HomeMy WebLinkAbout9A - Crystal Bay Preliminary
MEETING DATE:
AGENDA #:
PREPARED BY:
AGENDA ITEM:
DISCUSSION:
CITY COUNCIL AGENDA REPORT
SEPTEMBER 30, 2002
9A
JANE KANSIER, PLANNING COORDINATOR
CONSIDER APPROVAL OF A RESOLUTION APPROVING A
PLANNED UNIT DEVELOPMENT PRELIMINARY PLAN,
AND APPROVAL OF A RESOLUTION APPROVING A
PRELIMINARY PLAT TO BE KNOWN AS CRYSTAL BAY
Introduction: 212 Development, LLC, has applied for approval of a
development to be known as Crystal Bay on the property located south
ofCSAH 82, directly east of Fremont Avenue and approximately 12
mile west of CSAH 21. The application includes the following
requests:
. Approve a Planned Unit Development Preliminary Plan;
. Approve a Preliminary Plat.
The proposal calls for a townhouse development consisting of 24
dwelling units on 10.62 acres. The development also proposes private
open space and 21 boat slips for the use of the residents.
History: This item was originally scheduled for a public hearing
before the Planning Commission on August 12,2002. However, the
Planning Commission continued the public hearing to September 9,
2002, to allow the developer to address the issues raised by staff in the
original staff report. The developer also conducted a second
neighborhood meeting on August 28,2002.
The Planning Commission conducted a public hearing on this item on
September 9, 2002. Following the close ofthe public hearing, the
Commission generally agreed the development was consistent with the
PUD requirements. The Commissioners, however, requested the
developer submit new plans and information addressing six issues.
These issues included:
. Provide calculations indicating the impervious surface in each tier,
as well as the overall impervious surface. In recognition of the fact
that the developer is dedicating 75' of right-of-way for CSAH 82,
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16200 Eagle Creek Ave. S.E., Prior Lake, Minnesota 55372-1714 / Ph. (952) 447-4230 / Fax (952) 447-4245
AN EQUAL OPPORTUNITY EMPLOYER
rather than the standard 50', the Planning Commission indicated
the additional 25' of right-of-way may be included within the
impervious surface calculation, but the impervious surface may not
exceed the allowable 25% in each tier. The total amount of
impervious surface may not exceed 30 percent.
· Review the configuration of the boat slips with respect to water
safety and other issues. No more than 21 slips will be permitted.
· Revise the tree inventory to include only those trees considered
significant in the Zoning Ordinance. Identify which trees will be
removed for roads and utilities, and which trees will be removed
for building pads.
· Revise the landscaping plan to meet all ordinance requirements.
The landscaping should also address any required tree replacement.
The tree replacement requirements are over and above the required
landscaping.
· Provide details, including height and materials, on the proposed
privacy fence along the west lot line.
· Provide copies of the restrictive covenants for this development.
The developer provided additional information on these issues for
Planning Commission review at the September 23, 2002 meeting. The
Planning Commission recommended approval of these applications,
subject to conditions. Draft copies of the minutes of September 9,
2002 meeting and September 23, 2002 meeting are attached to this
report.
Current Circumstances: The following analysis summarizes the
proposed plan and its compliance with Zoning and Subdivision
Ordinance requirements.
Total Site Area: The total site consists of 10.62 acres. The net area
of this site, less County road right-of-way, is 8.99 acres.
Topoeraphy: This site has a varied topography, with elevations
ranging from 940' MSL at its highest point to 904' MSL at the lowest
point (the ordinary high water elevation of Prior Lake). The property
generally drains toward the existing drainageway at the center of the
site, and then to Prior Lake.
Veeetation: Originally, there were five single family homes located
on this site; three of those homes have been removed at this time.
There are also several stands of significant trees on this site. The
project is subject to the Tree Preservation requirements of the Zoning
Ordinance. The applicant has submitted an inventory of the significant
trees on the site, which identifies 5,130 caliper inches of significant
trees. The Tree Preservation Ordinance allows removal of 25% of the
total caliper inches of significant trees for grading and utilities, and
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removal of an additional 25% of the total caliper inches of significant
trees for building pads without tree replacement. Removal of
additional caliper inches requires replacement at a rate of 1/2 caliper
inch for each caliper inch removed.
Wetlands: There are no inventoried wetlands located within this site.
Access: Access to the site is from CSAH 82 on the north side of the
site and Fremont Avenue on the west side of the property. CSAH 82 is
classified as an arterial street in the Comprehensive Plan
Transportation Plan, and is expected to carry between 12,500 and
14,500 trips per day by 2020. The current traffic count on CSAH 82 is
9,800 trips per day. Fremont Avenue is classified as a minor collector
street and is expected to carry up to 4,000 trips per day by 2020. The
current traffic on Fremont Avenue is 2,350 average daily trips.
2020 Comprehensive Plan Desienation: This property is designated
for Urban Low to Medium Density Residential uses on the 2020
Comprehensive Plan Land Use Map. The entire site is located within
the current MUSA boundary.
Zonine: The site is zoned R-l (Low Density Residential). The
applicant is not requesting a rezoning as part of this application. The
R-1 district permits a maximum density of3.6 units per acre.
Shoreland: This property is also located within the Shoreland District
for Prior Lake. As such, the property is subj ect to the Shore land PUD
requirements listed in Section 1104 of the Zoning Ordinance.
Parcels utilizing the PUD process in the Shoreland District must be
divided into tiers. The tiers are created by drawing lines parallel to the
ordinary high water elevation (OHW). Tier 1 is the area within 200' of
the OHW; tier 2 is the area 267' from tier 1.
PROPOSED PLAN:
Lots: The preliminary plat consists of 24 lots for the townhouse units.
There are also two lots for the common open space.
Streets: This plan proposes two private streets. The first street is
Crystal Bay Lane, which is a 260' long cul-de-sac off of Fremont
Avenue. This street provides direct access to 12 of the townhouse
units. The second street is a 118' long cul-de-sac, called Drake
Avenue, located on the south side of CSAH 82, directly south of Fox
Tail Trail. This cul-de-sac provides direct access to 12 of the
townhouse units located on the east side of the property.
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The proposed private streets are designed with a 24' wide surface. The
setbacks from the curb to the street will accommodate the required
easements. The private street width must be platted as an outlot.
The plat also dedicates 75' of right-of-way for CSAH 82 along the
north side of the plat. This additional right-of-way will be utilized for
future upgrades to CSAH 82. In the meantime, the County is
evaluating the need for a right-turn lane onto Drake Circle.
Fremont Avenue at this location also requires upgrading. The road
section is currently without curb and gutter. As a condition of
approval of this preliminary plat, the developer should upgrade this
. section as part of this project. The City would financially participate
in this proj ect.
Sidewalks/Trails: No public sidewalks or trails are proposed as part
of this project.
Parks: This plan does not dedicate any parkland. Section 1004.1000
of the Subdivision Ordinance requires 10% of the gross area of the site
for parkland dedication. A cash dedication in lieu of land is also
possible, at the discretion of the City. The amount of park dedication
at this location is very small; in addition, there is a park on the north
side of CSAH 82 and on the west side of Fremont Avenue. A cash
dedication of $1,685.00 per unit, or $40,400.00 in lieu of land is
required.
Sanitary Sewer/Water Mains: Sanitary sewer and water mains will
be extended from the existing utilities located in CSAH 82 and in the
Glynwater development to the west. The sewer line is extended along
the right-of-way.
Storm Sewer: The plan proposes a series of storm sewer and ponds to
handle the storm water runoff. Revised storm water calculations were
recently submitted as part of the revised plans for this development.
The City staff is in the process of reviewing these calculations.
Density: The development proposes 24 townhouse units. Density for
this development is not only based on the R-1 district maximum
allowed density of 3.6 units per acre, but also on the Shoreland District
requirements. The following table compares the proposed density with
the permitted density.
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Permitted Proposed
Density Density
R-l 31 units 24 units
Shoreland District Tier 1
Base Density 14 units 18 units
With Multiplier 21 units
Shoreland District Tier 2
Base Density 12 units 4 units
With Multiplier 24 units
The density multipliers in the Shoreland District are permitted only if
the structure setback from the OHW is increased by 50% over the
required setback. To apply this multiplier, the structure setback must
be at least 112.5' from the OHW. The proposed plan meets the criteria
for the density multipliers.
Buildin2 Styles: The proposed townhouses are a 2-story walkout,
attached single family style dwelling with an attached garage. Each of
the units in these buildings includes a 3-car garage, rear yard decks and
patios, and approximately 3,990 square feet of living space. The
buildings are 15' high at the front, with exteriors consisting of a
combination of brick, rock, stucco and cedar siding.
Building elevations and sample floor plans for each of these buildings
are attached to this report.
Setbacks: The required and proposed setbacks for this development
are shown on the following table:
Setback Required Proposed
Front (from private street) 25' 20'
Side Street
CSAH 82 25' +30'
Fremont Avenue 25' 15'
Side (between buildings) 15' 15'
(Y2 the sum of the
building heights)
Lakeshore (OHW) 75' 112.5'
The developer is requesting a modification to the front and side street
setbacks. Modifications may be approved by the City Council through
the PUD process.
Lot Coveraee: The R-1 district allows a maximum ground floor area
of 0.30. The ground floor area proposed in this plan is 0.26.
Impervious Surface: The maximum impervious surface allowed in
the Shoreland District is 30% of the lot area above the OHW. In this
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case, 30% of the lot area is 2.7 acres; the development proposes 2.35
acres of impervious surface.
Impervious surface coverage is further limited to 25% of each tier area
in a Shoreland District PUD. In this case, 1.26 acres of impervious
surface is allowed in tier 1, and 1.23 acres is allowed in tier 2.
The attached chart lists the impervious surface calculations for each
tier in the development, including 25' of CSAH 82 right-of-way. The
overall impervious surface of the site is 27.2% of the land area. Tier 1
includes 25% impervious surface. Tier 2 includes 30.4% impervious
surface. To reduce the amount of impervious surface, the developer is
proposing to use a permeable pavement product, which is intended to
mitigate storm water runoff through infiltration, thereby reducing
volume flows, improving water quality and recharging groundwater.
Information on this type of product is also attached for your
information. The information attests to the product's effectiveness if
properly designed, installed and maintained. The Development
Contract will address design and installation, while the homeowner's
documents can address maintenance.
The Planning Commission recommended approval of a modification to
the 25% impervious surface coverage in tier 2, with the condition that
permeable pavement be utilized for all of the driveways in the
development. The Commissioners reasoned that the overall
impervious surface is less than 30% and that the ponding was sized to
accommodate all of the driveways, roads, and other areas. The
Commission also reasoned that a conventional development could
include impervious surface up to the 30% maximum.
Useable Open Space: The R-1 district also requires 600 square feet
of useab1e open space per unit for cluster developments. Although this
proposal is a PUD, it must also comply with that requirement. The
required open space for this development is 15,600 square feet; the
plan indicates a total of 15,875 square feet.
Shoreland Open Space Requirements: The Shoreland Ordinance
requires at least 50% of the total project area within a PUD be
preserved as open space. The common lots for this development meet
the 50% requirement.
The Shoreland PUD Ordinance also requires that 70% of the shore
impact zone (50% of the setback from the OHW) be preserved in its
natural state. With the exception of the area leading to the proposed
watercraft mooring area, the shore impact zone is undisturbed.
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Shore Recreation Facilities: Section 1104.805 (4,c) states the
following:
Shore recreation facilities, including but not limited to swimming
areas, docks, and watercraft mooring areas and launching ramps,
shall be centralized and located in areas suitable for them. Evaluation
of suitability shall include consideration of land slope, water depth,
vegetation, soils, depth to ground water and bedrock, or other relevant
factors. The number of spaces provided for continuous beaching,
mooring, or docking of watercraft shall not exceed one for each
allowable dwelling unit or site in the first tier (notwithstanding
existing mooring sites in an existing commercially used harbor).
Launching ramp facilities, including a small dock for loading and
unloading equipment, may be provided for use by occupants of
dwelling units or sites located in other tiers.
The developer
development.
requirements.
is proposing to install 21 boat slips to serve this
This is consistent with the Shoreland District
The Shoreland District requirements of the Zoning Ordinance regulate
the number of boat slips permitted. The actual configuration of the
mooring area is determined by the DNR as part of the permitting
process. The developer has submitted the attached plan for the
configuration for the boat slips. This plan pulls the slips as close to
shore as lake depths permit.
Parkine: The proposal provides at least 3 spaces per dwelling unit, in
that each unit will have a 3-car garage; the Zoning Ordinance requires
a minimum of 2 spaces per unit. No parking will be permitted on the
private streets.
Landscapin2: Section 1107.1900 lists the landscaping requirements
for this development. Perimeter landscaping is required for the
townhouse portion of the development with buildings consisting of 3
or more units at a rate of 1 tree per unit or 1 tree per 40' feet of
perimeter, whichever is greater. Our calculations indicate a total of 73
trees are required for this site. The landscaping plan submitted
includes 71 trees. This is not consistent with the ordinance
requirements. The Zoning Ordinance also requires that at least 25% of
the landscaping trees be deciduous, and 25% be coniferous. The plan
submitted must be revised to include more coniferous trees. In
addition, the Zoning Ordinance requires at least 20% of the plants
must exceed the minimum sizes of 2 1/2 caliper inches for deciduous
and 6' for coniferous. This requires that at least 20% of the deciduous
trees be 3 12 caliper inches, and at least 20% of the evergreens must be
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at least 8' high. The plan also does not indicate whether an irrigation
system will be provided.
Tree Replacement: The applicant has submitted an inventory
identifying 5,130 caliper inches of significant trees on the site. The
Zoning Ordinance allows up to 25% of the significant caliper inches to
be removed for road and utility purposes, and up to 25% for building
pads and driveways. Replacement is required for any percentage
above the 25% at a rate of 12 caliper inch for each 1 caliper inch
removed. The plan proposes to remove 12.55% of the significant
caliper inches for building pads and 40.47% of the caliper inches for
driveways and utilities. This will require replacement of 397 caliper
inches, or 159 2 12 inch trees. The revised landscaping plan must also
identify the required replacement trees.
Si2ns: There are no signs identified on this plan.
Liehtine: Street lights will be provided on the private streets.
Traffic Impact Report: The developer has submitted an elementary
traffic study for this development. This study indicates the proposed
development will generate a total of 172 daily trips. The report
assumes that approximately half of these trips will use Fremont
Avenue, and half will use CSAH 82, which is a fair assumption. The
additional trips onto Fremont and CSAH 82 are a small fraction of the
existing traffic on these streets. The report concludes the additional
trips will not have a significant impact on the existing streets.
Phasine: The developer proposes to construct this project in 2 phases.
The first phase will consist of the 12 units located on the east side of
the site. The second phase will consist of the cul-de-sac off of
Fremont Avenue and the remaining 12 units. No timeline has been
submitted for this phasing.
THE ISSUES:
There are two separate applications included in this proposal.
PUD PRELIMINARY PLAN: The PUD must be reviewed based on the
criteria found in Section 1106.100 and 1106.300 of the Zoning
Ordinance. Section 1106.100 discusses the purpose of a PUD. These
criteria are discussed below.
(1) Greater utilization of new technologies in building design,
materials, construction and land development.
The developer has attempted to design the buildings so they fit the
land, rather than force the land to fit the building design. The use
of permeable pavement for the driveways on the site will reduce
the runoff and allow further treatment of the storm water.
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(2) Higher standards of site and building design.
The density of this site is clustered to the north and set back
further from the lake shore than would be required under a
conventional development. The units have also been placed so as
to preserve the trees on the east boundary of the site. The
utilization of private streets further reduces the impervious surface
on the site.
(3) More efficient and effective use of streets, utilities, and public
facilities to support high quality land use development at a lesser
cost.
Maintenance of private streets, including plowing and future
repairs, is done by the homeowners association. This reduces City
costs in providing services to these homes.
(4) Enhanced incorporation of recreational, public and open space
components in the development which may be made more useable
and be more suitably located than would otherwise be provided
under conventional development procedures.
The developer is providing a private beach and recreation area for
the residents of the development, as well as private walking trails.
These trails will connect to the public trail along CSAH 82.
(5) Provides a flexible approach to development which allows
modifications to the strict application of regulations within the
various Use Districts that are in harmony with the purpose and
intent of the City's Comprehensive Plan and Zoning Ordinance.
The density and variety of housing units is consistent with the
Comprehensive Plan goals to provide a variety of housing styles.
(6) Encourages a more creative and efficient use of land.
The PUD allows the higher density areas to be clustered, and
preserves open space.
(7) Preserves and enhances desirable site characteristics including
flora and fauna, scenic views, screening and buffering, and
access.
The townhouse units are sited to take advantage of the natural
terrain.
(8) Allows the development to operate in concert with a
Redevelopment Plan in certain areas of the City and to insure the
redevelopment goals and objectives within the Redevelopment
District will be achieved.
This criterion is not applicable.
(9) Provides for flexibility in design and construction of the
development in cases where large tracts of land are under single
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ownership or control and where the users) has the potential to
significantly affect adjacent or nearby properties.
The use of the PUD allows the clustering of the homes and the use
of private streets.
(10) Encourages the developer to convey property to the public, over
and above required dedications, by allowing a portion of the
density to be transferred to other parts of the site.
There is no additional parkland dedication with this plan.
Section 1106.300 states the quality of building and site design
proposed by the PUD will enhance the aesthetics of the site and
implement relevant goals and policies of the Comprehensive Plan. In
addition, the following criteria shall be satisfied:
(1) The design shall consider the whole of the project and shall create
a unified environment within the boundaries of the project by
insuring architectural compatibility of all structures, efficient
vehicular and pedestrian circulation, aesthetically pleasing
landscape and site features, and efficient use and design of
utilities.
The design creates a unified environment. Revision of the
landscaping plan to meet the requirements of the Zoning
Ordinance will also enhance this area.
(2) The design of a PUD shall optimize compatibility between the
project and surrounding land uses, both existing and proposed
and shall minimize the potential adverse impacts of the PUD on
surrounding land uses and the potential adverse effects of the
surrounding land uses on the PUD.
The use of the PUD will allow the clustering of the townhouse
units and provide a greater setback from the shore line.
(3) If a project for which PUD treatment has been requested involves
construction over a period of time in two or more phases, the
applicant shall demonstrate that each phase is capable of
addressing and meeting each of the criteria independent of the
other phases.
This project will be completed in two phases. The utilities, roads
and landscaping will be completed for each phase.
(4) Approval of a PUD may permit the placement of more than one
building on a lot.
This is not applicable.
(5) A PUD in a Residential Use District shall conform to the
requirements of that Use District unless modified by the following
or other provisions of this Ordinance.
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a. The tract of land for which a project is proposed shall have
not less than 200 feet offrontage on a public right-of-way.
b. No building shall be nearer than its building height to any
property line when the property abutting the subject property
is in an "R-l" or "R-2" Use District.
c. No building within the project shall be nearer to another
building than Yz the sum of the building heights of the two
buildings, except for parking ramps which may be directly
connected to another building.
d. Private roadways within the project site may not be used in
calculating required off-street parking spaces.
The modifications requested by the developer include the
following:
. The use of private streets. Normally, a development of
this type would require a minimum right-of-way width of
50' and a 28' to 30' wide surface. The developer is
requesting a 24' wide private street. The additional 26' of
right-of-way would be accommodated by the use of
easements adjacent to the private road.
. Reduced front yard setbacks on the private streets. The
conventional setback requirement is 25' from the right-of-
way line. The developer is requesting a 20' front yard
setback, measured from the building face to the curb of the
private street.
. Reduced front yard setback along Fremont Avenue. The
conventional setback requirement is 25' from the right-of-
way line. The developer is requesting a 15' setback along
Fremont Avenue.!
. Impervious Surface. The developer is requesting a
modification to the maximum 25% impervious surface in
tier 2 of the development. The developer is proposing to
utilize permeable pavement for all of the driveways in the
development. This pavement, if installed and maintain
properly, should reduce the impact of the impervious
surface on the site. The overall impervious surface of the
site is 27.2 percent.
These modifications are permitted under the PUD provisions
at the discretion of the Council. The Planning Commission
found these modifications to be consistent with the goals and
intent of the PUD criteria in that they allowed the clustering of
the townhouses to preserve the natural terrain. The Planning
Commission also found the modification to the impervious
surface appropriate since the overall impervious surface is less
than 30% and the ponding is sized to accommodate all of the
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CONCLUSION:
FISCAL IMPACT:
ALTERNATIVES:
driveways, roads, and other areas. The Commission also
reasoned that a conventional development could include
impervious surface up to the 30% maximum.
PRELIMINARY PLAT: The preliminary plat generally meets the
requirements ofthe Zoning and Subdivision Ordinances.
If the PUD plan is approved, the preliminary plat may also be
approved. There are remaining Engineering issues that must be
addressed. These are basically design issues that can be addressed at
the final plat stage.
The Planning Commission and staff recommended approval of both
the preliminary PUD plan and the preliminary plat, subject to the
following conditions.
1. The tree inventory must be revised to include only those trees
considered significant in the Zoning Ordinance. All of the
necessary information must be submitted to staff to verify the
calculations.
2. The landscaping plan must be revised to meet all ordinance
requirements. Replacement trees must be included on the
landscape plan.
3. The private streets must be platted as outlots. A 13' wide drainage
and utility easements must be provided on either side of the outlot.
4. The developer must provide easements for the storm water pond.
5. All driveways in the development must be constructed with
permeable pavement. The design and installation of these drives
must be approved and inspected by the City.
6. Fremont Avenue must be improved adjacent to this site. The City
will participate in the cost of the project.
7. The homeowners' association documents must address the
maintenance of the permeable pavement.
8. All public improvements must be constructed to the standards of
the Public Works Design Manual. Revised plans must be
submitted for review by the City.
9. Provide a phasing plan for the project.
Budf(et Impact: There is no budget impact as a result of this action.
Approval of the project will facilitate the development of the area and
increase the City tax base.
The City Council has three alternatives:
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RECOMMENDED
MOTION:
REVIEWED BY:
1. Adopt a resolution approving the PUD Preliminary Plan subject to
the listed conditions, and adopt a resolution approving the
Preliminary Plat for this development subject to the listed
conditions, with the finding that the preliminary plat is consistent
with the intent and purpose ofthe Comprehensive Plan and the
Zoning and Subdivision Ordinances.
2. Deny the PUD Preliminary Plan, and the Preliminary Plat on the
basis they are inconsistent with the purpose and intent of the Zoning
and Subdivision Ordinances and/or the Comprehensive Plan. In
this case, the Council should direct the staff to prepare a resolution
with findings of fact based in the record for the denial of these
requests.
3. Defer consideration of this item and provide staff with specific
direction.
The staff recommends Alternative # 1. This action requires the
following motions:
1. A motion and second adopting a resolution approving a Planned
Unit Development Preliminary Plan to be known as Jeffers South
subject to the listed conditions;
2. A motion and second adopting a resolution approving a
Preliminary lat to be known as Jeffers South, subject to the listed
QJtiO
Frank B
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PLANNED UNIT DEVELOPMENT P~~~L1MINARY PLAN
RESOLUTION 02-~ / ~ s
RESOLUTION APPROVING THE CRYSTAL BAY PLANNED UNIT DEVELOPMENT
MOTION BY:
SECOND BY:
WHEREAS: 212 Development, LLC has submitted an application for a Planned Unit Development
Preliminary Plan to be known as Crystal Bay; and
WHEREAS: The Prior Lake Planning Commission considered the proposed Planned Unit
Development Preliminary Plan at a public hearing on September 3, 2002 and on
September 23, 2002; and
WHEREAS: Notice of the public hearing on said PUD Preliminary Plan has been duly published in
accordance with the applicable Prior Lake Ordinances; and
WHEREAS, The Planning Commission proceeded to hear all persons interested in this issue and
persons interested were afforded the opportunity to present their views and objections
related to the PUD Preliminary Plan; and
WHEREAS: The Prior Lake City Council considered the proposed PUD Preliminary Plan for Crystal
Bay on October 7, 2002; and
WHEREAS: The City Council finds the PUD Preliminary Plan consistent with the Comprehensive Plan
and the Zoning Ordinance; and
WHEREAS: The City Council finds the PUD Preliminary Plan is compatible with the stated purposes
and intent of the Section 1106 Planned Unit Developments of the Zoning Ordinance.
NOW, THEREFORE, BE IT HEREBY RESOLVED BY THE CITY COUNCIL OF PRIOR LAKE,
MINNESOTA:
1. The above recitals are herein fully incorporated herein as set forth above.
2. It hereby adopts the following findings:
a) Greater utilization of new technologies in building design, materials, construction and land
development.
The developer has attempted to design the buildings so they fit the land, rather than force
the land to fit the building design. The use of permeable pavement for the driveways on
the site will reduce the runoff and allow further treatment of the storm water.
b) Higher standards of site and building design.
The density of this site is clustered to the north and set back further from the lake shore
than would be required under a conventional development. The units have also been
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16200 Eagle Creek Ave. S.E., Prior Lake, Minnesota 55372-1714 / Ph. (952) 447-4230 / Fax (952) 447-4245
AN EQUAL OPPORTUNITY EMPLOYER
placed so as to preserve the trees on the east boundary of the site. The utilization of
private streets further reduces the impervious surface on the site.
c) More efficient and effective use of streets, utilities, and public facilities to support high
quality land use development at a lesser cost.
Maintenance of private streets, including plowing and future repairs, is done by the
homeowners association. This reduces City costs in providing services to these homes.
d) Enhanced incorporation of recreational, public and open space components in the
development which may be made more useable and be more suitably located than would
otherwise be provided under conventional development procedures.
The developer is providing a private beach and recreation area for the residents of the
development, as well as private walking trails. These trails will connect to the public trail
along CSAH 82.
e) Provides a flexible approach to development which allows modifications to the strict
application of regulations within the various Use Districts that are in harmony with the
purpose and intent of the City's Comprehensive Plan and Zoning Ordinance.
The density and variety of housing units is consistent with the Comprehensive Plan goals
to provide a variety of housing styles.
f) Encourages a more creative and efficient use of land.
The PUD allows the higher density areas to be clustered, and preserves open space.
g) Preserves and enhances desirable site characteristics including flora and fauna, scenic
views, screening and buffering, and access.
The townhouse units are sited to take advantage of the natural terrain.
h) Allows the development to operate in concert with a Redevelopment Plan in certain areas
of the City and to insure the redevelopment goals and objectives within the
Redevelopment District will be achieved.
This criterion is not applicable.
i) Provides for flexibility in design and construction of the development in cases where large
tracts of land are under single ownership or control and where the users) has the potential
to significantly affect adjacent or nearby properties.
The use of the PUD allows the clustering of the homes and the use of private streets.
j) Encourages the developer to convey property to the public, over and above required
dedications, by allowing a portion of the density to be transferred to other parts of the site.
There is no additional parkland dedication with this plan.
k) The design shall consider the whole of the project and shall create a unified environment
within the boundaries of the project by insuring architectural compatibility of all structures,
efficient vehicular and pedestrian circulation, aesthetically pleasing landscape and site
features, and efficient use and design of utilities.
The design creates a unified environment. Revision of the landscaping plan to meet the
requirements of the Zoning Ordinance will also enhance this area.
/) The design of a PUD shall optimize compatibility between the project and surrounding
land uses, both existing and proposed and shall minimize the potential adverse impacts of
the PUD on surrounding land uses and the potential adverse effects of the surrounding
land uses on the PUD.
1:\02fi1es\02subdivisions\02pre1im p1ats\crystal bay\pudres.doc
PAGE 2
The use of the PUD will allow the clustering of the townhouse units and provide a greater
setback from the shore line.
m) If a project for which PUD treatment has been requested involves construction over a
period of time in two or more phases, the applicant shall demonstrate that each phase is
capable of addressing and meeting each of the criteria independent of the other phases.
This project will be completed in two phases. The utilities, roads and landscaping will be
completed for each phase.
n) Approval of a PUD may permit the placement of more than one building on a lot.
This is not applicable.
0) A PUD in a Residential Use District shall conform to the requirements of that Use District
unless modified by the following or other provisions of this Ordinance. 1) The tract of land
for which a project is proposed shall have not less than 200 feet of frontage on a public
right-of-way; 2) No building shall be nearer than its building height to any property line
when the property abutting the subject property is in an "R-1" or "R-2" Use District; 3) No
building within the. project shall be nearer to another building than ~ the sum of the
building heights of the two buildings, except for parking ramps which may be directly
connected to another building; and 4) Private roadways within the project site may not be
used in calculating required off-street parking spaces.
The modifications requested by the developer include the following:
. The use of private streets. Normally, a development of this type would require a
minimum right-of-way width of 50' and a 28' to 30' wide surface. The developer is
requesting a 24' wide private street. The additional 26' of right-of-way would be
accommodated by the use of easements adjacent to the private road.
. Reduced front yard setbacks on the private streets. The conventional setback
requirement is 25' from the right-ot-way line. The developer is requesting a 20' front
yard setback, measured from the building face to the curb of the private street.
. Reduced front yard setback along Fremont Avenue. The conventional setback
requirement is 25' from the right-ot-way line. The developer is requesting a 15'
setback along Fremont Avenue.!
. Impervious Surface. The developer is requesting a modification to the maximum 25%
impervious surface in tier 2 of the development. The developer is proposing to utilize
permeable pavement for all of the driveways in the development. This pavement, it
installed and maintain properly, should reduce the impact of the impervious surface on
the site. The overall impervious surface ot the site is 27.2 percent.
These modifications are permitted under the PUD provisions at the discretion ot the
Council. The City Council found these modifications to be consistent with the goals and
intent of the PUD criteria in that they allowed the clustering of the townhouses to preserve
the natural terrain. The Council also tound the modification to the impervious surface
appropriate since the overall impervious surface is less than 30% and the ponding is sized
to accommodate all of the driveways, roads, and other areas. The Commission also
reasoned that a conventional development could include impervious surface up to the
30% maximum.
3. The Crystal Bay Planned Unit Development Preliminary Plan is hereby approved subject to the
following conditions
a) The tree inventory must be revised to include only those trees considered significant in the
Zoning Ordinance. All of the necessary information must be submitted to staff to verify the
calculations.
1:\02fi1es\02subdivisions\02pre1im plats\crysta\ bay\pudres.doc
PAGE 3
b) The landscaping plan must be revised to meet all ordinance requirements. Replacement
trees must be included on the landscape plan.
c) The private streets must be platted as outlots. A 13' wide drainage and utility easements
must be provided on either side of the outlot.
d) The developer must provide easements for the storm water pond.
e) All driveways in the development must be constructed with permeable pavement. The
design and installation of these drives must be approved and inspected by the City.
f) Fremont Avenue must be improved adjacent to this site. The City will participate in the
cost of the project.
g) The homeowners' association documents must address the maintenance of the
permeable pavement.
h) All public improvements must be constructed to the standards of the Public Works Design
Manual. Revised plans must be submitted for review by the City.
i) Provide a phasing plan for the project.
Passed and adopted this 7th day of October, 2002.
YES NO
Haugen \ Haugen
Gundlach \ Gundlach
LeMair \ LeMair
Petersen \ Petersen
Zieska \ Zieska
\
{Seal} Frank Boyles, City Manager
I:\02fi1es\02subdivisions\02prelim p1ats\crysta1 bay\pudres.doc PAGE 4
PRELIMINARY PLAT
RESOLUTION 02-~ /1.0 b
RESOLUTION OF THE PRIOR LAKE CITY COUNCIL APPROVING THE PRELIMINARY PLAT
OF "CRYSTAL BAY" SUBJECT TO THE CONDITIONS OUTLINED HEREIN.
MOTION BY:
SECOND BY:
WHEREAS: The Prior Lake Planning Commission conducted a public hearing on September 9, 2002 and on
September 23,2002 to consider an application from 212 Development, LLC., for the preliminary
plat of Crystal Bay; and
WHEREAS: Notice of the public hearing on said preliminary plat has been duly published and posted in
accordance with the applicable Minnesota Statutes and Prior Lake Ordinances; and
WHEREAS: All persons interested in this issue were afforded the opportunity to present their views and
objections related to the preliminary plat of Crystal Bay for the record at the Planning
Commission hearing; and
WHEREAS: The Planning Commission and City Council have reviewed the preliminary plat according to the
applicable provisions of the Prior Lake Zoning and Subdivision Ordinances and found said
preliminary plat to be consistent with the provisions of said ordinances; and
WHEREAS The Prior Lake City Council considered an application for preliminary plat approval of Crystal
Bay on October 7, 2002; and
WHEREAS: The City Council finds the preliminary plat of Crystal Bay to be consistent with the 2020
Comprehensive Plan.
NOW, THEREFORE, BE IT HEREBY RESOLVED BY THE CITY COUNCIL OF THE CITY OF
PRIOR LAKE, MINNESOTA:
A. The above recitals are incorporated herein as if fully set forth.
B. The preliminary plat of Crystal Bay is approved subject to the following conditions:
1) The tree inventory must be revised to include only those trees considered significant in the Zoning
Ordinance. All of the necessary information must be submitted to staff to verify the calculations.
2) The landscaping plan must be revised to meet all ordinance requirements. Replacement trees must be
included on the landscape plan.
3) The private streets must be platted as outlots. A 13' wide drainage and utility easements must be
provided on either side of the outlot.
1:\02files\02subdivisions\02prelim plats\crystal bay\platres.doc Page 1
16200 Eagle Creek Ave. S.E., Prior Lake, Minnesota 55372-1714 / Ph. (952) 447-4230 / Fax (952) 447-4245
AN EQUAL OPPORTUNITY EMPLOYER
4) The developer must provide easements for the storm water pond.
5) All driveways in the development must be constructed with permeable pavement. The design and
installation of these drives must be approved and inspected by the City.
6) Fremont Avenue must be improved adjacent to this site. The City will participate in the cost of the
proj ect.
7) The homeowners' association documents must address the maintenance of the permeable pavement.
8) All public improvements must be constructed to the standards of the Public Works Design Manual.
Revised plans must be submitted for review by the City.
9) Provide a phasing plan for the project.
Passed and adopted this 7th day of October, 2002.
YES NO
Haugen \ Haugen
Gundlach \ Gundlach
LeMair \ LeMair
Petersen '\ Petersen
Zieska \ Zieska
{Seal} City Manager
City of Prior Lake
1:\02files\02subdivisions\02prelim plats\crystal bay\plalres.doc
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~ochester
\1innesota
Land Surveying
Urban - Land Planning
nsulting - Civil Engineering
Geotechnical Engineering
onslrUction Material Testing
Landscape Architecture
1648 Third Avenue S.E.
Rochester, MN 55904
Tel. 507.289.3919
Fax. 507.289.7333
e-mail.mcghiebetts.com
F=<:t",hlic:h..rl 1 C\..:1F;
May 21,2002
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Ms. Jane Kansier, AICP
City of Prior Lake Planning Department
16200 Eagle Creek Ave. S.E.
Prior Lake, MN 55372-1714
Dear Ms. Kansier:
The purpose of a General Development Plan and Planned Unit Development is to
redevelop the existing 10.62 acre site by developing 26 townhomes along a 28'
private street with scenic views of the Upper Prior Lake Bay. The PUD includes
a 12' private driveway connection to Upper Prior Lake, a boat dock and a boat
slip for each unit.
We are seeking a PUD on this property in order to provide for a unique townhome
development, which includes many walkout style units and side-loaded garages.
The flexibility of the PUD process will allow the units to be placed in the most
efficient layout that maximize views of the lake while still maintaining the
character of the site.
The following public benefits include:
1. A higher standard of site design was needed to layout the town home units
that maximizes views of the lake while still preserving as much of the
natural character of the site as possible. The building design of the
town home also meets a higher standard of design by the use of an efficient
floor plan and an eye for quality details.
2. The townhomes were clustered with alternating side-loaded and front
loaded garages to minimize the separation between the units and thus
creating a more efficient use of street, utilities and public facilities.
The use of private streets and the use of a street connecting the two phases
does allow for a more efficient layout of public improvements.
3. The plan emphasizes the use of common open space, which nearly envelops
the development. The green space is particularly important where the stands
of trees are preserved along the east property lie and along the entire
shoreline. This allows everyone easy access to the lake. A traillboat access
..
EXHIBIT B
'I,~~
I~~
for the development is also available to all residents from the common open
space area.
4. The use of walkout style townhomes in areas that work with the topography
and full-basement units in area of level terrain minimizes the need
for grading and also minimize the views of the lake. This layout deals with
the site creativity and efficiency.
5. The preservation of existing trees along the eastern part of the site allows
the natural character to remain which has many public benefits. The
preserved trees help provide protection from the harsh elements (which
saves energy), provides for wildlife habitat and creates a buffer from the
neighborhood to the east and the lake.
Modifications from the existing district regulations include the following:
The proposed front yard setbacks would be 20' , with the exceptions of Unit 5/6
and Unit 7 of Phase n, which would be 19' plus 18' respectively. Typical front
yard setbacks are 25'. This plan proposes a combination of side loaded and front
loaded garages. In an effort to create a consistent streetscene, a more efficient
use of the property, and to minimize the amount of impervious surface a 20'
setback is proposed. This distance would still allow for adequate room for cars to
be parked in the driveways of front loaded units without impeding traffic flow or
snow storage from the pri v ate street.
The proposed side street yard setback of unit one in Phase n is 12' -0". Typical
side street yard setbacks in an R-1 district are 25'. In an effort to create an
efficient use of property and stay out of the 75' shoreland setback, it was
necessary to narrow the side street yard setback to 12' -0". This distance would
allow for landscaping between the unit and future sidewalks that would buffer the
unit from the street.
In an effort to make the project financially feasible, it was necessary to place
twelve units in the second phase. In order to maintain the 75' shoreland setback
and keep the orientation of the unit's living spaces to the lake, it was necessary to
deviate from the typical 25' rear yard setback along the future right of way for
County Road No. 82. The proposed rear yard setback is 6.38 feet. This setback
is to the garage and not the primary living space.
The last modification from district standards would be our request for 26 boat
slips, which would allow each unit to have one. The DNR's standard is 21 boat
slips based on the density along the lakefront.
..
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PhasinS!
Phase I proposes to build 14 units on approximately 7.22 acres, the construction
of the detention pond and the 12' bituminous path from Crystal Bay Drive to
Upper Prior Lake.
Phase IT will construct 12 units on approximately 3.40 Acres. This phase will
complete the project and the connection of Crystal Bay Dri ve to Fremont A venue
N.W. An existing home will remain in Phase IT, but will be removed/relocated
within two years after the project has started.
Densitv Calculations
Tier 1 Density: 5.02 Ac./ 18 units = 3.59 Units Per Acre
Tier 2 Density= 4.90 Acres / 8 Units = 1.63 Units Per Acre
Ground Floor Area= 51,870 SQ. Fr.
Floor Area Ratio = 0.22
ParkinS!
Each unit includes a three-car garage and three spaces per driveway. "Spill Over"
parking will be accommodated by on street parallel parking. Crystal Bay Drive
will have 26 parking spaces and Drake Circle will have four.
Comorehensive Plan Desienation
Residential low/medium density.
Zonine
R-lSD
TRAFFIC ANALYSIS
"
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Introduction
The Crystal Bay Development is located along Scott County Road No. 82 (l54th
Street NW) and Freemont A venue NW. The project consists of 26 townhome
units in 13 twinhome style structures.
The traffic analysis focuses on peak hours, trip generation based on full build-out
of the project.
Back2round
Crystal Bay Development will have a direct connection to both County Road No.
82 and Freemont Avenue NW via a private street. The project will be developed
in two phases with phase one consisting of 14 units on the northerly one half of
the site and 12 units for phase two which is the southerly one half of the project
site.
Historically, the site has been used for residential purposes so the projected new
trips are not entirely an increase of traffic generation.
Access of the private road to both Freemont and County Road No. 82 are
currently a stop and go situation. County Road No. 82 is a minor arterial and
Freemont is classified as a local street. The employment center and school
systems are primarily located to the north of the project site.
Assumotions
For the purpose of the Traffic Analysis, we have taken a more conservative
approach to the operations because of the size of the proposed development.
The assumptions made are as follows:
. One trip per unit outbound for AM peak hour
. Two-thirds trips in-bound and one-third outbound for PM peak hour
. 6.6 trips per day for each townhome unit
. 85% of out bound trips will be a right-turn movement and 15% left turn
~25....
~
Analysis Trip
Generationl
Distribution
Private Road! Private Road!
County Road No. 82 Freemont A venue
Total Daily Trips 14 Units x 6.6 12 units x 6.6 trips /unit=80
tripslunit=92 trips trips
AM Peak Hours 7:00 AM to 8:30 AM
PM Peak Hours 4:30 PM to 6:00 PM
AM Peak Trips 14 12
PM Peak Trips 14 12
Distribution of AM AM
Trip for Peaks 85% x 14=12 right turn 85% x 12=10 right turn
Hours 15% x 14 = 2 left turn 15% x 12 = 2 left turn
(all outbound) (all outbound)
Total Trips added 14 Total tri ps 12
added
PM PM
1/3rd x 14=5 right turn 1/3rd x 12=4 right turn
outbound outbound
2/3rds x 14 = 9 left turn 2/3rds x 12 = 8 left turn
inbound inbound
Total Trips added 14 Total Trips 12
added
Traffic Analvsis Summary
The Traffic Analysis indicates a total daily trip generation of 172. The AM peak
hour generates 14 trips outbound to the County Road No. 82 access and 12 trips
on Freemont. The PM traffic generation consists of a total of 19 inbound and 9
outbound trips.
The majority of the AM peak hour trips generation is right turn movements while
the PM is left turn inbound movements. The PM inbound movement (left turn) is
the operation that will create some delays. However, it is our opinion that the
total inbound movement on County Road No. 82 is insignificant compared to the
total volume on County Road No. 82 and will not create significant delays. The
same is true for Freemont A venue NW at the intersection with County Road No.
82.
The total trip generation does not warrant improvements to County Road No. 82
or Freemont A venue at this time. It is our understanding that the County has
plans to upgrade County Road No. 82 in the near future. The applicant is
dedicating through the platting process additional right of way for the
expansion of County Road No. 82.
ENVIRONMENT AL ISSUES
Environmental issues concerning the Site include the removal of existing homes
and outbuildings, the abandonment of private water wells and individual septic
treatment systems, temporary and permanent erosion and sediment control and
tree removal and replacement. There are no known or suspected dumps,
hazardous materials or threatened or endangered species.
Removal of Existim~: Homes
~
Five single-family residential homes and various outbuildings occupied the Site.
One home is served by municipal sewer and water service while the others have
private wells and individual septic systems. The applicant has moved the three
homes in the area proposed to be developed as Phase I and has contracted with
licensed well drillers and septic operators to abandon the wells and septic systems
in accordance with state statutes. Wells and septic systems will be properly
abandoned on the other properties as well. The project will result in all homes
being connected to municipal services and will remove the potential of septic
leakage or runoff into Prior Lake.
Erosion and Sediment Control
The construction and development will utilize best management practices to
control erosion and runoff with Prior Lake in accordance with the necessary
NPDES erosion control permits. A permanent sedimentation pond will be
constructed and will be protected by a public drainage easement. The existing
drainage from the city storm sewer will be extended through an easement
adjoining the storm water pond.
Sep 19 02 02:47p .
~orthfield
Jlinnesota
Land Surveying
Civil Engineering
Geotechnical Engineering
Construction Material
Testing
Environmental Services
1604 Riverview Lane
Northfield, MN 55057
Tel. 507.645.0964
Fax. 507.645.2842
e-mail. mlc(a~mbi-nf.co~-
McGhie & Betts - NF
(507)645-2842
p. 1
FACSIMILE TRANSMISSION COVER SHEET
A TTN: Ms. Jane Kansier
COMPANY: City ofPnor Lake - Planning
FAX NUMBER: 952-447-4245 TIME SENT:
PHONE NUMBER:
DATE SENT:
TOTAL # OF PAGES WITH COVER SHEET
.,
ORIGINAL WILL BE MAILED:
D~
RE: Map of Boat Slips
FROM:
Mark Osborn
If you do not receive the number of pages indicated or if you have problems with the
trcU1Smission, please call 507-645-0964.
i
I
I
I
i
~ane, we [mally received info regarding the lake contours. Our Boat I
!Slips will be as shown on the following map if approved by the DNR as :
:well as the City of Prior Lake. .
MESSAGE:
~s can be seen., we are an adequate distance from the surrounding boat
~1ips. The DNR. encouraged us to keep the slips as close to the west as !
jwe can be without crowding the existing slips.
!
~.o) 1 9~-
.J L~
...-.--..
--'-
--~--- ..~--~--_.
This te1cfaxcd information is intended only for the use of the individual or
entity to which it is lIddressed and contains information that is private.
privileged and confidential. If the reader of this message is not the intended
Irecipicnt, the cmployer, employee or agent rcsponsible: to deliver it to thc
intended recipient. you are hereby notified that dissemination, distribution or
copying of this communication by any means or in any manner is strictly
prohibited. If you have received this fax in error. please notify us
immediately by telephone and return the original message to us by mail- at the
above address. ·
UNI ECO-STONE@
GUIDE
AND
RESEARCH
SUMMARY
Permeable Pavement
for Stormwater Management
........e~
UNI-GROUP U.S.A.
.WlitCTWRS OF UNI PAVING STONES
',3 \~=...
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UNI-GROUP U.S.A.
4362 Northlake Blvd. . Suite 204. Palm Beach Gardens, FL 33410. (561) 626-4666. Fax (561) 627-6403 . (800) 872-1864
This paper is a summary of the Eco-Stone research and studies that have been done to date and includes a general design overview
and other information that may be helpful to the designer. For a copy of any of these reports, theses, or articles call UNI-GROUP
U.S.A. at 1-800-872-1864 or contact us via e-mail at info@uni-groupusa.org.
The information included in this report is intended to provide guidance and recommendations for the design and construction of
UNI Eco-Stonelll interlocking concrete permeable pavements. Recommendations are guidelines only and will vary with local
regulations, specifications, environmental conditions, materials, and established construction methods for an area. It is not intended
to replace the judgement or expertise of professional engineers or landscape architects, who should be consulted in the design and
construction of permeable pavements.
@ 2002 UNI-GROUP U.S.A.
This report may not be reproduced whole or in part without the express written consent of UN I-GROUP U.S.A.
ACKER STONE MUTUAL MATERIALS, INC.
13296 Temescal Canyon Rd., Corona, CA 91719 605 1I9rh Ave. N. E., Bellevue, WA 98005
(909) 674-0047 / FAX (909) 674-0477 (425) 452-2300 / FAX (425) 637-0794
(800) 477-3008
MUTUAL MATERIALS, INC.
6721 E. Trent, Spokane, WA99212
(509) 922-4100 / FAX (509) 922-7207
(800) 755-0413
MUTUAL MATERIALS, INC.
18230 S.w. Boones Ferry Rd.
Portland, OR 97224
(503) 624-8860 / FAX (503) 620-4709
(800) 477-7137
ANCHOR CONCRETE PRODUCTS
CORPORATE HEADQUARTERS
1913 Atlantic Ave., Manasquan, NJ 08736
(732) 292-2500 / FAX (732) 292.2650
ANCHORCONCrorrePRODU~
975 Burnt Tavern Rd., Brick, NJ 08724
(732) 458-6888 / FAX (732) 840-4283
ANCHORCONCRETEPRODU~
100 Foulrift Rd., Phillipsburg, N] 08865
(908) 475-1225 / FAX (908) 475-1787
ANCHORCONCrorrePRODU~
110 Bergen Turnpike, Little Ferry, NJ 07643
(201) 641-2161/ FAX (201) 641-2779
BALCON/BETCO
2630 Conway Rd., Crofton, MD 21 I 14
(410) 721-1900/ FAX (410) 793-0657
Baltimore (410) 793-0638
Merro Washington, DC (301) 261-0200
BORGERT PRODUCTS, INe.
8646 Ridgewood Rd., St. Joseph, MN 56374
(320) 363-4671 / FAX (320) 363-85 I 6
IDEAL CONCrorre BLOCK CO.
45 Power Rd., Wesuord, MA 01886
(781) 894-3200/ FAX (978) 692-0817
(800) 444-7287
IDEAL CONCrorre BLOCK CO.
232l.exingron St., Walrham, MA 02454
(781) 894-3200/ FAX (781) 894-8526
(800) 444-7287
INTERLOCK PAVING SYSTEMS, INe.
802 Wesr Pembroke Ave., Hampron, VA 23669
(757) 723-0774 / FAX (757) 723-8895
(800) 572-3189 (In NC & VA)
KIRCHNER BLOCK & BRICK, INC.
12901 St. Charles Rock Rd.,
Bridgeran, MO 63044
(314) 291-3200 / FAX (314) 291-0265
PAVESTONE COMPANY
1900 Clovis Barker Rd., San Marcos, TX 78666
(512) 558-7283 / FAX (512) 558-7289
PAVESTONE COMPANY
169 Peggy Lane, Tyrone, GA 30290
(770) 306-9691 / FAX (770) 306-8741
PAVESTONE COMPANY
64033 Highway 434, Lacombe, LA 70445
(504) 882-91 I I / FAX (504) 882-5225
PAVESTONE COMPANY
8479 Broadwell Rd., Cincinnati, OH 45244
(513) 474.3783 / FAX (513) 474-6683
PAVER SYSTEMS PAVESTONE COMPANY
6 I Rd W. P I ch FL 4 1015 S. 43rd Ave., Phoenix, AZ 85009
71 7 nterpace ., est am Bea, 33 07 (602) 257-4588 / FAX (602) 257.1224
(561) 844-5202/ FAX (561) 844-5454
(800) 226-0004 PAVESTONE COMPANY
PAVER SYSTEMS 601 N. E. Pavestone Dr.,
W. La d Rd 0 I d FL 4 Lee's Summit, MO 64064
39 est n sneet ., ran 0, 3282 (816) 524-9900/ FAX (816) 524-9901
(407) 859-9117/ FAX (407) 851-9316
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940 I E. 96rh Ave., Henderson, CO 80640
(303) 287-3700 / FAX (303) 287-9759
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8907 N. 12th St. & Busch Blvd.,
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(813) 932-2212/ FAX (813) 933-4914
(800) 356-PAVE
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(941) 377-9594 / FAX (941) 377.9780
PAVESTONE COMPANY
CORPORATE HEADQUARTERS
700 Heritage Square I
4835 LB] @ Dallas Parkway, Dallas, TX 75244
(972) 404-0400 / FAX (972) 404-9200
(800) 580.PAVE (Texas Only)
(800) 245-PAVE (National)
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(817) 481-5802 / FAX (817) 488-3216
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PAVESTONE COMPANY
27600 County Rd. 90, Winters CA 95694
(916) 452-5233 / FAX (916) 452-9242
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Visir our website ar www.uni-groupusa.org for
updated information on our manufacrurer
listings, research, design guides and more.
TABLE OF CONTENTS
UNI ECO-STONElI> PRO]ECTS......................................................................................................................................4
INTRODUCTION..........................................................................................................................................................5
LOW IMPACT DEVELOPMENT AND ENVIRONMENTAL DESIGN......................................................................6
UNI ECO-STONEe PERMEABLE INTERLOCKING CONCRETE PAVEMENTS....................................................7
Features and Benefits of the Uni Eco-Stonell> Pavement System...............................................................................7
Municipal Regulations, Infiltration Practices, and Objectives........................ ............................ ...................... .......7
General Construction Guidelines.......................................................................................................................... 8
Design Options - Full, Partial, or No Exfiltration......................................................................................8
Site Selection Guidelines.......................................................................................................................... 9
Infiltration Rate Design and Considerations............. ...... ............ .............. ..... .............. ......... ......... ..... ......9
Construction Materials and Installation Guidelines...... ......... ............ ..... ......... .............. ......... ..... ...........10
Maintenance........................................................................................................................................ . .11
Cold Climate Design Considerations..... .............. ....................... ........................... .......... ..... ..................11
RESEARCH AND TESTING - UNI ECO-STONElI> PERMEABLE PAVEMENT SYSTEM....................................... 12
Design Considerations for the UNI Eco-Stonell> Concrete Paver...........................................................................12
Drainage Design and Performance Guidelines for UNI Eco-Stonell> Permeable Pavement..................................... 13
Infiltration and Structural Tests of Permeable Eco- Paving............................ ............ ............. ..... ......... ........ ..........14
ONGOING RESEARCH AT GUELPH UNIVERSITY................................................................................................15
The Leaching of Pollutants From Four Pavements Using Laboratory Apparatus...................................................15
Stormwater Investigation of Thermal Enrichment of Storm water Runoff From Two Paving Surfaces.................... 19
Design and Installation of Test Sections of Porous Pavements for Improved Quality of Parking Lot Runoff...........21
Long-Term Stormwater Infiltration Through Concrete Pavers.............................................................................24
Feasibility of a Permeable Pavement Option in the Stormwater Management Model (SWMM) for
Long-Term Continuous Modeling..................................................................................................................... ..27
Restoration of Infiltration Capacity of Permeable Pavers.............. ......... .... ................ .......... ......... ......... ........ ...... .29
GUELPH SYNOPSES OF RESEARCH.........................................................................................................................32
ADDITIONAL UNI ECO-STONElI> RESEARCH AND TESTING.............................................................................34
The University of Washington Permeable Pavement Demonstration Project.........................................................34
Expert Opinion on UNI Eco-Stonell> - Pedestrian Use..........................................................................................34
Expert Opinion - In-Situ Test of Water Permeability of Two UNI Eco-Stonell> Pavements.....................................34
Drainage with Interlocking Pavers...................................................................................................................... .34
Development of Design Criteria for Flood Control and Groundwater Recharge Utilizing
UNI Eco-Stonell> and ECOLOClI> Paving Units....................................................................................................34
STRUCTURAL DESIGN SOFTWARE.........................................................................................................................35
PO'WERPOINTlI> PRESENTATION.............................................................................................................................35
CASE STUDIES..... ................. ................ ............. ..... ......... .......... ...... ................... .......... ......... .... ..... .... ..... ..... ....... ...... ..36
ADDITIONAL REFERENCES......................................................................................................................................37
INSPECTION FORMS FOR STORMWATER MANAGEMENT SYSTEMS.............................................................38
3
UNI ECO-STONE@ PROJECTS
. Rio Vista Water Treatment Plant
. Mickel Field & Highlands Park
· Wilcox Lake Park, City of Richmond Hill
. Annsville Creek (ECOLOC")
. Private Residence
. Atlanta Zoo
. Private Residence
. English Park
. Homestead Village, VI
. Private Residence
. Humberwood Development Center
. Commercial Parking Lot
. Kean Design
. Crazy Crab Restaurant
· Cumberland Island National Seashore Museum
. Booth's Cobblestone Parking Lot
. Private Residence
. Howard Hook, Port of New York/New Jersey (ECOLOC")
. Residential Housing Development
. Queenquay Community Center
. Wynnsong Cinemas
. Private Residence
· Jordan Cove - Glen Brook Green
. Regent Court Apartments
. St. Andrews Church
· Harbourfront Fire Station No.9
· Parkland Homes
. Sherwood Island State Park
. Corkscrew Swamp State Park
. Trinity United Church
. Commercial Parking Lot
. Newark Airport
. Ford Canada Corporation
. Private Resi.dence
. Private Residence
. Multnomah Arts Center
. Retail Center Parking Lot
Castaic Lake Water Agency, Santa Clarita, CA
Wilton Manors, FL
Oakridges, ON
Peekskill, NY
Winter Park, FL
Atlanta, GA
South Shore, MA
Atlanta, GA
Dallas, TX
Jupiter Island, FL
Etobicoke, ON
North Hampton, NH
Winter Park, FL
Hilton Head, SC
St. Mary's, GA
Orlando, FL
Dallas, TX
Staten Island, NY
Hilton Head Island, SC
Toronto, ON
Savannah, GA
Winter Park, FL
Waterford, CT
Vero Beach, FL
Sonoma, CA
Toronto, ON
Winter Park, FL
Westport, CT
Naples, FL
Grimsby, ON
Nantucket, MA
Newark, NJ
Oakville, ON
Long Island, NY
Sanibel Island, FL
Portland, OR
Hyannis, MA
27,000 sq ft
37,165 sq ft
8,000 sq ft
20,000 sq ft
1,200 sq ft
400 sq ft
1,000 sq ft
2,700 sq ft
3,000 sq ft
3,500 sq ft
9,000 sq ft
15,000 sq ft
3,000 sq ft
900 sq ft
4,000 sq ft
1,800 sq ft
4,000 sq ft
15,000 sq ft
1,800 sq ft
3,000 sq ft
10,000 sq ft
14,000 sq ft
15,000 sq ft
5,500 sq ft
3,500 sq ft
7,000 sq ft
2,000 sq ft
32,000 sq ft
2,500 sq ft
10,000 sq ft
23,000 sq ft
262,000 sq ft
2,500 sq ft
1,500 sq ft
395 sq ft
10,500 sq ft
19,000 sq ft
Please use this guide to review the extensive research that has been conducted by UNI-GROUP U.S.A. and UNI
International. The references and guidelines will help ensure that your UNI Eco-Stone" system will perform as intended
over its design life. For additional information, contact UNI-GROUP U.S.A. or your local UNI@ Manufacturer.
4
INTRODUCTION
As open land is developed and covered with impervious surfaces such as asphalt roadways, concrete parking
decks, and buildings, there is an increase in stormwater runoff that may result in downstream flooding, streambank
erosion, and excessive strain on existing drainage facilities. Numerous studies indicate that stormwater runoff is also the
primary source of pollutants found in surface waters and often contains a toxic combination of oils, pesticides, metals,
nutrients, and sediments. Approximately 40% of America's surveyed waterways are still too polluted for fishing or
swimming and 90% of our population lives within 10 miles of these bodies of water.
With the implementation of the United States Environmental
Protection Agency's National Pollutant Discharge Elimination System
(NPDES) stormwater regulations in the early 1990s, state agencies,
municipalities, and regional authorities began searching for new options in
stormwater management. Effective management of stormwater runoff offers
a number of benefits, including improved quality of surface waters,
_protection of wetland and aquatic ecosystems, conservation of water
resources, and flood mitigation. Traditional flood control measures that rely
on detention of peak flow are typical of many stormwater management
approaches, but generally do not target pollutant reduction, and often cause
unwanted changes in hydrology and hydraulics. The EPA recommends an
approach that integrates control of stormwater flows and the protection of
natural systems to sustain aquatic habitats.
Mick~/ Fi~VJ/High/ands Park, Wi/ton Manors. FL
Effective stormwater management is often achieved through a comprehensive management systems approach
instead of individual practices. Some individual practices may not be effective alone, but may be highly effective when
used in combination with other systems. The EPRs Phase II rule encourages system building to allow for the use of
appropriate situation-specific practices that will achieve the minimum measures. Ordinances or other regulations are used
to address post-construction runoff from new development or redevelopment projects. In addition, it is important to
ensure adequate long-term operation and maintenance of BMPs. Governing authorities must develop and implement
strategies that include a combination of structural and/or non-structural best management practices (BMPs) appropriate
for their communities. Non-structural BMPs are preventative actions that involve management and source controls.
Structural BMPs include storage practices, filtration practices, and infiltration practices that capture runoff and rely on
infiltration through a porous medium for pollutant reduction.
Permeable pavements are considered structural BMPs under infiltration practices. From an engineering
viewpoint, permeable pavements are infiltration trenches with paving over them to support pedestrian and vehicular
traffic. Much of the design and construction is derived from experience with
infiltration trench design, which has been used for years as a way to reduce
stormwater runoff and recharge groundwater. Permeable pavements should be
designed by civil engineers, architects, or landscape architects familiar with
stormwater management concepts, especially the Soil Conservation Service (SCS)
method, (now know as the National Resources Conservation Service or NRCS
method). For years, porous pavements consisted of cast-in-place asphalt or concrete
comprised of coarse aggregate, which had earned a poor reputation due to their
tendency for clogging, and there was no way to renew porosity. Today, permeable
interlocking permeable pavements offer a better solution.
UNI Eco-Stone~ is a permeable interlocking concrete pavement system
designed to mitigate stormwater runoff through infiltration, thereby reducing
volume flows, improving water quality, and recharging groundwater. UNI Eco-
Stone~ is a true interlocking paver that offers the structural support and stability of
traditional concrete pavers, combined with the environmental benefit of stormwater Wikox Lak~ Park. Oakridg~s. ON
management. Eco-Stone~ has a minimum compressive strength of 8000 psi, maximum 5% absorption, and meets or
exceeds ASTM C-936 and freeze-thaw testing per section 8 of ASTM C-67. ECOLOC~ features the same infiltration
benefits as Eco-Stone~, but offers increased structural strength and stability for industrial pavement applications.
5
LOW IMPACT DEVELOPMENT
AND ENVIRONMENTAL DESIGN
In addition to the EPA, other agencies and organizations are addressing the issue of development and the impact
of stormwater runoff on the environment and society. According to the National Resources Defense Council, Low
Impact Development (LID) has emerged as an attractive approach to controlling stormwater pollution and protecting
watersheds. LID attempts to replicate pre-development hydrology to reduce the impacts of development. By addressing
runoff close to the source, LID can enhance the environment and protect the public, while saving developers and local
municipalities money. One of the primary goals of LID design is to reduce runoff volume by infiltrating rainwater into
groundwater and finding beneficial uses for water as opposed to pouring it down storm sewers. Some of LID runoff
control objectives include reducing impervious cover, preserving and recreating natural landscape features, and facilitating
infiltration opportunities. LID principles are based on the premise that stormwater management should not be seen as
stormwater disposal, but instead that numerous opportunities exist within a developed landscape to control stormwater
close to the source. This allows development to occur with low environmental impact. LID is much more than the
management of stormwater - it is about innovation in the planning, designing, implementing, and maintaining of
projects. Permeable pavers, such as Eco-StoneCll, are listed as one of the ten common LID practices.
Increasing numbers of municipal green building programs are offering incentives for sustainable landscape
architecture and development. Programs that require LEED (Leadership in Energy and Environmental Design, a national
green building assessment system developed by the U.S. Green Building Council) certification to achieve benefits, come
the closest to a comprehensive approach for sustainable projects. While private sector participation is voluntary, many
municipalities are requiring that city-owned or funded projects achieve LEED objectives. Many municipalities
nationwide already have local programs in place and are forming departments dedicated to sustainable building. LEED is
a self-assessing, voluntary building system for rating new and existing commercial, institutional, and high-rise residential
buildings. It evaluates environmental performance from a '\yhole building" perspective over a building's life cycle,
providing a definitive standard for what constitutes a "green building". It is a feature-oriented system where credits are
earned for satisfying each criteria. UNI Eco-Stone4ll permeable pavers may qualify under two areas. Credit 6 - Stormwater
Management and Credit 7 - Landscape and Exterior Design to Reduce Heat Islands. The intent of Credit 6 is to limit
the disruption of natural water flows by minimizing stormwater runoff, increasing on-site infiltration, and reducing
contaminants - pervious pavements are recommended. Credit 7's intent is to reduce heat islands (thermal gradient
differences between developed and undeveloped areas) to minimize impact on microclimate and human and wildlife
habitat - light-colored, high-albedo materials and open grid paving are recommended. Concrete pavers albedo values can
range from 0.14 to 0.27 for standard colors, with higher values possible when pavers are manufactured using lighter color
aggregates or white cement (where available).
Many local municipalities, regional authorities, and state agencies such as Departments of Environmental
Protection are now recommending or requiring best management practices for the mitigation of stormwater and are
providing information to residents and the business community about BMP practices and stormwater solutions. The
City of Toronto, for example, promotes stormwater pollution education to residents and industry through advertising
and their website. Among other suggestions, they recommend replacing impermeable surfaces with materials that allow
for infiltration. The city has approved Eco-Stone4ll for parking pads in residential applications.
Web sites ofInterest:
Natural Resources Defense Council- www.nrdc.org/waterlpollution/storm/chap12.asp
Nonpoint Education for Municipal Officials - www.nemo.uconn.edu
EPA - www.epa.gov/npdes/menuofbmps/posc12.htm
EPA - www.epa.gov/nps/lid.pdf
EP A - www.epa.gov/OWOW/NPS/MMGI/Chapter4/ch4-2a.html
Stormwater Magazine - www.forester.net/sw_0203~reen.html
U.S. Green Building Council - www.usgbc.org
Center for Watershed Protection - www.cwp.org
Heat Island Group - www.eetd.lbl.gov/Heatlsland/Pavements/Albedo
City of Toronto - www.city.toronto.on.ca
6
UNI ECO-STONE@ PERMEABLE
INTERLOCKING CONCRETE PAVEMENTS
FEATURES AND BENEFITS OF THE UNI ECQ-STONE@ PAVEMENT SYSTEM
· The unique, patented design features funnel-like openings in the pavement surface, which facilitate the infiltration of
rainwater to reduce or eliminate stormwater runoff and maximize groundwater recharge and/or storage
· Mitigates pollution impact on surrounding surface waters and may lessen or eliminate downstream flooding and stream
bed and bank erosion
· Improves water quality by infiltrating water through the base and soil, and also reduces runoff temperatures
· Decreases project costs by reducing or eliminating drainage and retention systems required by impervious pavements
and reduces the cost of compliance with many stormwater regulatory requirements
· Permits better land-use planning, allowing more efficient use of available land for greater economic value
· Provides a highly durable, yet permeable pavement capable of supporting vehicular loads
Permeable interlocking concrete pavements do require greater initial site evaluation and design effort. They
require a greater level of construction skill, inspection during construction and after installation, and attention to
detail. In addition, maintenance is a critical aspect to help ensure long-term performance. It is recommended that a
qualified professional engineer with experience in hydrology and hydraulics be consulted for permeable interlocking
concrete pavement applications. This guide is intended as an overview of construction guidelines and research
conducted to date. Please see the research and reference sections for detailed guidance and additional information.
Eco-Stonee provides an attractive pavement surface that can be used for residential, commercial, and municipal
pedestrian and vehicular pavement applications. It can be used for parking lots, driveways, overflow parking and
emergency lanes, boat ramps, revetments, bike paths, sidewalks and pedestrian areas, and low-speed roadways.
MUNICIPAL REGULATIONS, INFILTRATION PRACTICES, AND OBJECTIVES
Municipal policy, design criteria, and local experience usually govern the use of infiltration systems such as
permeable pavements. Design criteria and regulations vary nationwide, as rainfall amounts, geography, climate, and land-
use development patterns can vary widely. Most BMPs are designed for a specific design storm, for example a 2-year, 24-
hour storm of 1.5 in.!hr. (33 mm/hr) or volume from the first '/2 to 1 in. (13
to 25 mm). Though initial infiltration rates can be quite high with UNI Eco-
Stonee permeable pavements, a few studies have shown that long-term
infiltration rates for permeable interlocking pavements in general range
between 1.0 and 2.5 in.!hr (25 and 65 mm/hr). Though higher rates may be
possible with optimal construction and regular maintenance, designers may
wish to use this conservative range as a guideline. This range would be able to
infiltrate frequent, short duration rainstorms, of which 70-80% of North
America storms are comprised.
Some municipalities regulate both water quality and quantity.
They may require a criteria for reducing specific types of pollutants, such as
phosphorous, metals, nitrogen, nitrates, and sediment, and water quality
regulations are often written to protect lakes, streams, and rivers from problems
associated with runoff. An increasing number of municipalities are limiting the
use of impervious surfaces and many have created stormwater utilities to help
cover the increasing costs of constructing, managing and maintaining
storm water drainage systems.
Newark International Airport, NJ
(Specialty a[g"gate surface texture)
Selection of base, bedding, and joint/drainage opening fill materials will be guided by local storm water management
objectives. Generally, for runoff control, regulations try to meet one or more of four management objectives.
7
· Capture and infiltrate the entire stormwater volume so there is zero discharge from the drainage area. Costs for
infiltrating or capturing all the runoff through the use of permeable pavements may be offset by reducing or eliminating
pipes and other drainage appurtenances.
· Infiltrate the increased runoff generated by development and impervious surfaces. The goal is to attain runoff
volumes equal to or near those prior to development. Volumes are estimated prior to and after development, and the
difference is to be infiltrated or stored, and then slowly released. Permeable pavements, vegetated swales, or rain gardens,
among other BMPs, can accomplish this.
· Infiltrate a fixed volume of runoff from every storm. This fixed amount of infiltrated water often is indicative of a
large percentage of the region's storms. The volume is usually expressed as depth in inches (or mm) of runoff over the
catchment area. Permeable interlocking concrete pavements are usually capable of infiltrating the first inch (25 mm) or
more of runoff, which helps reduce the "first flush" of pollutants in this initial runoff volume. Grass swales and sand
filters provide additional filtering and removal of some pollutants in rainwater, and designers may want to consider using
them in conjunction with permeable pavements for added benefits.
· Infiltrate sufficient water to control the peak rate of discharge. Many municipalities establish a maximum rate of peak
discharge (in cubic feet/second or liters/second) for specific storm sewers or bodies of water. This approach favors
detention ponds rather than infiltration as a means to control downstream flooding. Permeable interlocking concrete
pavements can be used as a means of detention, especially in densely-developed areas where ponds are not feasible, by
combining the benefits of a parking area with sub-surface detention.
Depending upon the amount of exfiltration (the downward movement of water through the crushed stone base
into the subgrade soil), UNI Eco-Stoneill can meet most of these stormwater management objectives.
GENERAL CONSTRUCTION GUIDELINES
UNI-GROUP U.S.A. provides design professionals with a variety of tools for designing Eco-Stoneill permeable
interlocking concrete pavements. Please refer to the research section of this guide for information on designing the Eco-
Stoneill pavement system. In addition, we offer Lockpaveill Pro structural design software and PC-SWMM'" Permeable
Pavement software for the hydraulic design of Eco-Stoneill permeable pavements. The computational engine is the Runoff
module of the USEPA's Stormwater Management Model. It allows the user to develop a simple model of a permeable
pavement design, run the model with a specified design storm, and analyze the results. A successful design is assumed in
the program to be one in which the entire volume of runoff is captured by the pavement (i.e. no surface runoff occurs).
Though this model is based on this zero runoff scenario, design parameters can be adjusted to meet other stormwater
management objectives. PC-SWMM'" for Permeable Pavements software is a tool to aid design professionals and
provides general guidance. It is intended for use by professional civil engineers and is not a substitute for engineering skill
and judgement and in no way is intended to replace the services of experienced, qualified engineers.
DESIGN OPTIONS - FULL, PARTIAL OR NO EXFILTRATION
Permeable interlocking concrete pavements are typically built over an open-graded or rapid-draining crushed stone base,
though a variety of aggregate materials, including free-draining and dense- """'""D""'.....-...
graded, may be used depending on design parameters. In all cases, fines passing ~r'=\""~"""
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permeable pavements may be designed to filter pollutants, treat the "first flush",
lower runoff temperature, and remove total suspended solids (TSS). Because it
provides for infiltration and partial treatment of stormwater, it is considered a
structural BMP (Best Management Practice). The most optimal installation is
infiltration through the base and complete exfiltration into a permeable
subgrade. However, the design of the pavement can be very flexible. Perforated .....
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installations where slow-draining subgrade soils are present and only partial Cross-uction a/typical Eco-Stonl" pavmzmt
exfiltration will occur, perforated pipes can drain excess runoff. Often, these pipes are sized smaller than typical drainage
pipes in traditional pavement applications. If no exfiltration will occur due to site limitations, all the stored water would
need to be directed to drains, though the flow rates would be reduced by the infiltration through the system.
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8
In addition, if high levels of pollutants are present, the pavement can be designed to filter and partially treat the
stormwater. In some cases an impervious liner may need to be placed between the base and the subgrade. According to
the EPA, there are four cases where permeable interlocking concrete pavements should not exfiltrate and where an
impervious liner might be used.
· When the depth from the bottom of the base to the high level of the water table is less than 2 ft (0.6 m), or when there
is not sufficient depth of the soil to offer adequate filtering and treatment of pollutants.
· Directly over solid rock, or over solid rock with no loose rock layer above it.
· Over aquifers where there isn't sufficient depth of soil to filter the pollutants before entering the groundwater. These
can include karst, fissured, or cleft aquifers.
· Over fill soils, natural or fill, whose behavior may cause unacceptable performance when exposed to infiltrating water.
This might include expansive soils such as loess, poorly compacted soils, gypsiferous soils, etc.
Even if these situations are not present, some soils may have a low permeability. A5 a result, water is usually
stored in the base to slowly infiltrate into the soils. In some cases, there may be a more permeable soil layer below a low
or non-permeable layer, where it may be cost effective to drain the water with a french drain or pipes through this layer
into the soil with greater permeability.
SITE SELECTION GUIDELINES
Eco-Stonell> permeable interlocking concrete pavers can be used for a wide variety of residential, commercial,
municipal and industrial applications (ECOLOCII>). In addition to some of the guidelines previously described,
permeable pavements should be at least 100 ft (30 m) from water supply wells, wetlands, and streams, though local
regulations may supercede this requirement.
There are however, certain circumstances when permeable pavements should not be used. Any site classified as a
storm water hotspot (anywhere there is risk that stormwater could infiltrate and contaminate groundwater) is not a
candidate for permeable pavements. This might include salvage and recycling yards, fueling, maintenance, and cleaning
stations, industrial facilities that store or generate hazardous materials, storage areas with contents that could damage
groundwater and soil, and land uses that drain pesticides and/or fertilizers into permeable pavements. In addition,
permeable pavements may not be feasible when the land surrounding and draining into the pavement exceeds a 20%
slope or the pavement is downslope from building foundations where the foundations have piped drainage at the footers.
INFILTRATION RATE DESIGN AND CONSIDERATIONS
One of the most common misconceptions in designing permeable pavements is the assumption that the amount
or percentage of open surface area is equal to the percentage of perviousness. For example, a designer might incorrectly
assume that a 20% open area is only 20% pervious. The permeability and amount of infiltration are dependent on the
infiltration rates of the joint and drainage opening material, bedding layer, and base materials. Compared to soils, Eco-
Stonell> permeable interlocking concrete pavements have a very high degree
of infiltration. The crushed aggregate used for the joints, drainage openings,
and bedding has an initial infiltration rate of over 500 in.lhr (over 10.3
m/sec), much greater than native soils. Rapid-draining and open-graded
base materials offer even higher infiltration rates of 500 to over 2000 in.lhr.
(over 10.3 to 10.2 m/sec).
Though the initial infiltration rates for these aggregate materials are
very high, it is important to consider the lifetime design infiltration of the
entire pavement cross-section, including the soil subgrade. A5 this may be
difficult to predict, designers may want to use a conservative approach when
calculating the design infiltration rate. Limited research has shown that permeability decreases with the age of the
pavement, rainfall intensities, and the conditions under which it is used and maintained. This holds true for infiltration
trenches as well. Therefore, engineers should account for these factors when designing infiltration rates for permeable
interlocking concrete pavements, and the establishment of a maintenance program should be encouraged to ensure long-
term performance.
Drainag( opmings in &o-Stonl" surfac(
9
~,~_'_~'''d''_'''___'~__'''''_~.___'_'d'''"''_'''_'__-'-'''~_'_'__........."..._,,__...,~_,__"_.-~ ---~~,.,.-......."."~-.___~.,________."...,_~_..~.~",_....___,, '. ~ .'''''''~--''''-'-''- ,,~.--..----_.._._.-
CONSTRUCTION MATERIALS AND INSTALlATION GUIDELINES
The objective of permeable pavements is to infiltrate and store the runoff and drain it into the subgrade, or if the
subgrade is impermeable, into a drainage system. Proper construction of permeable interlocking concrete pavements is
crucial to the long-term performance and success of the system. It is important that sediment be prevented from entering
the base and pavement surface during construction, as this will greatly reduce
permeability of the system. It is highly recommended that the designing engineer
inspect the site during the construction of permeable pavements (as is the case
with infiltration trenches). This will help ensure the specified materials and design
parameters selected by the engineer are followed. Though a range of materials
may be used for the joint and drainage opening, bedding, and base layers, some
general guidelines have been included here. Consult the UNI Eco-Stonelll design
manuals and the PC-SWMM'" program for more information on designing Eco-
Stonelll permeable pavements.
Jordan Cov~ Dro~/opmmt, WatnfOrd, CT
A professional engineer with soils experience should assess the site's subgrade
soils for design strength, permeability, and compaction requirements. The Unified Soils Classification System provides
general guidance on the suitability of soils for the infiltration of stormwater and bearing capacity. To help maximize
infiltration, the subgrade should have less than 5% passing the No. 200 (0.075 mm) sieve, though other soils may drain
adequately depending on site conditions and specific characteristics. A minimum tested infiltration for full exfiltration
subject to vehicular traffic is 0.52 in.lhr (3.7 x 10-6 m/sec), though some areas may require higher or lower rates. With
virtually all pavements, including permeable pavements, compaction of the subgrade soil is required to ensure adequate
structural stability and to minimize rutting. However, compaction does reduce the infiltration rate of soils. Therefore,
this should be considered in the drainage design calculations for the project. Typically, the soil subgrade should be
compacted to at least 95% standard Proctor density for pedestrian pavements, and to a minimum 95% modified Proctor
density for vehicular applications. Some native soils, typically silty sands and sands, have enough strength (a soaked CBR
of at least 5%) that compaction may not be required.
For many years, engineers attempted to design pavements that kept water out of the base and subgrade layers, as
water in a typical "impervious" pavement structure was recognized as a primary cause of distress. However, over the last
15 years, the Federal Highway Administration (FHWA), American Association of State Transportation and Highway
Officials (MSHTO), and the Corps of Engineers (COE) have given the subsurface drainage of pavements much
consideration. They have found that the use of rapid-draining or open-graded permeable bases in many pavement designs
can result in longer pavement life (see Additional Reference section for more information).
For the base layer, a crushed stone, open-graded or rapid-draining aggregate is generally recommended, though
as discussed earlier, other aggregate materials may be used depending on design parameters and objectives. The base must
be designed and constructed to prevent the pavement from becoming saturated and losing its load-bearing capacity in the
presence of water, and stability will be enhanced if nonplastic materials are used. The thickness of the base depends on
the amount of water storage required, the permeability and strength of the soil subgrade, and susceptibility to frost, as
well as anticipated traffic loads. The water infiltration capaciry of the base will vary with
its depth and the percentage of void spaces in it (void space of a certain material can be
supplied by the quarry or determined by testing). Please see the UNI-GROUP U.S.A.
Eco-Stonelll design manuals for additional information on base material selection and
contact your local UNIIIl manufacturer for guidance on recommended materials for your
region. The base is installed in 4 to 6 in. (100-150 mm) lifts and is compacted. If an
open-graded material with larger size aggregates creates an uneven surface when
compacted, a 2 in. (50 mm) layer of ASTM No.8 or No.9 crushed aggregate may be
"choked" into the top of the material to stabilize the surface and help meet filter criteria. ECOLOC" industrial p~rm~abu pav=
In some cases, open-graded bases may be stabilized with asphalt or cement if necessary to increase structural capacity.
However, it should be noted that this may reduce storage capacity of the base and must be carefully monitored during
construction. The Asphalt Institute and Portland Cement Association provide guidelines on constructing these bases.
For the bedding layer, testing has shown that a 2-5 mm clean, crushed aggregate containing no fines provides the
best performance in satisfying both structural and infiltration requirements. It should be screeded to a uniform depth of
1 to 1.5 in. (25-45 mm). This material is also recommended for the joint and drainage openings for the Eco-Stonelll
10
pavement. ASTM C-33 sand, which is used in traditional interlocking concrete pavement bedding layer construction, is
not recommended for permeable pavement installations as it reduces infiltration rates. In addition, we do not
recommend sweeping a fine sand into the joints after the pavers are installed.
If filter criteria between the layers of the pavement (subgrade, base, and bedding) cannot be maintained with the
aggregate materials selected for the project, or if traffic loads or soils require additional structural support, geotextiles or
geogrids are often used. They are almost always used between the subgrade and the base. Consult the FHWA and
AASHTO for information on geotextile filter criteria.
The UNI Eco-Stonelll pavers are installed on the screeded bedding layer and
are compacted with a plate compactor. After initial compaction, the joints and voids
are filled with the 2-5 mm aggregate material and the pavers are compacted again. M~chanica/ illItal/ation at Howard Hook
For vehicular areas, proof rolling may be preferable. UNI Eco-Stonelll pavers can be Port of N= York / N= Jersey
installed manually or mechanically. Mechanized installation can offer substantial cost savings on larger-scale installations.
Edge restraints are required for all permeable interlocking concrete
pavements. Cast-in-place, precast concrete, or granite curbs should be a minimum of
6 in. (150 mm) wide and 12 in. (300 mm) deep.
MAINTENANCE
One of the most important aspects of permeable interlocking concrete pavements is proper maintenance. Any
type of permeable pavement can become clogged with sediment overtime, reducing infiltration and storage capacity.
When properly constructed and maintained, permeable interlocking concrete pavements should provide a minimum
service life of 20 to 25 years. If base or utility repairs become necessary, Eco-Stonelll may be taken up and reinstalled after
the repairs are made. Traffic levels and type of usage, as well as sources that may wash sediment onto the paver surface
often dictate how quickly the pavement might experience reduced infiltration levels. The property owner plays an
important role in the maintenance of permeable pavements. Many local municipalities and regional governing authorities
require a maintenance agreement to help ensure long-term performance of all types of BMPs.
Recent testing at Guelph University in Ontario, Canada on Eco-Stonelll parking lot pavements installed in 1994
indicated that trafficked areas with high clogging potential had lower permeability values than areas with low clogging
potential such as parking stalls and areas near vegetated medians. Tests demonstrated that it was possible to regenerate
infiltration rates by removing some of the drainage void material and refilling the openings with fresh material. It should I
be noted that these pavements had NEVER been cleaned or maintained over the years, yet much of the pavement still
infiltrated sufficient amounts of stormwater. Numerous research studies done over the years at this site have found that
the Eco-Stonelll pavements were capable of substantially reducing contaminants in stormwater and exhibited reduced
thermal impact loads. Please see the research section of this guide for additional information.
It is higWy recommended that permeable pavers be inspected and cleaned at regular intervals to ensure optimum
performance. Depending on the amount and type of traffic on the pavement and its potential for clogging, cleaning may
be needed from twice a year to every 3 or 4 years. An indication that the pavement needs to be cleaned is when surface
ponding occurs after rain storms. Vacuum sweepers can be used to remove any encrusted sediment on the surface of the
drainage openings. As street sweeping is a BMP, this also satisfies other criteria in a comprehensive stormwater
management program. More aggregate material may be added to refill the drainage voids if necessary after cleaning.
Vegetated areas around permeable pavements should be encouraged to help filter runoff.
COLD CLIMATE DESIGN CONSIDERATIONS
In northern climates the pavement must be designed for freeze-thaw conditions. For cold climates in the
northern U.S. and Canada, the lowest recommended infiltration rate for the subgrade is 0.5 in.!hr. (3.5 x 10-6 m/sec).
Designers may wish to incorporate a 1-2% slope and catch basins as a safety factor for over-flow should the system not
be able to infiltrate all runoff under winter conditions. Snow can be plowed from Eco-Stonelll pavements using standard
equipment. Deicing salts are not recommended, as salt will infiltrate into the base and subgrade, and sand should be
avoided as it will reduce infiltration of the system. However, the Eco-Stonelll surface, made up of joints, openings, and the
units (as opposed to a continuous area of slick pavement) may help provide traction under snowy conditions.
11
RESEARCH AND TESTING
UNI ECO-STONE@ PERMEABLE PAVEMENT SYSTEM
DESIGN CONSIDERATIONS FOR THE UNI ECO-STONE@
CONCRETE PAVER
Raymond and Marion Rollings - 1993
GENERAL SUMMARY
This 32-page manual reviewed testing information from the U.S. and Germany and extrapolated from existing design
practice to provide basic design guidance on the development of designs for the UNI Eco-Stone~ pavement system.
Numerous references are included as well as tables on infiltration test and rates, permeability values, filter criteria,
potential drainage void gradations, and more. Sample design cross sections are also included. A 4-page addendum of
updated research was added in 1999.
OUTLINE
· INTRODUCTION
· Purpose
· Description
Subgrade and Base Course
Surfacing Materials
· DESIGN CONSIDERATIONS
· Structural Considerations
· Water Impact on Design
Wearing Course and Bedding Layer
Base and Subbase Courses
Subgrade
· Hydraulic Design
· Filter Requirements
· Special Considerations
· SPECIFICATIONS
· APPLICATIONS
· CONCLUSIONS
· REFERENCES
· SAMPLE DESIGN DRAWINGS
12
DRAINAGE DESIGN AND PERFORMANCE GUIDELINES FOR
UNI ECO-STONE@ PERMEABLE PAVEMENT
Dan G. Zollinger, Su Ling Cao, and Daryl Poduska - 1998
GENERAL SUMMARY
The information provided in this report, based on testing begun in 1994 at the Department of Civil Engineering at
Texas A & M University under the direction of professor Dan Zollinger, serves as a guideline for the design of concrete
paver block pavement systems using UNI Eco-Stonee. The guidelines are organized to give the reader a brief review of
basic hydrological concepts as they pertain to the design of pavements and the benefits of using UNI Eco-Stonee in
pavement construction projects. Information is provided on how runoff infiltration can be controlled in the pavement
subsurface and its interaction with the performance of the pavement system. A method is provided to determine the
amount of infiltration and the storage capacity of a permeable base relative to the time of retention and degree of
saturation associated with the characteristics of the base. The guidelines contain a simple step-by-step process for the
engineer to select the best pavement alternative in terms of base materials and gradations for the given drainage, subgrade
strength conditions, and the criteria for maximum allowable rutting.
OUTLINE
· INTRODUCTION
· Advantages of Using UNI Eco-Stonee Pavement
· The Considerations for Water
· The Purpose of This Report
. GENERAL HYDROWGY CONCEPTS
· Rainfall
· Intensity-Frequency Duration Curve
· The Depth of Rainfall
· Storm Water Runoff Volume
· Unit Hydrograph
. SURFACE DRAINAGE SYSTEM
· Computation of Runoff
· SUBSURFACE DRAINAGE DESIGN
· Introduction
· General Considerations
Properties of Material
Design Alternatives
· Design Criteria
Inflow Considerations
Outflow Considerations
Removal by Subgrade Percolation
Removal by Subsurface Drainage
The Selection of Base Material
Filter Criteria
Collection System
Maintenance
. PERFORMANCE OF PERMEABLE BWCK PAVEMENT SYSTEMS
· REFERENCES
· APPENDIXA
. Design Procedure for Drainage and Base Thickness for UNI Eco-Stonee
· Paver Block Pavement Systems
· APPENDIX B
. UNI Eco-Stonee Pavement Design and Drainage Worksheet
· APPENDIX C
· Storm Frequency Data
· APPENDIX D
. Permeability and Gradation Data
13
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INFILTRATION AND STRUCTURAL TESTS OF PERMEABLE
ECO-PAVING
B. ShackeL J 0. Kaligis, Y. Muktiarto, and Pamudji
GENERAL SUMMARY
In laboratory tests conducted on UNI Eco-Stone@ and UNI Eco-Loc@ in 1996 by Dr. Brian Shackel at the University of
New South Wales in Sydney, Australia, measurements of water penetration under heavy simulated rainfall were studied,
and the structural capacities of the paver surfaces were evaluated. A range of bedding, jointing, and drainage void
materials was tested, ranging from 2mm to 10mm aggregates. The best performance was achieved with a clean 2mm-
5mm aggregate containing no fines. The use of ASTM C-33 grading was found to be inappropriate where water
infiltration is the primary function of the pavement. The experimental data showed that it was possible to reconcile the
requirements of obtaining good water infiltration (capable of infiltrating rainfall intensities similar to those in tropical
conditions) with adequate structural capacity that is comparable to that of conventional concrete pavers.
OUTLINE
· CONCEPTS, BENEFITS, AND BACKGROUND OF ECO-PAVING
· BEDDING, JOINTING, AND DRAINAGE MATERIAlS
· Infiltration Tests
· Structural Tests
· SUMMARY AND CONCLUSIONS
1. Pavements laid using 4mm to 10mm gravels as the bedding, jointing, and drainage medium could accept rainfall
intensities of up to about 600 lIhalsec, with the best performance being given by a clean 2mm-5mm basalt
aggregate containing no fines.
2. Increase in the fines present in the jointing and drainage material led to a reduction in the ability of the
pavements to accept rainfall.
3. Blinding the pavements with a conventional laying sand reduced the amount of water penetrating the pavement
by nearly 50% at moderate rainfall intensities.
4. There was little significant difference in water infiltration in pavement blinded by sand from that observed for
pavements using a sand complying with ASTM grading C33, as the bedding, jointing, and drainage medium.
5. The use of ASTM grading C33 appears inappropriate where water infiltration is the prime function of the
pavement.
6. At crossfalls below 2%, the type of Eco-paver and the laying pattern did not significantly affect the infiltration of
water into the pavement.
7. At a cross fall of 10%, the Eco-Loc@ pavers accepted water more readily than Eco-Stone~.
8. It was not possible to obtain any significant structural capacity in pavements where the joints were left unfilled,
and where the mechanism of load transmission between the pavers was solely via the spacer nibs.
9. In pavements using a 10mm basalt aggregate as the bedding, joi~1ting, and drainage material, the joints were only
partially filled when normal construction practices were followed. This did, however, impart some load-bearing
structural capacity to the pavements.
10. Good load-bearing capability was achieved using gravels with a maximum particle size of about 4mm-5mm. The
values of mat modulus measured were then comparable to those reported for conventional pavers tested in the
same way using normal sand jointing materials.
11. Sand blinding a pavement, using basalt as the laying medium, gave little improvement in structural capacity. This
can be explained in terms of the difficulty of getting sand into joints that were already partially filled with
aggregate.
12. There was no structural problem associated with closely spaced continuous joints running through the Eco-Loc~
cluster pavements. Such joints are a severe simulation of the situation encountered when machine laying paving
clusters. In other words, in the tests described here, there was no intrinsic problem associated with cluster laying.
Overall, the test results indicated that permeable eco-paving may be able to fulfill many of the roles now served by
conventional pavers, even under significant traffic loads. This opens up new marketing opportunities for permeable eco-
paving once suitable design and specification procedures are established and verified.
14
ONGOING RESEARCH AT GUELPH UNIVERSITY
Professor William James
In 1994, laboratory and site testing of the UNI Eco-Stone~ Paving System was begun at Guelph University in Ontario,
Canada, under the direction of William James, Professor of Environmental Engineering and Water Resources
Engineering. The research has generated several graduate theses with a focus on environmental engineering and
stormwater management. Summaries of the theses are to follow.
THE LEACHING OF POLLUTANTS FROM FOUR PAVEMENTS USING
LABORATORY APPARATUS
Reem Shahin - 1994
GENERAL SUMMARY
This lBO-page thesis describes a laboratory investigation of pavement leachate. Four types of pavements were installed in
the engineering laboratory: asphalt, conventional interlocking pavers, and two UNI Eco-Stonelll pavements, to determine
the effect of free-draining porous pavement as an alternative to conventional impervious surfaces. Runoff volume,
pollutant load, and the quantity and quality of pollutants in actual rainwater percolating through or running off these
pavements under various simulated rainfall durations and intensities were studied. UNI Eco-Stone~ was found to
substantially reduce both runoff and contaminants. The report includes tables and charts documenting volumes of runoff
collected on various slopes, water penetration testing, water quality characteristics of the surface runoff - including trace
metals, pH, phenols, sodium, nitrates, and concentrations of pollutants at all levels within the pavements. Numerous
references are also included.
OUTLINE
1.0 INTRODUCTION
1.1 Objectives of the study
1.2 Scope of the study
2.0 LITERATURE REVIEW
2.1 Nature of Water
2.1.1 Properties of water
2.1.2 Acidity
2.1.3 Rainwater
2.1.4 Behaviour of rainwater in the environment
2.1.5 Water pollution
2.2 Urbanization Effects
2.2.1 Effects of urban storm water on aquatic ecosystems
2.3 Nature of Pollutants
2.3.1 Atmospheric sources of water pollution
2.3.2 Man-made sources of water pollution
2.4 Porous pavement
2.4.1 Types of porous pavements
2.4.2 Advantages and disadvantages
2.4.3 Porous pavement as an infiltration system
2.4.4 Previous research
2.5 Asphalt pavement
2.6 Temperature effects
3.0 PROCESSES AT THE PAVEMENT
3.1 Impact energy of raindrops
3.2 Splash distribution
3.3 Chemical reactions with the water
3.4 Erosion of loose particles
3.5 Particulate wash-off throughout the pavement
15
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3.6 Surface infiltration
3.6.1 Infiltration equations
3.6.2 Infiltration process
3.6.3 Infiltration zones
3.7 Water percolation
3.8 Solution of chemicals in the pavement
3.9 Clogging of pores
4.0 THE LABORATORY EXPERIMENTS
4.1 Water collection
4.1.1 Laboratory rainwater
4.1.2 Fresh rainwater
4.2 The rainfall simulator
4.2.1 Rainfall intensity calibration
4.2.2 Areal uniformity calibration
4.3 Test pavements
4.4 Instrumentation for sampling
4.5 Sampling in the field .
4.6 Laboratory analyses
4.6.1 Laboratory apparatus
4.7 Mass balance
5.0 RESULTS
5.1 Simulated rainwater calibration
5.2 Rainwater quality
5.3 Volume
5.3.1 Rate of removal
5.4 Water quality
5.4.1 Pollutant concentrations
5.4.2 Comparison between LAB rain leachate and tap water leachate
5.4.3 Mass of pollutants
6.0 DISCUSSION
6.1 Difference between LAB and WDS rain
6.2 Dynamics of water movement
6.2.1 Water movement within the soil
6.2.2 Surface percolation
6.2.3 Water movement in the subgrade
6.2.4 Runoff collection
6.2.5 Ponding
6.3 Water quality
6.3.1 pH
6.3.2 Oxygen demand parameter
6.3.3 Solids
6.3.4 Conductivity and transmittance
6.3.5 Oils and grease
6.3.6 Nutrients
6.3.7 Total phenols
6.3.8 Sodium and chloride
6.3.9 Sulphates
6.3. 1 o Metals
6.3.11 Bacteria counts
6.4 Rain-pavement interaction
6.5 Mass balance
7.0 CONCLUSIONS
1. Rainwater is very acidic in the city of Guelph, having a pH of approximately 3.4 when it first makes contact
with the ground. It takes almost 2 hours after collection to release C02 into the atmosphere and reach a pH
of 5.5. At this pH, it takes at least 72 hours before it neutralizes to a pH of 7.
16
2. Impervious asphalt pavements produce large amounts of surface runoff, compared to porous pavements, for
similar rainfall intensities and durations. Porous pavement is evidently a very effective way of reducing the
quantity of stormwater runoff from areas such as parking lots that are normally paved with asphalt.
3. For all gradients, EC3 (UNI Eco-Stone<<> with 3" base and joints filled with washed stone) performed the best
at reducing surface runoff from all the pavements studied.
4. The total void size on the porous pavement surfaces is one of the main factors that affects permeability, and
not the pore size in the joints. EC3 reduced the most surface runoff volume due to the large voids available at
the surface and at the subsurface layers. Hence more water infiltrated through the pavement.
5. In these experiments, EC3, EC4 (Eco-Stone<<> with 4" base and joints filled with a mixture of washed stone
and sand), and PC (regular concrete pavers) pavements did not clog, due to the short duration of all the
experiments. In addition, the pavements were placed in the laboratory, and hence, no dust or any other
particulate accumulated on the surface and in the joints.
6. PC, EC3, and EC4 performed well in reducing volume of surface runoff at 1 %, 5%, and 10% gradients with
rainfall intensities lower than 55.6mm.hr. At higher rainfall intensities, ponding occurred at the joints and at
the outlets, which slowed down the infiltration process to the subsurface layers.
7. Since the EC3 had washed stone as its bedding material, the water drained faster through its subgrade than it
did for the EC4 and PC subgrades, which had a mixture of stone and sand in one, and sand alone in the
other, respectively.
8. The runoff collected from porous pavement in the laboratory showed very low concentrations in all water
quality parameters, especially in oils and grease, phenols, heavy metals, and bacteria counts. Eco-Stone<<>
pavements showed the lowest concentrations in these parameters of the three pavements.
9. Percolation through the porous pavements surface and underlying media slowed the water flow. The process
allowed more time for oxidation; the water had more time to react with other chemicals, such as chlorides,
nitrates, and nitrites. Also, the pavement apparently filtered suspended solids and some contaminants, such
as sodium and sulphates.
10. Heavy metal removal through percolation appeared to be good, even though the concentrations were very
low. The biggest reduction was observed with zinc and iron in the surface runoff from the porous pavements,
which had lower concentrations than the surface runoff from the asphalt surface (AS).
11. The porous pavement surface runoff had pH values more alkaline than the asphalt surface gave pH values
that were almost neutral.
12. The surface runoff from asphalt contained a higher mass of all the parameters investigated compared to the
mass measured in the surface runoff of EC3.
13. Surface runoff from the AS surface contained a concentration of phenols higher than the concentrations
found in the porous pavement surface and subgrades.
14. The leachate from the pavements contained contaminants mainly from rainwater in the atmosphere. Hence,
the processes that take place at the surface of the pavements are mainly due to the process of rainfall as it
falls on the ground (i.e., raindrop distribution, rainfall energy, and acidity of the rainwater).
15. The laboratory experiments on porous pavement generally proved that the water is not being contaminated
from the surface of these pavements or their bedding materials, but rather from the external environment, as
proven by the parking lot runoff analyses. With AS, the surface is made from the combustion of petroleum
products, and hence, some of the pollutants will originate from the surface, as in oil, grease, and phenols.
16. Porous pavement appears to have significant long-term benefits compared to conventional asphalt pavements
in terms of its ability to reduce the quantity of stormwater pollutants. EC3 reduced the amount of
stormwater pollutants more than the other porous pavement.
8.0 RECOMMENDATIONS
Based on the data gathered and conclusions reached in this study, recommendations that may be made include:
1. In addition to the ability to reduce runoff, the porous pavements will have lower surface runoff temperature,
as the water penetrates through the pavement. Hence, an experiment to examine temperature of runoff under
laboratory conditions will be valuable. The water quality analyses were performed at a constant temperature
(250C). Temperature changes will have a great impact on water quality, since many parameters were found to
be related to pH, and pH changes with temperature.
2. Tests should be performed to determine long-term effects of maintenance and potential for clogging.
3. When performing tests on water quality of stormwater runoff, some parameters remained almost constant.
The contaminants that need not be examined in detail include TKN, NH., BOD, COD, and some metals
such as cadmium and chromium.
17
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4. On the other hand, some parameters exhibited very interesting behaviour, particularly pH, phenols, oils and
grease, sulphate, sodium and chloride, nitrates and nitrites, zinc, lead, nickel, and copper.
5. From the data obtained in this study, although the pH of runoff from asphalt seemed to be more neutral than
the porous pavement pH, more investigation of the pH is needed in order to reach a more definite
conclusion on the performance of AS vs porous pavement in terms of pH.
6. Since hydraulic conductivity is mainly dependent on temperature, when examining temperature, hydraulic
conductivity will be an important parameter.
7. The rising cost of petroleum-based asphalt is.diminishing the price difference between asphalt pavement and
porous pavement. Relative long-term predictions for the future cost of using asphalt and porous pavement
would be an interesting study.
8. Porous pavements should be used in many applications of low traffic volume to effect significant reductions
. in stormwater runoff. Qualitative and quantitative experiments should be carried out on porous pavement on
lightly used roads.
9. Future experiments can be conducted using different conditions to give a more complete and detailed
characterization of the performance of porous pavements.
18
EXPERIMENTAL INVESTIGATION OF THERMAL ENRICHMENT OF
STORMWATER RUNOFF FROM TWO PAVING SURFACES
Brian Verspagen - 1995
GENERAL SUMMARY
This 173-page study examines the thermal enrichment of surface runoff from an impervious asphalt surface and a UNI
Eco-StoneCl> permeable paver surface. The pavement samples were heated and a rainfall simulator was used to generate
rainfall and cool the pave-ment samples. Thermocouples monitored the temperature in the subgrade and at the surface
and inlet and outlet water temperatures were monitored. The primary objective of the research was to measure the
thermal enrichment of surface runoff from the two types of pavement. The study revealed that the UNI Eco-StoneCl>
pavement produced very little surface runoff and exhibited less thermal impact than the asphalt surface. The
environmental advantage with the Eco-StoneCl> permeable pavement is its ability to allow rainfall to infiltrate the surface
and thereby reduce total thermal loading on surrounding surface waters. Tables include surface runoff observations,
sample and instrumented pavement comparison and temperature differences, and surface temperature data. Figures
include the impact of urbanization on stream temperature, surface runoff temperature comparisons for asphalt and Eco-
StoneCl> pavements, surface energy budgets under various conditions, and surface runoff impact on receiving rivers. Many
references are sited.
OUTLINE
1.0 INTRODUCTION
1.1 Study Objective
1.2 Study Scope
2.0 BACKGROUND
2.1 Impacts of Thermally Enriched Urban Stormwater Runoff
2.2 Surface Energy Budgets
2.3 Heat Transfer
2.4 Application of Energy Budget and Heat Transfer Equations
2.5 Rainfall Simulation
3.0 THEORETICAL DEVEWPMENT
3.1 Sensitivity Analysis of Surface and Heat Transfer Equations
3.2 Thermal Enrichment of Surface Runoff
4.0 LABORATORY EQUIPMENT
4.1 The Test Pavements
4.2 The Rainfall Simulator
4.3 Rainfall Calibration and Intensity Selection
4.4 Data Collection and Sources
4.5 Heating the Test Samples
4.6 Comparison to Outdoor Conditions
5.0 RESULTS
5.1 Surface Temperature Observations
5.2 Low and Medium Intensity Rainfall (25mm'hr" & 115mm.hr")
5.3 High Intensity Rainfall (190mm.hr')
5.4 Regression Analysis
6.0 DISCUSSION
6.1 Accuracy of the Proposed Equations
6.2 Sensitivity Analysis of the Thermal Enrichment Relationship
6.3 Comparison of Asphalt and Paving Stone Surfaces
6.4 Applicability
7.0 CONCLUSIONS AND RECOMMENDATIONS
Several conclusions may be inferred from the information presented in this study:
1. Both the asphalt surface and the porous paving stone surface used for the experiments conducted in this
study caused increases in the temperature of the surface runoff, the paving stone surface less so than the
asphalt surface.
19
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2. Very little surface runoff was observed from the porous paving stone sample.
3. The rainfall intensity, thermal conductivity of the pavement, initial surface runoff temperature, and initial
rainfall temperature are the dominant parameters in a surface runoff thermal enrichment relationship.
4. The expression !::1Tsr = Aln(t) + B may be used to determine the thermal enrichment of surface runoff from
either impervious asphalt or porous paving stone (known as Eco-Stone@ and produced by UNI-GROUP
U.S.A. producers where:
A= 0.0047 X i - 5.18 X ks - 0.13 X Tis + 0.15 X Tir - 1.55
B = -0.0294 X i - 2.26 X ks + 0.52 X Tis + 0.07 X Tir - 14.62
where i is the rainfall intensity [mm.hd; ks is the thermal conductivity of the surface [kWm-J.oC]; Tis is the
initial surface runoff temperature[oC]; Tir is the initial rainfall temperature[oC]; and t is the time after the
start of the rainfall [min].
5. The accuracy of the relationship is :!: 4.0 oC in the first 10 minutes after rainfall begins and:!: 1.5 OC when
averaged over the entire duration of the rainfall event.
6. Research should continue to improve the accuracy of the relationship and further validate the relationship
over a range of rainfall intensities.
Consideration of these conclusions and the information presented in this study leads to the following
recommendations:
1. That thermal enrichment of urban stormwater runoff be considered when new developments are proposed.
2. That thermally-sensitive pavement materials be used more extensively than in current applications.
3. That the relationship presented in this study be used to estimate the magnitude of the thermal enrichment of
a new development on receiving waters.
4. That the relationship proposed in this study be used in a stormwater model to provide an estimate of the
thermal enrichment resulting from specific catchments.
5. That further research be conducted using different surface materials (e.g. roofing materials or concrete).
6. That further research be conducted into the cooling of stormwater in underground pipe networks leading to
receiving waters.
7. That monitoring of subgrade temperatures continue in the instrumented parking lot to obtain a database
with respect to initial surface runoff temperatures.
8. That infrared thermometers be installed to monitor the surface temperature of the instrumented parking lot.
20
DESIGN AND INSTALLATION OF TEST SECTIONS OF POROUS
PAVEMENTS FOR IMPROVED QUALITY OF PARKING LOT RUNOFF
Michael Kaestner Thompson, REng. - 1995
GENERAL SUMMARY
This 162-page thesis examines the design, construction, and instrumentation of four test sections of parking lot
pavement (one conventional interlocking paver, two UNI Eco-Stonell> using two different filter materials, and one
conventional asphalt) to assess alternatives to the impervious pavements commonly used in parking areas and low speed
roadways. Appropriately designed Eco-Stonetl pavements could reduce impacts from runoff and reduce pollutant load on
surrounding surface waters by infiltrating storm-water. Preliminary results showed reductions in surface contaminants
and temperatures when compared to impervious pavements. Figures include cross sections of pavement design and
instrumentation, subsurface drainage system grading, laboratory test pavement apparatus, longitudinal and lateral flow
paths, collection system orientation, thermocouple details, and drainage pattern. Photographs include the subbase
drainage system, base drainage system, surface inlet drains, connecting pipes, thermocouple, and wet/dry precipitation
sampler. The tables include a pollutant summary for highway runoff, pavement thickness and materials used, collected
event summary, temperature results, rainfall volume summary, surface and sub-surface load summary, contaminant
analysis and investigation, and concentrations and total loads. Results are presented under two categories - temperature
and contaminants. Once again, numerous pollutants were analyzed including heavy metals such as lead, zinc, iron,
cadmium, and nickel, phenols, nitrates and nitrites, chromium, chloride, phosphates, ammonium and E.coli. References
are included.
OUTLINE
1.0 INTRODUCTION
1.1 Goals and Objectives
2.0 BACKGROUND
2.1 Literature Review
2.1.1 Porous and Asphalt Runoff Quality
2.1.2 Temperature
2.1.3 Vehicular Particulate and Emissions Discharge
2.2 Porous Pavements
2.3 Instrumentation and Data Collection
3.0 CONCEPTUAL DEVELOPMENT FOR MATERIALS BUDGET
3.1 Materials Budget
3.1.1 Pollutant Build-up, PBU
3.1.2 Pollutant Wash-off, PWO
3.1.3 Net Accumulation, NAC
4.0 INSTRUMENTED PAVEMENTS
4.1 Test Pavements
4.2 Laboratory Test Pavements
4.3 Instrumentation
4.4 Flow Paths
5.0 INSTRUMENTATION, SAMPLING, AND MONITORING
5.1 Water Samplers
5.2 Tipping Bucket Runoff Gauge (TBRG)
5.3 Thermocouples
5.4 Datalogger and Accessories
5.4.1 Datalogger
5.4.2 Multiplexer
5.4.3 Programming
5.5 Weather Station
5.6 Wet/Dry Precipitation Collector
21
.~~~'
6.0 RESULTS AND DISCUSSION
6.1 Introduction
6.2 Temperatures
6.3 Contaminant Load Results
6.3.1 Flow Results
6.3.2 Contaminant Results
6.3.3 Contaminant Load Analysis
7.0 CONCLUSIONS AND RECOMMENDATIONS
7.1 Conclusions
The purpose of this study was to construct instrumented pavements for a study of porous pavement as an
alternative to impermeable pavement for use in parking lots where traffic speed is less than 50km/hr. Four
instrumented test pavements were built in parking lot PI 0 at the University of Guelph. A materials budget was
developed for the contributing variables at the scale of a parking lot. This study is only a preliminary step for
continuous work necessary to delineate the processes involved in a parking lot system. In this chapter, conclusions
are drawn related to the design, construction, and instrumentation of the facility. Recommendations are then made
for improvements to the work.
The following conclusions can be made:
1. No previous experimental workhas examined the effectiven.ess of porous pavements as an alternative to
impervious pavements. This study prepared a facility for future porous pavement research for application in
North America.
2. The materials budget that was developed provides a preliminary background on the build-up and wash-off
processes that are involved. The constructed and instrumented test pavements provided the information
necessary in understanding the materials budget.
3. Pavement temperatures were recorded between the months of June to September, 1994. Surface temperatures
are directly related to the meteorological conditions; the greatest temperature ranges were generated in the
asphalt surface. In fact, for most of the time, the asphalt surface generally had the highest maximum daily
temperatures and lowest minimum daily temperatures. Asphalt pavements show more adverse results than the
other pavements.
4. In the summer, average daily temperatures were generally similar for all the pavement surfaces. Average
temperatures for one pavement can be applied to all pavements.
5. Base temperatures measured approximately 15 cm below the surface, showed a lower diurnal range than the
surface temperatures. Maximum base temperatures were less than the surface temperatures, at least in early
summer.
6. Sub-base temperatures, measured up to 600 mm below the surface, showed little diurnal temperature
fluctuation. In early summer, sub-base temperatures were lower than surface temperatures.
7. Contaminant loads from asphalt surface were always greater than the other pavements and surfaces. This is
mostly due to the asphalt being 100% impervious, which increases the amount of runoff and pollutants
reaching the sewers and ultimately the receiving waters.
8. UNI Eco-Stone~ effectively reduces the amount of surface runoff. Runoff was only generated from the surface
when the rainfall intensity exceeded the infiltration rates of the pavement. UNI Eco-Stone~ proved to be an
adequate porous pavement for reducing surface contaminant runoff loads.
7.2 Recommendations
1. Improvements are necessary in the flow measurement. The use of a datalogger is recommended to adequately
record flows. However, the TBRGs require further improvement or replacement. A proposed simple
alternative to the TBRG could be large barrels located in the instrumentation chamber under each of the
catchments. This system would be inspected frequently to determine the best size barrel for each of the
catchments.
2. The present system is designed to measure ground temperatures and not runoff temperatures. Additional
work is necessary for reliable measurement of runoff and precipitation temperatures. A system is necessary to
accurately measure the runoff water temperature as it passes through the layers. This would allow a better
understanding of the role of temperatures, runoff, and pavements.
3. The asphalt surface thermocouple requires constant observation due to the damage originally sustained.
Continuous monitoring of the temperature from the asphalt is necessary to ensure accurate measurement of
temperature. This is also true for all the pavements and layers.
4. Particular work is necessary in the heat transfer process between the pavement and water. Appropriate
instrumentation is necessary to accurately assess these water temperatures.
22
5. With the long-term continuation of this work, care must be taken to ensure minimal settling of the
pavements. Additional work is necessary in improving surface drainage. Improvements are necessary to ensure
adequate drainage of the surfaces. Adequate drainage of the system can be effectively accomplished by
removing two of the pavements, i.e., the CP and the E3 pavements could be removed. CP would then be
replaced with E4, this doubling the size of the E4 surface. E3 would be replaced with the AS, thereby
doubling the size of the AS pavement. These changes would effectively reduce the drainage problems, as well
as provide the appropriate grading necessary for future use.
6. It is recommended that additional locations and other materials be investigated for porous pavement research.
7. More detailed observation of the effect of vehicles parking on the test pavements must be made to monitor
vehicle pollutant contribution.
8. Consideration must be given to the removal and restoration of the pavement in the long term when the study
is completed.
23
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LONG- TERM STORMWATER INFILTRATION THROUGH
CONCRETE PAVERS
Christopher Kresin - 1996
GENERAL SUMMARY
This 188-page study investigates the infiltration capacity of porous concrete paver installations of various ages. Using a
rainfall simulating infiltrometer, several test plots at four UNI Eco-Stonetll installations were subjected to a total of 60
tests comprising two simulated rainfalls of known intensity and duration. The first rainfall provides initial moisture losses
to wetting the drainage cell material, while data collected during the second rainfall is used to calculate effective
infiltration capacity. Long-term stormwater management modeling was reviewed and suggestions made to enhance the
modeling capabilities of the United States Environmental Protection Agency's Storm Water Management Model. These
changes will permit simulation of long-term responses of surfaces paved with permeable concrete pavers.
The study showed that although the infiltration capacity of the UNI Eco-Stonetll pavements decreased with age and
degree of compaction (traveled versus untraveled), it could be improved with removal of the top layer of the drainage cell
aggregate material. The report also noted that all but two of the sites studied were constructed with improper drainage
cell material, which restricted the potential infiltration. The thesis strongly recommends that Eco-Stonetll installations be
constructed and maintained as per the manufacturers' specifications to ensure adequate performance. The tables include
simulated rainfall intensities, effective infiltration rates and capacities, grain-size analysis results, drainage cell material
analysis, and SWMM run times. Figures show typical permeable pavement structure, soil moisture zones, SWMM
program organization, uniformity coefficients and intensities at various pressures, grain-size distribution curves for
previous research and test sites, and porous pavement water balance. Photographic documentation includes various trash,
oil deposits, and vegetation in drainage cells, the test plot delineator, test plor under rainfall conditions, rainfall simulator,
drainage cell material extraction and crust removal, stormwater runoff, and test site locations.
OUTLINE
1.0 INTRODUCTION
1.1 Study Objective
1.2 Study Scope
1.3 Need
2.0 REVIEW OF URBAN STORMWATER MANAGEMENT TECHNIQUES
2.1 Urban Stormwater Management
2.1.1 Traditional Stormwater Management Practices
2.1.2 Stormwater Best Management Practices
2.1.3 Environmentally Responsible (Better) Management Techniques
2.2 Permeable Pavement
2.2.1 Types of Porous Pavements
2.2.2 Permeable Pavement Structure
2.2.3 Application
2.2.4 Performance
2.2.5 Advantages and Disadvantages
2.2.6 Previous Research
2.3 Summary of Survey Results
3.0 APPLICABLE THEORY
3.1 The Rainfall-Runoff Process
3.2 Infiltration Hydrology
3.2.1 Determination ofInfiltration Capacity
3.3 Rainfall Simulators
3.3.1 Rainfall Simulation
3.4 Spatial Variability and Scale Effects
3.4.1 Spatial Variability
3.4.2 Scale Effects
24
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Page 1 of 1
Jane Kansier
From: Mark Osbom [mark@mbi-nf.com]
Sent: Thursday, September 19, 2002 3:36 PM
To: jkansier@cityofpriorlake.com
Subject: Crystal Bay Townhomes
Jane,
I recently spoke with Pat Lynch of the DNR regarding pervious pavements. I believe you have already spoken
with Pat regarding this subject, and he informed me that the DNR would not recommend the product but also
would not oppose it. They are interested in this product, but are unsure of it as of right now. He mentioned to me
that it might be beneficial (for potential use of this product) to have the ponds designed as if all of the pervious
pavement was actually impervious, thereby showing that we can detain and treat the stormwater runoff even if the
product fails to be pervious.
The current drainage plan does consider the entire pavement area as impervious, including the 9,065 sf listed as
pervious pavement in the impervious calculations. It was easier at the time to overdesign the ponds based upon
no pervious pavement being used.
I thought you should be aware of this.
Unfortunately I will not be able to attend the Planning Meeting on the 23 rd, but we will have someone present who
hopefully can answer any additional questions.
Thank you,
Mark Osbom, PE
McGhie & Betts, Inc.
" /1 "I" """
3.5 Event Versus Long-Term Hydrologic Modelling
3.6 Urban Stormwater Modelling
3.6.1 Stormwater Management Model (SWMM)
3.6.2 SWMM and Pervious Surfaces
4.0 FIELD EXPERIMENTS
4.1 Test Plot Specifications
4.2 The Rainfall Simulator
4.2.1 Rainfall Intensity Calibration and Spatial Uniformity
4.3 Experimental Procedure
4.4 Experimental Design
4.5 Description of Test Installations
4.6 Computational Methods
4.6.1 Computational Process - Example Calculations
5.0 RESULTS
5.1 Darcy Infiltration Capacities
5.2 EDC (External Drainage Cell) and Crust Materials
6.0 DISCUSSION
6.1 Regeneration of Infiltration Capacity
6.2 Reliability of Results
6.2.1 Data Collection Phase
6.2.2 Calculation Phase
6.3 Permeable Pavement Design and Installation
6.3.1 UNI Eco-Stone<<> Installation and Specifications
6.4 Cost Comparison - MICBEC (Modular Interlocking Concrete Block with External Drainage Cells) and PAP
(Porous Asphalt Pavement)
6.4.1 Capital
6.4.2 Maintenance and Repair
6.4.3 Environmental
6.5 SWMM and Permeable Pavement
6.5.1 LF90 Performance Enhancement
6.5.2 Accommodation of More Complex Models
6.5.3 Code Modifications
7.0 CONCLUSIONS AND RECOMMENDATIONS
7.1 Conclusions Based on Experimental Results
1. Infiltration capacity of UNI Eco-Stone<<> MICBEC pavers decreases as the installation ages.
2. Infiltration capacities at UNI Eco-Stone<<> installations decreases with increased compaction.
3. Infiltration capacity of the EDC crusts, found to be significantly affected by age, limits fEo.
4. fEo may be regenerated, most probably to some fraction of initial fEo, by street sweeping/vacuuming the
Eco-Stone<<> surface.
5. fEo is affected to a greater extent by EDC fines content than organic matter content.
6. Most fines are trapped near the surface of the EDC material.
7. Except for Sites 1A and 1B, UNI Eco-Stone<<> installations are constructed with improper EDC material,
which restricts potential fEo.
8. fEo values of the magnitudes presented in this study would not provide infiltration of the smallest storms
common to the Toronto area.
9. SWMM currently can not simulate the response of permeable pavement.
10. SWMM can be modified to model systems that include permeable pavements, over a long-term, efficiently
and effectively.
7.2 Conclusions Based on Literature Review and Observations
1. Infiltrating stormwater is environmentally beneficial.
2. Permeable pavement is an effective infiltration BMP.
3. Eco-Stone<<> offers limited benefits when used for small surface areas as stormwater does not have adequate
time to infiltrate the porous pavement.
4. Porous and conventional asphalt pavement has a greater potential to contaminate stormwater and the
adjacent environment than concrete pavers.
25
5. MICBEC pavements will always reduce stormwater runoff volumes through depressions storage.
7.3 Recommendations
From the conclusions, the following is recommended:
1. UNI Eco-Stone" installations must be constructed and maintained to manufacturer's specifications to ensure
adequate performance.
2. Permeable pavement installations should be constructed with minimal slope and to provide surface detention
so that greater volumes of stormwater may be captured and infiltrated.
3. Eco-Stone" should be installed in parking lots to detain stormwater on the surface and should be
swept/vacuumed every spring, which provides the required site maintenance.
4. Every effort should be made to maximize runon to pervious areas.
5. SWMM coding must be updated to FORTRAN 90 syntax and the RUNOFF block modified to allow better
catchment discretization.
Future research should be conducted to determine:
1. How deep into the permeable pavement do fines propagate and whether there is an optimal gradation of
EDC material that will capture fines as the surface, as well as provide adequate fEo.
2. How well UNI Eco-Stone" performs under freezing conditions.
3. An appropriate Eco-Stone" maintenance frequency.
26
FEASIBILITY OF A PERMEABLE PAVEMENT OPTION IN THE STORM
WATER MANAGEMENT MODEL (SWMM) FOR LONG-TERM
CONTINUOS MODELING
Craig Kipkie - 1998
GENERAL SUMMARY
The purpose of this 134-page project was to examine the feasibility of, and attempt to develop computer code for the
United States Environmental Protection Agency's Storm Water Management Model (SWMM). The code would allow
planners and designers to simulate the response of permeable pavements in long-term modeling applications. The
infiltration capacity of the permeable pave-ment was determined from past studies of UNI Eco-Stone<<> and accounts for
degradation over time and regeneration by mechanical means. Various simulations run with the proposed new code
indicated that using permeable pavements could greatly reduce flows when compared to impervious surfaces. Figures
include types of permeable pavers, typical permeable pavement structure, SWMM program structure, SWMM RUNOFF
subcatchment schematization, porous pavement water balance, and hydrographs for various dates from 1971 to 1981.
The tables include Kresin's experimental results, subcatchment surface classification, RUNOFF block input data, sample
calculations, and description of permeable pavement parameters for various tests. Also included is a potential source
code for a subroutine PERMPAV.FOR containing the calculations for the permeable pavement option for SWMM.
Numerous references also are included.
OUTLINE
1.0 INTRODUCTION
1.1 Project Objective
1.2 Project Scope
2.0 UTERATURE REVIEW
2.1 Urban Stormwater
2.2 Permeable Pavement
2.2.1 Porous Pavements
2.2.2 Permeable Pavement Structure
2.3 Permeable Pavement Applications
2.4 Water Quantity
2.5 Water Quality
2.6 Subsurface Quality
2.7 Stormwater Management Model (SWMM)
3.0 STORMWATER MANAGEMENT MODEL (SWMM)
3.1 Stormwater Modelling
3.2 U.S. EPA's Stormwater Management Model
3.3 SWMM: Overview of Program Structure
3.4 SWMM RUNOFF Block
3.5 Subcatchment Schematization
3.6 Infiltration in the SWMM RUNOFF Block
3.6.1 Horton Method
3.6.2 Horton Method in SWMM
3.6.3 Green-Ampt Method
3.7 Entering Data in SWMM
4.0 COMPIUNG WITH LF90 VER. 4.0
4.1 FORTRAN
4.2 Compiling
4.2.1 Lahey FORTRAN Compiler
4.3 Compiling SWMM 4.4
5.0 NEW CODE AND QUAliTY ASSURANCE
5.1 Changes made to the SWMM 4.4 Program
5.2 Changes to RHYDRO.FOR
5.3 Changes to CATCH.FOR
27
"~..__--.-.,_...~__~_.__." ,..,_ "'...~_.,~.uu_.~'"~..~________~.__~_....__,,_~~_.~____...........__._...~_.~""..,_..._~,"~.,-.,.."._~-~~--...-......",.-
5.4 Changes to WSHED.FOR
5.5 Addition ofPERMEA.INC
5.6 Addition ofPERMPAY.FOR
5.7 Quality Assurance
6.0 RESULTS AND DISCUSSION
6.1 Test File
6.1.1 Data File
6.1.2 Rain Data File
6.2 Test 1 - Comparison of Non-Degradable versus Degradable Permeable Pavement
6.3 Test 2 - Comparison of Impervious and Degradable Permeable Pavement
6.4 Test 3 - Comparison of Different Saturated Hydraulic Conductivities
7.0 CONCLUSIONS AND RECOMMENDATIONS
7.1 Conclusions
1. It is possible to insert new source code into SWMM to simulate the long-term hydrologic response of
permeable pavement.
2. Various simulations, with the proposed new source code, indicated that the model produces reasonable results
under a generalized set of input conditions.
3. As expected, simulations showed that using permeal:>le pavement can greatly reduce flows when compared to
impervious surfaces.
4. Difficulties can arise in receiving programming support with SWMM because of the size and complexity of
the code and numerous authors over the past 30 years.
7.2 Recommendations
1. The validity of the new source code must be tested using observed data from permeable pavement
installations.
2. Test should be conducted using shorter time steps (1 minute).
3. Modifications should be made to connect the permeable pavement subroutine to the groundwater routine.
4. Clarification of the water depth in the reservoir of the permeable pavement structure should be made.
5. Possible modifications to the new source code should be made after further alpha and beta testing.
6. Further research must be conducted on the degradation of the infiltration capacity.
7. Appropriate guidelines for maintenance frequency must be established to ensure that the flow reducing
qualities of permeable pavement remain effective.
8. Modifications to the SWMM code should be made to incorporate the water quality aspects of permeable
pavement for long-term, continuous simulations.
9. Proper documentation must be prepared to support the proposed new code.
10. Instructional material should be developed and distributed for instruction in the use of the proposed new
code.
28
RESTORATION OF INFILTRATION CAPACITY OF PERMEABLE PAVERS
Christopher Gerrits - 2001
GENERAL SUMMARY
This study investigated the infiltration capacity of UNI Eco-StoneCll permeable pavers at a research test section located at
the University of Guelph that was installed in 1994. The objectives were to determine how infiltration capacity, volatile
organic matter, heavy metal concentration, and particle size analysis of the drainage void material vary with average daily
traffic use and surface ponding. Using a rainfall infiltrometer, 110 test plots were subjected to 420 tests comprising two
simulated rainfall events of known intensity and duration. Data collected during the second rainfall was used to calculate
effective infiltration capacity. Preliminary results yielded different results for infiltration capacity and particle size analysis
of the drainage void material for the different average daily traffic uses. The purpose of the research was to test the
hypothesis that UNI Eco-StoneCll infiltration capacities decrease with age and traffic use, and that the infiltration
capacities could be improved by street sweeping/vacuuming. The tests plots with a coarser gradation of aggregate
materials had higher infiltration rates than the section with a greater percentage of fines in the base and bedding
materials. The greatest infiltration rates were found in areas with low average daily traffic and regeneration could be easily
accomplished. In areas of medium to heavy average daily traffic usage, infiltration rates were lower and regeneration was
limited, indicating a need to establish a periodic cleaning program to ensure optimum infiltration levels.
OUTLINE
1.0 INTRODUCTION
1.1 Study Objectives
1.2 Study Scope
2.0 URBAN STORMWATER MANAGEMENT TECHNIQUES - LITERATURE REVIEW
2.1 Urban Stormwater Management
2.1.1 Stormwater Management Practices
2.1.2 Urban Best Management Practices (BMPs)
2.1.3 Agricultural BMPs
2.1.4 Infiltration BMPs
2.1.5 Green/Open Space
2.2 Permeable Pavement
2.2.1 Types of Porous Pavements
2.2.2 Permeable Pavement Structure
2.2.3 Applications of Permeable Pavements
2.3 UNI Eco-StoneCll Paving System
2.4 Surface Sealing
2.5 Possible Maintenance Activities
2.5.1. High Pressure Washing with Water
2.5.2 Street Sweeping
2.6 Previous Research
2.6.1 Permeable Pavement Installation Maintenance
3.0 APPLICABLE THEORY
3.1 The Rainfall-Runoff Process
3.2 Infiltration
3.2.1 Determination of Infiltration Capacity
3.3 Rainfall Simulators
3.3.1 Rainfall Simulation
4.0 EXPERIMENTAL PROCEDURE
4.1 Test Plot Specifications
4.2 The Rainfall Simulator
4.2.1 Rainfall Intensity Calibrations and Spatial Uniformity
4.3 Experimental Procedure
4.4 Experimental Design
4.5 Description of Test Installations
4.6 Computational Methods
4.6.1 Example Calculations
29
5.0 RESULTS
5.1 Summary ofInfiltration Rates
5.2 Heavy Metal Analysis
6.0 DISCUSSION
6.1 Infiltration Rates
6.2 Particle Size Analysis
6.2.1. Bedding Material
6.3 Heavy Metal Analysis
6.4 Volatile Organic Matter (VOC Content)
6.5 Effect of Ponded Water
6.5.1 Frequently Flooded vs. Well-Drained Plots
6.6 Vegetated Plots
6.6.1 Vegetated vs. Unvegetated Plots
7.0 CONCLUSIONS
7.1 Conclusions
1. Since no previous experimental work has examined the regeneration of the infiltration capacity of permeable
pavement installations, this study will serve as a guideline for future permeable pavement research in
North America.
2. The infiltration capacity tested between May and September, 2001, was determined to be spatially variable
and dependent on the average daily traffic use, percentage of fine matter. in the EDC, and the test
installation subbase specifications. The infiltration capacity was also found to be dependent, to a lesser
degree, on the percentage of volatile organic matter within the EDC.
3. The infiltration rates were found to be greatest in the low ADT area and regeneration to the maximum
infiltration capacity could be accomplished by removing as little as 15mm of EDC material.
4. The infiltration rates in the medium ADT area were found to be less than the low ADT area. Although
regeneration to the critical infiltration capacity could not be reached by removal of 25mm of EDC material,
but results suggest that this could be possible with removal of more EDC material. Some degree of
regeneration was noted at all excavation depths.
5. The infiltration rates in the high ADT areas were found to be the lowest, and only a minimal amount of
regeneration could be obtained.
6. The infiltration rates were higher, and regeneration could be reached by removing less EDC matter, in the
Eco-Stone~ 3" installation. The infiltration rates within the Eco-Stone~ 4" installations were much lower
initially and regeneration to the critical infiltration capacity was not obtained for any test plot.
7. The infiltration rates are very spatially variable, as illustrated by the large coefficients of variation obtained.
8. The percentage of fine matter within the EDCs, measured up to 25mm from the top of the paver, was much
higher in the Eco-Stone~ 4" installation. The percentage of fine matter was also found to be inversely
proportional to the infiltration rate.
9. The infiltration rate was found to be lower for the plots that have water ponded on them for a period of
greater than one hour after a storm event, than plots where the water does not pond. The percent of fine
matter in the EDCs was found to be slightly greater within the first 5mm and approximately equal for all
other depths. The percent ofVOC was found to be significantly higher in the frequently flooded plots, for
all depths, not just the upper 5mm.
10. The percentage of volatile organic matter within the EDCs was found to be similar for both installations and
all traffic uses. The percent VOC was found to be much greater for the vegetated plots, underneath the large
coniferous tree along the grass verge. The infiltration rate was not found to be greatly affected by the percent
VOC, with the exception of plots where the percent VOC was significantly greater than the average VOC
percent. In this case, the infiltration rate was found to be an order of magnitude greater than the
unvegetated area.
11. The concentrations of heavy metals within the EDCs were found to be less than the Ontario Ministry of the
Environment's Guideline Concentrations for Selected Metals in Soils. All of the metals tested were below the
MOE guideline level, and, with the exception of zinc, below the expected value for Ontario soils.
30
7.2 Recommendations
1. It is necessary to minimize the amount of fine matter accumulating within the EOC. This can best be done
by periodically cleaning the permeable pavement installation to keep the EDCs clear of fine matter. The
frequency of cleaning will be dependent on the ADT, as well as land use practices on and adjacent to the
test installation
2. The percent VOC within the cells helped to keep fine matter from accumulating within the EDCs.
Whenever possible, coniferous trees should be encouraged to grow along permeable pavement installations
and on any islands or verges within the parking lot. Coniferous trees were found to be useful because the
needles falling off of the trees, into the EOCs, helped to maintain high infiltration capacities. Vegetation of
any kind should not be discouraged from growing within the EDCs.
3. Future permeable pavement installations should be constructed so that drainage is in the direction of the
highly vegetated areas near the curb.
4. Fine matter should not be used when installing the subbase material, as it decreases the infiltration capacity
and the ability to regenerate the infiltration capacity.
5. It is recommended that additional testing be done on other permeable pavement installations in order to
better identify the frequency of cleaning required to maintain and optimal infiltration rate.
6. Further studies should be aimed at testing permeable pavement installations on a larger scale. This would
allow for better estimation of the installation as a whole and lessen the spatial variability of testing at such
a small scale.
8.0 REFERENCES
31
The following synopses are all edited by Wtlliam James of Guelph University and are Proceedings of the
Stormwater and Water Quality Management Modeling Conferences, Toronto, Ontario 1994-2000. They
are based on the research conducted at Guelph University described on the previous pages.
PROVISION OF PARIONG-LOT PAVEMENTS FOR SURFACE WATER POLLUTION
CONTROL STUDIES
William James and Michael K Thompson - 1994
This study prepared a facility for future research on porous pavement for application in North America with comparative
test sections of UNI Eco-StoneCl> concrete pavers, traditional concrete pavers and asphalt in the laboratory and in a
parking application. The purpose was to investigate porous pavement as an alternative to impervious pavement for
parking lots. A large number of contaminants were investigated, including, heavy metals, chlorides, nutrients, phenolics,
solids, and solvents. Preliminary results showed that contaminant loads from the asphalt surface were always greater than
the other pavement surfaces. The Eco-StoneCl> pavement was shown to effectively reduce the amount of surface runoff,
with runoff generated only when rainfall intensity exceeded infiltration rates. However, this is likely to be a rare
occurrence due to high infiltration rates of the pavement.
CONTAMINANTS FROM FOUR NEW PERVIOUS AND IMPERVIOUS PAVEMENTS
IN A PARKING LOT
William James and Michael K Thompson- 1996
While the previous study described the design, construction, and instrumentation of four pavements in the laboratory
and parking lot, this study reports on the interim conclusions obtained from the parking-lot pavements for the first year
after installation. In addition to investigation of contaminants, temperature studies also were conducted. The Eco-StoneCl>
pavement continued to show significant reductions in surface runoff contaminant loads.
THERMAL ENRICHMENT OF STORMWATER BY URBAN PAVEMENT
William James and Brian Verspagen - 1996
This study covers the thermal enrichment of surface runoff from impermeable asphalt and the Eco-StoneCl> porous
concrete paver. Though more research was required, it was found that thermal enrichment of urban stormwater runoff
should be considered when new development is proposed, and thermally-sensitive pavement materials should be used
more extensively. The asphalt paving surface was found to increase the temperature of the runoff more than the Eco-
StoneCl> pavement.
OBSERVATIONS OF INFILTRATION THROUGH CLOGGED POROUS CONCRETE
BLOCK PAVERS
WilliamJames, Christopher Kresin and David Elrick - 1997
The purpose of this research was to test the hypothesis that, for a particular permeable paver (Eco-StoneCl>), infiltration
capacities may be improved by simply street sweeping and/or vacuuming the surface. The research used data collected at
several Eco-StoneCl> installations in the area. While studies showed infiltration capacity was reduced as the pavement aged,
it was found that infiltration could be improved with removal of the top layer of drainage cell material. It was found that
very little surface water runs off new installations of UNI Eco-StoneCl>, and that maintenance was recommended to renew
infiltration capacity. Research also found that fines in the drainage cell material affected infiltration to a greater extent
than organic material, which reinforces proper material specification guidelines be followed during installation.
A LABORATORY EXAMINATION OF POLLUTANTS LEACHED FROM FOUR
DIFFERENT PAVEMENTS BY ACID RAIN
William James, Rum Shahin - 199B
In this study, the contaminants investigated were phenols, pH, zinc, iron, oils and grease. It was found that pH of rain is
a significant factor, with asphalt having the least buffering, and that Eco-Stone reduced both runoff and contaminants
32
the most. Percolation through the permeable pavement surface and underlying media slowed the water flow, allowing
more time for oxidation. It also was shown to filter suspended solids and some contaminants such as sodium and sulfates.
Heavy metal removal through percolation appeared to be good. Surface runoff from asphalt contained a higher mass of
all the parameters investigated compared to the Eco-Stone runoff. It was found that generally, while water is not
contaminated by the surface of the porous pavement, asphalt surfaces are made from petroleum products and some
pollutants such as oils, grease, and phenols would be generated from the surface. It was found the Eco-Stone pavement
appears to have significant long-term benefits compared to conventional asphalt pavements in terms of its ability to
reduce the quantity of stormwater pollutants.
FEASIBILITY OF A PERMEABLE PAVEMENT OPTION IN THE STORMWATER
MANAGEMENT MODEL (SWMM) FOR LONG-TERM CONTINUOUS
MODELLING
William James, Craig William Kipkie -1998-9
This project focused on examining the feasibility of inserting new FORTRAN computer code into the USEPA's SWMM,
such that it would allow designers to simulate the hydrological response of permeable pavements in long-term modelling
applications. It was found that it was possible to insert new code, and the model produced reasonable results under a
generalized set of input conditions. Simulations showed that using permeable pavements can greatly reduce flows
compared to impervious surfaces.
STORMWATER MANAGEMENT MODEL FOR ENVIRONMENTAL DESIGN OF
PERMEABLE PAVEMENTS
William James, \v. Robert C James, and Harald von Langsdorff - 2000
This monograph details the underlying method and function of a free-ware program that uses the USEPA Stormwater
Management Model (SWMM) for the design of permeable pavement installations - PC-SWMM. The program allows
quick implementation of a BMP in SWMM and is very user-friendly. The SWMM code for groundwater and infiltration
has not been comprehensively tested against a specific permeable pavement field program due to lack of field testing to
date. PC-SWMM is a tool to aid designers and is intended for use by civil engineers that are competent in evaluation of
the significance and limitations of the computations and results. It is not a substitution for engineering judgement, nor is
it meant to replace the services of professional qualified engineers.
33
ADDITIONAL UNI ECO-STONE@ RESEARCH AND TESTING
THE UNIVERSITY OF WASHINGTON PERMEABLE PAVEMENT
DEMONSTRATION PROJECT
Professor Derek B. Booth, Jennifer Leavitt and Kim Peterson - Research Assistants - 1996
This project was initiated to review the types and characteristics of permeable pavements in the Pacific Northwest to
provide potential users of these systems with information. They constructed a well-instrumented full-scale test site in a
section of a new employee parking lot at the King County Public Works facility in Renton, WA, to evaluate the
durability, infiltratability, and water-quality benefits of four types of permeable pavements - UNI Eco-StoneCl>,
Grasspave2C1l, Gravelpave2C1l and Turfstone"'. An additional section of impervious asphalt was constructed as a control. The
intent of the project is to evaluate the long-term performance of the systems over a number of years. The study is being
conducted in conjunction with King County, the City of Olympia, Washington State Department of Ecology, and the
City of Renton. Initial results of this study showed the use of permeable pavements dramatically reduced surface runoff
volumes and attenuated peak discharge and though there were significant structural differences in the systems, the
hydrologic benefits were consistent. In addition, it was found that a significant contribution of permeable pavements is
the ability to reduce effective impervious area, which has a direct connection to downstream drainage systems. As a result,
it can be used to control runoff timing, reduce volume, and provide water quality benefits.
EXPERT OPINION ON UNI ECO-STONE@ - PEDESTRIAN USE
Professor Burkhard Bretschneider - 1994
This report tested UNI Eco-Stoneill for safety and walking ease under a pedestrian traffic application in the parking lot of
the Lenze Company in Aerzen, Germany. Bicycles, wheel chairs, baby carriages, and foot traffic were tested. Ladies high
heel shoes were tested for penetration depth in the drainage cell aggregate materials. The findings showed that proper
filling and compaction of the drainage cell materials was important for good overall performance.
EXPERT OPINION - IN-SITU TEST OF WATER PERMEABILITY OF TWO UN!
ECO-STONE@ PAVEMENTS
Dr. Soenke Borgwardt - Institute for Planning Green Spaces and for Landscape Architecture - University of Hannover - 1994
Tests were performed on two UNI Eco-StoneCl> pavements of various ages at two different locations in Germany. A
parking lot at the train station in Eldagsen was installed in 1992, while the Lenze Company parking lot in Gross Berkel
was installed in 1989. The results showed that the Eldagsen site was capable of infiltrating 350 lIseclha, and even after 60
minutes, absorbed more than 200 lIseclha. At the Lenze site, the Eco-Stoneill pavement was capable of infiltrating 430
l/seclha, and even after 60 minutes, a rainfall amount of 400 lIseclha was absorbed. Although the comparison shows that
the older test area had a higher permeability than the newer installation, laboratory tests showed the lesser permeability
values of the Eldagsen site were the result of the existence of fines. This reconfirms the recommendation for selecting
proper gradation of drainage cell and bedding materials in the 2mm to 5mm range and that ASTM C-33 grading should
not be used if infiltration is the primary function of the pavement.
DRAINAGE WITH INTERLOCKING PAVERS
Professor W Muth - Research Institute for mzter Resources - Karlsruhe University - 1994
The institute tested UNI Eco-StoneCl> pavers in comparison to traditional pavers for water permeability. Surface runoff
and the associated drainage were measured under a variety of rainfall amounts and intensities.
DEVELOPMENT OF DESIGN CRITERIA FOR FLOOD CONTROL AND
GROUNDWATER RECHARGE UTILIZING UNI ECO-STONE@ AND ECOLOC@
PAVING UNITS
Professor Thomas Phalen, Jr. - Northeastern University - 1992
The purpose of this research was to develop the technical data related to the paving system's permeability characteristics.
This early research was expanded on in the Rollings and Texas A&M design manuals.
34
STRUCTURAL DESIGN SOFTWARE
LOCKPAVE@ PRO
Dr. Brian Shackel
The LOCKPAVECI> PRO computer program has been developed to assist design professionals in the structural design of
interlocking concrete block pavements for a variety of appli=tions, including streets, airport, and industrial projects. It
provides a choice of mechanistic or empirical design methodology and offers the ability to select, analyze, and compare
alternative pavement types. It also includes UNI Eco-StoneCl> permeable pavement hydraulic modeling based on the
USEPNs SWMM model.
FEATURES OF PC-SWMM'" FOR PERMEABLE PAVEMENTS
· Allows user to develop a simple model of permeable pavement design, run the model with a specified design storm,
and analyze the results of the model
· An Input Wizard interface guides the user through the required parameters
· Model results include graphs of the input function (design storm), surface runoff (if any), depth of water in the base
material, and drainage of the base material for the duration of the model run
· A summary report includes user-defined input and tabulation of numerical results
· Features support for Run-On - flow contributions from adjacent impervious and pervious surfaces
· Incorporates new regeneration data from research studies
· The model accepts an arbitrary rainfall hyetograph and provides a step-by-step accounting (conservation of mass) of
water movement through the permeable pavement installation, including surface detention, overland flow, infiltration,
subsurface storage, and subsurface drainage
When designing Eco-StoneCl> pavements, please use LOCKPAVECI> PRO first to
establish the minimum requirements for the structural performance of the
pavement. The program defaults to the most conservative parameters - very
poor drainage conditions and saturation of the base more than 25% of the time
- for its structural analysis. Then run PC-SWMM~ to see if your drainage
design parameters are met. If the minimum base thickness established by
LOCKPAVECI> PRO is inadequate for your storage/drainage requirements,
increase the base layer thickness step-by-step until your hydraulic parameters are
met.
Private &sidenc~, Long Is!JZnd, NY
POWERPOINT PRESENTATION
ECO-STONE@ POWERPOINT PRESENTATION
This comprehensive slide/computer PowerPoint presentation is oriented to the design professional. It includes basic
design guidance, hydraulic information, research information, and project references and is based on the Design
Considerations for the UNI Eco-Stone'" Concrete Paver by Rollings and Rollings.
35
CASE STUDIES
RIO VISTA WATER TREATMENT PLANT
Case Study - 2-page
Case study on the Castaic Lake Water Agency of Santa Clarita, CA project - Water Conservatory Garden and Learning
Center Parking Lot. Features 27,000 sq ft parking lot installation of UN I Eco-Stonel!> permeable pavers.
MICKEL FIELD AND HIGHLANDS PARK
Case Study - 2-page
Case study on Mickel Field/Highlands Park of Wilton Manors, FL project - Renovation of community parks' walkways
and parking lots. Features over 37,000 sq ft of UNI Eco-Stonel!> permeable pavers.
JORDAN COVE URBAN WATERSHED STUDY
Case Study - 4-page
Case study is on an innovative research project funded in part by the Connecticut Department of Environmental
Protection through the USEPA's National Monitoring Program Section 319. Other participants in the project include the
University of Connecticut Natural Resources Management and Engineering Dept., the town of Water ford, CT, and the
developer John Lombardi. Over 15,000 sq ft of UN I Eco-Stonel!> pavers were used for the street cul-de-sac and driveways
of some homes in the "paired watershed" development. A variety of BMPs have been incorporated into the site for long-
term monitoring and comparison with traditional subdivision construction.
36
ADDITIONAL REFERENCES
American Association of State Highway and Transportation Officials (AASHTO), 1993. AASHTO Guide for Design of Pavement
Structures, Washington, DC.
American Society for Testing and Materials (ASTM), 1999. Annual Book of ASTM Standards, West Conshohocken, PA
American Society of Civil Engineers, 1992. Design and Comtruction of Urban Storm water Management Systems, ASCE, New York, NY.
Booth, D., J. Leavitt, and K. Peterson, 1995. The University of Washington Permeable Pavement Demonstration Project - Background
and First-Year Field Results, University of Washington, Department of Civil Engineering, Seattle, WA.
Cedegren, H., 1987. Drainage of Highway and Airfield Pavements, Krieger Publishing Company, Malabar, FL.
Corps of Engineers, 1991. Subsurface Drainage of Pavement Structures, Research and Development Service: Current Corps of Engineers
and Industry Practice, Hanover, NH.
Corps of Engineers, 1992. Engineering and Design Drainage Layers for Pavements, Engineer Technical Letter 1110-3~435,
Department of the Army, U.S. Army Corps of Engineers, Washington, DC.
Cote Jr., M., J. Clausen, B. Morton, P. Stacey, and S. Zaremba, 1997. Jordan Cove Urban Watershed National Monitoring Project,
USEPA, University of Connecticut, Aqua Solutions, Connecticut Department of Environmental Protection, Waterford, CT.
Federal Highway Administration (FHWA), 1990. FHWA Technical Guide Paper 90-01: Subsurface Pavement Drainage, FHWA,
Office of Engineering, Pavement Division, Washington, DC.
Federal Highway Administration (FHWA), 1992. Demomtration Project 87: Drainable Pavement Systems Participant Notebook, FHWA,
Publication No. FHWA-SA-92-008, Washington, DC.
Ferguson, B., 1991. "The Failure of Stormwater Detention and the Future of Stormwater Design", Landscape Design, Vol. 4, No. 12,
Gold Trade Publications, Van Nuys, CA.
Ferguson, B., 1994. Storm water Infiltration, Lewis Publishers, CRC Press, Boca Raton, FL.
Ferguson, B. and T. Debo, 1990. On-site Stormwater Management, Second Edition, Van Nostrand Reinhold, New York, NY.
Goforth, G., E. Diniz, and J. Rauhut, 1983. Storm water Hydrological Characteristics of Porous and Conventional Paving Systems, United
States Environmental Protection Agency, Grant No. R806338-01-2, Austin, TX.
National Cooperative Highway Research Program (NCHRP), 1982, 1997. Synthesis of Highway Practice 96: Pavement Subsurface
Drainage Systems, Sequim, WA.
National Resources Defense Council, 1999. Storm water Strategies, Community Responses to Runoff Pollution, New York, NY.
Portland Cement Association, 1992. Properties and Uses of Cement-Modified Soil, Skokie, IL.
Rollings, R. and M. Rollings, 1992. Applicatiom for Concrete Paving Block in the United States Market, Uni-Group U.SA., Palm
Beach Gardens, FL.
Shackel, B., 1990. Design and Comtruction of Interlocking Concrete Block Pavements, Elsevier Science Publishing Co., New York, NY.
Smith, D., 2001. Permeable Interlocking Concrete Pavements, Interlocking Concrete Pavement Institute, Washington, DC.
The Asphalt Institute, 1989. The Asphalt Handbook, MS-4, Lexington, KY.
United States Environmental Protection Agency (USEPA), Office of Water and Low Impact Development Center, 2000. Low Impact
Development (LID). A Literature Review, EPA-841-B-00-005, Washington, DC.
United States Environmental Protection Agency (USEPA), Office of Water, 2000. National Menu of Best Management Practices for
Storm Water Phase II, Washington, DC.
United States Environmental Protection Agency (USEPA), Office of Water, 2000. Non-Point Source Pollution, II Urban Runoff,
Washington, DC.
37
STORMWATER MANAGEMENT INSPECTION FORM
WATERSHED MANAGEMENT INSTITUTE AND USEPA
INFILTRATION PAVING CONSTRUCTION INSPECTION REPORT
DATE:
INDIVIDUAL CONTACTED:
PROJECT:
LOCATION:
SITE STATUS:
ACTIVE
INACTIVE
COMPLETED
Satisfactory
Unsatisfactory
1. Pre-construction
Runoff diverted
Area stabilized
2. Excavation
Size and location conforms to plans
Side slopes stable
Soil permeability
Groundwater/bedrock
3. Geotextile/Filter Fabric Placement
Fabric specification
Placement conforms to specifications
Sides of excavation covered
4. Aggregate Base Course
Size as specified, sieve analysis conforms to spec
Clean/washed material
Thickness, placement, and compaction meets spec
5. Permeable Interlocking Concrete Pavers
Meets ASTM or CSA standards as applicable
Elevations, slope, pattern, placement and compaction
as per specifications
Aggregate joint materials conform to specification
Drainage or bio swales, vegetated areas for emergency runoff
overflow and pre-treatment for filtering runoff
6. Final Inspection
Elevation and slope conform to drawings
Transitions to impervious pavement separated with
edge restraints
Stabilization of soil in areas draining onto pavement
(vegetative strips recommended)
Action to be taken:
No action necessary. Continue routine inspections
Correct noted site deficiencies by
1st notice 2nd notice
Submit plan modifications as noted in written comments by
Notice to Comply issued Final inspection, project completed
38
STORMWATER MANAGEMENT INSPECTION FORM
WATERSHED MANAGEMENT INSTITUTE AND USEPA
INFILTRATION PAVING MAINTENANCE INSPECTION REPORT
DATE:
TIME:
PROJECT:
LOCATION:
Individual Conducting Inspection:
''AI; built" plans available Y/N
Inspection frequency shown in parentheses
Satisfactory
Unsatisfactory
1. Debris on infiltration paving area (Monthly)
2. Vegetation areas (Monthly)
Mowing done when needed
Fertilized per specifications
No evidence of erosion
3. Dewatering (Monthly)
Infiltration paving dewaters between storms
4. Sediments (Monthly)
Area clean of sediments
Area vacuum swept on a periodic basis as needed
5. Structural condition (Annual)
No evidence of surface deterioration
No evidence of rutting or spalling
Inspection Frequency Key: Annual Monthly After major storm
Action to be taken:
If any of the answers to the above items is checked unsatisfactory, a time frame shall be established for their corrective
action or repair.
No action necessary. Continue routine inspections
Correct noted facility deficiencies by
Facility repairs were indicated and completed. Site reinspection is necessary to verify corrections or improvements.
Site reinspection accomplished on
Site reinspection was satisfactory. Next routine inspection is scheduled for approximately:
Signature ofInspector
39
e~
UNI-GROUP U.S.A.
MANUFACTURERS OF UNI PAVING STONES
4362 Northlake Blvd. . Suite 204 · Palm Beach Gardens, FL 33410 . (561) 626-4666 · Fax (561) 627-6403 . (800) 872-1864
www.uni-groupusa.org.info@uni-groupusa.org