HomeMy WebLinkAboutINVERNESS INNOVATION PARK EXHIBIT C - Filed DA-DEVELOPMENT AGREEMENT - 2010-08-18Exhibit C
Operating Procedures for
The Inverness Innovation Park, First Filing
Infiltration Pond & Collection System
July 20, 2010
(Note this document has been developed from and much of the content is taken directly from the "Douglas County, Colorado Standard
Operating Procedure (SOP) for Porous Landscape Detention (PLD) Inspection and Maintenance" as adapted from the Douglas County,
Colorado, Standard Operating Procedures for Extended Detention Basin (EDB) Inspection and Maintenance, July 2005.)
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Table PLD-3
Summary of Minor Maintenance Activities
Maintenance
Minimum
Look For:
Maintenance Action
Activity
Frequency
Remove and dispose of sediment
Sediment/Pollutant
As needed:
Sediment build-
removal
Based on
up; decrease in
infiltration
infiltration rate
performance
Repair eroded areas and re -vegetate.
Erosion Repair
As needed:
Rillying/Gullying
based on
and eroding of
Address cause.
inspections
soil on
embankments
Clean drains; let Vac as needed. Remove
Upstream Drainage
As needed
Sediment build-
System Cleaning
based on
up and non-
all sediments from drainage system and
inspections
draining pipes
dispose off site.
Overflow Spillway
As needed
Erosion,
Repair eroded areas and revegetate.
Maintenance
based on
sedimentation
Address cause. Remove foreign woody
inspections
and growth of
vegetation.
foreign woody
vegetation
PLD-3.7.1: Sediment/Pollutant Removal:
Sediment/pollutant removal is necessary to ensure proper function of the filter media. The
infiltration rate of the PLD needs to be checked in order to ensure proper functioning of the
PLD. Generally, a PLD should drain completely within 48 hours of a storm event. If drain
times exceed 72 hours then maintenance of the filter shall be required. To accomplish this
the top 3 inches of the filter media (pit run) shall be removed. Additional amounts of filter
media may need to be removed if deeper sections of the filter media are contaminated. It is
critical that the specified pit run (or a more pervious material approved by the Civil Engineer
of Record) material be utilized in the replacement of the filter media.
Other types of filter media may lead to clogging of the PLD. The minor sediment removal
activities can typically be addressed with shovels and rakes and other small equipment. Major
sediment removal activities will require larger and more specialized equipment. Extreme care
should be taken when utilizing motorized or heavy equipment to ensure damage to the filter
media and embankments does not occur. The major sediment activities will also require
surveying with an engineer's level to ensure design volumes/grades are achieved.
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Stormwater sediments removed from PLDs do not meet the regulatory definition of
"hazardous waste". However, these sediments can be contaminated with a wide array or
organic and inorganic pollutants and handling must be done with care. Sediments should be
transported by motor vehicle only after they are dewatered. All sediments must be taken to a
licensed landfill for proper disposal. Should a spill occur during transportation prompt and
thorough cleanup and disposal is imperative.
PLD-3.7.2: Erosion Repair:
The repair of eroded areas is necessary to ensure the proper functioning of the PLD, to
minimize sediment transport, and to reduce potential impacts to other features downstream.
Erosion can vary in magnitude from minor repairs to filter media and embankments, to rills
and gullies in the embankments and inflow points. The repair of eroded areas may require
the use of excavators, earthmoving equipment, riprap, concrete, and re -vegetation. Extreme
care should be taken when utilizing motorized or heavy equipment to ensure damage to the
filter media and embankments does not occur.
PLD-3.7.3: Upstream Drainage System Cleaning:
The upstream drainage system collects and transports stormwater to the PLD. This systems of
inlets and pipes can develop blockage that can result in a decrease of hydraulic capacity and
also create standing water upstream. Sedimentaion in the drainage system must be removed
in such a way that it does not flow into the PLD. This can be accomplished by hand methods
or the use of specialized equipment (jet -vac machines). All sediment removal activities in the
upstream drainage system must include provision for collection and disposal of sediment
material. In no case is it permissible for sediment material of any kind to be flushed into, or
enter into the PLD. All sediment material must be collected before reaching the PLD and
disposed of off site.
PLD-3.7.4: Overflow Spillway Maintenance:
Any erosion of the banks or sediments deposited on top of the bank must be corrected to
ensure the overflow bank is at the designed elevation, per the Civil Construction Drawings
approved by the City of Fort Collins. All foreign wood vegetation on or around the
embankments must be removed.
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PLD-3.8: Major Maintenance Activities:
This work consists of larger maintenance and operational problems and failures within the
stormwater management facilities. All of this work requires consultation with the civil engineer
of record and the City of Fort Collins to ensure proper maintenance is performed. This work may
also require more specialized maintenance equipment, design/details, surveying, or assistance
through private contractors.
Table PLD-4
Summary of Major Maintenance Activities
Maintenance Activity
Minimum Frequency
Look For:
Maintenance Action
Major
As needed: Based on
Large quantities of
Remove and dispose
Sediment/Pollutant
infiltration
sediment build-up;
of sediment. Replace
removal
performance
reduced infiltration
all contaminated filter
rate
media. Repair
vegetation as needed.
Major Erosion Repair
As needed: based on
Severe erosion,
Repair erosion — find
inspections
including gullying,
cause of problem and
excessive soil
address to avoid
displacement, areas of
future erosion.
settlement, holes.
Remove all material
deposited within PLD
due to erosion.
Structural Repair
As needed based on
Deterioration and/or
Structural repair to
inspections
damage to structural
restore the structure
components — broken
to its original design
concrete, damaged
pipes, and overflow
outlet.
PLD Rebuild As needed due to Removal of filter Contact Civil Engineer
complete failure of media of Record and the City
PLD
of Fort Collins
Stormwater
Department.
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PLD-3.8.1: Major Sediment/Pollutant Removal:
Major sediment removal consists of removal of large quantities of pollutants/sediment/filter
media/landscape material. Extreme care should be taken when utilizing motorized or heavy
equipment to ensure damage to drainage system does not occur. Stormwater sediments
removed from PLDs do not meet the regulatory definition of "hazardous waste". However,
these sediments can be contaminated with a wide array of organic and inorganic pollutants
and handling must be done with care. Sediments should be transported by motor vehicle only
after they are dewatered. All sediments must be taken to a licensed landfill for proper
disposal. Should a spill occur during transportation prompt and thorough cleanup and
disposal is imperative. Vegetated areas need special care to ensure design volumes and
grades are preserved or may need to be replaced due to the removal activities. Refer to
approved landscape drawings for re -vegetation requirements.
PLD-3.8.2: Major Erosion Repair:
Major erosion repair consists of filling and re -vegetating areas of severe erosion. Determining
the cause of the erosion as well as correcting the condition that caused the erosion should
also be part of the erosion repair. Care should be given to ensure design grades and volumes
are preserved. Extreme care should be taken when utilizing motorized or heavy equipment to
ensure damage to the filter media and drainage system does not occur. All sediment material
deposited within the PLD due to erosion must be removed.
PLD-3.8.3: Structural Repair:
Structural elements of the PLD include concrete earthen embankments, flare end sections,
drainage pipe, and riprap structures. These structures can degrade or be damaged and may
need to be repaired or reconstructed from time to time. Major repairs to structures require
consultation with the Civil Engineer of Record and the City of Fort Collins to ensure proper
repairs are made. This work may also require more specialized maintenance equipment,
design/details, surveying, or assistance through private contractors.
PLD-3.8.4: PLD Rebuild:
In very rare cases the PLD may need to be rebuilt. The need for a complete rebuild is a result
of improper construction, improper maintenance resulting in structural damage to the PLD, or
extensive contamination of the PLD. Consultation with the Civil Engineer of Record and the
City of Fort Collins Stormwater Department shall take place prior to any rebuild project.
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Appendix A
Inverness Innovation Park Operation and Maintenance Inspection Report
The undersigned has inspected the Infiltration Pond located in the Inverness Innovation Park (lip). The items listed below
have been reviewed and, if needed, action required is identified.
Actions:
Routine Maintenance
�
Completed or No
Action Needed
Action
Needed:
Course of Action Required:
Mowing
Trash/Debris Removal
Weed Control
Other
Minor Maintenance
Sediment/Pollutant
Removal
Erosion Repair
Upstream Drainage
Sytem Cleaning
Overflow Spillway
Maintenance
Major Maintenance
Major
Sediment/Pollutant
Removal
Major Erosion Repair
Structural Repair
Structural Repair
PLD Rebuild
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Table of Contents:
PLD-1: Acronyms and Defmit
PLD-2: "``1CiSpCbT1 Qf th�trtft#dfto
/Retention Pond
PLD-2.1: Access and Easements
PLD-2.2: Porous Landscape Detention (PLD) Features
Table PLD-1: Typical Inspection & Maintenance Requirements
PLD-2.2.1: Inflow Points
PLD-2.2.2: Landscaping
PLD-2.2.3: Filter Media
PLD-2.2.4: Overflow Spillway
PLD-2.2.5: Embankments
PLD-2.2.6: Upstream Drainage System
PLD-2.2.7: Miscellaneous
PLD-2.3: Completed Inspection Forms
PLD-3: Maintaining Porous Landscape Detentions (PLDs)
PLD-3.1: Maintenance Personnel
PLD-3.2: Equipment
PLD-3.3: PLD Maintenance Forms
PLD-3.4: Completed Maintenance Forms
PLD-3.5: PLD Maintenance Categories and Activities
PLD-3.6: Routine Maintenance Activities
Table PLD-2: Summary of Routine Maintenance Activities
PLD-3.6.1: Mowing
PLD-3.6.2: Trash/Debris Removal
PLD-3.6.3: Weed Control
PLD-3.7: Minor Maintenance Activities
Table PLD-3: Summary of Minor Maintenance Activities
PLD-3.7.1: Sediment/Pollutant Removal
PLD-3.7.2: Erosion Repair
PLD-3.7.3: Upstream Drainage System Cleaning
PLD-3.7.4: Overflow Spillway Maintenance
PLD-3.8: Major Maintenance Activities
Table PLD-4: Summary of Major Maintenance Activities
PLD-3.8.1: Major Sediment/Pollutant Removal
PLD-3.8.2: Major Erosion Repair
PLD-3.8.3: Structural Repair
PLD-3.8.4: PLD Rebuild
Appendix A — Inspection Form
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PLD-1: ACRONYMS:
SOP — Standard operating procedure
EDB — Extended detention basin
PLD — Porous landscape detention
PLD-2: INSPECTION OF THE INFILTRATION/RETENTION POND
PLD-2.1: Access and Easements
Inspection or maintenance personnel may access the PLD from the east end near the high
tension power line tower.
PLD-2.2: Porous Landscape Detention Features:
PLDs have a number of features that are designed to serve a particular function. Many times
the proper function of one feature depends on another. It is important for maintenance
personnel to understand the function of each of these features to prevent damage to any
feature during maintenance operations.
Table PLD-1
Typical Inspection & Maintenance Requirements
Sediment
Removal
Mowing &
Weed
Control
Trash &
Debris
Removal
Erosion
Overgrown
Vegetation
Removal
Removal /
Replacement
Structure
Repair
Inflow Points
X
X
X
Landscaping
X
X
X
X
X
Overflow Outlet
Works
X
X
X
Embankment
X
X
X
X
PLD-2.2.1: Inflow Points:
Inflow points or outfalls into PLDs are the point of stormwater discharge into the facility. The
inflow points are curb inlets in the parking lots and along Vine Drive.
An energy dissipater (riprap) is immediately downstream of the discharge point into the PLD
to protect the PLD from erosion.
q
Maintenance items are:
• Riprap displaced — Many times because of repeated impact/force of water the
riprap can shift and settle. If any portion of the riprap rundown appears to have
settled, soil is present between the riprap, or riprap has shifted, corrective
maintenance should be performed to ensure future erosion is prevented.
• Erosion Present/Outfall Undercut — Any erosion within the vicinity of the inflow
point will require maintenance to prevent damage to the structure and sediment
transport within the facility. Material utilized to correct erosion problems shall
meet the specifications of the original material as approved by the construction
drawings. Any deposited sediment material not meeting the specifications of the
original material must be removed.
• Sediment Accumulation — Because of the turbulence in the water created by the
energy dissipater, sediment often deposits immediately downstream of the inflow
point. To prevent a loss in performance of the upstream infrastructure, sediment
that accumulates in this area must be removed on a timely basis.
• Structural Damage — Structural damage can occur at anytime during the life of the
facility. Structural damage can lead to additional operating problems with the
facility, including loss of hydraulic performance. Any structural damage identified
shall be reported and corrective actions shall be taken as approved by the Civil
Engineer of Record.
PLD-2.2.2: Landscaping:
The landscape area consists of specific seed mix in the bottom of the PLD. These plantings
provide for aesthetic, as well as biological uptake and removal of pollutants. Maintenance of
this planting shall be as follows:
• Woody Growth/Weeds Present — undesirable vegetation can grow in and around
the landscaped area in the PLD and can significantly impact the performance of the
facility. Routine management to remove undesirable vegetation is essential to
prevent debris/sediment to accumulate and blockage of the filter media.
• General Landscape Care— The plantings in the PLD need to have regular care,
including mowing and fertilizing to ensure the aesthetics of the PLD.
PLD-2.2.3: Filter Media:
The filter media is the main pollutant removal component of the PLD. The filter media
consists of 24 inches of clean Pit Run from an approved source. The filter media removes
pollutants through several different processes including; sedimentation, filtration, adsorption,
infiltration, and microbial uptake.
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PLDs are not lined with an impervious liner to allow infiltration into the native soils. The
process also allows for additional pollutant removal.
Maintenance of the filter media consists of:
• Infiltration Rate Check — The infiltration rate of the PLD needs to be checked in order
to ensure proper functioning of the PLD. The PLD should drain completely within 72
hours of a storm event. If drain times exceed the 72 hour drain time than
maintenance of the filter media shall be required.
• Sediment Removal — If sediment is visible in the bottom of the PLD, steps should
immediately be taken to remove any foreign material to ensure filter media is not
clogged or otherwise prevented from performing as intended.
• Filter Scarification and Replacement — The top layer of the filter media is most
susceptible to pollutant loading. Therefore scarification of the top layer shall occur
when infiltration rates exceed 72 hours. If infiltration rates are not met after
scarification, replacement and proper disposal of the contaminated filter media will be
required.
PLD-2.2.4: Overflow Spillway:
The emergency overflow spillway structure is the earthen embankment on the south side of
the pond. The elevation of the top of this embankment is 4958 NAVD88. Proper inspection
and maintenance of the overflow spillway is essential to ensure the long-term operation and
safety of the PLD.
Maintenance of the overflow spillway shall consist of:
• Structural Damage — the 4958 contour of the top of bank must be maintained. Any
erosion or build up of the 4958 contour shall be corrected and brought back to
specifications.
• Woody Growth/Weeds Present —The presence of plant material not part of the
original landscaping can interfere with the stability and safety of the overflow spillway.
Routine management to remove undesirable vegetation is essential to ensure the
overflow outlet is working properly.
• Trash Debris — Trash and debris can accumulate along the overflow outlet after large
events or from illegal dumping. Routine maintenance to remove trash debris shall be
done to ensure the overflow outlet is maintained and working properly.
PLD-2.2.5: Embankment:
The PLD embankment is has been planted with trees, woody plants, and grasses. This plant
material is important to the aesthetic and function of the PLD.
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Maintenance of the plant material on the embankments shall consist of:
• Vegetation Sparse — The embankments are one of the most visible parts of the PLD
and therefore aesthetics is important. Adequate and properly maintained vegetation
can greatly increase the overall appearance of the PLD. The vegetation can also
reduce the potential for erosion and subsequent sediment transport to the filter
medial, thereby reducing the need for costly maintenance. Routine inspection and
care should be taken to ensure the original landscape material is healthy and coverage
is adequate to discourage propagation of foreign species and weeds.
• Foreign Vegetation - Foreign vegetation can result in improper functioning of the PLD
and the threat of embankment failure. The tops and upstream and downstream faces
of all embankments shall be kept clear of all woody plants to prevent roots from
penetrating the embankment.
• Erosion — Inadequate vegetative cover may result in erosion of the embankment,
which can cause clogging of the filter media. Proper maintenance and fertilization of
the grasses on the embankment should occur to ensure adequate cover and a healthy
growth.
PLD-2.2.6: Upstream Drainage System
The upstream drainage system is comprised of storm drainage inlets and pipes. The purpose
of this system is to collected and transport flows from the development to the PLD. This
system must be maintained in operating condition.
• Inlets - The inlets within the drainage basin of the PLD are fitted with sumps to
encourage sedimentation within the inlet. Sediment will be removed from all inlets
when the level of sedimentation is within 3 inches of the invert of outlet pipe from the
inlet. The sediment shall be removed and disposed of off site. In no case shall the
sediment be allowed to reach the PLD.
• Pipes — Sediment will be removed from all pipes when the accumulation of sediment
exceeds two inches. The sediment shall be removed and disposed of off site. In no
case shall the sediment be allowed to enter into the PLD.
PLD-2.2.7: Miscellaneous:
There are various items that could affect the aesthetics and functionality of the PLD. This
category on the inspection form is for maintenance items that are outside the items identified
above.
Miscellaneous items consist of:
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• Public Hazards — Public hazards include items such as containers of
unknown/suspicious substances, and exposed metal/jagged concrete on structures. if
any hazard is found within the facility area that poses an immediate threat to public
safety, contact the City of Fort Collins Police office at 911 immediately.
• Other —Any miscellaneous inspection/maintenance items not contained on the form
should be entered here.
PLD-2.3: Completed Inspection Forms:
The person(s) conduction the inspection activities shall complete the inspection reports. Copies
of the inspection reports shall be kept indefinitely by the Property Owner. In addition, copies of
inspection reports shall be sent to the Civil Engineer of Record and City Storm Water Department
at the end of each calendar year.
PLD-3: MAINTAINING POROUS LANDSCAPE DETENTIONS (PLDs)
PLD-3.1: Maintenance Personnel:
Maintenance personnel must be experienced to properly maintain PLDs.
PLD-3.2: Equipment:
It is imperative that the appropriate equipment and tools are taken to the site with the
operations/maintenance crew. The types of equipment will vary depending on the task at hand.
Below is a list of tools, equipment, and materials that may be necessary to perform the
maintenance work on the PLDs:
• Mowing tractors • Erosion control blankets
• Trimmers (extra string) • Illicit discharge cleanup kits
• Shovels • Trash bags
• Rakes • Tools (wrenches, screw drivers,
• Skid Steer hammers, etc.)
• Back Hoe • Confined space entry equipment
• Jet -Vac machine • These Operation Procedures
• Engineers Level (laser) • Pit Run
• Riprap (compatible with existing material)
Some of the items may not be needed for every maintenance operation. However, this
equipment should be available to the maintenance crews should the need arise.
7
PLD-3.3: PLD Maintenance Forms:
The PLD Maintenance Form provides a record of each maintenance operation performed by
maintenance contractors. The PLD Maintenance Form shall be filled out in the field after the
completion of the maintenance operation. The form is attached as Appendix A.
PLD-3.4: Completed Maintenance Forms:
A variety of maintenance activities, separated into categories are identified on the form. All
maintenance activities performed during the operation must be identified on the form. These
maintenance activities are described in more detail in this Manual. Maintenance forms shall be
completed by the contractor performing the required maintenance items.
PLD-3.5: PLD Maintenance Categories and Activities:
The PLD Maintenance Program shall consist of three broad categories of work: Routine, Minor,
and Major. Within each category of work, a variety of maintenance activities shall be performed.
A maintenance activity can be specific to each feature within the PLD or general to the overall
facility. This section of the SOP explains each of the categories and briefly describes the typical
maintenance activities for the PLD.
PLD-3.6: Routine Maintenance Activities:
The majority of this work consists of scheduled mowing, trash and debris pickup and landscape
care for the PLD during the growing season. It also includes activities such as week control. These
activities normally will be performed numerous times during the year.
The Routine Maintenance Activities are summarized below, and further described in the following
sections:
Table PLD-2
Summary of Routine Maintenance Activities
Maintenance Activity
Minimum Frequency
Look For:
Maintenance Action
Mowing
Once monthly
Excessive grass
2" —4" grass height
height/aesthetics
Trash/Debris Removal
Monthly
Trash and debris in the
Remove and dispose
PLD
of trash and debris
Weed Control
Monthly
Noxious weeds,
Treat w/herbicide or
unwanted vegetation
hand pull.
E
PLD-3.6.1: Mowing:
Routine mowing of the turf grass embankments and bottom is necessary to improve the
overall appearance of the PLD. Turf grass should be mowed to a height of 2" to 4" inches and
shall be bagged and removed from the PLD to prevent potential contamination of the filter
media.
PLD-3.6.2: Trash/Debris Removal:
Trash and debris must be removed from the entire PLD area to minimize outlet clogging and
to improve aesthetics. This activity must be performed prior to moving operations.
PLD-3.6.3: Weed Control:
Noxious weeds and other unwanted vegetation must be treated as needed throughout the
PLD. This activity can be performed either through mechanical means (mowing/pulling) or
with herbicides. Herbicides should be utilized sparingly and as a last resort. All herbicide
applications should be in accordance with the manufacturer's recommendations.
PLD-3.7: Minor Maintenance Activities:
This work consists of a variety of isolated or small-scale maintenance and operational problems.
Most of this work can be completed by a small crew, hand tools, and small equipment. In the
event the PLD needs to be dewatered, care should be given to ensure sediment, filter material,
and other pollutants are not discharged.
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