HomeMy WebLinkAbout2018.00053.CE.2018-04-18.RPT.O&M Manual
Napleton KIA of Carmel
East of the intersection of Randall Drive and East 96th Street
Carmel, Indiana
Stormwater
Operation and Maintenance Manual
Including:
Site Information
Operation and Maintenance
Inspection Checklist
Owner:
Napleton Automotive Group
One Oakbrook Terrace, Suite 600
Oakbrook Terrace, Illinois 60181
(630) 455-2010
April 18, 2018
BMP Operations and Maintenance Manual
BMP Owner Name: Napleton Automotive Group
One Oakbrook Terrace, Suite 600
Oakbrook Terrace, IL 60181
Contact Information: Name: _____________
Phone: 630-455-2010
Fax: _____________
Email: ______________
General Information
The purpose of water quality Best Management Practices is to filter the first flush of rainwater
before it enters the downstream lakes and streams. Through the use of these Best Management
Practices, the sediment and pollutant load in stormwater runoff is reduced, and in many cases the
quantity of stormwater water runoff generated is also reduced. The use of Best Management
Practices also helps to reduce hydrocarbons, trash and debris from entering waterways.
Owner Responsibility
The BMP Owner shall be responsible for all maintenance and costs associated with the proposed
BMPs. In addition, it is the owner’s responsibility to perform and/or pay for inspections and
maintenance as recommended below.
Right of Entry
The City of Carmel representatives have the right to enter the property to inspect and, if required,
maintain the BMPs at any time.
Annual Inspection Reports
Annual inspection reports shall be submitted to the City of Carmel for each BMP. The first report
is due one year after construction is completed, with subsequent reports due each year within the
same month of the initial report. If there are any deficiencies found during the inspection, these
should be addresses. If the inspection report is not received within the month it is due, if there are
deficiencies which were not included in the report, or it any deficiencies included in the report are
not addressed in a timely manner, the BMP owner faces enforcement action from the City.
Annual reports can be submitted to: City of Carmel Engineering Department, Attn: Storm Water
Administrator, One Civic Square, Carmel, IN 46032
Storm Structure Maintenance
Storm structures are set at storm sewer pipe connections. Unless you have OSHA
approved training and equipment, never enter a manhole.
Inspection
All inlet castings should be inspected monthly and after each rainfall event. More
frequent inspections should be performed in areas where there is higher potential for trash
or litter (e.g. retail establishments) and during the fall when leaves are present on the
ground. Check the frame and lid for cracks and wear, such as rocking lids or lids moved
by traffic.
Storm structures and the surrounding areas should be inspected annually for pollutants
such as leaks from dumpsters, minor spills, and oil dumping. Take action to have the
pollutant source removed.
Cleaning
Clean structures when there is a blockage of a water flow path or when sediment depth
reaches 6”. Cleaning should be performed in a way that ensures removed sediment and
water is not discharged back into the storm sewer.
Safety
Work inside underground structures requires special OSHA-required confined space
equipment and procedures. The most practical option may be to contract with a sewer
cleaning contractor.
Materials Handling
Disposal of waste from maintenance of drainage facilities shall be conducted in
accordance with federal, state, and local regulations. Removed sediment must be
disposed in the garbage as solid waste. Water should be disposed of in a sanitary sewer
after oils are removed using oil absorbent materials or other mechanical means. Used oil
absorbents should be recycled or disposed according to the manufacturer's instructions.
Repairs
Repair all security and access features so they are fully functional. This includes locking
lids, covers, and ladder rungs. Replace broken parts or lids that rock or are moved by
traffic.
Conveyances Maintenance (Storm Sewer)
Storm sewer pipes convey stormwater. Pipes are built from many materials and are
sometimes perforated to allow stormwater to infiltrate into the ground. Storm pipes are
cleaned to remove sediment or blockages when problems are identified. Storm pipes must
be clear of obstructions and breaks to prevent localized flooding.
Inspection
Pipes are difficult to inspect requiring special equipment and training. Usually, if a
problem occurs the owner needs to call a sewer or plumbing contractor to inspect, repair
or clean pipelines.
Cleaning
Clean pipes when sediment depth is greater than ¼ of pipe diameter, with a maximum
sediment depth of 6”. When cleaning a pipe, minimize sediment and debris discharges
from pipes to the storm sewer. Install downstream debris traps (where applicable) before
cleaning and then remove material. Generally, use mechanical methods to remove root
obstructions from inside storm sewer pipes. Do not put root-dissolving chemicals in
storm sewer pipes. If there is a problem, remove the vegetation over the line.
Safety
Work inside underground structures requires special OSHA-required confined space
equipment and procedures. The most practical option may be to contract with a sewer-
cleaning contractor.
Materials Handling
Sediment and debris from pipes should be disposed in the garbage as solid waste. Pick
out any rocks first.
Repairs
Repair or replace pipes when a dent or break closes more than 20 percent of the pipe
diameter. Repair or replace pipes damaged by deterioration.
Inlet Catch Basins (Sumps) Maintenance
Catch Basins trap sediment and some oils that can pollute water bodies. They need to be
inspected and cleaned annually to remove accumulated sediment, fluids, and trash.
Inspection
Inspect catch basins at least once per year. Periodically inspect the catch basin and
surrounding areas for pollutants such as leaks from dumpsters, minor spills, and oil
dumping. Act to have the pollutant source removed.
Cleaning
Clean catch basins when they become one third full to maintain sediment-trapping
capacity. Catch basin and manhole cleaning should be performed in a manner that keeps
removed sediment and water from being discharged back into the storm sewer. Clean
putrid materials from catch basins when discovered or reported. Keep the inlet cleared of
debris and litter.
Safety
Work inside underground structures requires special OSHA-required confined space
equipment and procedures. The most practical option may be to contract with a sewer
cleaning contractor.
Materials Handling
Disposal of waste from maintenance of drainage facilities shall be conducted in
accordance with federal, state, and local regulations. Removed sediment must be
disposed of in the garbage as solid waste. Water should be disposed of in a sanitary sewer
after oils are removed using oil absorbent materials or other mechanical means. Used oil
absorbents should be recycled or disposed according the manufacturer's instructions.
Repairs
Repair any damages that prevent the catch basin from functioning as designed.
Underground Detention System Maintenance
The site contains an underground detention system located on the north, east and south
side of the proposed building.
The underground detention system is designed to control stormwater outflow rates from
the site. After construction the underground detention system should be inspected every
6 months and cleaned as needed or once a year regardless of whether it has reached full
sediment capacity. Disposal of all sediment and debris must be in accordance with all
local, state and federal requirements. Refer to the appendices for additional inspection
and maintenance requirements.
Inspection
Inspect the underground system every six months. Utilize inspection ports to verify
depth of sediment accumulation. The inspection should determine sediment depth,
accumulation of trash and litter, and the specific maintenance and repairs needed.
Cleaning
Cleaning and maintenance of the system is accomplished with the JetVac process.
Sediment which is flushed into the access manhole can then be vacuumed out of the
system. Cleaning should be performed in a way that ensures removed sediment and
water is not discharged back into the storm sewer.
Safety
Work inside underground structures requires special OSHA-required confined space
equipment and procedures.
Materials Handling
Disposal of waste from maintenance of drainage facilities shall be conducted in
accordance with federal, state, and local regulations. Removed sediment must be
disposed in the garbage as solid waste. Water should be disposed of in a sanitary sewer
after oils are removed using oil absorbent materials or other mechanical means. Used oil
absorbents should be recycled or disposed according to the manufacturer's instructions.
Repairs
Repair any cracked or defective chambers or manifold piping. Repair all security and
access features so they are fully functional. This includes locking lids, covers, and ladder
rungs.
Pervious Pavers
The site contains pervious paver areas located at several locations onsite.
The pervious pavers are designed to treat first flush stormwater for water quality. The
pervious paver areas should be inspected every 6 months, typically spring and fall, and
vacuumed as needed or once a year regardless of whether it has reached full sediment
capacity. Disposal of all sediment and debris must be in accordance with all local, state
and federal requirements. Refer to the appendices for additional inspection and
maintenance requirements.
Inspection
Inspect the pervious paver areas every six months. Replenish aggregate in joints if more
than ½ inch from chamfer bottoms on paver surfaces. Inspect vegetation around PICP
perimeter for cover and soil stability, repair/replant as needed. Inspect and repai8r all
paver surface deformations exceeding ½ inch. Repair pavers offset by more than ¼ inch
above/below adjacent units or curbs, inlets, etc. Replace any cracked or defective pavers
impairing surface structural integrity. Check drains outfalls for free flow of water after a
major storm. If water ponding on surface immediately after a storm (paver joints or
openings severely loaded with sediment): test surface infiltration rate using ASTM
C1701.
Cleaning
Cleaning and maintenance of the system is accomplished with pavement vacuum
machine. Vacuum to remove surface sediment and soiled aggregate (typically 1/2 to 1
inch deep), refill joints with clean aggregate, sweep surface clean and test infiltration rate
again per C1701 to minimum 50% increase or minimum 10 inch/hour.
Materials Handling
Disposal of waste from maintenance of drainage facilities shall be conducted in
accordance with federal, state, and local regulations. Removed sediment must be
disposed in the garbage as solid waste. Water should be disposed of in a sanitary sewer
after oils are removed using oil absorbent materials or other mechanical means. Used oil
absorbents should be recycled or disposed according to the manufacturer's instructions.
Repairs
Repair pavers offset by more than ¼ inch above/below adjacent units or curbs, inlets, etc.
Replace any cracked or defective pavers impairing surface structural integrity.
Inspection and Maintenance Schedule
Structure/Unit Inspection Maintenance
Storm Structures Monthly & after rain events Accumulate 6” of sediment
Storm Sewers When problems occur Accumulate 6” of sediment
Pervious Pavers Every 6 months Per PICP checklist and
guidelines
Isolator Rows Every 6 months Per manufacturer’s
designated depth
Owner Acknowledgement Agreement (“Agreement”)
For good and valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the undersigned owner (“Owner”) hereby submits this Operation and
Maintenance Manual (“Manual”) to the City of Carmel, Indiana (“City”) as written
acknowledgement of Owner’s warranty and agreement to institute, maintain, and follow the
water quality Best Management Practices (“BMPs”) listed below, and to follow and abide by
the inspection schedule and maintenance activities listed in this Manual. The Owner also
hereby agrees to provide, at Owner’s cost, all additional maintenance, repair and/or
replacement services reasonably necessary to maintain the function and longevity of the
BMPs from and including the date this Agreement is executed by Owner to and including the
date on which a new Agreement is filed with the City by another party who assumes all of
the obligations and responsibilities of Owner as set forth herein.
BMPs: Stormtech Isolator Rows
Pervious Pavers
__________________________ ________________________
Owner Signature Date
__________________________ ________________________
Printed Name Company
STATE OF INDIANA )
) SS:
COUNTY OF HAMILTON )
BEFORE ME, the undersigned a Notary Public in and for said County and State,
personally appeared __________________________________ Owner subscribed and sworn before this
________ day of ___________________________, __________.
_______________________________
County of Residence
_______________________________
Commission Expiration Date
_______________________________
Printed Name
PLOT DATE: 4/18/2018 12:36 PMPLOT SCALE: 1:1EDIT DATE: 4/18/2018EDITED BY: CPATTERSONDRAWING FILE: P:\2018\00053\D. Drawings\Civil\Exhibits\Drainage\2018.00053.CE.3D_Design.2018-04-18.dwgProject Number
CERTIFIED BY
ISSUANCE INDEX
DATE:
PROJECT PHASE:
REVISION SCHEDULE
NO.DESCRIPTION DATE
4/18/2018
----
2018.00053
7260 Shadeland Station | Indianapolis, Indiana 46256
TEL 317.547.5580 | FAX 317.543.0270www.structurepoint.com
EX4
DEVELOPED WATER
QUAILITY
TREATMENT MAP
SCALE: 1" = 50'
Permeable Interlocking Concrete Pavements 73
Section 5. Maintenance
This Section provides maintenance guidelines and an in-service inspection checklist for municipalities
and project owners. Also included is a model maintenance agreement that can be used between a
project owner who has installed PICP and the local municipality to help ensure maintenance. As an ad-
ditional resource, a model zoning ordinance is provided that can be used as a template or starting point
for a city enabling PICP use by property owners. A growing number of municipalities provide financial
incentives to homeowners and commercial developers for using permeable pavements. The cost to the
municipality can be less than upsizing storm sewer systems operating at their capacity.
Like all permeable pavements, PICP surfaces can become clogged with sediment over time, thereby
slowing its infiltration rate. The rate of sedimentation depends on the amount of traffic and other
sources that wash sediment into the joints, base and soil. Sources can be eroding soil, leaves, mulch,
and sediment deposited from vehicles. PICP streets and parking lots can be cleaned with municipal
street cleaning equipment and snow plows. Many municipal streets receive cleaning a few times annu-
ally and that can be sufficient to control the buildup of sediment in PICP joints. The following provides
guidelines on managing surface infiltration based on research and experience.
Traffic and sediment sources vary with every PICP project. Regular surface cleaning will help maintain a
high surface infiltration rate and keep out vegetation. ICPI recommends inspection and cleaning once
or twice in the first year of service and adjusting cleaning intervals higher or lower as needed. Cleaning
can be done with vacuuming sweeping equipment such a regenerative air vacuum sweepers. Adjust-
ments to the vacuum force likely will be required to minimize removal of stones from the openings.
Sweeping alone is not effective since vacuuming removes much of the sediment. Sweeping only moves
it from one place to another.
When monitoring PICP, there are two means to determining if the surface is infiltrating:
(1) Observe drainage immediately after a heavy rainstorm for standing water; or
(2) Conduct surface infiltration tests using ASTM C1701 (ASTM 2009).
The test ASTM method was originally developed Bean (2007) for evaluating the surface infiltration of
PICP, concrete grid pavement and pervious concrete. The test method was refined and adopted by
ASTM for use on pervious concrete and successfully used on PICP. If there is a substantial area or areas
of standing water on PICP after a storm, or should the measured surface infiltration rate using C1701 fall
below the design infiltration rate, the surface should be cleaned with vacuum equipment. The type and
use of this equipment will be covered later. ICPI recommends cleaning if the tested surface infiltration
rate falls below 10 in./hr (250 mm/hr).
Figure 5-1 illustrates C1701 test apparatus for measuring PICP surface infiltration rate. A five gallon (20 l)
bucket of water is slowly poured into a 12 in. (300 mm) ring secured to the pavers with plumber’s putty.
The putty creates a waterproof seal and is placed in the joints (upon removal of jointing stone) directly
under the ring to direct water downward. The water inflow rate does not exceed a head of 3/8 in. (10
mm) while being timed with a stopwatch. The surface infiltration rate is calculated using formulas in the
test method.
74 Permeable Interlocking Concrete Pavements
Figure 5-2. Concrete pavers are removed from
a seven year-old PICP parking lot. Note the
accumulation of sediment in the square-shape
openings in the pavers.
Figure 5-3. No visible sediment was found in the
bedding or within the No. 57 stone base in this
heavily trafficked area.
Section 5. Maintenance
Some PICP surfaces do not require surface clean-
ing for years because they maintain adequate
infiltration. This was demonstrated at a PICP
parking lot in an arboretum in suburban Chicago
in 2009. The seven year-old, 500-car parking
lot had been infiltrating rainfall adequately. The
demonstration confirmed what other research-
ers have found, i.e., the small aggregates in
the joints have a dual function: (1) they receive
sediment and thereby reducing surface infiltra-
tion over time; and (2) the aggregates provide
a first line of defense by trapping sediment and
preventing it from entering the base and soil
subgrade. (See pages 20–21 for a literature
review.) Trapping sediment in joints can continue
for years and at some point they may require
cleaning. As noted above, that point is decided
by observation or by surface infiltration testing.
The arboretum PICP parking lot received much car and bus traffic, as well as sand and deicing materials
in the winter. The surface was not cleaned since its construction in 2002. Pavers and jointing material
were removed in a heavily trafficked delivery area to observe the path and penetration of sediments in
the joints. Figure 5-2 shows that much of the sediment was trapped in the first ½ to inch (12 to 25 mm)
of the openings. The pavers and jointing material were removed and there was no sediment visible on
the bedding material or in the No. 57 stone base as shown in Figure 5-3. This demonstrated the surface
sediment trapping capability of this PICP installation and this pattern has been observed on other
installations.
Since PICP is trapping sediment in the jointing aggregates, some cases with low infiltration will require
their removal and replacement. This procedure was demonstrated at the arboretum parking lot with a
vacuum machine capable of removing the stones and sediment captured in the joints. The vacuum ma-
chine was adjusted to so that only the top inch (25 mm) of stones and sediment were removed (Figures
5-4 and 5-5). This substantially increased the surface infiltration rate based on observing differences in
the rate of water poured on and penetrating undisturbed and restored surfaces. Stones were spread
Figure 5-1. Test apparatus on PICP for measuring
surface infiltration rate per ASTM C1701.
Permeable Interlocking Concrete Pavements 75
Figures 5-4 and 5-5. The vacuum machine removed the top inch (25 mm) of sediment and jointing stone.
Figures 5-6 and 5-7. Before and after cleaning with fresh stones swept into the joints
Section 5. Maintenance
and swept into the openings thereby refilling them to their original condition. Figure 5-6 shows the
joints prior to vacuuming and Figure 5-7 shows the cleaned joints filled with fresh stone. .
Besides this demonstration, research by Gerrits (2002) Bean (2004) and Chopra (2010) have shown
that removal of sediment in the openings increases surface infiltration rates. A significant maintenance
advantage of PICP over pervious monolithic pavements is the ability to restore heavily clogged joints
in PICP. This has been observed by Chopra in evaluating the ability to clean highly clogged perme-
able pavements, and favorable results with PICP, and by researchers at the University of Minnesota who
noted that sediment penetrating over 1/4 in. (6 mm) in pervious concrete was impossible to remove with
vacuum equipment (Vancura 2010).
Winter maintenance—Snow can be plowed from pavers as with any other pavement. Since deicing
salts will infiltrate into the base and soil, they should be applied sparingly, as they can accumulate in the
soil subgrade. Research at the Toronto and Region Conservation Authority (Van Seters 2007) indicates
that PICPs require less deicing salt than asphalt pavements, since permeable pavement remains warmer
throughout the winter.
Sand should not be applied on the PICP for traction, as it will accelerate surface clogging. If traction is
required, No. 8, 89 or 9 stone (or similar) should be used. If sand is used, PICP surface should be vacu-
76 Permeable Interlocking Concrete Pavements
Section 5. Maintenance
umed in the spring to reduce the risk of decreased surface infiltration.
Many years of experience and monitoring have demonstrated that PICP does not heave when frozen.
This is evidenced by many PICP projects in Chicago, Minneapolis and Toronto remaining stable during
freezing and thawing climates. This is due to the following factors:
• The pavement base and saturated soil subgrade drains prior to freezing;
• The air in the aggregate voids provides some insulating effect in slowing the movement of freez-
ing temperatures toward the soil subgrade;
• The moisture and earth provide some heat to delay freezing of the soil subgrade and base/sub-
base such that both can drain prior to freezing; and
• Should water freeze in the base or subbase, there is sufficient space in the aggregate voids for
the frozen water to expand as it freezes and avoid heaving.
A benefit of all permeable pavements is snow remaining after plowing can melt and infiltrate into the
surface when temperatures rise, thereby reducing or eliminating re-freezing at night and ice hazards.
This condition also reduces deicing salts and potential legal liability from injury claims due to falls.
Cracked or damaged paving units, bedding and base can be removed and replaced, and such repairs
can be done in the winter provided that aggregate materials are not frozen. This provides a mainte-
nance advantage over site-formed materials that require above freezing temperatures for placement, as
well as difficulty in finding a wintertime source of material supply.
Reinstatement—An advantage of PICP is that they can be removed for access to underground utilities.
The following steps are recommended:
1. Pavers are removed, cleaned and stacked for reinstatement. If the PICP installation has some age
to it, the pavers will require removal of dirt that typically accumulates in the stone filled openings
at the surface. Undisturbed pavers can be secured with wood or metal frame as show in Figure
5-8.
2. The bedding material (typi-
cally No. 8 stone) should be
removed and disposed of, then
replaced with fresh stones. The
reason for its disposal is that it
is mixed with No. 57 base stone
and it cannot be reinstated with
it.
3. The No 57 base layer (typically
4 in. or 100 mm thick) can be
removed and stored for rein-
statement as well as the No.
2 subbase material. Store in a
place where the aggregates will
remain clean. All dirty/contami-
nated aggregates should be
replaced with clean stone.
4. Repairs can then be made to
the utility pipe or box that is
slightly above, on or in the soil
subgrade.
Temporary wood or
metal edge around
opening perimeter
Figure 5-8. Restraining undisturbed pavers with a wood or
metal frame can save time when reinstating concrete pavers.
Permeable Interlocking Concrete Pavements 77
Section 5. Maintenance
5. Flowable concrete fill (200 to 500 psi or 1.4 to 3.5 MPa) should be used to support repaired
utilities. This material is also known as controlled low-strength material or CLSM. Flowable fill is
needed because open-graded base cannot adequately fill under pipes or boxes, nor can it be
compacted in these places. Many cities use flowable fill for utility repairs and have material and
installation specifications.
6. A minimum 4 in. (100 mm) layer of flowable concrete fill should be cover the pipe or box. Then
the subbase can be reinstated around it. Flowable fill will likely seep into the No. 2 stone, so
there needs to be a barrier to stop it. That can be plastic sheets or geotextile. Flowable fill takes
a few hours to stiffen. After 24 hours, the subbase stone should be reinstated and compacted.
There should be at least 12 in. (300 mm) distance between the top of the flowable fill and the
bottom of the plate compactor. The compactor force should be 13,500 lbf (60 kN).
7. The No. 57 base is reinstated and compacted.
8. New No. 2 stone is placed and screeded. Sometime it helps to remove a few courses of undis-
turbed pavers so the new and existing bedding layers can be screeded together.
9. Pavers are reinstated, joints filled and compacted. The pavers should be at least one inch (25
mm) above the surrounding undisturbed pavers prior to compaction. They will compact down
and probably settle a bit after compaction as all flexible pavements. Likewise, the same units can
be reinstated after repairs to the base, drain pipes, liners or underground utilities.
While not typically done, sealers can be applied to the pavers. Overflow onto the aggregates is avoid-
ed by using a roller. Such sealers can enhance appearance while making stains easier to remove.
As noted in the Section 4, PICP is
sometimes constructed with an obser-
vation well. The well is typically a 4 to
6 in. (100 to 150 mm) diameter perfo-
rated pipe with a screw cap just slightly
below the surface of the pavers that
can be removed to observe the exfiltra-
tion rate. The cap should lock and be
vandal-resistant. The depth to the soil
subgrade should be marked on the lid.
The observation well is located in the
furthest down-slope area within 3 ft (1
m) from the pavement edge. Figure 5-9
shows an observation well as a parking
lot at a U.S. Army base in Georgia. The
top of the pipe can also be placed under
the pavers. This hides the cap from van-
dals and a few pavers can be removed to
access the well cap and reinstated.
Long Term Performance and
Maintenance Agreements
When carefully constructed and regular-
ly maintained, PICP can provide as much
as 40 years of service. Their structural
service life is measured by the extent of rutting of the base/subbase or soil subgrade. Their hydrologic
service life is measured by the extent to which they continue infiltrating and storing runoff.
Figure 5-9. A PVC pipe with a screw cap serves as an
observation well on PICP parking lot at a U.S. Army base in
Georgia.
Permeable Interlocking Concrete Pavements 81
Section 5. Maintenance
PICP Maintenance Checklist
This can be included in the above agreement or used separately to manage in-service PICP.
PICP In-service Inspection Checklist
p 1 to 2 times annually (typically spring/fall): vacuum surface, adjust vacuuming schedule per sediment
loading and/or any sand deposits from winter
p Winter: Remove snow with standard plow/snow blowing equipment; monitor ice on surface for re-
duced salt use than typically used on impervious pavements
p Water ponding on surface immediately after a storm (paver joints or openings severely loaded with
sediment): test surface infiltration rate using ASTM C1701. Vacuum to remove surface sediment and
soiled aggregate (typically 1/2 to 1 in. or 13-25 mm deep), refill joints with clean aggregate, sweep
surface clean and test infiltration rate again per C1701 to minimum 50% increase or minimum 10 in./
hr (250 mm/hr).
Annual Inspection
p Replenish aggregate in joints if more than 1/2 in. (13 mm) from chamfer bottoms on paver surfaces
p Inspect vegetation around PICP perimeter for cover & soil stability, repair/replant as needed
p Inspect and repair all paver surface deformations exceeding 1/2 in. (13 mm)
p Repair pavers offset by more than 1/4 in. (6 mm) above/below adjacent units or curbs, inlets etc.
p Replace cracked paver units impairing surface structural integrity
p Check drains outfalls for free flow of water and outflow from observation well after a major storm