This appendix presents the operation and maintenance (O&M)
requirements for stormwater management facilities designed and installed
in the City of Springfield pursuant to SDC 4.3.110.
1.
Notice of Operations and Maintenance Agreement - (NOMA).
The NOMA must be in a form approved by the City Attorney and
must identify the property as having a stormwater management facility
and the responsible party for future operations and maintenance. The NOMA must be completed and recorded at Lane County Deeds and
Records. Signatures on the NOMA shall be notarized.
The intent of the NOMA is to ensure that the facility will be
identified to future property owners and that the facility will be
maintained according to the Springfield Development Code, Springfield
Municipal Code, the O&M Agreement, and the O&M Plan for the
site.
2.
Operations and Maintenance Agreement - (O&M Agreement).
The O&M Agreement must be on a form approved by the City
Attorney and must identify the property as having a stormwater management
facility; the owner's name, address, email, and phone number; the
site address; financially responsible party for ongoing operation
and maintenance; and parties responsible for inspecting and maintaining
the facility.
The O&M Agreement does not need to be recorded. The intent
of the Agreement is to ensure that the facility will be maintained
for functionality, aesthetics, and will identify accountability. The
stormwater site plan attached to the Agreement will help identify
to the owners and inspectors the location and the functions of the
stormwater facilities, and the Facility Specific O&M Plan will
identify the routine maintenance procedures and scheduling.
3.
Facility Specific Operations and Maintenance Plan - ( &M Plan).
This appendix provides pre-approved Facility Specific Operations
and Maintenance Plans (O&M Plans) for various types of stormwater
quality facilities. Stormwater facilities that are not
included in this appendix (i.e. a manufactured stormwater
treatment technology), are required to submit an O&M Plan that
meets the manufacturer's requirements and facility specific operations
and maintenance activities consistent with ongoing function of the
stormwater facility(ies).
The O&M Plan strategies in this appendix apply to all stormwater
management facilities and related facility components identified in
SDC 4.3.110. Stormwater destination facilities are required to be
operated and maintained in working condition for the life of the facility.
4.
Private Facilities.
Record a copy of the NOMA with Lane County Deeds and Records.
Submit with the final site plan, a recorded copy of
the NOMA, the O&M Agreement, and the Facility Specific Operations
and Maintenance Plan (O&M Plan) for each type of stormwater management
facility permitted on the site. The operations and maintenance activities
listed on the O&M Plan documents, which will be on file with the
City Engineer, may later be revised with City Engineer approval.
5.
Public Facilities.
Submit a copy of a Facility Specific O&M Plan with the Public
Improvement Permit Project. County recording of this plan is not necessary.
1.
Privately Maintained Facilities.
The O&M Plan for a privately maintained facility shall include
the following components for each development site. A complete Plan
must be submitted and approved as provided in SDC 4.3.110.
a.
A recorded copy of the Notice of Operation and Maintenance Agreement
(NOMA)
b.
Operations and Maintenance Agreement (O&M Agreement)
c.
Stormwater Management Site Plan (as approved under the Development
Agreement)
d.
Landscape Plan
e.
Stormwater Management Facility Inspection and Maintenance Log
f.
Facility-Specific Operations and Maintenance Plan(s) (O&M Plan(s))
2.
Detailed submission requirements for the above items are found below:
a.
Notice of Operations and Maintenance Agreement - (NOMA). The NOMA
identifies the property as having a stormwater management facility
and identifies the responsible party for future operations and maintenance. The Notice must be completed and recorded at Lane County Deeds and
Records. Signatures on the Notice shall be notarized. The
NOMA may be submitted in person or mailed, along with payment of the
applicable fees, to the County Recorder's Office. Lane County Deeds
and Records, 125 E 8th Avenue, Eugene, OR 97401.
https://www.lanecounty.org/government/county_departments/county_administration/operations/county_clerk/real_property_recording/document_recording_requirements
The property description on the NOMA must be a full legal description
of the property and may not be a tax lot number. Legal descriptions
may be obtained from the county assessor's office. The NOMA
shall be printed on legal-sized (8 1/2 x 14) paper to facilitate
the recording process. If printed on smaller paper, additional recording
fees may apply.
b.
Operations and Maintenance Agreement — (O&M Agreement).
The completed Agreement must identify the owner's name, address, and
phone number, the site address, financial method used to cover future
operation and maintenance, and parties responsible for inspecting
and maintaining the facility. The O&M Agreement does not need
to be recorded.
c.
Stormwater Management Site Plan. A copy of the Stormwater Management
Site Plan shall be attached to the O&M Agreement. The Plan must
show the location of the facility(ies) on the site, the sources of
runoff entering the facility, and the ultimate stormwater destination.
d.
Landscape Plan. A Landscape Plan (if separate from the Stormwater
Management Site Plan) shall be attached to the O&M Agreement.
The Plan must show the location, density, plant size, quantity, and
species by scientific and common name.
e.
Stormwater Management Facility Inspection and Maintenance Log. Stormwater
Management Facility Inspection and Maintenance Logs must be kept on
file by the facility owner(s). Logs should note all inspection dates,
the facility components that were inspected, and any maintenance or
repairs made. The Facility-Specific O&M Plans can serve as a checklist
for what should be included in the Log (e.g. the facility elements
that need to be inspected, frequency of inspection, conditions that
indicate maintenance is needed, etc.). Logs must include the information
listed in the form included in this appendix. Logs must be retained
on site for a minimum of 2 years.
f.
Facility Specific Operations and Maintenance Plans - (O&M Plan).
O&M Plans provided in this packet identify the specific operations
and maintenance activities that are required for each of the approved
stormwater management facilities listed in Appendix D Typical Facility
Details. The appropriate Plan must be attached to the O&M Agreement
and submitted as part of the application process. Applicants may either
select and use the pre-approved Facility Specific O&M Plans provided
in this packet or prepare a Facility Specific O&M Plan that incorporates
the specific activities that corresponds with their chosen type of
stormwater facilities through a Type II review process. The Facility
Specific O&M Plans do not have to be recorded. This allows the
future stormwater management facility owner to submit operations and
maintenance activity revisions to the City without the need to re-record
the O&M Plans with the County.
The facility specific operations and maintenance activities
for private facilities may be modified any time after permit issuance
subject to mutual agreement by the City and owner, in writing. Modifying
the operations and maintenance activities is optional, and is intended
to give the owner an opportunity to adjust maintenance needs according
to site-specific history and conditions. Modifications may require
the owner to apply for concurrent modification of a prior land use
approval. Proposed modifications to the O&M Plan must be submitted,
along with an updated O&M Agreement, to the City for review and
approval.
g.
Operations and Maintenance Plans for Proprietary Facilities. Proprietary
O&M Plans for approved proprietary facilities must describe the
inspection, cleaning, and operation and maintenance criteria for the
facility and provide manufacturer's recommended maintenance if applicable.
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Stormwater Management Facility Inspection and Maintenance Log
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Facility Specific Operations and Maintenance Plans
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Eco-Roofs
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Contained Planters
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Permeable Pavement
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Swales (Vegetated, Grassy and Street)
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Level Spreaders
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Vegetated Filter Strips
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Stormwater Planters
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Rain Gardens
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Sand Filters
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Soakage Trenches
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Wet, Extended Wet, and Dry Ponds
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Constructed Treatment Wetlands
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Underground Detention Tanks, Vaults and Pipes
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Drywells
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Spill Control Manholes
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Eco-Roofs
Operations and Maintenance Plan
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Eco-Roofs are lightweight vegetated roof systems
used in place of conventional roofs that retain and filter stormwater
and provide aesthetic and energy conservation benefits. All facility
components, including soil substrate or growth medium, vegetation,
drains, irrigation systems (if applicable), membranes, and roof structure
shall be inspected for proper operations, integrity of the waterproofing,
and structural stability throughout the life of the eco-roof. All
elements shall be inspected once a month from April through September.
The facility owner must keep a log, recording all inspection dates,
observations, and maintenance activities. The following items shall
be inspected and maintained as stated:
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Soil Substrate/Growing Medium shall be inspected
for evidence of erosion from wind or water. If erosion channels are
evident, they shall be stabilized with additional soil substrate/growth
medium and covered with additional plants.
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Structural Components shall be operated and maintained
in accordance with manufacturer's requirements. Drain inlets shall
be kept unrestricted.
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Inlet/outlet pipe shall be cleared when soil substrate, vegetation,
debris or other materials clog the drains. Sources of sediment and
debris shall be identified and corrected.
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Determine if drain pipe is in good condition and correct as
needed.
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Debris and Litter shall be removed to prevent clogging
of drains and interference with plant growth.
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Vegetation shall be maintained to provide 90 percent
plant cover.
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During the Establishment Period, plants shall be replaced once
per month as needed. During the long-term period, dead plants shall
generally be replaced once per year in the fall months.
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Fallen leaves and debris from deciduous plant foliage shall
be removed if build up occurs.
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Nuisance and prohibited vegetation shall be removed when discovered.
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Dead vegetation shall be removed and replaced with new plants.
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Weeding shall be manual with no herbicides or pesticides used.
Weeds shall be removed regularly and not allowed to accumulate.
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Fertilization is not necessary and fertilizers shall not be
applied.
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During drought conditions, mulch or shade cloth may be applied
to prevent excess solar damage and water loss.
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Mowing of grasses shall occur as needed. Clippings shall be
removed if build up occurs.
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Irrigation can be accomplished either through hand
watering or automatic sprinkler systems. If automatic sprinklers are
used, manufacturers' instructions for operations and maintenance shall
be followed.
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During the Establishment Period (1-3 years), water sufficient
to assure plant establishment and not to exceed 1/4 inch of water
once every 3 days shall be applied.
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During the long-term period (3+ years), water sufficient to
maintain plant cover and not to exceed 1/4 inch of water once every
14 days shall be applied.
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Spill Prevention measures from mechanical systems
located on roofs shall be exercised when handling substances that
can contaminate stormwater.
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Releases of pollutants shall be corrected as soon as identified.
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The presence of a green/eco-roof does not waive requirements
for containment of mechanical systems.
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Training and/or written guidance information for
operating and maintaining rooftop gardens shall be provided to all
property owners and tenants. A copy of the O&M Plan shall be provided
to all property owners and tenants.
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Access and Safety to the eco-roof shall be safe
and efficient.
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Egress and ingress routes shall be maintained to design standards.
Walkways shall be clear of obstructions and maintained to design standards.
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Aesthetics of the rooftop garden shall be maintained
as an asset to the property owner and community.
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Evidence of damage or vandalism shall be repaired and accumulation
of trash or debris shall be removed upon discovery.
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Insects shall not be harbored on the eco-roof.
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Standing water creating an environment for development of insect
larvae shall be eliminated by manual means. Chemical sprays shall
not be used.
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Contained Planters
Operations and Maintenance Plan
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Contained planters are designed to intercept rainfall
that would normally fall on impervious surfaces. In this respect,
contained planters convert impervious surfaces to pervious surfaces,
decreasing the amount of stormwater runoff from a site. Water should
drain through the planter within 3-4 hours after a storm event. All
facility components and vegetation shall be inspected for proper operations
and structural stability. These inspections shall occur, at a minimum,
quarterly for the first 2 years from the date of installation and
2 times per year thereafter. The facility owner must keep a log, recording
all inspection dates, observations, and maintenance activities. The
following items shall be inspected and maintained as stated:
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Filter Media consisting of sand or topsoil shall
allow stormwater to percolate uniformly through the planter.
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Planter shall be excavated and cleaned, and gravel or soil shall
be replaced to correct low infiltration rates.
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Holes that are not consistent with the design and allow water
to flow directly through the planter to the ground shall be plugged.
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Litter and debris shall be removed routinely (e.g., no less
than quarterly) and upon discovery
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Planter shall contain filter media and vegetation.
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Structural deficiencies in the planter including rot, cracks,
and failure shall be repaired.
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Planter Reservoir receives and detains storm water
prior to infiltration. If water does not drain from reservoir within
3-4 hours of storm event, sources of clogging shall be identified
and corrected. Topsoil may need to be amended with sand or replaced
all together.
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Vegetation shall be healthy and dense enough to
provide filtering while protecting underlying soils from erosion.
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Mulch shall be replenished at least annually.
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Planter vegetation shall be irrigated to ensure survival.
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Vegetation or trees that limit access or interfere with planter
operation shall be pruned or removed.
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Fallen leaves and debris from deciduous plant foliage shall
be raked and removed.
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Nuisance and prohibited vegetation shall be removed when discovered.
Invasive vegetation contributing up to 25 percent of vegetation of
all species (measured in a 10 x 10 foot plot) shall be removed and
replaced.
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Dead vegetation shall be removed to maintain less than 10 percent
of area coverage or when planter function is impaired. Vegetation
shall be replaced within a specific timeframe, e.g., 3 months, or
immediately if required to maintain cover density and control erosion
where soils are exposed.
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Training and/or written guidance information for
operating and maintaining planters shall be provided to all property
owners and tenants. A copy of the O&M Plan shall be provided to
all property owners and tenants.
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Access to the stormwater planter shall be safe
and efficient. Egress and ingress routes shall be maintained to design
standards. Roadways shall be maintained to accommodate size and weight
of vehicles, if applicable.
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Obstacles preventing maintenance personnel and/or equipment
access to the planter shall be removed.
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Gravel or ground cover shall be added if erosion occurs, e.g.,
due to vehicular or pedestrian traffic.
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Insects and Rodents shall not be harbored at the
stormwater planter. Pest control measures shall be taken when insects/rodents
are found to be present.
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Standing water creating an environment for development of insect
larvae shall be eliminated.
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If a complaint is received or an inspection reveals that a stormwater
facility is significantly infested with mosquitoes or other vectors,
the property owner/owners or their designee may be required to eliminate
the infestation at the City inspector's discretion. Control of the
infestation shall be attempted by using first nonchemical methods
and secondly, only those chemical methods specifically approved by
the City's inspector. Acceptable methods include, but are not limited
to, the following:
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Installation of predacious bird or bat nesting boxes.
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ii.
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Alterations of water levels approximately every 4 days in order
to disrupt mosquito larval cycles.
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iii.
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Stocking ponds and other permanent water facilities with fish
or other predatory species.
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iv.
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If non-chemical methods have proved unsuccessful, contact the
City inspector prior to use of chemical methods such as the mosquito
larvicides Bacillus thurengensis var. israeliensis or other approved
larvicides. These materials may only be used with City inspector approval
if evidence can be provided that these materials will not migrate
off site or enter the public stormwater system. Chemical larvicides
shall be applied by a licensed individual or contractor.
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Holes in the ground located in and around the stormwater planter
shall be filled and compacted.
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Debris and Litter shall be removed to maintain
soil health and to prevent interference with plant growth.
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Permeable Pavement
Operations and Maintenance Plan
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Permeable Pavement is a porous pavement surface
with an underlying stone reservoir that temporarily stores surface
runoff before infiltrating into the subsoil or being collected in
underlying drain pipes and being discharged off site. There are many
types of permeable pavement including plastic rings planted with grass,
stone or concrete blocks with pore spaces backfilled with gravel or
sand, porous asphalt, and porous concrete. Permeable pavement accepts
only precipitation, not stormwater runoff. All facility components,
vegetation, and source controls shall be inspected for proper operations
and structural stability, at a minimum, quarterly for the first 2
years from the date of installation, 2 times per year thereafter,
and within 48 hours after each major storm event. The facility owner
must keep a log, recording all inspection dates, observations, and
maintenance activities. The following items shall be inspected and
maintained as stated:
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Surface: In most permeable pavement design, the
pavement itself acts as pretreatment to the stone reservoir below.
The surface shall be kept clean and free of leaves, debris, and sediment.
The surface shall not be overlaid with an impermeable paving surface.
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Regular sweeping shall be implemented for porous asphalt or
concrete systems. Vacuum sweeping is preferred and can greatly prolong
the effective life of the pavement.
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Overflows or Emergency Spillways are used in the
event that the facility's infiltration capacity is exceeded. Overflow
devices shall be inspected for obstructions or debris, which shall
be removed upon discovery. Overflow or emergency spillways shall be
capable of transporting high flows of stormwater to an approved stormwater
receiving system.
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Sources of erosion damage shall be identified and controlled
when native soil is exposed near the overflow structure.
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Vegetation (where applicable) shall be healthy
and dense enough to provide filtering while protecting underlying
soils from erosion. Vegetation, such as trees and shrubs, should not
be located in or around the permeable pavement because roots from
trees can penetrate the pavement, and leaves from deciduous trees
and shrubs can increase the risk of clogging the surface.
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Vegetation and large shrubs/trees that limit access or interfere
with porous pavement operation shall be pruned.
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Fallen leaves and debris from deciduous plant foliage shall
be raked and removed.
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Poisonous, nuisance, dead or odor producing vegetation shall
be removed immediately.
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Grass shall be mowed to less than 4 inches and grass clippings
shall be bagged and removed.
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Irrigation shall be provided as needed.
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Source Control measures prevent pollutants from
mixing with stormwater. Typical non-structural control measures include
raking and removing leaves, street sweeping, vacuum sweeping, limited
and controlled application of pesticides and fertilizers, and other
good housekeeping practices.
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Spill Prevention measures shall be exercised when
handling substances that can contaminate stormwater. A spill prevention
plan shall be implemented at all non-residential sites and in areas
where there is likelihood of spills from hazardous materials. However,
virtually all sites, including residential and commercial, present
potential danger from spills. All homes contain a wide variety of
toxic materials including gasoline for lawn mowers, antifreeze for
cars, solvents, pesticides, and cleaning aids that can adversely affect
stormwater if spilled. It is important to exercise caution when handling
substances that can contaminate stormwater. Releases of pollutants
shall be corrected as soon as identified. In addition, long term exposure
to low levels of petroleum products, such as that form a leaky vehicle,
can severely degrade the pavement.
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Training and/or written guidance information for
operating and maintaining permeable pavement shall be provided to
all property owners and tenants. A copy of the O&M Plan shall
be provided to all property owners and tenants.
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Access to the permeable pavement shall be safe
and efficient. Egress and ingress routes shall be maintained to design
standards. Roadways shall be maintained to accommodate size and weight
of vehicles, if applicable. Obstacles preventing maintenance personnel
and/or equipment access to the porous pavement shall be removed. Gravel
or ground cover shall be added if erosion occurs, e.g., due to vehicular
or pedestrian traffic.
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Debris and Litter shall be removed to prevent clogging.
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Insects and Rodents shall not be harbored at the
permeable pavement. Pest control measures shall be taken when insects/rodents
are found to be present.
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Standing water creating an environment for development of insect
larvae shall be eliminated.
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•
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If a complaint is received or an inspection reveals that a stormwater
facility is significantly infested with mosquitoes or other vectors,
the property owner/owners or their designee may be required to eliminate
the infestation at the City inspector's discretion. Control of the
infestation shall be attempted by using first non-chemical methods
and secondly, only those chemical methods specifically approved by
the City's inspector. Acceptable methods include, but are not limited
to, the following:
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i.
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Installation of predacious bird or bat nesting boxes.
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ii.
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Alterations of pond water levels approximately every 4 days
in order to disrupt mosquito larval development cycles.
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iii.
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Stocking ponds and other permanent water facilities with fish
or other predatory species.
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iv.
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If non-chemical methods have proved unsuccessful, contact the
City inspector prior to use of chemical methods such as the mosquito
larvicides Bacillus thurengensis var israeliensis or other approved
larvicides. These materials may only be used with City inspector approval
if evidence can be provided that these materials will not migrate
off site or enter the public stormwater system. Chemical larvicides
shall be applied by a licensed individual or contractor.
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Holes in the ground located in and around the permeable pavement
shall be filled and compacted.
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If used at this site, the following will be applicable:
Signage may serve to educate people about the importance
or function of the site's stormwater protection measures. It may also
discourage behaviors that adversely affect stormwater protection measures.
For example, if debris is a problem, a sign reminding people not to
litter may partially solve the problem. Broken or defaced signs shall
be replaced/repaired.
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Placing of permeable pavement on site:
Permeable pavement should not be placed in any area where there
is high likelihood of spills or contamination such as vehicle fueling
areas, washing areas, loading docks, trash enclosures or material
handling areas. Permeable pavement is not well suited to high traffic
areas or areas where heavy vehicles will frequently travel. Such areas
include parking lot lanes, entrance lanes and any areas subject to
vehicle braking and turning movements. Parking lot stalls, emergency
access areas and infrequently used areas are typically suitable for
permeable pavement treatment.
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Swales (Vegetated, Grassy and Street)
Operations and Maintenance Plan
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Swales are vegetated or grassed open channels that
trap pollutants by filtering and slowing flows, allowing particles
to settle out. The swale should drain within 48 hours of a storm event.
All facility components, vegetation, and source controls shall be
inspected for proper operations and structural stability, at a minimum,
quarterly for the first 2 years from the date of installation, 2 times
per year thereafter, and within 48 hours after each major storm event.
The facility owner must keep a log, recording all inspection dates,
observations, and maintenance activities. The following items shall
be inspected and maintained as stated:
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Swale Inlet (such as curb cuts or pipes) shall
maintain a calm flow of water entering the swale.
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Source of erosion shall be identified and controlled when native
soil is exposed or erosion channels are forming.
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Sediment accumulation shall be hand-removed with minimum damage
to vegetation using proper erosion control measures. Sediment shall
be removed if it is more than 3 inches thick or so thick as to damage
or kill vegetation.
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Inlet shall be cleared when conveyance capacity is plugged.
Sources of sediment and debris shall be identified and corrected.
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Rock splash pads, spreaders and dissipaters shall be replenished
to prevent erosion.
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Side Slopes shall be maintained to prevent erosion
that introduces sediment into the swale.
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Slopes shall be stabilized and planted using appropriate erosion
control measures when native soil is exposed or erosion channels are
forming.
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Swale Media shall allow stormwater to percolate
uniformly through the landscape swale. If the swale does not drain
within 48 hours, it shall be tilled and replanted according to design
specifications.
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Swale area shall be protected during construction from compaction.
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Annual or semi-annual tilling shall be implemented if compaction
or clogging continues.
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Debris in quantities that inhibit operation shall be removed
routinely (e.g., no less than quarterly), or upon discovery.
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Swale Outlet shall maintain sheet flow of water
exiting swale unless a collection drain is used. Source of erosion
damage shall be identified and controlled when native soil is exposed
or erosion channels are forming.
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Outlets such as drains and overland flow paths shall be cleared
when 50 percent of the conveyance capacity is plugged.
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Outlet structures shall be cleaned of sediment and debris at
least 1 time per year or when the level is at 50 percent of the conveyance
capacity.
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Sources of sediment and debris shall be identified and corrected.
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Vegetation shall be healthy and dense enough (at
least 90 percent cover) to provide filtering while protecting underlying
soils from erosion. Mulch shall be replenished as needed to ensure
survival of vegetation.
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Vegetation, large shrubs or trees that interfere with landscape
swale operation shall be pruned.
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Fallen leaves and debris from deciduous plant foliage shall
be removed if build up is damaging vegetation.
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Grassy swales shall be mowed to keep grass 4 inches to 9 inches
in height. Clippings shall be removed when possible, to remove pollutants
absorbed in grasses, or when build up is damaging vegetation.
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Nuisance and prohibited vegetation (such as blackberries and
English Ivy) shall be removed when discovered. Invasive vegetation
contributing up to 25 percent of vegetation of all species shall be
removed and replaced.
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Dead vegetation and woody material shall be removed to maintain
less than 10 percent of area coverage or when swale function is impaired.
Vegetation shall be replaced within 3 months, or immediately if required
to maintain cover density and control erosion where soils are exposed.
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Debris and Litter shall be removed to ensure stormwater
conveyance and to prevent clogging of inlet and outlet drains and
interference with plant growth.
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Spill Prevention measures shall be exercised when
handling substances that contaminate stormwater. Releases of pollutants
shall be corrected as soon as identified.
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Training and/or written guidance information for
operating and maintaining swales shall be provided to all property
owners and tenants. A copy of the O&M Plan shall be provided to
all property owners and tenants.
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Access to the swale shall be safe and efficient.
Egress and ingress routes shall be maintained to design standards.
Roadways shall be maintained to accommodate size and weight of vehicles,
if applicable.
| |||
|
•
|
Obstacles preventing maintenance personnel and/or equipment
access to the swale shall be removed.
| ||
|
•
|
Gravel or ground cover shall be added if erosion occurs, e.g.,
due to vehicular or pedestrian traffic.
| ||
|
Insects and Rodents shall not be harbored in the
swale. Pest control measures shall be taken when insects/rodents are
found to be present.
| |||
|
•
|
If a complaint is received or an inspection reveals that a stormwater
facility is significantly infested with mosquitoes or other vectors,
the property owner/owners or their designee may be required to eliminate
the infestation at the City inspector's discretion. Control of the
infestation shall be attempted by using first non-chemical methods
and secondly, only those chemical methods specifically approved by
the City's inspector. Acceptable methods include but are not limited
to the following:
| ||
|
i.
|
Installation of predacious bird or bat nesting boxes.
| ||
|
ii.
|
Alterations of pond water levels approximately every 4 days
in order to disrupt mosquito larval development cycles.
| ||
|
iii.
|
Stocking ponds and other permanent water facilities with fish
or other predatory species.
| ||
|
iv.
|
If non-chemical methods have proved unsuccessful, contact the
City inspector prior to use of chemical methods such as the mosquito
larvicides Bacillus thurengensis var. israeliensis or other approved
larvicides. These materials may only be used with City inspector approval
if evidence can be provided that these materials will not migrate
off site or enter the public stormwater system. Chemical larvicides
shall be applied by a licensed individual or contractor.
| ||
|
•
|
Holes in the ground located in and around the swale shall be
filled.
| ||
|
If used at this site, the following will be applicable:
| |||
|
Check Dams, flow spreaders and dissipaters shall
control and distribute flow.
| |||
|
•
|
Causes for altered water flow or short circuits shall be identified,
and obstructions cleared upon discovery.
| ||
|
•
|
Causes for channelization shall be identified and repaired.
| ||
|
•
|
Systems shall remain free of sediment build up and debris.
| ||
|
Level Spreaders
Operations and Maintenance Plan
| |||
|---|---|---|---|
|
Level Spreaders are used to spread and disperse
a concentrated flow thinly over a vegetated or forested riparian buffer
or filter strip. Stormwater enters the spreader as a concentrated
flow and discharges as sheet flow across a buffer area. All facility
components and the vegetated buffer shall be inspected for proper
operations and structural stability. These inspections shall occur,
at a minimum, quarterly for the first 2 years from the date of installation,
2 times per year thereafter, and within 48 hours after each major
storm event. The facility owner must keep a log, recording all inspection
dates, observations, and maintenance activities. The following items
shall be inspected and maintained as stated:
| |||
|
Level Spreader shall allow runoff to enter the
vegetative filter as predominantly sheet flow.
| |||
|
•
|
Source of erosion damage shall be identified and controlled
when native soil is exposed or erosion channels are forming.
| ||
|
•
|
Sediment build-up near or exceeding 2 inches in depth shall
be removed.
| ||
|
Inlet shall assure unrestricted stormwater flow
to the level spreader.
| |||
|
•
|
Sources of erosion shall be identified and controlled when native
soil is exposed or erosion channels are present.
| ||
|
•
|
Sediment accumulation shall be hand-removed with minimum damage
to vegetation using proper erosion control measures. Sediment shall
be removed if it is more than 3 inches thick or so thick as to damage
or kill vegetation.
| ||
|
•
|
Inlet shall be cleared when conveyance capacity is plugged.
| ||
|
•
|
Rock splash pads and dissipaters shall be replenished to prevent
erosion.
| ||
|
Spreader lip shall allow water to exit the level
spreader as sheet flow.
| |||
|
•
|
Sources of erosion damage shall be identified and controlled
when native soil is exposed or erosion channels are deeper than 2
inches.
| ||
|
•
|
Outlet shall be cleared when 50 percent of the conveyance capacity
is plugged. Sources of sediment and debris shall be identified and
corrected.
| ||
|
Vegetated buffer shall be healthy and dense enough
(at least 90 percent cover) to provide filtering while protecting
underlying soils from erosion.
| |||
|
•
|
Nuisance and prohibited vegetation (such as blackberries and
English Ivy) shall be removed when discovered. Invasive vegetation
contributing up to 25 percent of vegetation of all species shall be
removed and replaced.
| ||
|
•
|
Dead vegetation shall be removed to maintain less than 10 percent
of area coverage or when vegetation function is impaired. Vegetation
shall be replaced immediately to control erosion where soils are exposed
and within 3 months to maintain cover density.
| ||
|
Spill Prevention measures shall be exercised when
handling substances that contaminate stormwater. Releases of pollutants
shall be corrected as soon as identified.
| |||
|
Training and/or written guidance information for
operating and maintaining level spreaders shall be provided to all
property owners and tenants. A copy of the O&M Plan shall be provided
to all property owners and tenants.
| |||
|
Access to the level spreaders shall be safe and
efficient. Egress and ingress routes shall be maintained to design
standards. Obstacles preventing maintenance personnel and/or equipment
access to the facility shall be removed.
| |||
|
Insects and Rodents shall not be harbored in the
level spreader. Pest control measures shall be taken when insects/rodents
are found to be present.
| |||
|
•
|
If a complaint is received or an inspection reveals that a stormwater
facility is significantly infested with mosquitoes or other vectors,
the property owner/owners or their designee may be required to eliminate
the infestation at the City inspector's discretion. Control of the
infestation shall be attempted by using first non-chemical methods
and secondly, only those chemical methods specifically approved by
the City's inspector. Acceptable methods include but are not limited
to the following:
| ||
|
i.
|
Installation of predacious bird or bat nesting boxes.
| ||
|
ii.
|
Alterations of pond water levels approximately every 4 days
in order to disrupt mosquito larval development cycles.
| ||
|
iii.
|
If non-chemical methods have proved unsuccessful, contact the
City inspector prior to use of chemical methods such as the mosquito
larvicides Bacillus thurengensis var. israeliensis or other approved
larvicides. These materials may only be used with City inspector approval
if evidence can be provided that these materials will not migrate
off site or enter the public stormwater system. Chemical larvicides
shall be applied by a licensed individual or contractor.
| ||
|
•
|
Holes in the ground located in and around the level spreader
shall be filled.
| ||
|
Vegetated Filter Strips
Operations and Maintenance Plan
| |||
|---|---|---|---|
|
Vegetated Filter Strips are gently sloped vegetated
areas that stormwater runoff is directed to flow and filter through.
Stormwater enters the filter as sheet flow from an impervious surface
or is converted to sheet flow using a flow spreader. Flow control
is achieved using the relatively large surface area and check dams.
Pollutants are removed through infiltration and sedimentation. The
vegetative filter should drain within 48 hours of storm event. All
facility components and vegetation shall be inspected for proper operations
and structural stability. These inspections shall occur, at a minimum,
quarterly for the first 2 years from the date of installation, 2 times
per year thereafter, and within 48 hours after each major storm event.
The facility owner must keep a log, recording all inspection dates,
observations, and maintenance activities. The following items shall
be inspected and maintained as stated:
| |||
|
Flow Spreader shall allow runoff to enter the vegetative
filter as predominantly sheet flow.
| |||
|
•
|
Source of erosion damage shall be identified and controlled
when native soil is exposed or erosion channels are forming.
| ||
|
•
|
Sediment build-up near or exceeding 2 inch in depth shall be
removed.
| ||
|
Filter Inlet shall assure unrestricted stormwater
flow to the vegetative filter.
| |||
|
•
|
Sources of erosion shall be identified and controlled when native
soil is exposed or erosion channels are present.
| ||
|
•
|
Sediment accumulation shall be hand-removed with minimum damage
to vegetation using proper erosion control measures, ediment shall
be removed if it is more than 2 inches thick or so thick as to damage
or kill vegetation.
| ||
|
•
|
Inlet shall be cleared when conveyance capacity is plugged.
| ||
|
•
|
Rock splash pads shall be replenished to prevent erosion.
| ||
|
Filter Media shall allow stormwater to percolate
uniformly through the vegetative filter.
| |||
|
•
|
If the vegetative filter does not drain within 48 hours, it
shall be re-graded and replanted according to design specifications.
Established trees shall not be removed or harmed in this process.
| ||
|
•
|
Debris in quantities more than 2 inch deep or sufficient to
inhibit operation shall be removed routinely (e.g., no less than quarterly),
or upon discovery.
| ||
|
Check Dams and Dissipaters shall direct and control
flow.
| |||
|
•
|
Causes for altered water flow and channelization shall be identified,
and obstructions cleared upon discovery.
| ||
|
•
|
Cracks, rot, and structural damage shall be repaired.
| ||
|
Filter Outlet shall allow water to exit the vegetative
filter as sheet flow, unless a collection drainpipe is used.
| |||
|
•
|
Sources of erosion damage shall be identified and controlled
when native soil is exposed or erosion channels are deeper than 2
inches.
| ||
|
•
|
Outlet shall be cleared when 50 percent of the conveyance capacity
is plugged. Sources of sediment and debris shall be identified and
corrected.
| ||
|
Vegetation shall be healthy and dense enough (at
least 90 percent cover) to provide filtering while protecting underlying
soils from erosion.
| |||
|
•
|
Fallen leaves and debris from deciduous plant foliage shall
be raked and removed if build up is damaging vegetation.
| ||
|
•
|
Nuisance and prohibited vegetation (such as blackberries and
English Ivy) shall be removed when discovered. Invasive vegetation
contributing up to 25 percent of vegetation of all species shall be
removed and replaced.
| ||
|
•
|
Dead vegetation shall be removed to maintain less than 10 percent
of area coverage or when vegetative filter function is impaired. Vegetation
shall be replaced immediately to control erosion where soils are exposed
and within 3 months to maintain cover density.
| ||
|
Debris and Litter shall be removed to ensure stormwater
conveyance and to prevent clogging of inlet and outlet drains and
interference with plant growth.
| |||
|
Spill Prevention measures shall be exercised when
handling substances that contaminate stormwater. Releases of pollutants
shall be corrected as soon as identified.
| |||
|
Training and/or written guidance information for
operating and maintaining vegetated filters shall be provided to all
property owners and tenants. A copy of the O&M Plan shall be provided
to all property owners and tenants.
| |||
|
Access to the vegetative filter shall be safe and
efficient. Egress and ingress routes shall be maintained to design
standards. Obstacles preventing maintenance personnel and/or equipment
access to the facility shall be removed. Gravel or ground cover shall
be added if erosion occurs, e.g., due to vehicular or pedestrian traffic.
| |||
|
Insects and Rodents shall not be harbored in the
vegetated filter. Pest control measures shall be taken when insects/rodents
are found to be present.
| |||
|
•
|
If a complaint is received or an inspection reveals that a stormwater
facility is significantly infested with mosquitoes or other vectors,
the property owner/owners or their designee may be required to eliminate
the infestation at the City inspector's discretion. Control of the
infestation shall be attempted by using first non-chemical methods
and secondly, only those chemical methods specifically approved by
the City's inspector. Acceptable methods include but are not limited
to the following:
| ||
|
i.
|
Installation of predacious bird or bat nesting boxes.
| ||
|
ii.
|
Alterations of pond water levels approximately every 4 days
in order to disrupt mosquito larval development cycles.
| ||
|
iii.
|
Stocking ponds and other permanent water facilities with fish
or other predatory species.
| ||
|
iv.
|
If non-chemical methods have proved unsuccessful, contact the
City inspector prior to use of chemical methods such as the mosquito
larvicides Bacillus thurengensis var. israeliensis or other approved
larvicides. These materials may only be used with City inspector approval
if evidence can be provided that these materials will not migrate
off site or enter the public stormwater system. Chemical larvicides
shall be applied by a licensed individual or contractor.
| ||
|
•
|
Holes in the ground located in and around the vegetated filter
shall be filled.
| ||
|
Stormwater Planters
Operations and Maintenance Plan
| |||
|---|---|---|---|
|
Stormwater Planters are designed to allow runoff
to filter through layers of topsoil (thus capturing pollutants) and
then either infiltrate into the native soils (infiltration planter)
or be collected in a pipe to be discharged off-site (flow-through
planter). The planter is sized to accept runoff and temporarily store
the water in a reservoir on top of the soil. The flow-through planter
is designed with an impervious bottom or is placed on an impervious
surface. Water should drain through the planter within 3-4 hours after
a storm event. All facility components and vegetation shall be inspected
for proper operations and structural stability. These inspections
shall occur, at a minimum, quarterly for the first 2 years from the
date of installation, 2 times per year thereafter, and within 48 hours
after each major storm event. The facility owner must keep a log,
recording all inspection dates, observations, and maintenance activities.
The following items shall be inspected and maintained as stated:
| |||
|
Downspout from rooftop or sheet flow from paving
allows unimpeded stormwater flow to the planter.
| |||
|
•
|
Debris shall be removed routinely (e.g., no less than every
6 months) and upon discovery.
| ||
|
•
|
Damaged pipe shall be repaired upon discovery.
| ||
|
Splash Blocks prevent splashing against adjacent
structures and convey water without disrupting media.
| |||
|
•
|
Any deficiencies in structure such as cracking, rotting, and
failure shall be repaired.
| ||
|
Planter Reservoir receives and detains storm water
prior to infiltration. Water should drain from reservoir within 3-4
hours of storm event.
| |||
|
•
|
Sources of clogging shall be identified and corrected to prevent
short circuiting.
| ||
|
•
|
Topsoil may need to be amended with sand or replaced all together
to achieve a satisfactory infiltration rate.
| ||
|
Filter Media consisting of sand, gravel and topsoil
shall allow stormwater to percolate uniformly through the planter.
The planter shall be excavated and cleaned, and gravel or soil shall
be replaced to correct low infiltration rates.
| |||
|
•
|
Holes that are not consistent with the design and allow water
to flow directly through the planter to the ground shall be plugged.
| ||
|
•
|
Sediment accumulation shall be hand removed with minimum damage
to vegetation using proper erosion control measures. Sediment shall
be removed if it is more than 4 inches thick or so thick as to damage
or kill vegetation.
| ||
|
•
|
Litter and debris shall be removed routinely (e.g., no less
than quarterly) and upon discovery.
| ||
|
Planter shall contain filter media and vegetation.
| |||
|
•
|
Structural deficiencies in the planter including rot, cracks,
and failure shall be repaired.
| ||
|
Overflow Pipe safely conveys flow exceeding reservoir
capacity to an approved stormwater receiving system.
| |||
|
•
|
Overflow pipe shall be cleared of sediment and debris when 50
percent of the conveyance capacity is plugged.
| ||
|
•
|
Damaged pipe shall be repaired or replaced upon discovery.
| ||
|
Vegetation shall be healthy and dense enough (at
least 90 percent cover) to provide filtering while protecting underlying
soils from erosion.
| |||
|
•
|
Mulch shall be replenished at least annually.
| ||
|
•
|
Vegetation, large shrubs or trees that limit access or interfere
with planter operation shall be pruned or removed.
| ||
|
•
|
Fallen leaves and debris from deciduous plant foliage shall
be raked and removed if build up is damaging vegetation.
| ||
|
•
|
Nuisance or prohibited vegetation shall be removed when discovered.
Invasive vegetation contributing up to 25 percent of vegetation of
all species shall be removed and replaced.
| ||
|
•
|
Dead vegetation shall be removed to maintain less than 10 percent
of area coverage or when planter function is impaired. Vegetation
shall be replaced within a specific timeframe, e.g., 3 months, or
immediately if required to maintain cover density and control erosion
where soils are exposed.
| ||
|
Debris and Litter shall be removed to ensure stormwater
infiltration and to prevent clogging of overflow drains and interference
with plant growth.
| |||
|
Spill Prevention measures shall be exercised when
handling substances that contaminate stormwater. Releases of pollutants
shall be corrected as soon as identified.
| |||
|
Training and/or written guidance information for
operating and maintaining stormwater planters shall be provided to
all property owners and tenants. A copy of the O&M Plan shall
be provided to all property owners and tenants.
| |||
|
Access to the stormwater planter shall be safe
and efficient. Egress and ingress routes shall be maintained to design
standards. Roadways shall be maintained to accommodate size and weight
of vehicles, if applicable.
| |||
|
•
|
Obstacles preventing maintenance personnel and/or equipment
access to the stormwater planter shall be removed.
| ||
|
•
|
Gravel or ground cover shall be added if erosion occurs, e.g.,
due to vehicular or pedestrian traffic.
| ||
|
Insects and Rodents shall not be harbored in the
stormwater planter. Pest control measures shall be taken when insects/rodents
are found to be present.
| |||
|
•
|
If a complaint is received or an inspection reveals that a stormwater
facility is significantly infested with mosquitoes or other vectors,
the property owner/owners or their designee may be required to eliminate
the infestation at the City inspector's discretion. Control of the
infestation shall be attempted by using first non-chemical methods
and secondly, only those chemical methods specifically approved by
the City's inspector. Acceptable methods include but are not limited
to the following:
| ||
|
i.
|
Installation of predacious bird or bat nesting boxes.
| ||
|
ii.
|
Alterations of pond water levels approximately every 4 days
in order to disrupt mosquito larval development cycles.
| ||
|
iii.
|
Stocking ponds and other permanent water facilities with fish
or other predatory species.
| ||
|
iv.
|
If non-chemical methods have proved unsuccessful, contact the
City inspector prior to use of chemical methods such as the mosquito
larvicides Bacillus thurengensis var. israeliensis or other approved
larvicides. These materials may only be used with City inspector approval
if evidence can be provided that these materials will not migrate
off site or enter the public stormwater system. Chemical larvicides
shall be applied by a licensed individual or contractor.
| ||
|
•
|
Holes in the ground located in and around the stormwater planter
shall be filled and compacted.
| ||
|
Rain Gardens
Operations and Maintenance Plan
| |||
|---|---|---|---|
|
A vegetated Infiltration Basin or rain garden is
a vegetated depression created by excavation, berms, or small dams
to provide for short-term ponding of surface water until it percolates
into the soil. The basin shall infiltrate stormwater within 24 hours.
All facility components and vegetation shall be inspected for proper
operations and structural stability, at a minimum, quarterly for the
first 2 years from the date of installation, 2 times per year thereafter,
and within 48 hours after each major storm event. The facility owner
must keep a log, recording all inspection dates, observations, and
maintenance activities. The following items shall be inspected and
maintained as stated:
| |||
|
Basin Inlet shall assure unrestricted stormwater
flow to the vegetated basin.
| |||
|
•
|
Sources of erosion shall be identified and controlled when native
soil is exposed or erosion channels are present.
| ||
|
•
|
Inlet shall be cleared when conveyance capacity is plugged.
| ||
|
•
|
Rock splash pads shall be replenished to prevent erosion.
| ||
|
Embankment, Dikes, Berms and Side Slopes retain
water in the infiltration basin.
| |||
|
•
|
Structural deficiencies shall be corrected upon discovery:
| ||
|
○
|
Slopes shall be stabilized using appropriate erosion control
measures when soil is exposed/flow channels are forming.
| ||
|
○
|
Sources of erosion damage shall be identified and controlled.
| ||
|
Overflow or Emergency Spillway conveys flow exceeding
reservoir capacity to an approved stormwater receiving system.
| |||
|
•
|
Overflow shall be cleared when 25 percent of the conveyance
capacity is plugged.
| ||
|
•
|
Sources of erosion damage shall be identified and controlled
when soil is exposed.
| ||
|
•
|
Rocks or other armament shall be replaced when only 1 layer
of rock exists.
| ||
|
Filter Media shall allow stormwater to percolate
uniformly through the infiltration basin. If water remains 36-48 hours
after storm, sources of possible clogging shall be identified and
corrected.
| |||
|
•
|
Basin shall be raked and, if necessary, soil shall be excavated,
and cleaned or replaced.
| ||
|
•
|
Infiltration area shall be protected from compaction during
construction.
| ||
|
Sediment/Basin Debris Management shall prevent
loss of infiltration basin volume caused by sedimentation. Gauges
located at the opposite ends of the basin shall be maintained to monitor
sedimentation.
| |||
|
•
|
Sediment and debris exceeding 3 inch in depth shall be removed
every 2-5 years or sooner if performance is affected.
| ||
|
Debris and Litter shall be removed to ensure stormwater
infiltration and to prevent clogging of overflow drains and interference
with plant growth.
| |||
|
•
|
Restricted sources of sediment and debris, such as discarded
lawn clippings, shall be identified and prevented.
| ||
|
Vegetation shall be healthy and dense enough (at
least 90 percent cover) to provide filtering while protecting underlying
soils from erosion.
| |||
|
•
|
Mulch shall be replenished as needed to ensure healthy plant
growth
| ||
|
•
|
Vegetation, large shrubs or trees that limit access or interfere
with basin operation shall be pruned or removed.
| ||
|
•
|
Grass shall be mowed to 4 inches to 9 inches high and grass
clippings shall be removed no less than 2 times per year.
| ||
|
•
|
Fallen leaves and debris from deciduous plant foliage shall
be raked and removed if build up is damaging vegetation.
| ||
|
•
|
Nuisance or prohibited vegetation (such as blackberries or English
Ivy) shall be removed when discovered. Invasive vegetation contributing
up to 25 percent of vegetation of all species shall be removed.
| ||
|
•
|
Dead vegetation shall be removed to maintain less than 10 percent
of area coverage or when infiltration basin function is impaired.
Vegetation shall be replaced within 3 months, or immediately if required
to control erosion.
| ||
|
Spill Prevention measures shall be exercised when
handling substances that contaminate stormwater. Releases of pollutants
shall be corrected as soon as identified.
| |||
|
Training and/or written guidance information for
operating and maintaining vegetated infiltration basins shall be provided
to all property owners and tenants. A copy of the O&M Plan shall
be provided to all property owners and tenants.
| |||
|
Access to the infiltration basin shall be safe
and efficient. Egress and ingress routes shall be maintained to design
standards. Roadways shall be maintained to accommodate size and weight
of vehicles, if applicable.
| |||
|
•
|
Obstacles preventing maintenance personnel and/or equipment
access to the infiltration basin shall be removed.
| ||
|
•
|
Gravel or ground cover shall be added if erosion occurs, e.g.,
due to vehicular or pedestrian traffic.
| ||
|
Insects and Rodents shall not be harbored in the
infiltration basin. Pest control measures shall be taken when insects/rodents
are found to be present.
| |||
|
•
|
If a complaint is received or an inspection reveals that a stormwater
facility is significantly infested with mosquitoes or other vectors,
the property owner/owners or their designee may be required to eliminate
the infestation at the City inspector's discretion. Control of the
infestation shall be attempted by using first non-chemical methods
and secondly, only those chemical methods specifically approved by
the City's inspector. Acceptable methods include but, are not limited
to, the following:
| ||
|
i.
|
Installation of predacious bird or bat nesting boxes.
| ||
|
ii.
|
Alterations of pond water levels approximately every 4 days
in order to disrupt mosquito larval development cycles.
| ||
|
iii.
|
Stocking ponds and other permanent water facilities with fish
or other predatory species.
| ||
|
iv.
|
If non-chemical methods have proved unsuccessful, contact the
City inspector prior to use of chemical methods such as the mosquito
larvicides Bacillus thurengensis var. israeliensis or other approved
larvicides. These materials may only be used with City inspector approval
if evidence can be provided that these materials will not migrate
off site or enter the public stormwater system. Chemical larvicides
shall be applied by a licensed individual or contractor.
| ||
|
•
|
Holes in the ground located in and around the infiltration basin
shall be filled.
| ||
|
If used at this site, the following will be applicable:
| |||
|
Fences shall be maintained to preserve their functionality
and appearance.
| |||
|
•
|
Collapsed fences shall be restored to an upright position.
| ||
|
•
|
Jagged edges and damaged fences shall be repaired or replaced.
| ||
|
Sand Filters
Operations and Maintenance Plan
| |||
|---|---|---|---|
|
Sand filters consist of a layer of sand in a structural
box used to trap pollutants. The water filters through the sand and
then flows into the surrounding soils or an underdrain system that
conveys the filtered stormwater to a discharge point. All facility
components, vegetation, and source controls shall be inspected for
proper operations and structural stability. These inspections shall
occur, at a minimum, quarterly for the first 2 years from the date
of installation, and 2 times per year thereafter, and within 48 hours
after each major storm event. The facility owner must keep a log,
recording all inspection dates, observations, and maintenance activities.
The following items shall be inspected and maintained as stated:
| |||
|
Filter Inlet shall allow water to uniformly enter
the sand filter as calm flow, in a manner that prevents erosion.
| |||
|
•
|
Inlet shall be cleared of sediment and debris when 40 percent
of the conveyance capacity is plugged.
| ||
|
•
|
Source of erosion damage shall be identified and controlled
when native soil is exposed or erosion channels are forming.
| ||
|
•
|
Sediment accumulation shall be hand-removed with minimum damage
to vegetation using proper erosion control measures. Sediment shall
be removed if it is more than 4 inches thick or so thick as to damage
or kill vegetation.
| ||
|
•
|
Rock splash pads shall be replenished to prevent erosion.
| ||
|
Reservoir receives and detains stormwater prior
to infiltration. If water does not drain within 2-3 hours of storm
event, sources of clogging shall be identified and correction action
taken.
| |||
|
•
|
Debris in quantities more than 1 cu ft or sufficient to inhibit
operation shall be removed routinely (e.g., no less than quarterly),
or upon discovery.
| ||
|
•
|
Structural deficiencies in the sand filter box including rot,
cracks, and failure shall be repaired upon discovery.
| ||
|
Filter Media shall allow to stormwater to infiltrate
uniformly through the sand filter. If water remains 36-48 hours after
storm, sources of possible clogging shall be identified and corrected.
| |||
|
•
|
Sand filter shall be raked and if necessary, the sand/gravel
shall be excavated, and cleaned or replaced.
| ||
|
•
|
Sources of restricted sediment or debris (such as discarded
lawn clippings) shall be identified and prevented.
| ||
|
•
|
Debris in quantities sufficient to inhibit operation shall be
removed no less than quarterly, or upon discovery.
| ||
|
•
|
Holes that are not consistent with the design structure and
allow water to flow directly through the sand filter to the ground
shall be filled.
| ||
|
•
|
The infiltration area shall be protected from compaction during
construction.
| ||
|
Underdrain Piping (where applicable) shall provide
drainage from the sand filter, and Cleanouts (where applicable) located
on laterals and manifolds shall be free of obstruction, and accessible
from the surface.
| |||
|
•
|
Under-drain piping shall be cleared of sediment and debris when
conveyance capacity is plugged. Cleanouts may have been constructed
for this purpose.
| ||
|
•
|
Obstructions shall be removed from cleanouts without disturbing
the filter media.
| ||
|
Overflow or Emergency Spillway conveys flow exceeding
reservoir capacity to an approved stormwater receiving system.
| |||
|
•
|
Overflow spillway shall be cleared of sediment and debris when
50 percent of the conveyance capacity is plugged.
| ||
|
•
|
Source of erosion damage shall be identified and controlled
when erosion channels are forming.
| ||
|
•
|
Rocks or other armament shall be replaced when sand is exposed
and eroding from wind or rain.
| ||
|
Vegetation
| |||
|
•
|
Vegetation, large shrubs or trees that limit access or interfere
with sand filter operation shall be pruned.
| ||
|
•
|
Fallen leaves and debris from deciduous plant foliage shall
be raked and removed.
| ||
|
•
|
Nuisance or prohibited vegetation (such as blackberries or English
Ivy) shall be removed when discovered. Invasive vegetation contributing
up to 25 percent of vegetation of all species shall be removed.
| ||
|
Debris and Litter shall be removed to ensure stormwater
infiltration and to prevent clogging.
| |||
|
Spill Prevention measures shall be exercised when
handling substances that contaminate stormwater. Releases of pollutants
shall be corrected as soon as identified.
| |||
|
Training and/or written guidance information for
operating and maintaining sand filters shall be provided to all property
owners and tenants. A copy of the O&M Plan shall be provided to
all property owners and tenants.
| |||
|
Access to the sand filter shall be safe and efficient.
Egress and ingress routes shall be maintained to design standards.
Roadways shall be maintained to accommodate size and weight of vehicles,
if applicable.
| |||
|
•
|
Obstacles preventing maintenance personnel and/or equipment
access to the facility shall be removed.
| ||
|
•
|
Gravel or ground cover shall be added if erosion occurs, e.g.,
due to vehicular or pedestrian traffic.
| ||
|
Insects and Rodents shall not be harbored in the
sand filter. Pest control measures shall be taken when insects/rodents
are found to be present.
| |||
|
•
|
If a complaint is received or an inspection reveals that a stormwater
facility is significantly infested with mosquitoes or other vectors,
the property owner/owners or their designee may be required to eliminate
the infestation at the City inspector's discretion. Control of the
infestation shall be attempted by using first non-chemical methods
and secondly, only those chemical methods specifically approved by
the City's inspector. Acceptable methods include but are not limited
to the following:
| ||
|
i.
|
Installation of predacious bird or bat nesting boxes.
| ||
|
ii.
|
Alterations of pond water levels approximately every 4 days
in order to disrupt mosquito larval development cycles.
| ||
|
iii.
|
Stocking ponds and other permanent water facilities with fish
or other predatory species.
| ||
|
iv.
|
If non-chemical methods have proved unsuccessful, contact the
City inspector prior to use of chemical methods such as the mosquito
larvicides Bacillus thurengensis var. israeliensis or other approved
larvicides. These materials may only be used with City inspector approval
if evidence can be provided that these materials will not migrate
off site or enter the public stormwater system. Chemical larvicides
shall be applied by a licensed individual or contractor.
| ||
|
•
|
Holes in the ground located in and around the infiltration basin
shall be filled.
| ||
|
Soakage Trenches
Operations and Maintenance Plan
| |||
|---|---|---|---|
|
Soakage Trenches consist of drain rock and sand,
and receive stormwater from roof downspouts and/or area drains. There
are various components within the system - piping, silt basin and
the trench itself. The Conveyance Piping consists of
an inlet pipe (downspout or area drain), an outlet pipe located between
the silt basin and the soakage trench, and a perforated pipe, located
on top of the aggregate bed of the soakage trench. The Silt
Basin is a structure receiving runoff from an inlet pipe and
conveying it to the soakage trench. The silt basin serves as the pre-treatment
system for the soakage trench, removing sediments and other debris
that can impact its proper functioning. All facility components, vegetation,
and source controls shall be inspected for proper operations and structural
stability. These inspections shall occur, at a minimum, quarterly
for the first 2 years from the date of installation, then 2 times
per year afterwards, or within 48 hours after each major storm. The
facility owner must keep a log, recording all inspection dates, observations,
and maintenance activities. The following items shall be inspected
and maintained as stated:
| |||
|
Soakage trench infiltration: If water is noticed
on top of the trench within 48 hours of a major storm, the soakage
trench may be clogged.
| |||
|
•
|
Check for debris/sediment accumulation, rake and remove and
evaluate upland causes (erosion, surface or roof debris, etc.
| ||
|
•
|
Assess the condition of the aggregate and the filter fabric
in the trench. If there is sediment in the aggregate, excavate and
replace.
| ||
|
•
|
If there is a tear in the filter fabric, repair or replace.
| ||
|
•
|
The soakage trench area shall be protected from compaction during
construction.
| ||
|
Conveyance Piping: If water ponds over the trench
for more than 48 hours after a major storm and no other cause if identified,
it may be necessary to remove the filter fabric to determine if the
perforated pipe is clogged with sediment or debris.
| |||
|
•
|
Any debris or algae growth located on top of the soakage trench
should be removed and disposed of properly.
| ||
|
•
|
If the piping has settled more than 1-inch, add fill material.
If there are cracks or releases, replace or repair the pipe. If there
are signs of erosion around the pipe, this may be an indication of
water seeping due to a crack or break.
| ||
|
Silt Basin: If water remains in the soakage trench
for 36-48 hours after storm, check for sediment accumulation in the
silt basin
| |||
|
•
|
If less than 50 percent capacity remains in the basin or 6 inches
of sediment has accumulated, remove and dispose the sediment.
| ||
|
Spill Prevention: Virtually all sites, including
residential and commercial, present dangers from spills. All homes
contain a wide variety of toxic materials including gasoline for lawn
mowers, antifreeze for cars, nail polish remover, pesticides, and
cleaning aids that can adversely affect groundwater if spilled. It
is important to exercise caution when handling substances that can
contaminate stormwater.
| |||
|
•
|
Activities that pose the chance of hazardous material spills
shall not take place near soakage trenches.
| ||
|
A Shut-Off Valve or Flow-Blocking Mechanism may
have been required with the construction of the soakage trench to
temporarily prevent stormwater from flowing into it, in the event
of an accidental material spill. This may also involve mats kept on
site that can be used to cover inlet drains in parking lots. The shut-off
valve shall remain in good working order, or if mats or other flow-blocking
mechanisms are used, they shall be kept in stock on-site.
| |||
|
Training and/or written guidance information for
operating and maintaining soakage trenches shall be provided to all
property owners and tenants. A copy of the O&M Plan shall be provided
to all property owners and tenants.
| |||
|
Access to the soakage trench is required for efficient
maintenance. Egress and ingress routes will be maintained to design
standards at inspections.
| |||
|
Insects and Rodents shall not be harbored in the
soakage trench. Pest control measures shall be taken when insects/rodents
are found to be present.
| |||
|
•
|
If a complaint is received or an inspection reveals that a stormwater
facility is significantly infested with mosquitoes or other vectors,
the property owner/owners or their designee may be required to eliminate
the infestation at the City inspector's discretion. Control of the
infestation shall be attempted by using first non-chemical methods
and secondly, only those chemical methods specifically approved by
the City's inspector. Acceptable methods include but are not limited
to the following:
| ||
|
i.
|
Installation of predacious bird or bat nesting boxes.
| ||
|
ii.
|
Alterations of pond water levels approximately every 4 days
in order to disrupt mosquito larval development cycles.
| ||
|
iii.
|
Stocking ponds and other permanent water facilities with fish
or other predatory species.
| ||
|
iv.
|
If non-chemical methods have proved unsuccessful, contact the
City inspector prior to use of chemical methods such as the mosquito
larvicides Bacillus thurengensis var. israeliensis or other approved
larva ides. These materials may only be used with City inspector approval
if evidence can be provided that these materials will not migrate
off site or enter the public stormwater system. Chemical larvicides
shall be applied by a licensed individual or contractor.
| ||
|
•
|
Holes in the ground located in and around the soakage trench
shall be filled.
| ||
|
Wet, Extended Wet, and Dry Ponds
Operations and Maintenance Plan
| |||
|---|---|---|---|
|
Wet Ponds are constructed ponds with a permanent
pool of water. Pollutants are removed from stormwater through gravitational
settling and biologic processes. Extended Wet Ponds are
constructed ponds with a permanent pool of water and open storage
space above for retention or short-term detention of large storm events.
Pollutants are removed from stormwater through gravitational settling
and biologic processes. Dry Ponds are constructed ponds
with temporary storage for the retention or detention of large storm
events. The stormwater is stored and released slowly over a matter
of hours. All facility components, vegetation, and source controls
shall be inspected for proper operations and structural stability.
These inspections shall occur, at a minimum, quarterly for the first
2 years from the date of installation, and 2 times per year thereafter,
and within 48 hours after each major storm event. The facility owner
must keep a log, recording all inspection dates, observations, and
maintenance activities. The following items shall be inspected and
maintained as stated:
| |||
|
Pond Inlet shall assure unrestricted stormwater
flow to the wet pond.
| |||
|
•
|
Inlet pipe shall be cleared when conveyance capacity is plugged.
Sources of sediment and debris shall be identified and corrected.
| ||
|
•
|
Determine if pipe is in good condition:
| ||
|
○
|
If more than 1 inch of settlement, add fill material and compact
soils.
| ||
|
○
|
If alignment is faulty, correct alignment.
| ||
|
○
|
If cracks or openings exist indicated by evidence of erosion
at leaks, repair or replace pipe as needed.
| ||
|
Forebay traps coarse sediments, reduces incoming
velocity, and distributes runoff evenly over the wet pond. A minimum
1-foot freeboard shall be maintained.
| |||
|
•
|
Sediment buildup exceeding 50 percent of the facility capacity
shall be removed every 2-5 years or sooner if performance is being
affected.
| ||
|
Embankment, Dikes, Berms and Side Slopes retain
water in the wet pond.
| |||
|
•
|
Slopes shall be stabilized using appropriate erosion control
measures when native soil is exposed or erosion channels are forming.
| ||
|
•
|
Structural deficiencies shall be corrected upon discovery:
| ||
|
○
|
If cracks exist, repair or replace structure.
| ||
|
○
|
If erosion channels deeper than 2 inches exist, stabilize surface.
Sources of erosion damage shall be identified and controlled.
| ||
|
Control Devices (e.g., weirs, baffles, etc.) shall
direct and reduce flow velocity. Structural deficiencies shall be
corrected upon discovery:
| |||
|
•
|
If cracks exist, repair or replace structure.
| ||
|
Overflow Structure conveys flow exceeding reservoir
capacity to an approved stormwater receiving system.
| |||
|
•
|
Overflow structure shall be cleared when 50 percent of the conveyance
capacity is plugged. Sources of sediment and debris shall be identified
and corrected.
| ||
|
•
|
Sources of erosion damage shall be identified and controlled
when native soil is exposed at the top of overflow structure or erosion
channels are forming.
| ||
|
•
|
Rocks or other armoring shall be replaced when only 1 layer
of rock exists above native soil.
| ||
|
Sediment and Debris Management shall prevent loss
of wet pond volume caused by sedimentation.
| |||
|
•
|
Wet ponds shall be dredged when 1 foot of sediment accumulates
in the pond.
| ||
|
•
|
Gauges located at the opposite ends of the wet pond shall be
maintained to monitor sedimentation. Gauges shall be checked 2 times
per year.
| ||
|
•
|
Sources of restricted sediment or debris, such as discarded
lawn clippings, shall be identified and prevented.
| ||
|
•
|
Debris in quantities sufficient to inhibit operation shall be
removed routinely, e.g. no less than quarterly, or upon discovery.
| ||
|
•
|
Litter shall be removed upon discovery.
| ||
|
Vegetation shall be healthy and dense enough to
provide filtering while protecting underlying soils from erosion and
minimizing solar exposure of open water areas.
| |||
|
•
|
Mulch shall be replenished at least annually.
| ||
|
•
|
Vegetation, large shrubs or trees that limit access or interfere
with wet pond operation shall be pruned or removed.
| ||
|
•
|
Grass (where applicable) shall be mowed to 4 inches to 9 inches
high and grass clippings shall be removed if build up is damaging
vegetation.
| ||
|
•
|
Fallen leaves and debris from deciduous plant foliage shall
be raked and removed if build up is damaging vegetation.
| ||
|
•
|
Nuisance or prohibited vegetation (such as blackberries or English
Ivy) shall be removed when discovered. Invasive vegetation contributing
up to 25 percent of vegetation of all species shall be removed and
replaced.
| ||
|
•
|
Dead vegetation shall be removed to maintain less than 10 percent
of area coverage or when wet pond function is impaired. Vegetation
shall be replaced within 3 months, or immediately if required to maintain
cover density and control erosion where soils are exposed. If removing
a dead or hazard tree a permit may be required, contact the City's
Public Works Department for details on tree removal.
| ||
|
•
|
Vegetation producing foul odors shall be eliminated.
| ||
|
Spill Prevention measures shall be exercised when
handling substances that can contaminate stormwater Releases of pollutants
shall be corrected as soon as identified.
| |||
|
Training and/or written guidance information for
operating and maintaining ponds shall be provided to all property
owners and tenants. A copy of the O&M Plan shall be provided to
all property owners and tenants.
| |||
|
Access to the wet pond shall be safe and efficient.
Egress and ingress routes shall be maintained to design standards.
Roadways shall be maintained to accommodate size and weight of vehicles,
if applicable.
| |||
|
•
|
Obstacles preventing maintenance personnel and/or equipment
access to the wet pond shall be removed.
| ||
|
•
|
Gravel or ground cover shall be added if erosion occurs, e.g.,
due to vehicular or pedestrian traffic.
| ||
|
Insects and Rodents shall not be harbored in the
pond. Pest control measures shall be taken when insects/rodents are
found to be present.
| |||
|
•
|
If a complaint is received or an inspection reveals that a stormwater
facility is significantly infested with mosquitoes or other vectors,
the property owner/owners or their designee may be required to eliminate
the infestation at the City inspector's discretion. Control of the
infestation shall be attempted by using first non-chemical methods
and secondly, only those chemical methods specifically approved by
the City's inspector. Acceptable methods include but are not limited
to the following:
| ||
|
i.
|
Installation of predacious bird or bat nesting boxes.
| ||
|
ii.
|
Alterations of pond water levels approximately every 4 days
in order to disrupt mosquito larval development cycles.
| ||
|
iii.
|
Stocking ponds and other permanent water facilities with fish
or other predatory species.
| ||
|
iv.
|
If non-chemical methods have proved unsuccessful, contact the
City inspector prior to use of chemical methods such as the mosquito
larvicides Bacillus thurengensis var. israeliensis or other approved
larvicides. These materials may only be used with City inspector approval
if evidence can be provided that these materials will not migrate
off site or enter the public stormwater system. Chemical larvicides
shall be applied by a licensed individual or contractor.
| ||
|
•
|
Holes in the ground located in and around the pond shall be
filled.
| ||
|
If used at this site, the following will be applicable:
| |||
|
Signage shall clearly convey information.
| |||
|
•
|
Broken or defaced signs shall be replaced or repaired.
| ||
|
Fences shall be maintained to preserve their functionality
and appearance.
| |||
|
•
|
Collapsed fences shall be restored to an upright position.
| ||
|
•
|
Jagged edges and damaged fences and shall be repaired or replaced.
| ||
|
Constructed Treatment Wetlands
Operations and Maintenance Plan
| |||
|---|---|---|---|
|
Constructed Treatment Wetlands remove pollutants
through several processes: sedimentation, filtration, and biological
processes. All facility components, vegetation, and source controls
shall be inspected for proper operations and structural stability.
These inspections shall occur, at a minimum, quarterly for the first
2 years from the date of installation, and 2 times per year thereafter,
and within 48 hours after each major storm event. The facility owner
must keep a log, recording all inspection dates, observations, and
maintenance activities. The following items shall be inspected and
maintained as stated:
| |||
|
Wetland Inlet shall assure unrestricted stormwater
flow to the wetland.
| |||
|
•
|
Inlet pipe shall be cleared when conveyance capacity is plugged.
Sources of sediment and debris shall be identified and corrected.
| ||
|
•
|
Determine if pipe is in good condition:
| ||
|
○
|
If more than 1 inch of settlement, add fill material and compact
soils.
| ||
|
○
|
If alignment is faulty, correct alignment.
| ||
|
○
|
If cracks or openings exist indicated by evidence of erosion
at leaks, repair or replace pipe as needed.
| ||
|
Forebay traps coarse sediments, reduces incoming
velocity, and distributes runoff evenly over the wetland. A minimum
1-foot freeboard shall be maintained.
| |||
|
•
|
Sediment buildup exceeding 50 percent of the facility capacity
shall be removed every 2-5 years or sooner if performance is being
affected.
| ||
|
Embankment, Dikes, Berms and Side Slopes retain
water in the wetland.
| |||
|
•
|
Slopes shall be stabilized using appropriate erosion control
measures when native soil is exposed or erosion channels are forming.
| ||
|
•
|
Structural deficiencies shall be corrected upon discovery:
| ||
|
○
|
If cracks exist, repair or replace structure.
| ||
|
○
|
If erosion channels deeper than 2 inches exist, stabilize surface.
Sources of erosion damage shall be identified and controlled.
| ||
|
Control Devices (e.g., weirs, baffles, etc.) shall
direct and reduce flow velocity.
| |||
|
•
|
Structural deficiencies shall be corrected upon discovery:
| ||
|
○
|
If cracks exist, repair or replace structure.
| ||
|
Overflow Structure conveys flow exceeding reservoir
capacity to an approved stormwater receiving system.
| |||
|
•
|
Overflow structure shall be cleared when 50 percent of the conveyance
capacity is plugged. Sources of sediment and debris shall be identified
and corrected.
| ||
|
•
|
Sources of erosion damage shall be identified and controlled
when native soil is exposed at the top of overflow structure or erosion
channels are forming.
| ||
|
•
|
Rocks or other armament shall be replaced when only 1 layer
of rock exists above native soil.
| ||
|
Sediment and Debris Management shall prevent loss
of wetland volume caused by sedimentation.
| |||
|
•
|
Wetlands shall be dredged when 1 foot of sediment accumulates.
| ||
|
•
|
Gauges located at the opposite ends of the wetland shall be
maintained to monitor sedimentation. Gauges shall be checked 2 times
per year.
| ||
|
•
|
Sources of restricted sediment or debris, such as discarded
lawn clippings, shall be identified and prevented.
| ||
|
•
|
Debris in quantities sufficient to inhibit operation shall be
removed routinely, e.g. no less than quarterly, or upon discovery.
| ||
|
•
|
Litter shall be removed upon discovery.
| ||
|
Vegetation shall be healthy and dense enough to
provide filtering while protecting underlying soils from erosion and
minimizing solar exposure of open water areas.
| |||
|
•
|
Mulch shall be replenished when needed.
| ||
|
•
|
Vegetation, large shrubs or trees that limit access or interfere
with wetland operation shall be pruned.
| ||
|
•
|
Fallen leaves and debris from deciduous plant foliage shall
be raked and removed.
| ||
|
•
|
Nuisance or prohibited vegetation (such as blackberries or English
Ivy) shall be removed when discovered. Invasive vegetation contributing
up to 25 percent of vegetation of all species shall be removed and
replaced.
| ||
|
•
|
Dead vegetation shall be removed to maintain less than 10 percent
of area coverage or when wetland function is impaired. Vegetation
shall be replaced within 3 months, or immediately if required to maintain
cover density and control erosion where soils are exposed.
| ||
|
•
|
Vegetation producing foul odors shall be eliminated.
| ||
|
Spill Prevention measures shall be exercised when
handling substances that can contaminate stormwater Releases of pollutants
shall be corrected as soon as identified.
| |||
|
Training and/or written guidance information for
operating and maintaining treatment wetlands shall be provided to
all property owners and tenants. A copy of the O&M Plan shall
be provided to all property owners and tenants.
| |||
|
Access to the wetland shall be safe and efficient.
Egress and ingress routes shall be maintained to design standards.
Roadways shall be maintained to accommodate size and weight of vehicles,
if applicable.
| |||
|
•
|
Obstacles preventing maintenance personnel and/or equipment
access to the wetland shall be removed.
| ||
|
•
|
Gravel or ground cover shall be added if erosion occurs, e.g.,
due to vehicular or pedestrian traffic.
| ||
|
Insects and Rodents shall not be harbored in the
constructed treatment wetland. Pest control measures shall be taken
when insects/rodents are found to be present.
| |||
|
•
|
If a complaint is received or an inspection reveals that a stormwater
facility is significantly infested with mosquitoes or other vectors,
the property owner/owners or their designee may be required to eliminate
the infestation at the City inspector's discretion. Control of the
infestation shall be attempted by using first non-chemical methods
and secondly, only those chemical methods specifically approved by
the City's inspector. Acceptable methods include but are not limited
to the following:
| ||
|
i.
|
Installation of predacious bird or bat nesting boxes.
| ||
|
ii.
|
Alterations of pond water levels approximately every 4 days
in order to disrupt mosquito larval development cycles.
| ||
|
iii.
|
Stocking ponds and other permanent water facilities with fish
or other predatory species.
| ||
|
iv.
|
If non-chemical methods have proved unsuccessful, contact the
City inspector prior to use of chemical methods such as the mosquito
larvicides Bacillus thurengensis var. israeliensis or other approved
larvicides. These materials may only be used with City inspector approval
if evidence can be provided that these materials will not migrate
off-site or enter the public stormwater system. Chemical larvicides
shall be applied by a licensed individual or contractor.
| ||
|
•
|
Holes in the ground located in and around the constructed treatment
wetland shall be filled.
| ||
|
If used at this site, the following will be applicable:
| |||
|
Signage shall clearly convey information.
| |||
|
•
|
Broken or defaced signs shall be replaced or repaired.
| ||
|
Fences shall be maintained to preserve their functionality
and appearance.
| |||
|
•
|
Collapsed fences shall be restored to an upright position.
| ||
|
•
|
Jagged edges and damaged fences and shall be repaired or replaced.
| ||
|
Underground Detention Tanks, Vaults and Pipes
Operations and Maintenance Plan
| |||
|---|---|---|---|
|
Underground Detention Tanks, Vaults, and Pipes are
designed to fill with stormwater during large storm events, slowly
releasing it over a number of hours. There are numerous components
to each system. Drain Inlet Pipes convey stormwater into
the detention facility. The Detention Chamber is the
structure in which stormwater accumulates during a storm event. Orifice Structure/Outlet Drain Pipe restricts the flow out
of the detention chamber, allowing it to fill up and slowly drain
out. The orifice structure is located at the downstream end of the
detention chamber. Underground facilities shall be inspected quarterly
and within 48 hours after each major storm event. The facility owner
must keep a log, recording all inspection dates, observations, and
maintenance activities. The following items shall be inspected and
maintained as stated:
| |||
|
Proprietary Structures such as oil-water separators,
sedimentation manholes, grit chambers, etc. are required to have an
O&M plan submitted with material from the manufacturer for that
specific product for the O&M Agreement.
| |||
|
•
|
If such material is not available or satisfactory for maintenance
needs, city staff will assist developer/property owner in preparing
the O&M plan.
| ||
|
Drain Inlet Pipes shall be inspected for clogging
or leaks where it enters the vault or basin during every inspection
and cleanout.
| |||
|
•
|
Debris/sediment that is found to clog the inlet shall be removed,
and disposed of in accordance with applicable federal and state requirements.
| ||
|
Detention Chamber shall be inspected for cracks
or damage during each inspection.
| |||
|
•
|
The detention chamber shall be cleaned out yearly or after an
inch of sediment has accumulated. If there is a valve on the outlet
pipe it shall be closed otherwise the outlet shall be plugged prior
to cleanout. Grit and sediment that has settled to the bottom of the
chamber shall be removed during each cleaning.
| ||
|
•
|
Water and sediment in the detention chamber shall be removed,
and disposed of in accordance with regulations.
| ||
|
•
|
Cleaning shall be done without use of detergents or surfactants.
A pressure washer may be used if necessary.
| ||
|
Orifice Structure/Outlet Drain Pipe shall be inspected
for clogging during unit inspections/cleanouts.
| |||
|
•
|
Debris/sediment that is found to clog the inlet shall be removed,
and disposed of in accordance with applicable federal and state requirements.
| ||
|
Vegetation such as trees should not be located
in or around the detention facility because roots from trees can penetrate
the unit body, and leaves from deciduous trees and shrubs can increase
the risk of clogging the intake pipe.
| |||
|
•
|
Large shrubs or trees that are likely to interfere with detention
facility operation shall be identified at each inspection then removed.
| ||
|
Source Control measures typically include structural
and non-structural controls. Non-structural controls can include street
sweeping and other good housekeeping practices. It is often easier
to prevent pollutants from entering stormwater than to remove them.
| |||
|
•
|
Source control measures shall be inspected and maintained (where
applicable).
| ||
|
Spill Prevention procedures require high-risk site
users to reduce the risk of spills. However, virtually all sites,
including residential and commercial, present dangers from spills.
Homes contain a wide variety of toxic materials including gasoline
for lawn mowers, antifreeze for cars, pesticides, and cleaning aids
that can adversely affect storm water if spilled. It is important
for everyone to exercise caution when handling substances that can
contaminate stormwater. Spill prevention procedures shall be implemented
in areas where there is likelihood of spills from hazardous materials.
| |||
|
Training and/or written guidance information for
operating and maintaining detention facilities shall be provided to
all property owners and tenants. A copy of the O&M Plan shall
be provided to all property owners and tenants.
| |||
|
Access to the detention facility is required for
efficient maintenance. Egress and ingress routes shall be open and
maintained to design standards.
| |||
|
Signage may serve to educate people about the importance
or function of the site's stormwater protection measures. Signs may
also discourage behavior that adversely impacts the stormwater protection
measures and encourages behavior that enhances or preserves stormwater
quality. If debris is a problem, a sign reminding people not to litter
may partially solve the problem. Signage (where applicable) will be
maintained and repaired as needed during or shortly after inspections.
| |||
|
Insects and Rodents shall not be harbored in the
detention facility. Pest control measures shall be taken when insects/rodents
are found to be present
| |||
|
•
|
If a complaint is received or an inspection reveals that a stormwater
facility is significantly infested with mosquitoes or other vectors,
the property owner/owners or their designee may be required to eliminate
the infestation at the City inspector's discretion. Control of the
infestation shall be attempted by using first non-chemical methods
and secondly, only those chemical methods specifically approved by
the City's inspector. Acceptable methods include but are not limited
to the following:
| ||
|
i.
|
Installation of predacious bird or bat nesting boxes.
| ||
|
ii.
|
Alterations of pond water levels approximately every 4 days
in order to disrupt mosquito larval development cycles.
| ||
|
iii.
|
Stocking ponds and other permanent water facilities with fish
or other predatory species.
| ||
|
iv.
|
If non-chemical methods have proved unsuccessful, contact the
City inspector prior to use of chemical methods such as the mosquito
larvicides Bacillus thurengensis var. israeliensis or other approved
larvicides. These materials may only be used with City inspector approval
if evidence can be provided that these materials will not migrate
off site or enter the public stormwater system. Chemical larvicides
shall be applied by a licensed individual or contractor.
| ||
|
•
|
Holes in the ground located in and around the detention facility
shall be filled.
| ||
|
Drywells
Operations and Maintenance Plan
| |||
|---|---|---|---|
|
Drywells are designed to infiltrate stormwater
into the ground. Stormwater is piped to drywells from roof downspouts
or pollution control facilities such as swales or planters. The pollution
control facility is designed to settle out sediments and separate
oils and greases from the water before releasing it through a pipe
to the drywell. This prolongs the life of the drywell and helps to
prevent the contamination of soils and groundwater. The drywell is
a concrete or plastic manhole section with many small holes in the
sides to allow stormwater to infiltrate into the surrounding soil.
The drywell system shall be inspected and cleaned quarterly and within
48 hours after each major storm event. The facility owner must keep
a log, recording all inspection dates, observations, and maintenance
activities. Drywells are considered Underground Injection Wells in
Oregon and are subject to State regulations for permitting and testing
by the Oregon DEQ. The following items shall be inspected and maintained
as stated:
| |||
|
Stormwater Drain Pipe shall be inspected for clogging
or leaks where it enters the drywell.
| |||
|
•
|
Debris/sediment that is found to clog the pipe shall be removed
and disposed of in accordance with applicable federal and state requirements.
| ||
|
Drywell shall be inspected during each cleanout.
Ponding around the catch basins or sedimentation manhole or drywell
lids may indicate that the drywell is failing due to siltation, or
the clogging of the sediment pores surrounding the drywell. Clogged
drywells must be replaced.
| |||
|
Vegetation such as trees should not be located
in or around the drywell because roots from trees can penetrate the
unit body, and leaves from deciduous trees and shrubs can increase
the risk of clogging the intake pipe.
| |||
|
•
|
Large shrubs or trees that are likely to interfere with operation
will be identified at each inspection and removed.
| ||
|
Source Control measures typically include structural
and non-structural controls. Non-structural controls can include parking
lot or street sweeping and other good housekeeping practices. It is
often easier to prevent pollutants from entering stormwater than to
remove them.
| |||
|
•
|
Source control measures shall be inspected and maintained (where
applicable).
| ||
|
Spill Prevention procedures require high-risk site
users to reduce the risk of spills. However, virtually all sites,
including residential and commercial, present dangers from spills.
Homes contain a wide variety of toxic materials including gasoline
for lawn mowers, antifreeze for cars, solvents, pesticides, and cleaning
aids that can adversely affect storm water if spilled. It is important
to exercise caution when handling substances that can contaminate
stormwater. Spill prevention procedures shall be implemented in areas
where there is likelihood of spills from hazardous materials.
| |||
|
A Shut-Off Valve or Flow-Blocking Mechanism may
have been required with the construction of the drywell to temporarily
prevent stormwater from flowing into it, in the event of an accidental
material spill. This may also involve mats kept on-site that can be
used to cover inlet drains in parking lots. The shutoff valve shall
remain in good working order, or if mats or other flow-blocking mechanisms
are used, they shall be kept in stock on-site.
| |||
|
Training and/or written guidance information for
operating and maintaining drywell systems shall be provided to all
property owners and tenants. A copy of the O&M Plan shall be provided
to all property owners and tenants.
| |||
|
Access to the drywell is required for efficient
maintenance. Egress and ingress routes shall be open and maintained
to design standards.
| |||
|
•
|
City inspection staff may require owners to provide proof of
registration, permitting and maintenance logs for the facility as
required by the Oregon DEQ.
| ||
|
Insects and Rodents shall not be harbored in the
drywell. Pest control measures shall be taken when insects/rodents
are found to be present.
| |||
|
•
|
If a complaint is received or an inspection reveals that a stormwater
facility is significantly infested with mosquitoes or other vectors,
the property owner/owners or their designee may be required to eliminate
the infestation at the City inspector's discretion. Control of the
infestation shall be attempted by using first non-chemical methods
and secondly, only those chemical methods specifically approved by
the City's inspector. Acceptable methods include but are not limited
to the following:
| ||
|
i.
|
Installation of predacious bird or bat nesting boxes.
| ||
|
ii.
|
Alterations of pond water levels approximately every 4 days
in order to disrupt mosquito larval development cycles.
| ||
|
iii.
|
Stocking ponds and other permanent water facilities with fish
or other predatory species.
| ||
|
iv.
|
If non-chemical methods have proved unsuccessful, contact the
City inspector prior to use of chemical methods such as the mosquito
larvicides Bacillus thurengensis var. israeliensis or other approved
larvicides. These materials may only be used with City inspector approval
if evidence can be provided that these materials will not migrate
off site or enter the public stormwater system. Chemical larvicides
shall be applied by a licensed individual or contractor.
| ||
|
•
|
Holes in the ground located in and around the drywell shall
be filled.
| ||
|
Signage may serve to educate people about the importance
or function of the site's stormwater protection measures. Signs may
also discourage behavior that adversely impacts the stormwater protection
measures and encourages behavior that enhances or preserves stormwater
quality. If debris is a problem, a sign reminding people not to litter
may partially solve the problem. Signage (where applicable) shall
be maintained and repaired as needed during or shortly after inspections.
| |||
|
Spill Control Manholes
Operations and Maintenance Plan
| |||
|---|---|---|---|
|
Spill Control Manholes operate using the principal
that oil and water are immiscible (do not mix) and have different
densities. Oil, being less dense than water, floats to the surface.
The spill control manhole shall be inspected and cleaned quarterly.
The facility owner must keep a log, recording all inspection dates,
observations, and maintenance activities. The following items shall
be inspected and maintained as stated:
| |||
|
Stormwater Drain Inlet Pipe shall be inspected
for clogging or leaks where it enters the manhole during every inspection
and cleanout. Debris/sediment that is found to clog the inlet shall
be removed, tested, and disposed of in accordance with applicable
federal and state requirements.
| |||
|
Manhole Chamber shall be inspected for cracks or
damage during each inspection.
| |||
|
•
|
The manhole shall be cleaned out quarterly. Cleanout shall be
done in a manner to minimize the amount of trapped oil entering the
outlet pipe. If there is a valve on the outlet pipe it shall be closed
otherwise the outlet will be plugged prior to clean-out.
| ||
|
•
|
Water and oil shall be removed, tested, and disposed of in accordance
with regulations. Grit and sediment that has settled to the bottom
of the chamber shall be removed during each cleaning
| ||
|
•
|
Cleaning shall be done without use of detergents or surfactants.
A pressure washer along with a vacuum may be used if necessary.
| ||
|
Absorbent Pillows and Pads (where applicable) absorb
oil from the separation chamber.
| |||
|
•
|
Replacement shall occur at least twice a year, in the spring
and fall, or as necessary to retain oil-absorbing function.
| ||
|
Stormwater Drain Outlet Pipe shall be inspected
for clogging or leaks where it exits the manhole. Particular attention
shall be paid to ensure that the joint where the tee joins the outlet
pipe is watertight.
| |||
|
•
|
Debris/sediment that is found to clog the outlet shall be removed,
tested, and disposed of in accordance with applicable federal and
state requirements.
| ||
|
Vegetation such as trees should not be located
in or around the spill control manhole because roots can penetrate
the unit body, and leaves from deciduous trees and shrubs can increase
the risk of clogging.
| |||
|
•
|
Large shrubs or trees that are likely to interfere with manhole
operation shall be identified at each inspection and removed.
| ||
|
Source Control measures typically include structural
and non-structural controls. Non-structural controls can include street
sweeping and other good housekeeping practices.
| |||
|
•
|
Source control measures shall be inspected and maintained.
| ||
|
Spill Prevention procedures require high-risk site
users to reduce the risk of spills. However, virtually all sites,
including residential and commercial, present dangers from spills.
Homes contain a wide variety of toxic materials including gasoline
for lawn mowers, antifreeze for cars, pesticides, and cleaning aids
that can adversely affect storm water if spilled. It is important
to exercise caution when handling substances that can contaminate
stormwater. Spill prevention procedures shall be implemented in areas
where there is likelihood of spills from hazardous materials.
| |||
|
Training and/or written guidance information for
operating and maintaining spill control manholes shall be provided
to all property owners and tenants. A copy of the O&M Plan shall
be provided to all property owners and tenants.
| |||
|
Access to the spill control manhole is required
for efficient maintenance. Egress and ingress routes shall be open
and maintained to design standards.
| |||
|
Insects and Rodents shall not be harbored in the
spill control manhole. Pest control measures shall be taken when insects/rodents
are found to be present.
| |||
|
•
|
If a complaint is received or an inspection reveals that a stormwater
facility is significantly infested with mosquitoes or other vectors,
the property owner/owners or their designee may be required to eliminate
the infestation at the City inspector's discretion. Control of the
infestation shall be attempted by using first non-chemical methods
and secondly, only those chemical methods specifically approved by
the City's inspector. Acceptable methods include but are not limited
to the following:
| ||
|
i.
|
Installation of predacious bird or bat nesting boxes.
| ||
|
ii.
|
Alterations of pond water levels approximately every 4 days
in order to disrupt mosquito larval development cycles.
| ||
|
iii.
|
Stocking ponds and other permanent water facilities with fish
or other predatory species.
| ||
|
iv.
|
If non-chemical methods have proved unsuccessful, contact the
City inspector prior to use of chemical methods such as the mosquito
larvicides Bacillus thurengensis var. israeliensis or other approved
larvicides. These materials may only be used with City inspector approval
if evidence can be provided that these materials will not migrate
off site or enter the public stormwater system. Chemical larvicides
shall be applied by a licensed individual or contractor.
| ||
|
•
|
Holes in the ground located in and around the manhole shall
be filled.
| ||
|
Signage may serve to educate people about the importance
or function of the site's stormwater protection measures. Signage
(where applicable) shall be maintained and repaired as needed during
or shortly after inspections.
| |||
