Porous Pavement in Cold Climates Part 2: Costs and Performance. Robert Roseen and Thomas Ballestero, UNH Stormwater Center (presented March 17, 2011)

1. Porous Pavement in Cold ClimatesPorous Pavement in Cold Climates
Part: Performance and CostPart: Performance and Cost
Onondaga Environmental InstituteOnondaga Environmental Institute
17 March 201117 March 2011
Thomas Ballestero, PhD, PE, PH, CGWP, PG,Thomas Ballestero, PhD, PE, PH, CGWP, PG,
Robert Roseen, PE, PhD, D.WRE,Robert Roseen, PE, PhD, D.WRE,
James Houle, CPSWQJames Houle, CPSWQ
University of New Hampshire Stormwater CenterUniversity of New Hampshire Stormwater Center
Department of Civil Engineering, University of New HampshireDepartment of Civil Engineering, University of New Hampshire

2. OverviewOverview
1.1. Hydrology of Permeable PavementsHydrology of Permeable Pavements
2.2. Water Quality PerformanceWater Quality Performance
3.3. Hydraulic PerformanceHydraulic Performance
4.4. Cold Climate FunctionalityCold Climate Functionality
5.5. Normal MaintenanceNormal Maintenance
6.6. Winter MaintenanceWinter Maintenance
22

3. State of the PracticeState of the Practice
Water quality performance is strong toWater quality performance is strong to
excellent depending on designexcellent depending on design
Hydraulic performance is excellentHydraulic performance is excellent
Cold climate performance is strongCold climate performance is strong
Winter maintenance has tremendousWinter maintenance has tremendous
potential for salt reductionpotential for salt reduction
33

4. Concerns On PerformanceConcerns On Performance
Little removal of nitrogenLittle removal of nitrogen
No removal of many common ionic formsNo removal of many common ionic forms
However, a large number of installationsHowever, a large number of installations
STILL continue to be subSTILL continue to be sub--standardstandard
44

5. Porous Pavement Design OverviewPorous Pavement Design Overview
 Porous pavements for new andPorous pavements for new and
redevelopment are a watershedredevelopment are a watershed--
based strategy that can bothbased strategy that can both
mitigate impacts for newmitigate impacts for new
development and reverse impactsdevelopment and reverse impacts
in areas with redevelopment.in areas with redevelopment.
 Porous pavement (PP) systemsPorous pavement (PP) systems
combine stormwater infiltration,combine stormwater infiltration,
storage, and structural pavementstorage, and structural pavement
in a single system.in a single system.
 PP are a layer cake system, withPP are a layer cake system, with
each layer possessing structuraleach layer possessing structural
or water quality purposes.or water quality purposes.
55

6. 66
Porous Asphalt Path, Grey Towers
National Historic Site, PA
(Source: CH2M HILL)
Porous Asphalt Commercial Parking Lot,
Greenland Meadows, Greenland, NH
(Source: UNHSC)
Porous Asphalt Section of State Highway,
South Portland, ME (Source: ME DOT)
Porous Asphalt Basketball Court,
Upper Darby, PA
(Source: CH2M HILL)
Porous Asphalt Residential Lane, Pelham, NH
(Source: UNHSC)
Parking Lot with Standard Aisle and
Porous Asphalt Stalls, Morris Arboretum,
Philadelphia, PA (Source: CH2M HILL)

7. Typical Porous Pavement SystemTypical Porous Pavement System
SectionsSections
77
Typical Section for Storage and Infiltration

8. Typical Porous PavementTypical Porous Pavement
System SectionsSystem Sections
88
Choker Course: 4”-8” (10 – 20 cm) minimum
Pervious pavement: 4-6” (10 - 15 cm) of porous asphalt
Filter Course: 8” - 12” (20 - 30 cm) minimum thickness of subbase
(aka. bank run gravel or modified 304.1)
Native materials
Filter Blanket: intermediate setting bed: 3” (8 cm) thickness of 3
/8” (1 cm) pea gravel
Reservoir Course: 4” (10 cm) minimum thickness of 3
/4” (2 cm) crushed stone for
frost protection, 4-6” (10-15 cm) diameter perforated subdrains with 2” cover
Optional-Liner for land uses where infiltration is undesirable
(e.g., hazardous materials handling, sole-source aquifer protection)
Section with Filter Course for Water Quality

9. Water QualityWater Quality
Performance ResultsPerformance Results

10. 1010
Porous Pavements and Pond WaterPorous Pavements and Pond Water
QualityQuality
100
90
80
70
60
50
40
30
20
10
0
%RemovalEfficiency
TSS
TPH-D Zn DIN TP
Porous Asphalt
Pervious Concrete
Retention Pond
‘

11. TSS Removal PerformanceTSS Removal Performance

12. 1212

13. 1313

14. 1414

15. 1515

16. HydrologicHydrologic
Performance ResultsPerformance Results

17. 1717
Hydrologic Performance ofHydrologic Performance of
Porous PavementsPorous Pavements
Pervious Concrete (HSGPervious Concrete (HSG--B)B)Porous Asphalt (HSGPorous Asphalt (HSG--C)C)

18. 0
10
20
30
40
50
0 200 400 600 800 1,000
Time (min)
Flow(gpm)
0
0.03
0.06
0.09
0.12
0.15
5-MinPrecip(in)
D-Box Flow
Effluent Flow
Precip
0.6 in depth
1818
Flow AttenuationFlow Attenuation
0
10
20
30
40
50
0 500 1,000 1,500 2,000 2,500 3,000
Time (min)
Flow(gpm)
0
0.03
0.06
0.09
0.12
0.15
5-MinPrecip(in)
D-Box Flow
Effluent Flow
Precip
2.96 in depth

19. 1919
Lag Time (kLag Time (kLL)) Peak Reduction (kPeak Reduction (kPP))
55 22 11 0.50.5 0.10.1
Hydraulic PerformanceHydraulic Performance
3/23/20113/23/2011

20. Curve NumberCurve Number
2020

21. 2121

22. RESULTSRESULTSRESULTS
2222
Method 1
Q-P
Method 3
Q p
Method 3
Q p
Tbase Tpeak Tcentroid NRCS Folmar
88 7 1 1 1 28
90 1 1 1 1 5
10 15 2 2 2 37
Method 2
Lag
Mean
Median
Standar Deviation

23. 2323
Porous Asphalt Surface Infiltration RatesPorous Asphalt Surface Infiltration Rates
 Low maintenance sensitivity due to excess infiltration capacityLow maintenance sensitivity due to excess infiltration capacity
 Clogged areas can drain to adjacent unclogged areasClogged areas can drain to adjacent unclogged areas
Even with 99% clogging the IR=10
in/hr > most sands & soils
 Worst case scenario, no maintenanceWorst case scenario, no maintenance performed forperformed for 3 yrs3 yrs
 Certain areas have reduced IC (drive lanes) while parking areasCertain areas have reduced IC (drive lanes) while parking areas
remain unchangedremain unchanged

24. New England SitesNew England Sites
2424

25. Infiltration Capacity by AgeInfiltration Capacity by Age
315
7,045
4,013
2,598 2,905
54
2,354
140
4,365
10
100
1,000
10,000
100,000
URI-
PA-02
UNH-
PA-04
URI-
PA-04
Grswld-
PC-05
Frpt-
PA-06
Sski-
PA-06
SlvrLk-
PA-06
StoYo-
PA-06
UNH-
PC-07
ICviaSItest(cm/hr)
2525

26. How Do They Really Work?How Do They Really Work?
43 in rainfall event in 3 minutes!43 in rainfall event in 3 minutes!

27. Cold ClimateCold Climate
Performance ResultsPerformance Results

28. 2828
Frost PenetrationFrost Penetration
Can be related to pavement failureCan be related to pavement failure
Measured with aMeasured with a ‘‘fieldfield--assembledassembled’’
frost gaugefrost gauge (Ricard et al., 1976)(Ricard et al., 1976)
Show relationships betweenShow relationships between
pavements and soilspavements and soils

29. 2929
Porous Asphalt Frost PenetrationPorous Asphalt Frost Penetration

30. 3030
Seasonal Performance EfficienciesSeasonal Performance Efficiencies
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
TSS TPH-D DIN Zn TP
Retention Pond
Summer
Winter
Annual

31. 3131
Winter Maintenance &Winter Maintenance &
Salt ReductionSalt Reduction

32. Where should reductions occur?Where should reductions occur?
Sources of Salt Loading
From Vehicular Surface Deicing
(Rockingham County, NH)
(NHDES 2007)
50%
3%
27%
9%
11%
Parking Lots
Private Roads
Municipal Roads
State Roads
Other

33. 3333
PA Study Area OrientationPA Study Area Orientation

34. 3434
Measuring Skid Resistance w/ BPTMeasuring Skid Resistance w/ BPT
ASTM STANDARD E303‐93

35. 3535
Lots oneLots one--hour after plowing,hour after plowing, --4*C (11AM on 2/3/07)4*C (11AM on 2/3/07)
PA/DMA Snow & Ice CoverPA/DMA Snow & Ice Cover
PAPA DMADMA

36. 3636
Conditions after thawing and subsequent refreezing (9AM on 3/18/Conditions after thawing and subsequent refreezing (9AM on 3/18/07)07)
 No black ice formation on PANo black ice formation on PA
PA/DMA Snow & Ice CoverPA/DMA Snow & Ice Cover
PAPA DMADMA

37. 3737
PC Snow & Ice CoverPC Snow & Ice Cover
Conditions after thawing and subsequent refreezing (1PM on 2/16/Conditions after thawing and subsequent refreezing (1PM on 2/16/08)08)
 No black ice formation on PCNo black ice formation on PC
PCPC Stnd. Asphalt Ref. LotStnd. Asphalt Ref. Lot

38. 3838
 Shading contributes to amount of cover on PCShading contributes to amount of cover on PC
PC Snow & Ice CoverPC Snow & Ice Cover
PC in sunPC in sun
PC in partialPC in partial
sunsunPC in shadePC in shade

39. Weighted Skid Resistance (BPN)
0
10
20
30
40
50
60
70
80
90
100
100 50 25 0
%Salt Application
SkidResistance(BPN)
Dense Mix Asphalt
Porous Asphalt
0
10
20
30
40
50
60
70
80
90
100
100 50 25 0
%IceCover
% Salt Application
% Ice Cover
Dense Mix Asphalt
Porous Asphalt
Weighted Skid Resistance (BPN)
0
10
20
30
40
50
60
70
80
90
100
100 50 25 0
%Salt Application
SkidResistance(BPN)
Dense Mix Asphalt
Porous Asphalt
PA after spring rain on snow eventPA after spring rain on snow event
DMA after spring rain on snow eventDMA after spring rain on snow event

40. Effective Salt ReductionsEffective Salt Reductions
PavementPavement
TypeType
20062006--20072007 20072007--20082008 Reductions PossibleReductions Possible
when compared towhen compared to
DMA withDMA with
100% App. Rate100% App. Rate
AntiAnti--
IcingIcing
Apps.Apps.
DeicingDeicing
Apps.Apps.
AntiAnti--
IcingIcing
Apps.Apps.
DeicingDeicing
Apps.Apps. App.App.
RateRate
AverageAverage
MassMass
Reduction*Reduction*
((’’0606--’’08)08)
DMADMA 1515 1414 2323 2222 100%100% 0%0%
PAPA 1515 66 2323 2727 25%25% 75%75%
PCPC --
shadeshade
-- -- 2323 3131 100%100% --20%20%
PCPC -- sunsun -- -- 2323 2323 100%100% --2%2%
** Reduction possible with no loss in skid resistance (safety)Reduction possible with no loss in skid resistance (safety)

41. Winter Maintenance GuidanceWinter Maintenance Guidance
 Salt reduction potential will be site specific and varySalt reduction potential will be site specific and vary
depending on shading and climate.depending on shading and climate.
 Plow after every storm.Plow after every storm.
 Apply antiApply anti--icing treatments prior to storms. Antiicing treatments prior to storms. Anti--icingicing
has the potential to provide the benefit of increasedhas the potential to provide the benefit of increased
traffic safety at the lowest cost and with lesstraffic safety at the lowest cost and with less
environmental impact.environmental impact.
 Deicing is NOT required for black ice development.Deicing is NOT required for black ice development.
 Apply deicing treatments during, and after storms asApply deicing treatments during, and after storms as
necessary to control compact snow and ice notnecessary to control compact snow and ice not
removed by plowing. Excess may be required.removed by plowing. Excess may be required.
4141

42. Winter Maintenance GuidanceWinter Maintenance Guidance
 Mixed precipitation and compact snow or ice isMixed precipitation and compact snow or ice is
particularly problematic for porous surfaces. This isparticularly problematic for porous surfaces. This is
prevented by appropriate plowing and corrected byprevented by appropriate plowing and corrected by
application of excess deicing chemicals.application of excess deicing chemicals.
 In certain instances of compact snow and ice,In certain instances of compact snow and ice,
excess salt may be required, however loading isexcess salt may be required, however loading is
offset by the overall reduced salt during routineoffset by the overall reduced salt during routine
winter maintenance and salt reduction.winter maintenance and salt reduction.
 With good sun exposure some porous asphaltWith good sun exposure some porous asphalt
installations will require no deicing.installations will require no deicing.
 Porous asphalt provides exceptional treatment forPorous asphalt provides exceptional treatment for
rain on snow events which commonly result inrain on snow events which commonly result in
dangerous refreezingdangerous refreezing
4242

43. Future Research NeededFuture Research Needed
Additional research is needed to examineAdditional research is needed to examine
salting loading at high loading ratessalting loading at high loading rates
common to commercial applicationscommon to commercial applications
MN Recommended application rates ofMN Recommended application rates of
3lbs per 1000 square feet appear to be3lbs per 1000 square feet appear to be
exceptionally low in comparison toexceptionally low in comparison to
commercial rates.commercial rates.
Salt substitutes: water, viscous brineSalt substitutes: water, viscous brine
4343

44. 4444
Post Construction O&MPost Construction O&M
Curing time needs are site specific but there should be at
least 24-48 hrs of curing. Common sense clause may
lead to lower threshold for small jobs with lighter loading
such as when pavement surface is less than 100 F (one-
time measurement). Problems occur when the surface
temperature is greater than 120 F.

45. Cost of Porous MaterialsCost of Porous Materials
4545

46. 4646
Cost InformationCost Information
 ~10-20% more for materials
 2009, DMA $75-100/ton, PA $89-125/ton placed
by machine for parking and residential road and
driveways
 Complicated jobs with handwork are more
expensive
 DMA $2.25/sf, PA $2.80/sf, not including
subbase
 Costs offset by lack of stormwater infrastructure
 Cost break even is achieved when designing for
quantity management ~Q10-Q25

47. MaintenanceMaintenance
4747

48. PrePre--Tx Extent of Debris/CloggingTx Extent of Debris/Clogging
Infiltration capacity via the PreInfiltration capacity via the Pre--Tx DRI test varied from 0 to 53Tx DRI test varied from 0 to 53
cm/hr, all effectively clogged when slope is considered.cm/hr, all effectively clogged when slope is considered. 4848

49. PrePre--TxTx
Infiltration atInfiltration at
Grid LocationsGrid Locations
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
D E J G Q H A I F V S N K M W P L U R O B T C
Test Location
ICviaSITest(cm/hr)
4949

50. Treatment Effectiveness for CloggedTreatment Effectiveness for Clogged
LocationsLocations
0
50
100
150
200
250
300
PW & Vac Soap, PW, & Vac
Cleaning Treatment
MeanIC(cm/hr)
Pre-Tx IC
Post-Tx IC
5050

51. Pervious Concrete SpallingPervious Concrete Spalling
5151

52. 5252

53. 5353

54. 5454

55. 5555

56. 5656

57. 5757

58. 5858

59. Boulder Hills, Pelham, NHBoulder Hills, Pelham, NH
 2009 Installation of 9002009 Installation of 900’’ ofof
first PA private residentialfirst PA private residential
road in Northeastroad in Northeast
 Site will be nearly ZeroSite will be nearly Zero
dischargedischarge
 LID subdivision 55+ ActiveLID subdivision 55+ Active
Adult CommunityAdult Community
 Large sand depositLarge sand deposit
 Cost 25% greater per tonCost 25% greater per ton
installedinstalled
3/23/20113/23/2011 5959

60. But there is moreBut there is more……
Salted twice, then never again (less salt to receivingSalted twice, then never again (less salt to receiving
stream)stream)
 Better traction than standard DMABetter traction than standard DMA
 Fire fighting storage from rooftop captureFire fighting storage from rooftop capture
 No concern about mosquitoes in the pondsNo concern about mosquitoes in the ponds
 Very little site runoff (pollutant load to stream veryVery little site runoff (pollutant load to stream very
small, no thermal pollution)small, no thermal pollution)
 Receiving stream geomorphic equilibrium not taxedReceiving stream geomorphic equilibrium not taxed
 The project sold 2 units in 2009, and 11 units sinceThe project sold 2 units in 2009, and 11 units since
January 2010January 2010……much easier to sell GREENmuch easier to sell GREEN
6060

61. Questions?Questions?