area to be sanded (acres) x 500 pounds/Acre-storm
÷ 90 pounds/ft3 x 10 storms/year
= cubic feet of sediment/year
|
(g)
The developer shall maintain any BMPs used to
trap sediment during construction to prevent sediment from leaving
the site, and shall remove all sediment from all BMPs when construction
is finished and the site is stabilized.
C.
Flooding protection. The following standards should
be followed to control peak discharge rates and improve the overall
effectiveness of the BMPs. These are minimum design standards.
(1)
The post-development peak discharge rate shall be
equal to or less than the pre-development (e.g., forested) peak discharge
rate (based on a two-year and ten-year, twenty-four-hour storm); and
(2)
The post-development peak discharge rate shall be
equal to or less than the existing development peak discharge rate
based on a one-hundred-year, twenty-four-hour storm;
(3)
The site shall be designed to ensure that all runoff
from the site up to the one-hundred-year storm enters the control
structure. For example, the drainage system may only be sized to handle
a ten-year storm, with larger storms flooding the distribution system
and traveling overland. This overland flow, or overflow, must be directed
into the peak control structure; and
(4)
The applicant shall account for all run-on and run-off
(including off-site impacts) in both pre- and post-development conditions;
and
(5)
The applicant shall prepare hydrographs for pre- and
post-development conditions; and
(6)
The pre-developed condition shall be a forested land
cover in good condition; and
(7)
Use TR-55 to develop hydrographs and peak flow rates
for the proposed development site. Make sure all areas are accounted
for in the pre-/post-runoff calculations. The total tributary area
that contributes flow from the proposed site, including runoff entering
the site through piped drainage or surface runoff from off-site sources,
must be included even if a portion does not contribute flow to the
BMP. The objective is for the development's storm drain design to
account for total runoff leaving the site; and
(8)
The length of overland sheet flow used in tc calculations shall be limited to no more than 100 feet
for pre- and post-development conditions; and
(9)
Use naturalized basins over typical detention basins
for peak control. Naturalized basins are attractively landscaped basins
that fit better into a natural landscape, with naturally landscaped
areas at the ground surface. Naturalized planting themes incorporate
native plants and use an informal pattern to mimic the natural environment;
and
(10)
Basins shall be easily accessible for maintenance.
D.
Water quality volume. The water quality volume required
to be treated shall be calculated as:
|
Water Quality Volume (ft3) = Impervious Surfaces (ft2) X 1.0 (inch)
/ 12 (inches per foot)
|
E.
Pollutant removal. Stormwater management systems must
be designed to remove 80% of the average annual post-construction
load of total suspended solids (TSS).
F.
Erosion control. Land clearing and grading for construction
purposes leaves soils susceptible to erosion. If not controlled, eroded
soils may reach streams and lakes, filling them in and adding pollutants
attached to the soil particles. It is important to have controls in
place to prevent and control the erosion of disturbed lands. The following
standards shall be met for erosion control:
(1)
Prior to any land disturbance activities commencing
on the site, the developer shall physically mark limits of no land
disturbance on the site with tape, signs, or orange construction fence,
so that workers can see the areas to be protected. The physical markers
shall be inspected daily; and
(2)
Appropriate erosion and sediment control measures
shall be installed prior to soil disturbance. Measures shall be taken
to control erosion within the project area. Sediment in runoff water
shall be trapped and retained within the project area. Wetland areas
and surface waters shall be protected from sediment; and
(3)
Sediment shall be removed once the volume reaches
1/4 to 1/2 the height of the silt fence or hay bale; and
(4)
Divert off-site runoff from highly erodible soils
and steep slopes to stable areas; and
(5)
Land disturbance activities requiring a stormwater management permit under Chapter 198, Stormwater Management — Low-Impact Development, must submit a sequencing plan that requires stormwater controls to be installed and the soil stabilized. A construction phasing plan shall be submitted to the Planning Department prior to any construction on the site. Mass clearings and grading of the entire site shall be avoided; and
(6)
Soil stockpiles must be stabilized or covered at the
end of each workday. Stockpile side slopes shall not be greater than
2:1. All stockpiles shall be surrounded by sediment controls; and
(7)
The area of disturbance shall be kept to a minimum.
Disturbed areas remaining idle for more than 14 days shall be stabilized;
and
(8)
For active construction areas such as borrow or stockpile
areas, roadway improvements and areas within 50 feet of a building
under construction, a perimeter sediment control system shall be installed
and maintained to contain soil; and
(9)
A tracking pad shall be constructed at all entrance/exit
points of the site to reduce the amount of soil carried onto roadways
and off the site; and
(10)
Dust shall be controlled at the site; and
(11)
On the cut side of roads, ditches shall be stabilized
immediately with rock rip-rap or other nonerodible liners or, where
appropriate, vegetative measures such as sod; and
(12)
Permanent seeding shall be undertaken in the
spring from March through May, and in late summer and early fall from
August to October 15. During the peak summer months and in the fall
after October 15, when seeding is found to be impractical, an appropriate
temporary mulch shall be applied. Permanent seeding may be undertaken
during the summer if plans provide for adequate mulching and watering;
and
(13)
All slopes steeper than 3:1 (h:v, 33.3%), as
well as perimeter dikes, sediment basins or traps, and embankments
must, upon completion, be immediately stabilized with sod, seed and
anchored straw mulch, or other approved stabilization measures. Areas
outside of the perimeter sediment control system must not be disturbed;
and
(14)
Monitoring and maintenance of erosion and sediment
control measures throughout the course of construction shall be required.
The applicant shall submit an Operation and Maintenance Plan for temporary
and permanent erosion control measures as part of the application
package; and
(15)
Temporary sediment trapping devices must not
be removed until permanent stabilization is established in all contributory
drainage areas. Similarly, stabilization must be established prior
to converting sediment traps/basins into permanent (post-construction)
stormwater management facilities. All facilities used as temporary
measures shall be cleaned prior to being put into final operation;
and
(16)
All temporary erosion and sediment control measures
shall be removed after final site stabilization. Disturbed soil areas
resulting from the removal of temporary measures shall be permanently
stabilized within 30 days of removal.
G.
Hydrologic and hydraulic criteria for all designs.
(1)
Impervious cover is measured from the site plan and
includes any material or structure on or above the ground that prevents
water from infiltrating through the underlying soil. Impervious surface
is defined to include, without limitation: paved parking lots, sidewalks,
rooftops, driveways, patios, and paved, gravel and compacted dirt
surfaced roads.
(2)
The specified design storms shall be defined as a
twenty-four-hour storm using the rainfall distribution recommended
by the United States Department of Agriculture (USDA) Natural Resources
Conservation Service (NRCS).
(3)
Proposed residential, commercial, or industrial subdivisions
shall apply these stormwater management criteria to the land development
as a whole. Individual lots in new subdivisions shall not be considered
separate land development projects, but rather the entire subdivision
shall be considered a single land development project. Hydrologic
parameters shall reflect the ultimate land development and shall be
used in all engineering calculations.
H.
Operation and maintenance. A long-term operation and
maintenance (O&M) plan must be developed and implemented to ensure
that stormwater management systems function as designed. The long-term
O&M plan shall include the following:
(1)
Stormwater management system owners;
(2)
Responsible parties for operation and maintenance,
including how future property owners will be notified of the presence
of the stormwater management system and the requirement for proper
operation and maintenance;
(3)
The routine and nonroutine maintenance tasks to be
undertaken after construction is complete and a schedule for implementing
those tasks;
(4)
Plan that is drawn to scale and shows the location
of all stormwater BMPs in each treatment train along with the discharge
point;
(5)
Description and delineation of public safety features;
and
(6)
Estimated operations and maintenance budget.
A.
Bioretention design guidelines. Bioretention systems
offer excellent pollutant removal, while providing some retention
of stormwater runoff. Bioretention systems rely on the soil and planting
media to remove pollutants and provide absorption of stormwater runoff.
The following design standards should be followed to achieve the maximum
benefit:
(1)
Construction components. Bioretention systems are
constructed in an excavated hole and consist of, from bottom up:
(a)
Optional stone reservoir to provide additional
holding capacity.
(b)
A minimum three-inch-thick transition layer
of 3/8-inch pea gravel.
(c)
A layer of lightly compacted soil media at least
18 inches thick.
(d)
Vegetation consisting of dense plantings of
woody shrubs, herbaceous perennials and, if the soil media is deep
enough for the roots, small trees. The plants should be native if
possible and must be both drought and flood tolerant.
(e)
A cover of three inches of aged, fibrous bark
mulch.
(f)
A maximum six-inch depression for surface stormwater
storage.
(3)
Filter fabric. Filter fabric should not be used between
the soil media and native soils or soil media and transition stone/stone
reservoir. The use of fabric between these layers will cause system
failure due to clogging from fines located within the soil media.
If an underdrain is to be used to drain the bioretention area, then
filter fabric can be used between the underdrain bedding and the native
soils to prevent the migration of native soils into the underdrain
bedding.
B.
Naturalized basin design guidelines.
(1)
Naturalized basins have several advantages over traditional
basins, including:
(a)
The deeper root systems of the native plant
materials encourage infiltration, recharging groundwater tables and
increasing base flows.
(b)
The plants trap pollutants, increasing the water
quality of the discharge.
(c)
The vegetation serves to cool water temperatures
and slow stormwater velocities.
(d)
They are visually more attractive and can help
beautify a neighborhood, increasing property values.
(e)
They require less maintenance. Generally, annual
mowing and periodic trimming of trees and plants is sufficient.
(2)
The following design standards shall be followed to
achieve the maximum benefit:
(a)
The basin shall be easily accessible for maintenance.
(b)
Construct basin with a sediment forebay at the
inlet, sized to hold a minimum of one year's worth of sediment accumulation
if no other pretreatment is proposed.
(c)
Construct basin to have a natural low-flow channel
with turf reinforcement material to remove pollutants and prevent
erosion.
(d)
Incorporate a naturally landscaped area at the
ground surface. The ground surface around the basin shall be large
enough to be in scale with the overall landscaped area. The purpose
is to filter and soften views from residential areas.
(e)
Plant all areas of the naturalized basin, including
basin floors, side slopes, berms, impoundment structures, or other
earth structures, with suitable vegetation such as naturalized meadow
plantings or lawn grass specifically suited for stormwater basins.
Suggested plants include:
[1]
Grasses: Big Bluestem, Switchgrass and wildflower
mixes. In wet areas, plant Sweetflag and Soft Rush for color and texture.
[2]
Shrubs: Red Chokeberry (Aronia arbutifolia),
Silky Dogwood (Cornus ammomum), Arrowwood (Viburnun Dentatum), Cranberrybush
(Viburnum trilobum), service berry/shadbush (Amelanchier cavadensis
or laevis) and elderberry (sambucus).
[3]
Trees: Red Maple (Acer rubrum), River Birch
(Betula nigra), various willows.
(f)
Trees may not be planted below the pool area
of the basin. If shrubs are used, they must be adapted to wet or moist
soils conditions.
(g)
Mulch may be used in shrub beds located within
the pool area with a non-floating-type mulch.
(h)
Group trees or shrubs to avoid a spotty effect.
(i)
Provide access to the basin for maintenance.
Blend access area in with the surrounding landscape to the extent
feasible.
(j)
The forebay/sediment trap shall be at least
10 feet long and sized to hold at least the annual sediment loading.
(k)
Maintenance access shall be planted with grass
and at least 10 feet wide with a maximum slope of 15% and a maximum
cross slope of 3%.
(l)
Provide a means to prevent soil compaction on
the floor of the basin during construction.
(m)
Size treatment storage area to hold the water
quality volume.
(n)
The perimeter of all basins shall be curvilinear
so that from most edges of the basin, the whole basin will not be
in view. A more traditionally shaped (oval or rectangular) basin may
be permitted when conditions such as topography, parcel size, or other
site conditions warrant. Basins shall follow natural landforms to
the greatest extent possible or be shaped to mimic a naturally formed
depression.
(o)
Place inlets and outlets to maximize the flow
path through the facility. At a minimum, the flow path shall be twice
as long as wide. Baffles, pond shaping or islands can be added within
the permanent pool to increase the flow path. If there are multiple
inlets, the length-to-width ratio shall be based on the average flow
path length for all inlets.
(p)
Minimum one foot of freeboard above the twenty-five-year
storm elevation.
(q)
The interior slopes of the basin within the
pool area shall not exceed a slope of four horizontal to one vertical.
(r)
A minimum of six inches of topsoil with at least
6% organic content shall be provided for all planting ground cover
beds or lawn areas.
(s)
Low-flow outlets shall be designed to prevent
clogging.
(t)
For basins that cannot infiltrate the water
quality volume, use a soil filter conforming to the following:
[1]
Impoundment depth: Peak storage depth within
the filter area for water quality volume may not exceed 18 inches.
[2]
Pipe layout and spacing: Layout of the pipe
underdrain system must be sufficient to effectively drain the entire
filter area. There must be at least one line of underdrain pipe for
every eight feet of the filter area's width. The slope of the pipe
must be 1% or greater.
[3]
Pipe bedding: Minimum 12 inches over top of
drainage pipe, six inches thick at sides, and six inches below drainage
pipe of clean well-graded gravel.
[4]
Filter bed: The soil must consist of loamy,
coarse sand. The soil filter must extend across the bottom of the
entire filter area. The soil must be at least 18 inches deep and underlain
by a gravel bedding.
[5]
Surface cover: The top of the underdrain system
must be covered with a four-inch layer of sandy loam and then covered
with plantings consisting of species tolerant of frequent inundation.
[6]
Underdrain outlet: Each system must discharge
to an area capable of withstanding concentrated flows and saturated
conditions without eroding.
[Adopted 5-1-2008; amended 2-18-2016]
A.
Statutory provision: Code of the Town of Groton, § 218-30.2,
as amended, and § 218-23, as amended.
B.
Purpose. The purposes of these guidelines are broadly
as follows:
(1)
To reduce the amount of area allocated to parking
spaces while accommodating typical peak parking needs of the Town
Center Overlay District.
(2)
To encourage and maximize the creation of a well-connected,
parking, walking and bicycle access system throughout the Town Center
Overlay District.
(3)
To enhance the environment of this area for its adjacent
neighborhoods, Groton residents, workers, and visitors to the Town
Center Overlay District.
(4)
To adequately accommodate the Town Center Overlay
District's typical peak parking demands and its commercial loading
and goods delivery requirements.
(5)
To avoid the creation of "overflow" parking demands
from the Town Center Overlay District into the Town center's adjacent
residential and commercial areas, whether on- or off-street.
C.
Relationship to Code of the Town of Groton. Parking
and loading in the Town Center Overlay District is governed by § 218-23
of the Code of the Town of Groton, in its entirety, and these Town
Center Overlay District Parking and Loading Guidelines.
D.
Implementation. In accordance with the purposes described
above, all parking and loading in the Town Center Overlay District
are hereby regulated and restricted by Code of the Town of Groton
§ 218-23, in its entirety, and as hereinafter provided.
For the purposes of these guidelines, the following
terms are defined for estimating necessary parking supply within the
Town Center Overlay District:
This involves reducing the overall parking supply cited in
§ 218-23 by assuming that the future public on- and off-street
parking supply created within the Town Center Overlay District will
be shared by Town Center Overlay District land uses and recreational
resources (i.e., the Nashua River Rail Trail) located within a convenient
walking distance of the destinations of parkers.
This involves reducing overall parking requirements cited
in § 218-23 of the Code of the Town of Groton by creating
an agreement between affected property owners to share available parking
spaces when those spaces are located within a convenient walking distance
of the parker's destination. Such agreements can be applied when land
uses having different parking demand patterns are able to use the
same parking spaces and areas throughout the day and thereby reduce
their combined demands. Shared parking is most effective when sharing
land uses have significantly different peak parking characteristics
that vary by time of day, day of week, and/or season of the year.
In these situations, shared parking strategies will result in fewer
total parking spaces needed when compared to the total number of parking
spaces needed for each individual land use or business. Mixed land
uses tending to benefit from specific shared parking arrangements
include the Nashua River Rail Trail and the mixed uses being considered
for the Town Center Overlay District. This also refers to parking
demands that may be reduced at retail facilities because a proportion
of patrons are expected to walk or bike to the Town Center Overlay
District. For purposes of the Town Center Overlay District, land uses
that may have parking reductions include office, institutional (i.e.,
Town Hall/Fire Department employees and visitors) and certain types
of retail uses (i.e., coffee shops, small retail shops and Nashua
River Rail Trail-oriented retail uses).
This is a scaled plan (e.g., one inch equals 40 feet) delineating
the parking areas that are to be shared under a shared use agreement.
This is a binding legal agreement by and between signatories
representing land uses within the Town Center Overlay District to
share the construction, maintenance, and liability for identified
shared parking facilities within the Town Center Overlay District.
That portion of the Town of Groton described and defined
in § 218-30.2, as amended, of the Code of the Town of Groton.
A.
Adequate parking must be available in the Town Center
Overlay District to service the typical net increase in peak parking
demands.
B.
Massachusetts General Law (MGL) Chapter 90, § 16A, Stopped Motor Vehicles; Operation of Engine; Time Limit Penalty, will be strictly enforced in the Town Center Overlay District. As a convenience to the reader, M.G.L. C. 60, § 16A, is quoted here: "No person shall cause, suffer, allow or permit the unnecessary operation of the engine of a motor vehicle while said vehicle is stopped for a foreseeable period of time in excess of five minutes. This section shall not apply to (a) vehicles being serviced, provided that operation of the engine is essential to the proper repair thereof, or (b) vehicles engaged in the delivery or acceptance of goods, wares, or merchandise for which engine assisted power is necessary and substitute alternate means cannot be made available, or (c) vehicles engaged in an operation for which the engine power is necessary for an associate power need other than movement and substitute alternate power means cannot be made available provided that such operation does not cause or contribute to a condition of air pollution. Whoever violates any provision of this section shall be punished by a fine of not more than one hundred dollars for the first offense, nor more than five hundred dollars for each succeeding offense."
A.
Standards for individual land uses set forth in § 218-23,
as amended, will apply to land uses within the Town Center Overlay
District that do not participate in a shared use agreement. If an
alternative shared loading modification can be justified to the satisfaction
of the Planning Board, the applicant may propose modifications of
§ 218-23, Off-Street Parking and Loading, requirements.
B.
No parcel located in the Town Center Overlay District
may count on-street parking spaces located within the Town Center
Overlay District toward the number of spaces required by Code of the
Town of Groton § 218-23.
A.
Retail, office, institutional, and residential applicants
for new development within the Town Center Overlay District shall
examine the feasibility of using shared parking arrangements to reduce
the total required parking supply in the Town Center Overlay District.
B.
Shared parking agreements shall reduce individual
land use parking space requirements cited in § 218-23, usually
less than 20%, including public on- and off-street public parking
resources. The use of smaller/compact parking spaces (refer to § 218-23.1,
Subsection K) shall be limited to 1/3 or fewer of the total shared
parking supply. The application of shared parking to reduce the overall
supply of parking in the Town Center Overlay District for certain
land uses may necessitate strict adherence to temporal restrictions
to keep peak demands from coinciding.
C.
Where the Planning Board deems appropriate, signatories
to a shared parking agreement shall be required to identify and adhere
to temporal restrictions on operating hours associated with the land
uses involved in the shared parking agreement.
A.
The minimum number of parking spaces for a mixed-use
development where shared parking is proposed shall be determined by
a study prepared by the applicant following the procedures of the
Urban Land Institute (ULI) Shared Parking Report (Second Edition,
2005) or the ITE Parking Generation Report (3rd Edition, 2004), ITE
Shared Parking Guidelines (1996), or other resources that the Planning
Board may find acceptable. A formal parking study may be waived for
small developments where there is established experience with the
land use mix or its impact is expected to be minimal. The actual number
of proposed parking spaces shall be based on well-recognized sources
of parking data, such as the ULI or ITE sources cited above or local
parking usage surveys.
B.
If the proposed shared parking plan assumes shared
use of an existing parking facility, field surveys shall be conducted
to determine the actual hour-by-hour use of the existing parking supply.
If the shared parking plan assumes the shared use of a future public
parking supply, assumptions regarding the peak use of the future parking
supply with and without the shared parking plan in place shall be
provided to the Planning Board.
C.
The applicant shall determine the minimum number of
parking spaces needed by a mixed-use development by following the
following four-step procedure:
(1)
Step 1: Determine combined "stand alone" parking requirements
under § 218-23 by individual land uses proposed within the
shared parking arrangement.
(2)
Step 2: Estimate the peak "combined" parking demand
weekday and weekend hours. Section 218-23 represents individual land
use peak demand requirements. The applicant shall estimate the hourly
distribution of its peak demands, typically using the 85th percentile
demands as published in available resources such as the Urban Land
Institute (ULI) Shared Parking report (as amended) and the Institute
of Transportation Engineers (ITE) Parking Generation report (as amended)
for retail, restaurant, office, and residential parking demands.
(a)
It is common that the residential parking supply
may not necessarily be included in a shared parking agreement, but
the Planning Board will not preclude residential shared parking resources.
(b)
The following four combined parking peaks should
be assessed, with the worst-case parking space demands prevailing
for estimating the peak "combined" parking demand requirements, including
a "peak season" estimate, if applicable:
(c)
Justifiable variations from nationally published
peak parking demand rates will be considered by the Planning Board
as long as the applicant provides the data for the differences compared
to rates contained in industry standard resources, such as either
of the two resources cited above, such that the Planning Board can
make a determination as to which peak "combined" estimate should be
employed as it pertains to the administration of this article. The
Planning Board may require strict adherence to proposed operating
hours by use which will run with the space. Changes in use may require
a review of operating hours by the Planning Board to ensure the performance
requirements of this article are achieved.
(3)
Step 3: Determine the availability of public parking
resources for serving the peak "combined" parking demand under a shared
parking agreement. Public parking within the Town Center Overlay District
consists of two components: on-street parking and off-street parking.
The exact number of off-street public parking supply within the Town
Center Overlay District to be considered under Step 3 is highly dependent
upon Town decisions concerning land adjacent to the Rail Trail and
the ultimate disposition of a privately owned parcel of land behind
Town Hall. On-street parking within the Town Center Overlay District
may not be counted toward the number of parking spaces required by
Code of the Town of Groton § 218-23. The estimate of the
available public parking supply shall be coordinated with the Planning
Board at the time the application is submitted. Allocation of the
available public supply shall be estimated based on the proportion
of land within the overall Town Center Overlay District being considered
for a shared parking agreement.
(4)
Step 4: Compile a shared parking plan summary. After
determining the peak parking demand and the component of public parking
resources expected to be available during the peak "combined" parking
demand period, essentially, the minimum requirement at the maximum
demand across all periods, the applicant shall compile a shared parking
plan summary that identifies the total number of spaces that would
be needed under § 218-23 by use, the total number of parking
spaces that will be constructed by the applicant, and the proposed
spaces assumed to be shared through the public parking supply.
D.
The shared parking plan summary is to be submitted
to the Planning Board for review and concurrence. While mindful of
the need to ensure adequate parking for users of the Rail Trail, at
its discretion, the Planning Board may accept a significant reduction
in the "stand alone" parking requirement, usually less than 20%, and
may require the saved space to be dedicated to such uses as open green
space or bicycle storage facilities.
A.
The closer shared parking spaces are to the land uses
they serve, the more likely the arrangement will be a success. Shared
spaces for residential units, if to be included in the shared parking
arrangement, must be located within a three-hundred-foot radius of
the dwelling unit entrances they serve. Shared parking spaces for
other uses should be located within a five-hundred-foot radius of
the principal building entrances of all sharing uses. Up to 20% of
the shared parking spaces for nonresidential uses may be located between
a five-hundred-foot radius and a one-thousand-foot radius from the
principal entrances.
B.
Clear, safe, Massachusetts Architectural Access Board/Americans
with Disabilities Act-compliant sidewalks and pedestrian access as
direct as possible must be provided between the building entrances
and the shared parking spaces.
C.
Similarly, the provision of convenient and secure
bicycle storage facilities close to the well-used entrances of Town
Center Overlay District buildings, with signage, markings, and possibly
shower facilities for cyclists should be incorporated in the design
of the Town Center Overlay District developments. Proper maintenance
of the bicycle parking facilities required shall be a continuing obligation
of the property owner. The following summarizes bicycle parking requirements
within the SAOD:
D.
Optionally, an applicant may also contribute additional
bicycle parking spaces (gift under M.G.L. C. 44, § 53A)
and/or bicycle parking equipment to the Town for the Nashua River
Rail Trail (NRRT) bicycle parking supply. The Town, in coordination
with the Department of Conservation and Recreation (DCR) which has
jurisdiction over the NRRT, will determine the location of all contributed
bicycle parking spaces and the placement of contributed bicycle parking
equipment.
A.
A model shared parking agreement form is attached
(see Appendix A).[1] Provisions for funding future maintenance of shared parking
spaces shall be clearly identified in the agreement to ensure that
routine maintenance (e.g., striping, potholes, etc.) is addressed
in a timely manner.
[1]
Editor's Note: A model agreement is included as an attachment to this chapter.
B.
The shared parking agreement shall include a shared
parking plan with the following elements:
(1)
A scaled plan at one inch equals 40 feet of the entire shared parking spaces layout prepared by an architect or engineer registered in the Commonwealth of Massachusetts showing the location and types of shared parking spaces and their proximity to the uses they will serve. The plan should also show the location and proposed percentage of small and regular parking spaces in accordance with § 381-60 below, as well as accessible spaces in accordance with Massachusetts Architectural Access Board Regulations, 521 CMR, and the Americans with Disabilities Act MAAB/ADA requirements. The location of assumed on-street parking spaces, while not included in the shared parking total, shall be shown on the plan.
(2)
If applicable, the location of trail-blazing signage
that directs drivers to the most convenient and compact vehicle parking
areas for each particular use or group of users.
(3)
If applicable, highlight the location of public and
shared parking spaces assumed to be subject to regulation (e.g., no
overnight parking in nonresidential shared parking spaces; possible
one- or two-hour parking for certain on-street spaces in front of
retail establishments).
(4)
Specific pedestrian and bicycle circulation features
illustrating the connections and walkways between parking areas and
land uses, as well as those buildings that will include cyclist-friendly
facilities such as showers or lockers. Pedestrian paths should be
as direct and short as possible. Exclusive bikeways (i.e., the Nashua
River Rail Trail) and other specific features encouraging bicycle
use or walking such as the location and quantity of bicycle storage
facilities should be highlighted.
(5)
Safety and security features such as lighting and
the maintenance plan for parking areas, including snow removal, disposal,
and routine maintenance.
(6)
The location and type of bicycle parking/storage facilities
to be provided.
(7)
Annual maintenance activities to be performed and
responsible parties.
Design of shared parking spaces for regular and accessible spaces shall generally comply with Chapter 218 of the Code of the Town of Groton, § 218-23, Off-street parking and loading. Small-size parking spaces should also be considered by Town Center Overlay District development applicants. Table 14-7 from the ITE Traffic Engineering Handbook (1999) is referenced as a source for small-size parking dimension guidelines that may be employed if some of the parking spaces in the Town Center Overlay District are dedicated for small cars. Such spaces must be clearly signed in the field and shall not include more than 1/3 of the non-public components of the shared parking supply. Compact car spaces shall not be less than eight feet by 16 feet in area versus Groton's standard car spaces that are nine feet by 18 feet in area. For example, a minimum twenty-four-foot aisle for two-way traffic is necessary to accommodate emergency vehicle circulation and backing maneuvers, even for compact car areas. Therefore, an entire parking bay, i.e., a row of only compact cars at 90º parking from on the left and the right, can be a minimum of 54 feet wide versus 60 feet for a similar full-size parking bay. Alternating full size with small car rows can preserve green space. On-street parking, parallel or angle configurations, shall be permitted and encouraged where its design will not present a hazard to pedestrians, block visibility from exiting driveways, or be detrimental to emergency egress from the Fire Department. Sidewalk curb extensions will be considered in areas where motorist visibility of traffic would otherwise be impaired by vehicles parked in close proximity to parked driveways.
