All stormwater management system installations shall be inspected during the time of construction as outlined in Chapter 324, Site Plan Review, Article III, § 324-17. All stormwater management systems and storm networks shall be inspected on an annual basis for compliance with this chapter and the NJDEP regulations.
As used in this chapter, the following terms
shall have the meanings indicated:
Any type of detention, retention or infiltration facility
designed to manage the rate and volume of stormwater runoff.
A stormwater management system which temporarily impounds
runoff and discharges it through an hydraulic outlet structure to
a downstream conveyance system. While a certain amount of outflow
may also occur via infiltration through the surrounding soil, such
amounts are negligible when compared to the outlet structure discharge
rates and are, therefore, not considered in the facility's design.
Since a detention facility impounds runoff only temporarily, it is
normally dry during nonrainfall periods. (Taken from New Jersey Department
of Environmental Protection Stormwater Management Facilities Maintenance
Manual, June 1989.)
A stormwater management system which temporarily impounds
runoff and discharges it via infiltration through the surrounding
soil. While an infiltration facility may also be equipped with an
outlet structure to discharge impounded runoff, such discharge is
normally reserved for overflow and other emergency conditions. Since
an infiltration facility impounds runoff only temporarily, it is normally
dry during nonrainfall periods. (Taken from New Jersey Department
of Environmental Protection Stormwater Management Facilities Maintenance
Manual, June 1989.)
A stormwater management system which, similar to a detention
facility, temporarily impounds runoff and discharges its outflow through
an hydraulic structure to a downstream conveyance system. Unlike a
detention facility, however, a retention facility also includes a
permanent impoundment and, therefore, is normally wet, even during
nonrainfall periods. Storm runoff inflows are temporarily stored above
this permanent impoundment. (Taken from New Jersey Department of Environmental
Protection Stormwater Management Facilities Maintenance Manual, June
1989.)
A detention facility constructed below the ground surface
usually constructed of piping, concrete vaults or the void space in
stone.
A.
All stormwater management systems shall be designed in accordance with Chapter 324, Site Plan Review, Article IV, §§ 324-23 through 324-29, or Chapter 400, Zoning, Article V, § 400-34, and shall be designed following all NJDEP regulations utilizing the techniques and BMPs outlined in the NJDEP stormwater regulations.
B.
Existing lakes, ponds, swales or wetland areas (including
buffer areas) shall not be permitted to act as a stormwater management
system in any manner whatsoever.
C.
Detention and retention basins must be constructed
to minimize sediment, pollutants and any other detrimental effects
upon adjoining or downstream wetlands, ditches, swales and other types
of water bodies. Detention and retention basins must be constructed
utilizing best management practices and techniques and shall include
bioengineering methods such as sedimentation areas, biofilters and
aquatic beach areas. Prior to the design of all stormwater management
systems, soil borings and/or backhoe test pits shall be performed
in the presence of the Municipal Engineer to verify subsurface soil
conditions.
D.
Wetlands vegetation in the form of mature trees, shrubs
and grasses must be incorporated in the basin design and must be shown
on an appropriate landscaping plan. The plan shall be subject to review
and comment by the Gibbsboro Environmental Commission.
E.
Existing inlet structures must be properly labeled
to meet NJDEP standards. New inlet castings must meet NJDEP BMP standards.
A.
All proposed stormwater management systems are to
have a postconstruction inspection prior to final acceptance by the
Borough. Final inspection shall be performed by the Municipal Engineer.
(1)
All silt is to be removed from retention or detention
basins before final basin grading and permanent stabilization.
(2)
A postconstruction percolation test will be required
in the basin bottom to verify previously determined percolation rates.
(3)
All retention or detention basin side slopes as well
as the basin bottom shall be properly stabilized with permanent stabilization.
(4)
All stormwater piping and inlets which feed retention,
detention or subsurface basins shall be cleaned of all sand, silt
and debris before final acceptance.
(5)
All subsurface stormwater management systems shall
be cleaned of all sand, silt and debris before final acceptance.
(6)
A written stormwater maintenance plan must be prepared
and shall be part of the subdivision or site plan approval process.
The plan shall follow the guidelines and procedures listed in the
NJDEP stormwater regulations.
(7)
All streets must be swept prior to acceptance.
B.
A cash contribution by the developer shall be provided
to establish a basin maintenance trust for the Borough for those stormwater
management systems to be dedicated to or to be maintained by the municipality.
Contributions will be required to be deposited into an interest-bearing
reinvestment trust established for the sole purpose of future stormwater
management system maintenance and repair.
(1)
Contributions for the maintenance of detention and
retention basins shall be in accordance with the following schedule.
The schedule is subject to an annual review by the Planning Board
Engineer and shall be adjusted according to the current rates for
basin lawn care.
|
Minimum Basin Property Size
(acres)*
|
Cash Contribution
| |
|---|---|---|
|
0 - 0.5
|
$7,500
| |
|
0.6 - 1.0
|
$11,250
| |
|
1.1 - 1.5
|
$15,000
| |
|
1.5 - 2.0
|
$18,750
| |
|
2.1 - 3.0
|
$22,500
| |
|
3.1 and greater
|
To be determined
|
|
*NOTE:
Basin property area shall include all associated
buffers and access easements.
|
(2)
Contributions for subsurface stormwater management
systems shall be determined by the Borough Engineer and the Planning
Board on a case-by-case basis.
(3)
Contributions must be posted within the municipality
at the time of the submittal of the performance bond.
C.
All proposed basins, regardless of ownership, must
have a dedicated access from the public right-of-way. The access should
include a stabilized hard surface suitable for the passage of maintenance
and inspection equipment and vehicles. The access must be secure by
means of gates or an equivalent, and locks and keys shall be provided
to the municipality.
D.
Annual inspection of existing basins not maintained
by the municipality is required and must include checking for obstructions
and the removal of debris and accumulated particles such as silt and
sediment.
(1)
Annual inspection shall include:
(a)
Removal of all accumulated silt and debris from
stone riprap energy dissipater aprons associated with basin inflow
pipes; replacement of stone riprap if necessary.
(b)
Removal of debris from outflow structure orifices,
weirs, overflow grating, inlets and piping, etc.
(c)
All landscaping shall be properly trimmed, mulched
and maintained. Dead landscaping shall be replaced in accordance with
the approved subdivision plan and/or approval by the Mayor and Council
of the Borough.
(d)
All fencing which is broken, deteriorated, missing
or out of alignment must be replaced and/or repaired.
E.
Mowing of the grass on a regular basis is required
to ensure the aesthetic and hydraulic quality of the basin.
(1)
Mowing should be performed when grass is between four
inches and six inches high. The grass should never be allowed to exceed
six inches in height.
(2)
All clippings must be removed from the basin immediately
following mowing.
(3)
Removal of leaves from the basin during the fall is
also required.
F.
In order to ensure proper function of all basins,
every five years each basin bottom shall be scarified to a depth of
four inches to remove sediments and silts. Then, four inches of granular
topsoil must be added and the surface reseeded as detailed previously.
G.
At no time after final basin grading and permanent
stabilization should any equipment be allowed to operate within the
basin which could smear or compact the soils leading to a reduction
in the percolation rate. This includes mowing and the annual removal
of accumulated silt.
H.
Property owners and homeowners' associations who have
lakes or ponds which are classified as dam structures or which fall
under the guidelines of the New Jersey Department of Environmental
Protection Dam Safety Section must also meet the minimum requirements
of that state agency.
