Technical Paper - KloroTech, Inc.
February 10th, 2014 Mr. Kevin Kunz KloroTech, Inc. 4118 E. 33rd Avenue Spokane, Washington 99223 RE:
Technical Paper Engineering Properties of KloroStone™ Pervious Paver Units
Dear Mr. Kunz: Strata, A Professional Services Corporation (STRATA) is pleased to provide this technical paper presenting our findings from recent testing and analyses of KloroStone™ pervious paver units. The purpose of our services was to independently test and evaluate the paver units to help characterize the system’s engineering and physical properties. KloroTech, Inc. (KloroTech) and STRATA developed an evaluation approach comprising infiltration characteristics, material strength and durability, stormwater treatment capability, and traffic support characteristics for use in several categories of system applications. This paper primarily addresses KloroStone’s™ inherent material properties and related stormwater disposal and treatment applications. Our testing and evaluation program identified excellent material strength and durability properties. The pervious paver units meet compressive and flexural strength, durability and other physical properties specified for standard and heavy-duty paver applications as listed in published ASTM International (ASTM) standards1. Our evaluation program also established a performance baseline for the system and its stormwater disposal and treatment characteristics to help establish stormwater design criteria when used in disposal applications. Our findings suggest the pervious paver surface units exceed infiltration rates of most regional surficial soils, and thus the system can enhance project value via porous flatwork applications. We also found the system has a low susceptibility to reduced infiltration rates from clogging with fine-grained soil. Finally, our results show that the typical porous paver system we tested effectively reduced stormwater pollutant levels, meeting treatment objectives as set by the Washington State Department of Ecology (Ecology) for pollution constituent reductions7. In summary, our findings indicate the paver units are made from strong, durable material that is highly resistant to cold weather conditions and deicer chemicals, possess excellent stormwater infiltration and treatment capabilities, and have minimal maintenance requirements. Such system properties can dramatically reduce site runoff volumes, allow aerial infiltration at relatively high rates, reduce stormwater constituents in the treatment zone, and support commercial traffic volumes without paver damage, degradation or long-term reduction in system effectiveness. We appreciate the opportunity to assist your product testing, research and development needs. Please do not hesitate to contact us if you have any questions or comments. Sincerely, STRATA
Chris M. Comstock, P.E. Project Manager and Engineer
Ryan M. Lewis, E.I.T. Staff Engineer
10020 E. Knox Avenue, Suite 200 Spokane, WA 99206 Phone.509.891.1904 Fax.509.891.2012 www.stratageotech.com
Technical Paper Engineering Properties of KloroStone™ Pervious Paver Systems
PREPARED FOR: KloroTech, Inc. Mr. Kevin Kunz 4118 E 33rd Avenue Spokane, Washington 99223
PREPARED BY: STRATA, A Professional Services Corporation 10020 E Knox Avenue, Suite 200 Spokane Valley, Washington 99206 February 10th, 2014 Abstract: KloroStone™ pervious pavers are a ceramic-based porous paving unit with strength and durability characteristics that meet ASTM minimum requirements for commercial traffic applications1. The paver units allow exponentially higher long-term infiltration rates when compared to traditional cement-based pavers. Measured infiltration and biological treatment characteristics demonstrate the system’s ability to accept stormwater through both conventional areal infiltration and concentrated disposal applications. The stormwater constituent treatment testing has shown the system’s ability to substantially filter and treat stormwater in a similar manner to systems with more traditional biological treatment and filtration abilities. The findings presented in this paper suggest the durable pervious paver system can support traffic loads, reduce site runoff via porous paving surfaces, accept and dispose concentrated runoff via high infiltration rates, and treat stormwater constituents to meet local jurisdictional requirements. Sedimentation impacts appear minimal, which allows for reduced maintenance and high long-term design infiltration values.
TABLE OF CONTENTS Page
LIST OF FIGURES .......................................................................................................................... II LIST OF TABLES ............................................................................................................................ II LIST OF APPENDIXES ................................................................................................................... II SUMMARY OF FINDINGS .................................................. ERROR! BOOKMARK NOT DEFINED. INTRODUCTION ............................................................................................................................. 1 Product Characteristics and Applications .............................................................................. 1 Product Development and Technical Evaluation ................................................................... 1 TECHNICAL PAPER PURPOSE .................................................................................................... 2 EVALUATION APPROACH AND PROCEDURES ......................................................................... 3 Large-Scale Testing .................................................................................................................. 4 Apparatus Design and Method Development .................................................................... 4 Infiltration Testing ................................................................................................................. 7 Laboratory Testing .................................................................................................................... 8 INFILTRATION TEST RESULTS AND INTERPRETATION .......................................................... 8 System 1 Test Results .............................................................................................................. 9 System 2 Test Results ............................................................................................................ 10 System 3 Test Results ............................................................................................................ 11 Stage 5 Results ................................................................................................................... 12 Infiltration Test Summary ....................................................................................................... 14 ANALYSES, OPINIONS AND DISCUSSION ............................................................................... 17 Infiltration ................................................................................................................................. 17 Stage 1 Response to Design Storm .................................................................................. 17 Stage 2 Infiltration Characteristics .................................................................................... 18 Sedimentation Effects ........................................................................................................ 18 Hydraulic Conductivity Analyses ...................................................................................... 19 Stormwater Treatment ............................................................................................................ 20 CONCLUSIONS ............................................................................................................................ 21 REFERENCES .............................................................................................................................. 22
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LIST OF FIGURES Figure 1 – Typical KloroStone™ Pervious Paver Unit .................................................................... 1 Figure 2 – Large-Scale Apparatus .................................................................................................. 4 Figure 3 – Typical completed system prior to testing ..................................................................... 6 Figure 4 – System 1 Graphical Test Results Summary .................................................................. 9 Figure 5 – System 2 Graphical Test Results Summary ................................................................ 10 Figure 6 – System 3 Graphical Test Results Summary ................................................................ 12 Figure 7 – Stage 1 Test Results Summary ................................................................................... 15 Figure 8 – Stage 2 Test Results Summary ................................................................................... 15 Figure 9 – Stage 3 Test Results Summary .................................................................................. 16 Figure 10 – Stage 4 Test Results Summary ................................................................................. 16
LIST OF TABLES Table 1 – Rainfall Intensity for 100-year, 1-hour Design Storm ...................................................... 5 Table 2 – Soil Laboratory Testing Program Summary .................................................................... 8 Table 3 – Stormwater Constituent Summary ................................................................................ 13 Table 4 – Infiltration Test Results Summary ................................................................................. 14 Table 5 – System Response and Storage Volume ....................................................................... 17 Table 6 – Porosity Summary ........................................................................................................ 18 Table 7 – Stage 2 Hydraulic Conductivity Analysis Summary ...................................................... 19 Table 8 – Individual Layer Hydraulic Conductivity Values ............................................................ 20 Table 9 – System 3, Stage 5 Infiltration Rate Reduction Summary .............................................. 20
LIST OF APPENDIXES Appendix A – Physical Strength Properties Appendix B – Large-Scale Infiltration Test Method Appendix C – Cross-Section of Infiltration Systems Appendix D – Laboratory Testing Appendix E – Infiltration Test Results Appendix F – Analytical Laboratory Test Results Appendix G – Hydraulic Conductivity Analyses
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INTRODUCTION KloroStone™ is a versatile Low Impact Development (LID) paving solution comprised of high-strength, pervious ceramic pavers that can reduce site runoff, allow for surface infiltration in stormwater disposal areas and treat stormwater constituents on site. The product represents a unique and proprietary fused-ceramic technology intended for construction of paved roadways, parking lots, walkways, sidewalks, plazas, patios, flatwork and other hardscapes.4 Microscopic pores within the pavers allow water to seep through, but do not allow dirt and debris to infiltrate the system, thereby providing significant product advantage over other permeable paving solutions such as segmented pavers and porous concrete, which tend to clog over time and require expensive ongoing maintenance.
Figure 1 – Typical KloroStone™ Pervious Paver Unit
Product Characteristics and Applications KloroStone™ paver units vary in thickness from 1.2 to 2.4 inches (30mm to 60mm) and are available in a variety of shapes, including a Standard Brick (4 by 8 inches), a Small Square (4 by 4 inches) and a Large Square (8 by 8 inches). Detailed product dimensions and physical characteristics are provided in Appendix A – Physical Characteristics of KloroStone™ Pervious Pavers. STRATA evaluated physical strength properties, engineering properties and other durability-related characteristics of the pavers. Our testing demonstrated that the KloroStone™ pavers meet compressive and flexural strength requirements and durability requirements as outlined in numerous ASTM International (ASTM) standard specifications for similar, nonpervious pavement applications. Essentially, our strength and durability testing showed the KloroStone™ product exceeds ASTM long-term strength and durability requirements for trafficrated pavers, while still allowing water infiltration through the pavers. KloroStone™ pavers can be used for traditional paving applications, although their high permeability expands their functionality to include system designs where reduced stormwater runoff and areal infiltration of water is desired. In contrast to the low infiltration and high runoff characteristics of conventional pavements and flatwork, KloroStone™ pavers are designed to capture and convey precipitation and collected runoff directly to the subsoil. Other innovative uses for the pervious product include stormwater filtration and biological treatment, in contrast to treating stormwater via traditional grassed swales or ponds. Relying upon durable porous paver surfaces to capture and treat stormwater can shrink stormwater facility footprints, thereby reducing development costs and using project areas more effectively. Product Development and Technical Evaluation Sustainable design and LID continue to gain traction in communities across North America. Owners, designers and regulators are responding by incorporating innovative and sustainable design features such as permeable pavements into existing municipal standards and design practices. KloroTech serves the sustainable design community by offering a unique, next-generation pervious paver product for use in “green” pavement applications.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 2
The performance characteristics of KloroStone™ pervious pavers appear useful to landscape architects, civil engineers, general contractors and municipal and county officials. Most notably these include high strength and durability characteristics, effective long-term design infiltration properties, reduced maintenance considerations and demonstrated stormwater treatment capacity coupled with varied traffic support applications. This paper and STRATA’s involvement focus primarily on the KloroStone’s™ material and hydraulic properties, and associated system components specific to various stormwater management applications. TECHNICAL PAPER PURPOSE STRATA collaborated with KloroTech to delineate the following goals for evaluating the KloroStone™ product, specifically with respect to material properties, the system’s infiltration capacity and stormwater treatment characteristics. •
Material Characteristics o Determine compressive and flexural strength o Evaluate material durability o Evaluate strength and durability reductions after simulated deicer application o Establish physical properties
•
Infiltration Characteristics o Evaluate the dry system’s response to water infiltration o Characterize the system’s volume storage ability o Evaluate the system’s response to a typical design storm o Identify the system’s maximum vertical infiltration rate o Consider long-term sedimentation impacts to system
•
Stormwater Treatment and Filtration o Quantify the system’s relative reduction of typical stormwater constituents o Evaluate the system’s treatment effectiveness over time
Most stormwater management, conveyance, treatment and disposal systems comprise more than just flatwork and pavements; they typically incorporate piped or channelized conveyance, constituent treatment and subsurface disposal components. In practice, KloroStone™ pavers enhance project value through a variety of beneficial system applications, including reducing stormwater runoff, providing filtration and treatment of detained stormwater, allowing areal or concentrated disposal, or a combination thereof. The KloroStone™ product can be effectively used in composite design applications by providing both durable traveling surfaces and important stormwater functions. To evaluate these dual-use paver characteristics, we considered the following permeable paving system applications:
System 1 – Typical Pedestrian Pavement Application
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 3
1.57" (40mm) KloroStone™Paver 2” ASTM C33 Sand System 2 - Traffic-rated application including crushed aggregate base support 1.57" (40mm) KloroStone™Paver 2” ASTM C33 Sand 6" Crushed Surfacing Top Course (CSTC)
System 3 - Stormwater treatment application with underlying filtration media 1.57" (40mm) KloroStone™Paver
2”Lane Mountain #20/30 Sand (LM #20/30)
10” ASTM C33 Sand EVALUATION APPROACH AND PROCEDURES To address the above goals it became apparent that a combination of field-simulated infiltration testing combined with a robust laboratory program was needed. In lieu of small-scale, single-paver laboratory testing, we developed a large-scale infiltration test method as described below coupled with a laboratory-testing program to characterize the physical and hydraulic properties of soil and aggregate used in the large-scale test. We also tested many physical characteristics of the paver units themselves to identify material properties required for infiltration analyses, but also to establish paver properties for KloroTech’s research and development use. Ultimately, we used both large scale and laboratory test results to: • • •
Evaluate individual system components as well as properties of the composite system, Establish material properties related to material strength and durability, and Ascertain stormwater infiltration and treatment characteristics.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 4
Large-Scale Testing STRATA developed a large-scale infiltration test method and apparatus to characterize infiltration rates and stormwater constituent treatment using various influent flow rates for the 3paver system configurations introduced above. The method and apparatus is intended to reduce test boundary conditions, provide user flexibility in water flow rates and allow apparatus re-use for different system configurations. The apparatus required measurement of influent and effluent flow rates, simulated and consistently distributed rainfall, and water-tight construction among other ancillary needs. Ultimately, the test method and apparatus required accurate control, collection and measurement of water flows while retaining several hundred pounds of compacted soil and aggregate without losing material to the collection bin. Apparatus Design and Method Development The large-scale apparatus was designed large enough to simulate a real-world scenario and reduce boundary condition (edge) effects, while small enough to fit indoors and allow convenient wood construction. The apparatus comprises a 42-inch-square wood box standing approximately 64 inches tall, as shown in Figure 2 below. The apparatus allowed various intensity design storms to be applied over a 36-inch-square surface area of KloroStone™ paver units. The inside box of the apparatus was lined with a fiberglass refrigeration panel to prevent water absorption to the wood framing. The base of the box contained several ½-inch-diameter holes drilled through the refrigeration panels and plywood to allow water collection via 2 plastic tubs. The holes were sized to accommodate 4 orders of magnitude higher flow rates than we applied to the apparatus to avoid the discharge point (holes) limiting flow rates. The collection tubs were angled to a low point where we constructed drains to convey water to a container placed on a scale for outflow measurement. After constructing the layered paver system by compacting sand and aggregate to specific dry unit weights, we placed a water distribution system over the apparatus box. The water distribution system was calibrated to allow even distribution of the selected design storm through a combination of a calibrated, low-rate flow meter and a series of drip holes with specific aperture sizes to allow even water distribution. Appendix B provides additional details of the test method and apparatus schematics.
Figure 2 – Large-Scale Apparatus
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 5
To evaluate system response to water application, sedimentation effects and treatment capability, we established the following stages for each infiltration test to achieve objectives listed in the Technical Paper Purpose section above: •
Determine system response and storage under design storm loading (Stage 1) o Identify system response time to water flow o Evaluate system’s ability to accept design storm loading as aerial infiltration o Characterize unsaturated system storage and residual moisture properties
•
Determine maximum infiltration rate of system at initial “ponding” (Stage 2) o Evaluation maximum infiltration rate at ponded conditions o Characterize saturated system storage and residual moisture properties
•
Evaluate sediment impacts during simulated design storm (Stage 3) o Identify infiltration reductions from sedimentation under design storm loading o Evaluate long-term sedimentation impacts to aerial infiltration
•
Evaluate sedimentation impacts during ponding (Stage 4) o Identify infiltration reductions from sedimentation under ponded conditions o Evaluate long-term sedimentation impacts to concentrated disposal systems
Evaluate system filtration and treatment capabilities (Stage 5) o Evaluate influent and effluent concentrations to identify treatment trends o Identify long-term infiltration rate reductions from constituents and sediment Large-scale infiltration testing referenced the established test method and apparatus provided in Appendix B, and we applied Stages 1 through 5 during testing to the 3-paver system application configurations (Systems 1 through 3 above). A detailed explanation of how each stage was applied to the large-scale tests is provided as Annex 1 as a supplement to the infiltration test method provided in Appendix B. •
To establish loading (inflow) rates for the simulated design storm, we researched rainfall characteristics in the area and applied an assumed design storm based on published 100-year, 1-hour rainfall intensity values in the Seattle and Spokane regions of Washington3,5. We applied a simulated design storm with inflow rates exceeding the maximum rainfall intensity for the King County region, as presented in Table 1 below. Table 1 – Rainfall Intensity for 100-year, 1-hour Design Storm Rainfall Intensity Range (inches per hour) 1.0 to 1.5
Location or Test Stage Spokane County, Washington
1.0 to 2.0
King County, Washington Stage 1 – Design Storm Stage 2 – Maximum Infiltration Rate at Ponding a. b.
1.92 to 2.24
a
3.81 to 5.47
b
Range of applied Stage 1 test inflows to simulate 100-year design storm intensity. Range of maximum measured outflows during Stage 2. Represents probable maximum infiltration rate of the paver system(s) and is analogous to the maximum rainfall intensity the paver system could accommodate with minimal ponding.
Although rainfall intensities and durations can be established for any given region, the timing, magnitude and duration of stormwater runoff conveyed to on-site disposal facilities differs for every site and is specific to that project’s stormwater design and site conditions. Accordingly, we established two primary rainfall simulations; Stage 1 - an assumed design storm intended to evaluate the initial system response to 100-year, site-wide rainfall; and Stage 2 - a maximum infiltration rate to evaluate the system’s ability to dispose concentrated and/or
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 6
conveyed runoff similar to disposal facilities such as swales, ponds or other retention/detention systems. We established the “maximum” design storm simulation as the rate at which minor ponding (¼-inch to ½-inch) was maintained above the KloroStone™ paver units during the Stage 2 and analogous Stage 4 test. As the installed paver system thickness varied for each application tested (Systems 1 through 3), the applied inflow rate at which ponding occurred also varied for each System. In effect, the “maximum” design storm to produce ponding was required only to simulate each systems response to maximum loading; i.e. the maximum infiltration rate of the system. For the sake of this document, units associated with the terms inflow/outflow rate, infiltration rate, and design storm loading are generally interchangeable between inches per hour (in/hr), gallons per minute (gpm) and cubic feet per second (cfs). Each term ultimately describes a flow rate through the apparatus having a consistent cross-sectional area, thereby allowing data conversion from “flow rate” to “vertical infiltration rate” derived by standardizing the total system flow rate to a unit infiltration rate. For clarity, we referenced infiltration rate in units of inches per hour (in/hr) throughout the remainder of this document. Infiltration rates reported herein are specific to the system tested and the head conditions during testing; actual infiltration rates may be higher under field conditions and for those systems subject to higher hydraulic head. The Washington State Department of Ecology (Ecology) provides guidelines for typical stormwater constituent concentrations and target treatment goals for 5 typical stormwater constituents comprising dissolved copper, dissolved zinc, Total Petroleum Hydrocarbons (oil treatment), total suspended solids (TSS), and total phosphorous7. To simulate a conventional “bio-swale” treatment application using the paver System 3 configuration, we mixed the aforementioned constituents in a 55-gallon barrel to create a simulated stormwater batch having Ecology-established constituent concentrations and we applied the influent to the apparatus during Stage 5. Appendix B provides additional details regarding constituent concentrations, stormwater batching, and influent/effluent sampling procedures. Prior to installing each System configuration (Systems 1 through 3), we established target soil/aggregate density, moisture content, and compaction properties for the selected soil and aggregate products for each System. We used laboratory test results and soil weight-volume relationships to estimate the dry weight of each material required to achieve the specified compaction for each soil layer at an established test thickness2. The individual soil and aggregate layers were moisture-conditioned, placed in the large-scale apparatus box in lifts, and compacted with a tamper. Compaction values were selected at 95 percent (CSTC) and 90 percent (sand bedding) to mimic actual field conditions and typical compaction specifications for aggregate support in traffic loading scenarios. We placed the paver units over the bedding sand in a staggered grid pattern. The aperture (gaps) between pavers were filled with “chinking” comprising commercially-available silica sand (Land Mountain #70)6. A completed System is shown below in Figure 3; Appendix C provides cross sections with specified Figure 3 –Completed layer thickness, materials and associated apparatus layers for system prior to testing each System tested.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 7
Infiltration Testing STRATA developed the large-scale infiltration test method as described above to meet the aforementioned objectives. As previously discussed, we considered 3 typical paver configurations (Systems 1 through 3) to gauge system response for each potential application. We performed 3 infiltration tests referencing the staged test approach for each system configuration. Appendix C presents cross-sections of each system and corresponding infiltration test; specific test details are outlined below. System 1 Testing The purpose of System 1 testing was to evaluate the hydraulic properties of System 1 comprising a typical pedestrian pavement application without aggregate support (System 2) or an underlying sand filtration layer (System 3). This system and corresponding infiltration test was limited to KloroStone™ paver units and bedding sand only; aggregate base course, filtration sand, geosynthetic fabrics, and stormwater constituents were not used for this test. The goal of System 1 testing was to identify a baseline response from a standard pervious paver system with no underlying soil or aggregate. As the System 1 configuration would not typically be used in a stormwater treatment capacity, we did not perform Stage 4 or 5 for this test. However, in an effort to identify system differences and help refine our findings, we performed a comparison test following Stage 3 to help gauge impacts from system maintenance. Specifically, we removed the sediment from the paver surface using a wet/dry vacuum, reapplied the LM #70 “chinking” sand in the paver apertures and re-ran Stage 3 to compare the system response with sediment present to the response after cleaning. System 2 Testing We developed System 2 testing to evaluate the hydraulic response to a paver system configuration intended to support vehicle loads. The test simulated a roadway or other paved surface application by installing the pavers and bedding sand thickness for System 1 over an aggregate layer designed to support vehicle loading. Typically, well-graded aggregate surfacing contains more soil fines (percent passing the No. 200 sieve) than bedding sand or filtration sand, and the layer also requires compaction to generate aggregate strength to support tire loads. The presence of soil fines and compacted nature of the crushed aggregate can limit infiltration of the overlying paver system, as the pavers are more permeable than compacted crushed aggregate. As such, System 2 testing was intended to evaluate whether the system as a whole could accommodate the assumed design storm and to characterize the maximum infiltration rate of a paver system having compacted aggregate support with potentially lower permeability materials than the baseline pedestrian application. Since this test was not intended to evaluate stormwater treatment, we did not perform Stage 5. System 2 testing also included a comparison test to consider test accuracy and associated impacts resulting from the method of introducing influent to the paver surface. During the test we identified that some water droplets falling from the rainfall simulator were eroding the sediment and chinking sand (LM #70) placed in the paver apertures. Although this could occur in a real-world scenario, we sought to identify testing-related inaccuracies such as those associated with such erosion of sediment and sand chinking from the rainfall simulator. We installed a lightweight, non-woven geotextile fabric over the paver surface to help dissipate energy from the falling water droplets and re-ran Stage 3 of the test. Our findings and opinions regarding testing impacts from water eroding sediment and chinking sand are discussed in later report sections.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 8
System 3 Testing The System 3 test approach was developed to evaluate the infiltration response and stormwater treatment performance using a layered paver system in contrast to a conventional bio-swale application comprising topsoil, filtration media and receiving soil. After completing Stages 1 through 4 for this test, we initiated Stage 5 to gauge system response to water with stormwater constituents, evaluate treatment and filtration characteristics, and identify rate reductions from sediment in addition to stormwater constituents. Laboratory Testing STRATA performed various laboratory testing on the paver units, soil and aggregate layers used for Systems 1 through 3. Laboratory testing provided information regarding paver strength and durability, but also allowed soil material characterization to support our analyses. Strength and durability-related testing we completed for the paver units is described and presented in Appendix A. Soil laboratory testing included grain size distribution, specific gravity, moisture content, hydrometer, maximum dry density and optimum moisture determination (proctor), and rigid wall permeameter testing. Analytical water testing included dissolved zinc, dissolved copper, TSS, Total phosphorous, and Total Petroleum Hydrocarbons (TPH, including diesel, gasoline and lube oil). Table 2 below summarizes the laboratory testing program for soil used in testing and the associated reasoning or justification for the testing. Appendix D presents actual soil-related test results and Appendix E presents analytical test results and the test methods performed. Table 2 – Soil Laboratory Testing Program Summary Soil Parameter Grain Size Distribution (Sieve Analysis/ Hydrometer) Maximum Density and Optimum Moisture Content (Modified Proctor)
Soil Unit Tested ASTM C33 Sand LM #20/30 Sand LM #70 Sand a CSTC Fine-Grained Sediment ASTM C33 Sand LM #20/30 Sand CSTC
Determine compaction characteristics of soil placed in apparatus and ensure compaction mimics typical construction and design specifications.
Hydraulic Conductivity (Rigid Wall Permeameter)
KloroStone Paver Unit ASTM C33 Sand LM #20/30 Sand
Specific Gravity
KloroStone Paver Unit ASTM C33 Sand
TM
TM
a.
Reasoning or Justification Establish soil material compatibility and geosynthetic separation fabric properties. Validate specified material meet designated material standards. Correlate hydraulic conductivity (permeability) and calibrate large-scale test results.
Correlate infiltration rate of large-scale testing to individual soil materials. Perform hydrogeologic analyses to compare theoretical equivalent hydraulic conductivity of each system to actual large-scale results. Characterize paver system hydraulic properties. Estimate system porosity and storage. Allow correlation of soil properties using weightvolume relationships.
Crushed Surfacing Top Course (CSTC) meeting requirements of Section 9-03.9(3) of the Washington State Department of Transportation (WSDOT) Standard Specifications for Road, Bridge and Municipal Construction, 2012 (WSDOT Standards).
INFILTRATION TEST RESULTS AND INTERPRETATION STRATA performed the 3 system infiltration tests discussed above corresponding to the 3 aforementioned typical paver applications and associated system configurations. The following sections discuss results from each test and our corresponding interpretations. Appendix E presents graphical and tabular infiltration test data.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 9
System 1 Test Results Inflow
1.0E-‐03
Stage 2
4.5
Flow Rate (cfs)
3.5 6.0E-‐04
3.0
Stage 3
Stage 1
2.5 2.0
4.0E-‐04
1.5
Infiltra)on Rate (in/h)
4.0
8.0E-‐04
1.0
2.0E-‐04
0.5 0.0E+00 0
50
100
150 200 250 300 0 50 100 0 Elapsed Time (minutes)
350 50
400 100
0.0 450 150
Figure 4 – System 1 Graphical Test Results Summary System 1 represents the thinnest paver system we tested to gauge a baseline response for a common pedestrian paver application. In addition to completing Stages 1 through 3 for this test, we repeated Stage 3 after cleaning sediment from the paver surface to evaluate cleaning and maintenance impacts and compare the sediment-laden infiltration condition to a recently cleaned system. Stage 1 testing confirmed System 1 ability to accommodate the conservative design storm as shown in Figure 8 below, which presents inflow (influent) and outflow (effluent) rates through the test duration. The System realized outflow about 20 cumulative minutes after test initiation. Stage 1 flows varied slightly in the first 25 minutes after the initial outflow response. Thus, outflows reasonably matched inflow about 45 minutes after the start of the design storm, indicating a relatively quick system response and achievement of steady-state flow conditions. We initiated Stage 2 by increasing the inflow rate until ponding occurred and monitoring outflow over an approximate 60-minute duration. Inflows and outflows converged to steady-state conditions about 25 minutes following Stage 2 initiation with a maximum outflow rate of 3.81 inches per hour (in/hr). The system began draining to the collection bin shortly as indicated by quickly falling outflow rates after inflow was terminated. We initiated Stage 3 testing as described above under design storm loading conditions. Outflows were slightly variable over the first 2 sediment cycles, but became more consistent after 35 minutes of testing. Our interpretation of test results is that outflows varied due to the system adjusting to sediment addition. Steady-state stage 3 flows were slightly less than steady-state Stage 1 flows, having an approximate outflow reduction of 5 percent. Maximum and average steady-state flows for Stage 1 were 2.38 in/hr and 2.1 in/hr respectively, while Stage 3 average steady-state flow was about 2.0 in/hr. Ultimately, the presence of sediment had minor impact to System 1 ability to accommodate the design storm.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 10
As presented on Figure E.4 in Appendix E, Stage 3 outflow following sediment removal increased the infiltration rate to an average value of about 2.0 in/hr, which is similar to Stage 3 outflows prior to removing sediment. As such, our interpretation is that although sediment slightly impacts design storm infiltration rates, the impact is minor and removing sediment did not improve outflows substantially for Stage 3 testing. System 2 Test Results 1.8E-‐03
1.4E-‐03 Flow Rate (cfs)
8.0
Stage 2 Stage 4
Inflow
7.0 6.0
1.2E-‐03 1.0E-‐03
5.0
8.0E-‐04
4.0 Stage 3
Stage 1
6.0E-‐04
3.0
4.0E-‐04
2.0
2.0E-‐04
1.0
0.0E+00 0
50
100
150 200 250 300 0 50 100 0 Elapsed Time (minutes)
350 50
400 100
Infiltra)on Rate (in/h)
1.6E-‐03
0.0 450 150
Figure 5 – System 2 Graphical Test Results Summary We tested System 2 to identify system response in a traffic-rated paver application. We performed Stages 1 through 4 for this test to evaluate design storm response and maximum infiltration rate for both clean and sediment-laden conditions. Similar to System 1 results, System 2, Stage 1 testing confirmed System 2 ability to accommodate the design storm. Figure 9 below presents inflow and outflow results for System 2; detailed tabular and graphical data is shown in Appendix E. The system realized outflow about 20 cumulative minutes after test initiation, but took longer to reach steady state conditions. This is likely due to lower permeability values for the compacted CSTC creating a slower system response as well as the additional storage volume in the CSTC layer. Also, we observed outflow containing soil fines at the onset of Stage 1 testing and lasting for approximately 50 minutes. We did not observe soil fines piping through the double-layered screen at the base of the apparatus box during System 1 or System 3 testing. Since the CSTC contains elevated soil fines compared to other sand products tested, and since this soil layer exists at the base of the box, our interpretation is the soil fines piped through the screen under the Stage 1 hydraulic gradient. As water continued to flow, the soil stabilized and we did not observe soil fines suspected from the base of the CSTC layer in remaining test stages. The system also drained slower than System 1 testing after termination of Stage 1 inflow.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 11
System 2, Stage 2 findings confirmed a higher maximum infiltration rate than System 1, Stage 2, which is counter-intuitive, as System 1 is theoretically better drained. Our interpretation, as supported by subsequent hydraulic conductivity analyses, is that the aperture between pavers has more impact to the system’s infiltration rate than the underlying soil and aggregate materials we tested. Our findings regarding overall system performance for each infiltration test are summarized in subsequent report sections. Stage 2 inflows and outflows converged to steady-state conditions about 25 minutes following Stage 2 initiation with a maximum outflow rate of 5.1 in/hr. System 2, Stage 3 test results were similar to System 1 results in that the system accommodated design storm inflows without ponding or sediment reductions. Stage 3 outflows were consistent as 5 sediment cycles were applied throughout the stage’s duration. Stage 4 testing identified a reduced infiltration rate at ponding compared to Stage 2. Steady-state Stage 4 flows were on the order of 4.0 in/hr, compared to Stage 2 maximum rate of 5.1 in/hr. This represents a 22 percent reduction in maximum outflows due to sedimentation. The higher maximum outflow rate for System 2, Stage 2 when compared to System 1, Stage 2, combined with the higher relative outflow reduction from Stage 4 sedimentation strongly suggests the paver apertures are more controlling of infiltration rates and sedimentation impacts than the paver or underlying materials themselves. During Stage 4, we observed that water droplets from the rain simulator were eroding the sediment and chinking sand between pavers. It appeared this created a more direct path for water to reach the underlying sand and aggregate layers, possibly increasing effective infiltration rate results. Given our deduction that paver apertures generally control infiltration rates, we suspected such erosion could impact test results and create overall test inconsistencies. Accordingly, we re-distributed the sediment and chinking sand after Stage 4 completion and installed a lightweight, high-permeability, geosynthetic separation fabric at the paver surface to help dissipate simulated rainfall. We re-ran Stage 4 with the energy dissipator and documented a lower infiltration rate of about 3.2 in/hr compared to 4.0 in/hr for Stage 4 without energy dissipation. Our resulting interpretations are that indeed, erosion and redistribution of sediment and chinking sand from rainfall impacted test results; by eliminating the rainfall erosion effect, infiltration rates were 20 percent lower. System 3 Test Results System 3 represents the primary pervious paver application with respect to stormwater infiltration and treatment, incorporating all 5 test stages as previously described. The System 3 configuration comprised the baseline conventional paver system (pavers over 2-inches of bedding sand), underlain by 10 inches of filtration and treatment media comprising ASTM C33 sand, a common stormwater treatment soil product in the region. Stage 1 through Stage 4 results showed similar trends as Systems 1 and 2, although the thicker sand layer delayed system response for Stage 1 until 75 minutes after introducing inflow, compared to 20 minutes for System 1 and 2. Also, due to soil capillary effects, complex unsaturated water flow, and aforementioned system response delays, we had to adjust test inflow during Stage 2 and Stage 4 to produce consistent, steady-state maximum outflow rates. Similar to Systems 1 and 2, Stage 1 confirmed System 3 ability to accommodate the design storm inflow and similarly, Stage 3 of this test confirmed no notable infiltration rate reduction from sedimentation. Inflow and outflow rates for System 3 testing are shown in Figure 6 below and should be reviewed in conjunction with detailed test data presented in Appendix E.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 12
1.6E-‐03 Stage 2 Inflow Ou;low
1.2E-‐03 Flow Rate (cfs)
Stage 4
7.0 6.0 5.0
1.0E-‐03
4.0
8.0E-‐04 Stage 3
Stage 1
6.0E-‐04
3.0
4.0E-‐04
2.0
2.0E-‐04
1.0
0.0E+00 0
50
100
150 200 250 300 0 50 100 0 Elapsed Time (minutes)
350 50
400 100
Infiltra)on Rate (in/h)
1.4E-‐03
0.0 450 150
Figure 6 – System 3 Graphical Test Results Summary We measured a Stage 2 (clean system) maximum outflow rate of 5.2 in/hr and a Stage 4 (sediment impacted) rate varying between 3.7 and 4.4 in/hr. Stage 4 infiltration rates varied due to aforementioned unsaturated flow mechanics, system sedimentation adjustments, and inflow rate regulation, although late-time outflow data stabilized around 4.3 in/hr. As shown in Figure E.11 inflow rates (measured at the rainfall simulator) were less than outflow rates during the last 10 minutes of Stage 4. Even though inflow was less than outflow, our opinion is these late-time Stage 4 outflow measurements reflect steady-state maximum infiltration conditions since the hydraulic head in the apparatus (i.e. the ponded surface elevation) controls outflow rates independently from inflow rates during ponding. Also, we specifically note that sedimentationimpacted outflow reductions comparing Stage 2 and Stage 4 were on the order of 17 percent, similar to System 2 results (22 percent reduction). Stage 5 Results After completing Stages 1 through 4, we initiated Stage 5 by switching the influent from tap water to the simulated stormwater batch prepared as described previously. Stage 5 did not include energy dissipation or sediment removal, and the System was allowed to drain for 1.5 hours following Stage 4 completion. Stage 5 comprised 3 individual treatment cycles, each applied under design storm conditions of 0.20 GPM corresponding to 2.14 in/hr at the paver surface. Inflow variability was minor and within the previously discussed design storm range. Although Stage 5 was designed to evaluate stormwater treatment ability, we identified slight outflow rate reductions with each treatment cycle, likely due to stormwater constituents being filtered and deposited at the paver system surface. We suspect suspended solids and oil may have clogged the paver unit aperture. Stage 5 outflow rates for Cycles 1 through 3 were measured at 2.2, 2.05 and 1.97 in/hr, respectively.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 13
As previously discussed, STRATA sampled water using a dedicated valve just upstream of the flow meter (influent) and from the collection bin discharge point after the Stage 5 stormwater had flowed through the paver system (effluent). We placed samples in laboratoryprovided containers selected for each constituent, which were immediately placed on ice and shipped to the analytical laboratory in accordance with test method and laboratory quality requirements. We sampled tap water at the end of Stage 4 before switching influent lines to the simulated stormwater batch. Appendix F presents chain-of-custody forms and analytical laboratory test results for the baseline and 3 treatment cycles. Table 3 below summarizes analytical results for each stormwater constituent compared to Ecology guidelines for stormwater treatment goals7. Table 3 – Stormwater Constituent Summary Parameter Dissolved Copper Dissolved Zinc b Oil Treatment TSS Total P Parameter Dissolved Copper Dissolved Zinc Oil Treatment TSS Total P Parameter Dissolved Copper Dissolved Zinc Oil Treatment TSS Total P Parameter Dissolved Copper Dissolved Zinc Oil Treatment TSS Total P Parameter Dissolved Copper Dissolved Zinc Oil Treatment TSS Total P a. b. c. d.
Ecology Guidelines a Influent Range Effluent Goal 0.005 - 0.02 >30% removal 0.02 - 0.3 >60% removal >10 (TPH) 200 mg/L >80% removal 0.1- 0.5 >50% removal Baseline a a Influent Effluent % Removal c 0.00175 ND 100% 0.00875 ND 100% d NT NT
Technical Paper Engineering Properties of KloroStone™ Pervious Paver Units
Dear Mr. Kunz: Strata, A Professional Services Corporation (STRATA) is pleased to provide this technical paper presenting our findings from recent testing and analyses of KloroStone™ pervious paver units. The purpose of our services was to independently test and evaluate the paver units to help characterize the system’s engineering and physical properties. KloroTech, Inc. (KloroTech) and STRATA developed an evaluation approach comprising infiltration characteristics, material strength and durability, stormwater treatment capability, and traffic support characteristics for use in several categories of system applications. This paper primarily addresses KloroStone’s™ inherent material properties and related stormwater disposal and treatment applications. Our testing and evaluation program identified excellent material strength and durability properties. The pervious paver units meet compressive and flexural strength, durability and other physical properties specified for standard and heavy-duty paver applications as listed in published ASTM International (ASTM) standards1. Our evaluation program also established a performance baseline for the system and its stormwater disposal and treatment characteristics to help establish stormwater design criteria when used in disposal applications. Our findings suggest the pervious paver surface units exceed infiltration rates of most regional surficial soils, and thus the system can enhance project value via porous flatwork applications. We also found the system has a low susceptibility to reduced infiltration rates from clogging with fine-grained soil. Finally, our results show that the typical porous paver system we tested effectively reduced stormwater pollutant levels, meeting treatment objectives as set by the Washington State Department of Ecology (Ecology) for pollution constituent reductions7. In summary, our findings indicate the paver units are made from strong, durable material that is highly resistant to cold weather conditions and deicer chemicals, possess excellent stormwater infiltration and treatment capabilities, and have minimal maintenance requirements. Such system properties can dramatically reduce site runoff volumes, allow aerial infiltration at relatively high rates, reduce stormwater constituents in the treatment zone, and support commercial traffic volumes without paver damage, degradation or long-term reduction in system effectiveness. We appreciate the opportunity to assist your product testing, research and development needs. Please do not hesitate to contact us if you have any questions or comments. Sincerely, STRATA
Chris M. Comstock, P.E. Project Manager and Engineer
Ryan M. Lewis, E.I.T. Staff Engineer
10020 E. Knox Avenue, Suite 200 Spokane, WA 99206 Phone.509.891.1904 Fax.509.891.2012 www.stratageotech.com
Technical Paper Engineering Properties of KloroStone™ Pervious Paver Systems
PREPARED FOR: KloroTech, Inc. Mr. Kevin Kunz 4118 E 33rd Avenue Spokane, Washington 99223
PREPARED BY: STRATA, A Professional Services Corporation 10020 E Knox Avenue, Suite 200 Spokane Valley, Washington 99206 February 10th, 2014 Abstract: KloroStone™ pervious pavers are a ceramic-based porous paving unit with strength and durability characteristics that meet ASTM minimum requirements for commercial traffic applications1. The paver units allow exponentially higher long-term infiltration rates when compared to traditional cement-based pavers. Measured infiltration and biological treatment characteristics demonstrate the system’s ability to accept stormwater through both conventional areal infiltration and concentrated disposal applications. The stormwater constituent treatment testing has shown the system’s ability to substantially filter and treat stormwater in a similar manner to systems with more traditional biological treatment and filtration abilities. The findings presented in this paper suggest the durable pervious paver system can support traffic loads, reduce site runoff via porous paving surfaces, accept and dispose concentrated runoff via high infiltration rates, and treat stormwater constituents to meet local jurisdictional requirements. Sedimentation impacts appear minimal, which allows for reduced maintenance and high long-term design infiltration values.
TABLE OF CONTENTS Page
LIST OF FIGURES .......................................................................................................................... II LIST OF TABLES ............................................................................................................................ II LIST OF APPENDIXES ................................................................................................................... II SUMMARY OF FINDINGS .................................................. ERROR! BOOKMARK NOT DEFINED. INTRODUCTION ............................................................................................................................. 1 Product Characteristics and Applications .............................................................................. 1 Product Development and Technical Evaluation ................................................................... 1 TECHNICAL PAPER PURPOSE .................................................................................................... 2 EVALUATION APPROACH AND PROCEDURES ......................................................................... 3 Large-Scale Testing .................................................................................................................. 4 Apparatus Design and Method Development .................................................................... 4 Infiltration Testing ................................................................................................................. 7 Laboratory Testing .................................................................................................................... 8 INFILTRATION TEST RESULTS AND INTERPRETATION .......................................................... 8 System 1 Test Results .............................................................................................................. 9 System 2 Test Results ............................................................................................................ 10 System 3 Test Results ............................................................................................................ 11 Stage 5 Results ................................................................................................................... 12 Infiltration Test Summary ....................................................................................................... 14 ANALYSES, OPINIONS AND DISCUSSION ............................................................................... 17 Infiltration ................................................................................................................................. 17 Stage 1 Response to Design Storm .................................................................................. 17 Stage 2 Infiltration Characteristics .................................................................................... 18 Sedimentation Effects ........................................................................................................ 18 Hydraulic Conductivity Analyses ...................................................................................... 19 Stormwater Treatment ............................................................................................................ 20 CONCLUSIONS ............................................................................................................................ 21 REFERENCES .............................................................................................................................. 22
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LIST OF FIGURES Figure 1 – Typical KloroStone™ Pervious Paver Unit .................................................................... 1 Figure 2 – Large-Scale Apparatus .................................................................................................. 4 Figure 3 – Typical completed system prior to testing ..................................................................... 6 Figure 4 – System 1 Graphical Test Results Summary .................................................................. 9 Figure 5 – System 2 Graphical Test Results Summary ................................................................ 10 Figure 6 – System 3 Graphical Test Results Summary ................................................................ 12 Figure 7 – Stage 1 Test Results Summary ................................................................................... 15 Figure 8 – Stage 2 Test Results Summary ................................................................................... 15 Figure 9 – Stage 3 Test Results Summary .................................................................................. 16 Figure 10 – Stage 4 Test Results Summary ................................................................................. 16
LIST OF TABLES Table 1 – Rainfall Intensity for 100-year, 1-hour Design Storm ...................................................... 5 Table 2 – Soil Laboratory Testing Program Summary .................................................................... 8 Table 3 – Stormwater Constituent Summary ................................................................................ 13 Table 4 – Infiltration Test Results Summary ................................................................................. 14 Table 5 – System Response and Storage Volume ....................................................................... 17 Table 6 – Porosity Summary ........................................................................................................ 18 Table 7 – Stage 2 Hydraulic Conductivity Analysis Summary ...................................................... 19 Table 8 – Individual Layer Hydraulic Conductivity Values ............................................................ 20 Table 9 – System 3, Stage 5 Infiltration Rate Reduction Summary .............................................. 20
LIST OF APPENDIXES Appendix A – Physical Strength Properties Appendix B – Large-Scale Infiltration Test Method Appendix C – Cross-Section of Infiltration Systems Appendix D – Laboratory Testing Appendix E – Infiltration Test Results Appendix F – Analytical Laboratory Test Results Appendix G – Hydraulic Conductivity Analyses
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INTRODUCTION KloroStone™ is a versatile Low Impact Development (LID) paving solution comprised of high-strength, pervious ceramic pavers that can reduce site runoff, allow for surface infiltration in stormwater disposal areas and treat stormwater constituents on site. The product represents a unique and proprietary fused-ceramic technology intended for construction of paved roadways, parking lots, walkways, sidewalks, plazas, patios, flatwork and other hardscapes.4 Microscopic pores within the pavers allow water to seep through, but do not allow dirt and debris to infiltrate the system, thereby providing significant product advantage over other permeable paving solutions such as segmented pavers and porous concrete, which tend to clog over time and require expensive ongoing maintenance.
Figure 1 – Typical KloroStone™ Pervious Paver Unit
Product Characteristics and Applications KloroStone™ paver units vary in thickness from 1.2 to 2.4 inches (30mm to 60mm) and are available in a variety of shapes, including a Standard Brick (4 by 8 inches), a Small Square (4 by 4 inches) and a Large Square (8 by 8 inches). Detailed product dimensions and physical characteristics are provided in Appendix A – Physical Characteristics of KloroStone™ Pervious Pavers. STRATA evaluated physical strength properties, engineering properties and other durability-related characteristics of the pavers. Our testing demonstrated that the KloroStone™ pavers meet compressive and flexural strength requirements and durability requirements as outlined in numerous ASTM International (ASTM) standard specifications for similar, nonpervious pavement applications. Essentially, our strength and durability testing showed the KloroStone™ product exceeds ASTM long-term strength and durability requirements for trafficrated pavers, while still allowing water infiltration through the pavers. KloroStone™ pavers can be used for traditional paving applications, although their high permeability expands their functionality to include system designs where reduced stormwater runoff and areal infiltration of water is desired. In contrast to the low infiltration and high runoff characteristics of conventional pavements and flatwork, KloroStone™ pavers are designed to capture and convey precipitation and collected runoff directly to the subsoil. Other innovative uses for the pervious product include stormwater filtration and biological treatment, in contrast to treating stormwater via traditional grassed swales or ponds. Relying upon durable porous paver surfaces to capture and treat stormwater can shrink stormwater facility footprints, thereby reducing development costs and using project areas more effectively. Product Development and Technical Evaluation Sustainable design and LID continue to gain traction in communities across North America. Owners, designers and regulators are responding by incorporating innovative and sustainable design features such as permeable pavements into existing municipal standards and design practices. KloroTech serves the sustainable design community by offering a unique, next-generation pervious paver product for use in “green” pavement applications.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 2
The performance characteristics of KloroStone™ pervious pavers appear useful to landscape architects, civil engineers, general contractors and municipal and county officials. Most notably these include high strength and durability characteristics, effective long-term design infiltration properties, reduced maintenance considerations and demonstrated stormwater treatment capacity coupled with varied traffic support applications. This paper and STRATA’s involvement focus primarily on the KloroStone’s™ material and hydraulic properties, and associated system components specific to various stormwater management applications. TECHNICAL PAPER PURPOSE STRATA collaborated with KloroTech to delineate the following goals for evaluating the KloroStone™ product, specifically with respect to material properties, the system’s infiltration capacity and stormwater treatment characteristics. •
Material Characteristics o Determine compressive and flexural strength o Evaluate material durability o Evaluate strength and durability reductions after simulated deicer application o Establish physical properties
•
Infiltration Characteristics o Evaluate the dry system’s response to water infiltration o Characterize the system’s volume storage ability o Evaluate the system’s response to a typical design storm o Identify the system’s maximum vertical infiltration rate o Consider long-term sedimentation impacts to system
•
Stormwater Treatment and Filtration o Quantify the system’s relative reduction of typical stormwater constituents o Evaluate the system’s treatment effectiveness over time
Most stormwater management, conveyance, treatment and disposal systems comprise more than just flatwork and pavements; they typically incorporate piped or channelized conveyance, constituent treatment and subsurface disposal components. In practice, KloroStone™ pavers enhance project value through a variety of beneficial system applications, including reducing stormwater runoff, providing filtration and treatment of detained stormwater, allowing areal or concentrated disposal, or a combination thereof. The KloroStone™ product can be effectively used in composite design applications by providing both durable traveling surfaces and important stormwater functions. To evaluate these dual-use paver characteristics, we considered the following permeable paving system applications:
System 1 – Typical Pedestrian Pavement Application
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 3
1.57" (40mm) KloroStone™Paver 2” ASTM C33 Sand System 2 - Traffic-rated application including crushed aggregate base support 1.57" (40mm) KloroStone™Paver 2” ASTM C33 Sand 6" Crushed Surfacing Top Course (CSTC)
System 3 - Stormwater treatment application with underlying filtration media 1.57" (40mm) KloroStone™Paver
2”Lane Mountain #20/30 Sand (LM #20/30)
10” ASTM C33 Sand EVALUATION APPROACH AND PROCEDURES To address the above goals it became apparent that a combination of field-simulated infiltration testing combined with a robust laboratory program was needed. In lieu of small-scale, single-paver laboratory testing, we developed a large-scale infiltration test method as described below coupled with a laboratory-testing program to characterize the physical and hydraulic properties of soil and aggregate used in the large-scale test. We also tested many physical characteristics of the paver units themselves to identify material properties required for infiltration analyses, but also to establish paver properties for KloroTech’s research and development use. Ultimately, we used both large scale and laboratory test results to: • • •
Evaluate individual system components as well as properties of the composite system, Establish material properties related to material strength and durability, and Ascertain stormwater infiltration and treatment characteristics.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 4
Large-Scale Testing STRATA developed a large-scale infiltration test method and apparatus to characterize infiltration rates and stormwater constituent treatment using various influent flow rates for the 3paver system configurations introduced above. The method and apparatus is intended to reduce test boundary conditions, provide user flexibility in water flow rates and allow apparatus re-use for different system configurations. The apparatus required measurement of influent and effluent flow rates, simulated and consistently distributed rainfall, and water-tight construction among other ancillary needs. Ultimately, the test method and apparatus required accurate control, collection and measurement of water flows while retaining several hundred pounds of compacted soil and aggregate without losing material to the collection bin. Apparatus Design and Method Development The large-scale apparatus was designed large enough to simulate a real-world scenario and reduce boundary condition (edge) effects, while small enough to fit indoors and allow convenient wood construction. The apparatus comprises a 42-inch-square wood box standing approximately 64 inches tall, as shown in Figure 2 below. The apparatus allowed various intensity design storms to be applied over a 36-inch-square surface area of KloroStone™ paver units. The inside box of the apparatus was lined with a fiberglass refrigeration panel to prevent water absorption to the wood framing. The base of the box contained several ½-inch-diameter holes drilled through the refrigeration panels and plywood to allow water collection via 2 plastic tubs. The holes were sized to accommodate 4 orders of magnitude higher flow rates than we applied to the apparatus to avoid the discharge point (holes) limiting flow rates. The collection tubs were angled to a low point where we constructed drains to convey water to a container placed on a scale for outflow measurement. After constructing the layered paver system by compacting sand and aggregate to specific dry unit weights, we placed a water distribution system over the apparatus box. The water distribution system was calibrated to allow even distribution of the selected design storm through a combination of a calibrated, low-rate flow meter and a series of drip holes with specific aperture sizes to allow even water distribution. Appendix B provides additional details of the test method and apparatus schematics.
Figure 2 – Large-Scale Apparatus
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 5
To evaluate system response to water application, sedimentation effects and treatment capability, we established the following stages for each infiltration test to achieve objectives listed in the Technical Paper Purpose section above: •
Determine system response and storage under design storm loading (Stage 1) o Identify system response time to water flow o Evaluate system’s ability to accept design storm loading as aerial infiltration o Characterize unsaturated system storage and residual moisture properties
•
Determine maximum infiltration rate of system at initial “ponding” (Stage 2) o Evaluation maximum infiltration rate at ponded conditions o Characterize saturated system storage and residual moisture properties
•
Evaluate sediment impacts during simulated design storm (Stage 3) o Identify infiltration reductions from sedimentation under design storm loading o Evaluate long-term sedimentation impacts to aerial infiltration
•
Evaluate sedimentation impacts during ponding (Stage 4) o Identify infiltration reductions from sedimentation under ponded conditions o Evaluate long-term sedimentation impacts to concentrated disposal systems
Evaluate system filtration and treatment capabilities (Stage 5) o Evaluate influent and effluent concentrations to identify treatment trends o Identify long-term infiltration rate reductions from constituents and sediment Large-scale infiltration testing referenced the established test method and apparatus provided in Appendix B, and we applied Stages 1 through 5 during testing to the 3-paver system application configurations (Systems 1 through 3 above). A detailed explanation of how each stage was applied to the large-scale tests is provided as Annex 1 as a supplement to the infiltration test method provided in Appendix B. •
To establish loading (inflow) rates for the simulated design storm, we researched rainfall characteristics in the area and applied an assumed design storm based on published 100-year, 1-hour rainfall intensity values in the Seattle and Spokane regions of Washington3,5. We applied a simulated design storm with inflow rates exceeding the maximum rainfall intensity for the King County region, as presented in Table 1 below. Table 1 – Rainfall Intensity for 100-year, 1-hour Design Storm Rainfall Intensity Range (inches per hour) 1.0 to 1.5
Location or Test Stage Spokane County, Washington
1.0 to 2.0
King County, Washington Stage 1 – Design Storm Stage 2 – Maximum Infiltration Rate at Ponding a. b.
1.92 to 2.24
a
3.81 to 5.47
b
Range of applied Stage 1 test inflows to simulate 100-year design storm intensity. Range of maximum measured outflows during Stage 2. Represents probable maximum infiltration rate of the paver system(s) and is analogous to the maximum rainfall intensity the paver system could accommodate with minimal ponding.
Although rainfall intensities and durations can be established for any given region, the timing, magnitude and duration of stormwater runoff conveyed to on-site disposal facilities differs for every site and is specific to that project’s stormwater design and site conditions. Accordingly, we established two primary rainfall simulations; Stage 1 - an assumed design storm intended to evaluate the initial system response to 100-year, site-wide rainfall; and Stage 2 - a maximum infiltration rate to evaluate the system’s ability to dispose concentrated and/or
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 6
conveyed runoff similar to disposal facilities such as swales, ponds or other retention/detention systems. We established the “maximum” design storm simulation as the rate at which minor ponding (¼-inch to ½-inch) was maintained above the KloroStone™ paver units during the Stage 2 and analogous Stage 4 test. As the installed paver system thickness varied for each application tested (Systems 1 through 3), the applied inflow rate at which ponding occurred also varied for each System. In effect, the “maximum” design storm to produce ponding was required only to simulate each systems response to maximum loading; i.e. the maximum infiltration rate of the system. For the sake of this document, units associated with the terms inflow/outflow rate, infiltration rate, and design storm loading are generally interchangeable between inches per hour (in/hr), gallons per minute (gpm) and cubic feet per second (cfs). Each term ultimately describes a flow rate through the apparatus having a consistent cross-sectional area, thereby allowing data conversion from “flow rate” to “vertical infiltration rate” derived by standardizing the total system flow rate to a unit infiltration rate. For clarity, we referenced infiltration rate in units of inches per hour (in/hr) throughout the remainder of this document. Infiltration rates reported herein are specific to the system tested and the head conditions during testing; actual infiltration rates may be higher under field conditions and for those systems subject to higher hydraulic head. The Washington State Department of Ecology (Ecology) provides guidelines for typical stormwater constituent concentrations and target treatment goals for 5 typical stormwater constituents comprising dissolved copper, dissolved zinc, Total Petroleum Hydrocarbons (oil treatment), total suspended solids (TSS), and total phosphorous7. To simulate a conventional “bio-swale” treatment application using the paver System 3 configuration, we mixed the aforementioned constituents in a 55-gallon barrel to create a simulated stormwater batch having Ecology-established constituent concentrations and we applied the influent to the apparatus during Stage 5. Appendix B provides additional details regarding constituent concentrations, stormwater batching, and influent/effluent sampling procedures. Prior to installing each System configuration (Systems 1 through 3), we established target soil/aggregate density, moisture content, and compaction properties for the selected soil and aggregate products for each System. We used laboratory test results and soil weight-volume relationships to estimate the dry weight of each material required to achieve the specified compaction for each soil layer at an established test thickness2. The individual soil and aggregate layers were moisture-conditioned, placed in the large-scale apparatus box in lifts, and compacted with a tamper. Compaction values were selected at 95 percent (CSTC) and 90 percent (sand bedding) to mimic actual field conditions and typical compaction specifications for aggregate support in traffic loading scenarios. We placed the paver units over the bedding sand in a staggered grid pattern. The aperture (gaps) between pavers were filled with “chinking” comprising commercially-available silica sand (Land Mountain #70)6. A completed System is shown below in Figure 3; Appendix C provides cross sections with specified Figure 3 –Completed layer thickness, materials and associated apparatus layers for system prior to testing each System tested.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 7
Infiltration Testing STRATA developed the large-scale infiltration test method as described above to meet the aforementioned objectives. As previously discussed, we considered 3 typical paver configurations (Systems 1 through 3) to gauge system response for each potential application. We performed 3 infiltration tests referencing the staged test approach for each system configuration. Appendix C presents cross-sections of each system and corresponding infiltration test; specific test details are outlined below. System 1 Testing The purpose of System 1 testing was to evaluate the hydraulic properties of System 1 comprising a typical pedestrian pavement application without aggregate support (System 2) or an underlying sand filtration layer (System 3). This system and corresponding infiltration test was limited to KloroStone™ paver units and bedding sand only; aggregate base course, filtration sand, geosynthetic fabrics, and stormwater constituents were not used for this test. The goal of System 1 testing was to identify a baseline response from a standard pervious paver system with no underlying soil or aggregate. As the System 1 configuration would not typically be used in a stormwater treatment capacity, we did not perform Stage 4 or 5 for this test. However, in an effort to identify system differences and help refine our findings, we performed a comparison test following Stage 3 to help gauge impacts from system maintenance. Specifically, we removed the sediment from the paver surface using a wet/dry vacuum, reapplied the LM #70 “chinking” sand in the paver apertures and re-ran Stage 3 to compare the system response with sediment present to the response after cleaning. System 2 Testing We developed System 2 testing to evaluate the hydraulic response to a paver system configuration intended to support vehicle loads. The test simulated a roadway or other paved surface application by installing the pavers and bedding sand thickness for System 1 over an aggregate layer designed to support vehicle loading. Typically, well-graded aggregate surfacing contains more soil fines (percent passing the No. 200 sieve) than bedding sand or filtration sand, and the layer also requires compaction to generate aggregate strength to support tire loads. The presence of soil fines and compacted nature of the crushed aggregate can limit infiltration of the overlying paver system, as the pavers are more permeable than compacted crushed aggregate. As such, System 2 testing was intended to evaluate whether the system as a whole could accommodate the assumed design storm and to characterize the maximum infiltration rate of a paver system having compacted aggregate support with potentially lower permeability materials than the baseline pedestrian application. Since this test was not intended to evaluate stormwater treatment, we did not perform Stage 5. System 2 testing also included a comparison test to consider test accuracy and associated impacts resulting from the method of introducing influent to the paver surface. During the test we identified that some water droplets falling from the rainfall simulator were eroding the sediment and chinking sand (LM #70) placed in the paver apertures. Although this could occur in a real-world scenario, we sought to identify testing-related inaccuracies such as those associated with such erosion of sediment and sand chinking from the rainfall simulator. We installed a lightweight, non-woven geotextile fabric over the paver surface to help dissipate energy from the falling water droplets and re-ran Stage 3 of the test. Our findings and opinions regarding testing impacts from water eroding sediment and chinking sand are discussed in later report sections.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 8
System 3 Testing The System 3 test approach was developed to evaluate the infiltration response and stormwater treatment performance using a layered paver system in contrast to a conventional bio-swale application comprising topsoil, filtration media and receiving soil. After completing Stages 1 through 4 for this test, we initiated Stage 5 to gauge system response to water with stormwater constituents, evaluate treatment and filtration characteristics, and identify rate reductions from sediment in addition to stormwater constituents. Laboratory Testing STRATA performed various laboratory testing on the paver units, soil and aggregate layers used for Systems 1 through 3. Laboratory testing provided information regarding paver strength and durability, but also allowed soil material characterization to support our analyses. Strength and durability-related testing we completed for the paver units is described and presented in Appendix A. Soil laboratory testing included grain size distribution, specific gravity, moisture content, hydrometer, maximum dry density and optimum moisture determination (proctor), and rigid wall permeameter testing. Analytical water testing included dissolved zinc, dissolved copper, TSS, Total phosphorous, and Total Petroleum Hydrocarbons (TPH, including diesel, gasoline and lube oil). Table 2 below summarizes the laboratory testing program for soil used in testing and the associated reasoning or justification for the testing. Appendix D presents actual soil-related test results and Appendix E presents analytical test results and the test methods performed. Table 2 – Soil Laboratory Testing Program Summary Soil Parameter Grain Size Distribution (Sieve Analysis/ Hydrometer) Maximum Density and Optimum Moisture Content (Modified Proctor)
Soil Unit Tested ASTM C33 Sand LM #20/30 Sand LM #70 Sand a CSTC Fine-Grained Sediment ASTM C33 Sand LM #20/30 Sand CSTC
Determine compaction characteristics of soil placed in apparatus and ensure compaction mimics typical construction and design specifications.
Hydraulic Conductivity (Rigid Wall Permeameter)
KloroStone Paver Unit ASTM C33 Sand LM #20/30 Sand
Specific Gravity
KloroStone Paver Unit ASTM C33 Sand
TM
TM
a.
Reasoning or Justification Establish soil material compatibility and geosynthetic separation fabric properties. Validate specified material meet designated material standards. Correlate hydraulic conductivity (permeability) and calibrate large-scale test results.
Correlate infiltration rate of large-scale testing to individual soil materials. Perform hydrogeologic analyses to compare theoretical equivalent hydraulic conductivity of each system to actual large-scale results. Characterize paver system hydraulic properties. Estimate system porosity and storage. Allow correlation of soil properties using weightvolume relationships.
Crushed Surfacing Top Course (CSTC) meeting requirements of Section 9-03.9(3) of the Washington State Department of Transportation (WSDOT) Standard Specifications for Road, Bridge and Municipal Construction, 2012 (WSDOT Standards).
INFILTRATION TEST RESULTS AND INTERPRETATION STRATA performed the 3 system infiltration tests discussed above corresponding to the 3 aforementioned typical paver applications and associated system configurations. The following sections discuss results from each test and our corresponding interpretations. Appendix E presents graphical and tabular infiltration test data.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 9
System 1 Test Results Inflow
1.0E-‐03
Stage 2
4.5
Flow Rate (cfs)
3.5 6.0E-‐04
3.0
Stage 3
Stage 1
2.5 2.0
4.0E-‐04
1.5
Infiltra)on Rate (in/h)
4.0
8.0E-‐04
1.0
2.0E-‐04
0.5 0.0E+00 0
50
100
150 200 250 300 0 50 100 0 Elapsed Time (minutes)
350 50
400 100
0.0 450 150
Figure 4 – System 1 Graphical Test Results Summary System 1 represents the thinnest paver system we tested to gauge a baseline response for a common pedestrian paver application. In addition to completing Stages 1 through 3 for this test, we repeated Stage 3 after cleaning sediment from the paver surface to evaluate cleaning and maintenance impacts and compare the sediment-laden infiltration condition to a recently cleaned system. Stage 1 testing confirmed System 1 ability to accommodate the conservative design storm as shown in Figure 8 below, which presents inflow (influent) and outflow (effluent) rates through the test duration. The System realized outflow about 20 cumulative minutes after test initiation. Stage 1 flows varied slightly in the first 25 minutes after the initial outflow response. Thus, outflows reasonably matched inflow about 45 minutes after the start of the design storm, indicating a relatively quick system response and achievement of steady-state flow conditions. We initiated Stage 2 by increasing the inflow rate until ponding occurred and monitoring outflow over an approximate 60-minute duration. Inflows and outflows converged to steady-state conditions about 25 minutes following Stage 2 initiation with a maximum outflow rate of 3.81 inches per hour (in/hr). The system began draining to the collection bin shortly as indicated by quickly falling outflow rates after inflow was terminated. We initiated Stage 3 testing as described above under design storm loading conditions. Outflows were slightly variable over the first 2 sediment cycles, but became more consistent after 35 minutes of testing. Our interpretation of test results is that outflows varied due to the system adjusting to sediment addition. Steady-state stage 3 flows were slightly less than steady-state Stage 1 flows, having an approximate outflow reduction of 5 percent. Maximum and average steady-state flows for Stage 1 were 2.38 in/hr and 2.1 in/hr respectively, while Stage 3 average steady-state flow was about 2.0 in/hr. Ultimately, the presence of sediment had minor impact to System 1 ability to accommodate the design storm.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 10
As presented on Figure E.4 in Appendix E, Stage 3 outflow following sediment removal increased the infiltration rate to an average value of about 2.0 in/hr, which is similar to Stage 3 outflows prior to removing sediment. As such, our interpretation is that although sediment slightly impacts design storm infiltration rates, the impact is minor and removing sediment did not improve outflows substantially for Stage 3 testing. System 2 Test Results 1.8E-‐03
1.4E-‐03 Flow Rate (cfs)
8.0
Stage 2 Stage 4
Inflow
7.0 6.0
1.2E-‐03 1.0E-‐03
5.0
8.0E-‐04
4.0 Stage 3
Stage 1
6.0E-‐04
3.0
4.0E-‐04
2.0
2.0E-‐04
1.0
0.0E+00 0
50
100
150 200 250 300 0 50 100 0 Elapsed Time (minutes)
350 50
400 100
Infiltra)on Rate (in/h)
1.6E-‐03
0.0 450 150
Figure 5 – System 2 Graphical Test Results Summary We tested System 2 to identify system response in a traffic-rated paver application. We performed Stages 1 through 4 for this test to evaluate design storm response and maximum infiltration rate for both clean and sediment-laden conditions. Similar to System 1 results, System 2, Stage 1 testing confirmed System 2 ability to accommodate the design storm. Figure 9 below presents inflow and outflow results for System 2; detailed tabular and graphical data is shown in Appendix E. The system realized outflow about 20 cumulative minutes after test initiation, but took longer to reach steady state conditions. This is likely due to lower permeability values for the compacted CSTC creating a slower system response as well as the additional storage volume in the CSTC layer. Also, we observed outflow containing soil fines at the onset of Stage 1 testing and lasting for approximately 50 minutes. We did not observe soil fines piping through the double-layered screen at the base of the apparatus box during System 1 or System 3 testing. Since the CSTC contains elevated soil fines compared to other sand products tested, and since this soil layer exists at the base of the box, our interpretation is the soil fines piped through the screen under the Stage 1 hydraulic gradient. As water continued to flow, the soil stabilized and we did not observe soil fines suspected from the base of the CSTC layer in remaining test stages. The system also drained slower than System 1 testing after termination of Stage 1 inflow.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 11
System 2, Stage 2 findings confirmed a higher maximum infiltration rate than System 1, Stage 2, which is counter-intuitive, as System 1 is theoretically better drained. Our interpretation, as supported by subsequent hydraulic conductivity analyses, is that the aperture between pavers has more impact to the system’s infiltration rate than the underlying soil and aggregate materials we tested. Our findings regarding overall system performance for each infiltration test are summarized in subsequent report sections. Stage 2 inflows and outflows converged to steady-state conditions about 25 minutes following Stage 2 initiation with a maximum outflow rate of 5.1 in/hr. System 2, Stage 3 test results were similar to System 1 results in that the system accommodated design storm inflows without ponding or sediment reductions. Stage 3 outflows were consistent as 5 sediment cycles were applied throughout the stage’s duration. Stage 4 testing identified a reduced infiltration rate at ponding compared to Stage 2. Steady-state Stage 4 flows were on the order of 4.0 in/hr, compared to Stage 2 maximum rate of 5.1 in/hr. This represents a 22 percent reduction in maximum outflows due to sedimentation. The higher maximum outflow rate for System 2, Stage 2 when compared to System 1, Stage 2, combined with the higher relative outflow reduction from Stage 4 sedimentation strongly suggests the paver apertures are more controlling of infiltration rates and sedimentation impacts than the paver or underlying materials themselves. During Stage 4, we observed that water droplets from the rain simulator were eroding the sediment and chinking sand between pavers. It appeared this created a more direct path for water to reach the underlying sand and aggregate layers, possibly increasing effective infiltration rate results. Given our deduction that paver apertures generally control infiltration rates, we suspected such erosion could impact test results and create overall test inconsistencies. Accordingly, we re-distributed the sediment and chinking sand after Stage 4 completion and installed a lightweight, high-permeability, geosynthetic separation fabric at the paver surface to help dissipate simulated rainfall. We re-ran Stage 4 with the energy dissipator and documented a lower infiltration rate of about 3.2 in/hr compared to 4.0 in/hr for Stage 4 without energy dissipation. Our resulting interpretations are that indeed, erosion and redistribution of sediment and chinking sand from rainfall impacted test results; by eliminating the rainfall erosion effect, infiltration rates were 20 percent lower. System 3 Test Results System 3 represents the primary pervious paver application with respect to stormwater infiltration and treatment, incorporating all 5 test stages as previously described. The System 3 configuration comprised the baseline conventional paver system (pavers over 2-inches of bedding sand), underlain by 10 inches of filtration and treatment media comprising ASTM C33 sand, a common stormwater treatment soil product in the region. Stage 1 through Stage 4 results showed similar trends as Systems 1 and 2, although the thicker sand layer delayed system response for Stage 1 until 75 minutes after introducing inflow, compared to 20 minutes for System 1 and 2. Also, due to soil capillary effects, complex unsaturated water flow, and aforementioned system response delays, we had to adjust test inflow during Stage 2 and Stage 4 to produce consistent, steady-state maximum outflow rates. Similar to Systems 1 and 2, Stage 1 confirmed System 3 ability to accommodate the design storm inflow and similarly, Stage 3 of this test confirmed no notable infiltration rate reduction from sedimentation. Inflow and outflow rates for System 3 testing are shown in Figure 6 below and should be reviewed in conjunction with detailed test data presented in Appendix E.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 12
1.6E-‐03 Stage 2 Inflow Ou;low
1.2E-‐03 Flow Rate (cfs)
Stage 4
7.0 6.0 5.0
1.0E-‐03
4.0
8.0E-‐04 Stage 3
Stage 1
6.0E-‐04
3.0
4.0E-‐04
2.0
2.0E-‐04
1.0
0.0E+00 0
50
100
150 200 250 300 0 50 100 0 Elapsed Time (minutes)
350 50
400 100
Infiltra)on Rate (in/h)
1.4E-‐03
0.0 450 150
Figure 6 – System 3 Graphical Test Results Summary We measured a Stage 2 (clean system) maximum outflow rate of 5.2 in/hr and a Stage 4 (sediment impacted) rate varying between 3.7 and 4.4 in/hr. Stage 4 infiltration rates varied due to aforementioned unsaturated flow mechanics, system sedimentation adjustments, and inflow rate regulation, although late-time outflow data stabilized around 4.3 in/hr. As shown in Figure E.11 inflow rates (measured at the rainfall simulator) were less than outflow rates during the last 10 minutes of Stage 4. Even though inflow was less than outflow, our opinion is these late-time Stage 4 outflow measurements reflect steady-state maximum infiltration conditions since the hydraulic head in the apparatus (i.e. the ponded surface elevation) controls outflow rates independently from inflow rates during ponding. Also, we specifically note that sedimentationimpacted outflow reductions comparing Stage 2 and Stage 4 were on the order of 17 percent, similar to System 2 results (22 percent reduction). Stage 5 Results After completing Stages 1 through 4, we initiated Stage 5 by switching the influent from tap water to the simulated stormwater batch prepared as described previously. Stage 5 did not include energy dissipation or sediment removal, and the System was allowed to drain for 1.5 hours following Stage 4 completion. Stage 5 comprised 3 individual treatment cycles, each applied under design storm conditions of 0.20 GPM corresponding to 2.14 in/hr at the paver surface. Inflow variability was minor and within the previously discussed design storm range. Although Stage 5 was designed to evaluate stormwater treatment ability, we identified slight outflow rate reductions with each treatment cycle, likely due to stormwater constituents being filtered and deposited at the paver system surface. We suspect suspended solids and oil may have clogged the paver unit aperture. Stage 5 outflow rates for Cycles 1 through 3 were measured at 2.2, 2.05 and 1.97 in/hr, respectively.
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Technical Paper KloroStone™ Pervious Pavers File: SP13051B Page 13
As previously discussed, STRATA sampled water using a dedicated valve just upstream of the flow meter (influent) and from the collection bin discharge point after the Stage 5 stormwater had flowed through the paver system (effluent). We placed samples in laboratoryprovided containers selected for each constituent, which were immediately placed on ice and shipped to the analytical laboratory in accordance with test method and laboratory quality requirements. We sampled tap water at the end of Stage 4 before switching influent lines to the simulated stormwater batch. Appendix F presents chain-of-custody forms and analytical laboratory test results for the baseline and 3 treatment cycles. Table 3 below summarizes analytical results for each stormwater constituent compared to Ecology guidelines for stormwater treatment goals7. Table 3 – Stormwater Constituent Summary Parameter Dissolved Copper Dissolved Zinc b Oil Treatment TSS Total P Parameter Dissolved Copper Dissolved Zinc Oil Treatment TSS Total P Parameter Dissolved Copper Dissolved Zinc Oil Treatment TSS Total P Parameter Dissolved Copper Dissolved Zinc Oil Treatment TSS Total P Parameter Dissolved Copper Dissolved Zinc Oil Treatment TSS Total P a. b. c. d.
Ecology Guidelines a Influent Range Effluent Goal 0.005 - 0.02 >30% removal 0.02 - 0.3 >60% removal >10 (TPH) 200 mg/L >80% removal 0.1- 0.5 >50% removal Baseline a a Influent Effluent % Removal c 0.00175 ND 100% 0.00875 ND 100% d NT NT
