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Green Parking Lot Resource Guide

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Green Parking Lot Resource Guide

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  • 1. Green Parking Lot Resource Guide
  • 2. TABLE OF CONTENTSINTRODUCTION ............................................................................... 1CHAPTER 1: IMPACTS OF PARKING LOTS ........................................... 2Environmental Impacts of Parking Lots .....................................................................................................2 Costs of Parking Lots.......................................................................................................................................5CHAPTER 2: “GREEN” PARKING LOT TECHNIQUES............................. 7Planning Aspects .............................................................................................................................................7On-Site Stormwater Management ..............................................................................................................8Parking Surface Material Selection .............................................................................................................9 Landscaping and Irrigation ...........................................................................................................................9 CHAPTER 3: PLANNING ASPECTS ..................................................... 10Municipal Parking Requirements ............................................................................................................. 10Parking Lot Placement and Aesthetics.................................................................................................... 12Linking Parking to Smart Growth ............................................................................................................. 13CHAPTER 4: STORMWATER MANAGEMENT....................................... 14Green Parking Lot Stormwater Management Techniques ................................................................. 14BMP Pollutant Removal and Effectiveness ............................................................................................. 17BMP Cost Considerations............................................................................................................................ 18 Case Study 1: Stormwater Best Management (BMP) —Bloedel Donovan Park, Bellingham, Washington .................................................................. 20CHAPTER 5: ALTERNATIVE PARKING SURFACE MATERIALS ............... 22Porous Pavement .......................................................................................................................................... 22Alternative Pavers ......................................................................................................................................... 23Design and Installation Considerations .................................................................................................. 24Maintenance of Permeable Pavement .................................................................................................... 25Infiltration & Pollutant Removal Effectiveness of Permeable Pavements ...................................... 27Cost Considerations ..................................................................................................................................... 29 Case Study 2: Parking Surface Alternatives—Heifer International, Little Rock, Arkansas 31 Case Study 3: Parking Surface Alternatives—University of Rhode Island, Kingston, Rhode Island ........................................................................................................................................ 33 Green Parking Lot Resource Guide—February 2008 i
  • 3. CHAPTER 6: LANDSCAPING AND IRRIGATION .................................... 35Overview of Natural Landscaping and Irrigation ................................................................................. 35 Environmental Benefits of Using Natural Landscaping and Associated Irrigation ...................... 38Cost Effectiveness of Using Natural Landscaping ................................................................................ 40 Case Study 4: Landscaping and Irrigation—Heifer International, Little Rock, Arkansas .. 42CHAPTER 7: REDUCED INFRASTRUCTURE BURDEN ............................. 44Regional Stormwater and Wastewater Impacts.................................................................................... 45Cost Effectiveness ......................................................................................................................................... 45 Case Study 5: Reduced Infrastructure Burden —Green Streets Program, Portland, Oregon ............................................................................... 47KEY RESOURCES .................................................................................... 49United StatesEnvironmental Protection AgencyOffice of Solid Waste and Emergenc Response (5101T)EPA-510-B-08-001February 2008http://epa.gov/oswer/iwg/Recycled/Recyclable—Printed with vegetable oil based inks on 100% postconsumer,process chlorine free recycled paper. Table of Contents ii
  • 4. INTRODUCTIONG ■ “ reen” parking lot is a term increas­ Chapter 2 provides an overview of the ingly used to describe parking lots benefits of green parking lot development that may incorporate a variety of techniques, briefly describing major plan­environmentally preferable features, includ­ ning, design, and material considerations.ing a minimized footprint and/or impervi­ ■ Chapters 3 through 6 provide detailedous surfaces, stormwater best management information on specific elements of sus­practices (BMPs), and alternative parking tainable parking lot approaches includingsurface materials. To date, however, informa­ planning and design approaches (Chaptertion on green parking lots has been scattered 3), sustainable stormwater managementacross planning, construction, stormwater, techniques (Chapter 4), alternatives toengineering, and landscaping resources. The asphalt parking surfaces (Chapter 5), andgoal of this resource guide is to present the water efficient landscaping and irrigationfundamental planning and design concepts (Chapter 6).of a green parking lot and connect readers toexisting resources on the environmental ben­ ■ Chapter 7 discusses how green parkingefits and cost effectiveness of green parking lots can help municipalities reduce futureapproaches. This document is expected to be stormwater infrastructure and utilityparticularly useful for local government of­ maintenance costs.ficials involved in planning and development Case studies are included throughout theactivities, as well as construction industry guide to provide real world examples ofprofessionals (developers, project managers, green parking lot techniques.facility managers and other decision makers)interested in green parking lot technologies. Key resources consulted in developing this guide are listed in the back of the document.The guide is organized into seven chapters:■ Chapter 1 describes the environmental and cost impacts associated with conven­ tional parking lots. Green Parking Lot Resource Guide—February 2008 1
  • 5. CHAPTER 1IMPACTS OF PARKING LOTSP arking lots are a ubiquitous feature high rate and volume, negatively impacting of the American landscape. Perhaps the surrounding ecosystem. Hence, parking because they are so commonplace, lots degrade water quality, strain stormwa­the significant environmental and cost im­ ter management systems, consume largepacts associated with parking lots are often amounts of land and resources, and enableoverlooked. In this chapter, we provide an urban sprawl. Furthermore, materials usedoverview of these impacts. to construct parking lots have a variety of impacts on air, water, and biodiversityENVIRONMENTAL IMPACTS OF throughout their life cycle. Some of the majorPARKING LOTS environmental impacts of traditional parkingThe prevailing low-density American devel­ lots are described below.opment pattern (i.e., urban sprawl) necessi­ Water Quality Impactstates reliance on automobiles, along with theconstruction of parking lots to accommodate, Parking lot runoff is a major contributor toand many times overaccomodate, demand non-point source pollution of our waterways.for parking. As parking lots have become a Conventional parking lots quickly movedominant feature of urban and suburban stormwater into receiving water bodies. Aslandscapes, their environmental impacts it flows across pavement, the water picks uphave also become increasingly apparent. pollutants from the surface. This results in large volumes of polluted runoff enteringMost parking lots are made of pavement—a surface water and groundwater resources,combination of asphalt concrete, the most negatively affecting water quality.widely used paving material in the UnitedStates, and aggregates such as sand, gravel, Contaminants in parking lot runoff canor crushed stone. Pavement is an impervi­ originate from a variety of sources, includ­ous, heat absorbing material that collects ing the paving materials used to build them.stormwater on its surface and does not allow Recently, the U.S. Geological Survey (USGS)it to filter into the soil, inhibiting the natural pinpointed parking lot sealants as a signifi­water cycle. With this in mind, parking lots cant source of non-point source pollution,have traditionally been built with the primary specifically polycyclic aromatic hydrocarbonsgoal of channeling stormwater into receiving (PAHs), a known carcinogen that can be toxicwater bodies as quickly as possible, via means to fish and wildlife.1 Automobiles are also asuch as gutters, drains, and pipes. As a result, major source of pollutants in parking lot run­runoff that is contaminated with many types off, including antifreeze, oil, hydrocarbons,of petroleum residues, fertilizers, pesticides, metals from wearing brake linings, rubberand other pollutants from parking surfaces particles from tires, nitrous oxide from carenters receiving waters at an unnaturally exhausts, and grease. CHAPTER 1—Impacts of Parking Lots 2
  • 6. Water Supply Impacts ide (CO), volatile organic compound (VOCs), polycyclic aromatic hydrocarbons (PAHs), andConventional parking lots consist of large ar­ carbon dioxide (CO2) during the manufactur­eas of impervious surfaces that do not permit ing process. The activities associated withthe infiltration of water into the soil. Unlike the construction and maintenance of park­natural conditions where rainwater filters ing lots also generate emissions, typically ininto the ground, impervious surfaces halt the form of dust, fumes, and equipment andthis process, inhibiting a watershed’s natural vehicle exhaust. For example, the use of hothydrological cycle and preventing ground­ mix asphalt, a common process where thewater recharge. As a result, water tables are asphalt is heated to extremely high tempera­lowered, reducing streamflow during dry tures prior to application, can cause healthperiods, depleting water supplies, and exac­ problems for workers including headache,erbating the negative impacts of droughts. skin rash, fatigue, throat and eye irritation,Stormwater Management breathing problems, and coughing. DieselImpacts emissions from on-site equipment can also cause similar health effects.2 In addition, theAccording to the USGS, an impervious, typical after effects of parking lot construc­man-made surface will generate two to six tion, such as fewer trees and less vegetationtimes more runoff than a natural surface. In due to clearing, as well as heat island effectaddition to the direct impact of paving, con­ (see below), also lead to higher amounts ofventional parking lots also typically include CO2 in the air.pipes, curbing, gutters, and drains to helpspeed water off of parking surfaces. These Heat Island Effectsystems cause runoff to move even faster Heat island effect (HIE) occurs in urban areasdownstream, increasing the risk of stream where materials that have heat-absorbingflooding. Sewer systems often become over­ properties, such as asphalt, are prevalent.whelmed by the rapid runoff of stormwater, In urban areas, the combined effect of suchcausing them to overflow and, in the case of surfaces can cause a change in the energycombined sewer and stormwater systems, (temperature) balance, leading to hotter airdischarge raw sewage into receiving water­ and surface temperatures. Recent researchways. In addition to the human health risks indicates that urban areas are 2 to 8ºF hotterrelated to combined sewer overflows, these in summer due to this increased absorbeddischarges can cause algal blooms to form, heat.3depleting aquatic oxygen levels and alteringa waterbody’s habitat. Parking lots contribute significantly to HIE. Asphalt, one of the most common pavingAir Emission Impacts materials used in parking lots, is a dark, heatPollutant air emissions occur throughout absorbing material.4 When asphalt cools atthe lifecycle of a parking lot. Asphalt cement night, all the heat it has absorbed duringplants emit particulate matter, nitrogen ox­ the day is released into the air, slowing theides (NOX), sulfur oxides (SOX), carbon monox­ rate of nighttime cooling. This hot surface, Green Parking Lot Resource Guide—February 2008 3
  • 7. combined with stormwater runoff from the fauna. The velocity and volume of runoff fromparking lot also affects surrounding water- parking lots can damage plant, fish and inver­bodies. When water is forced to flow quickly tebrate habitat. During storm events, runoffoff the lot’s surface, not enough time is al­ can erode stream banks and alter the naturallowed for evaporation to occur, again limiting shape of a waterway. Stream edge habitatnatural cooling of the air. In addition, the land and stream channel protection removedclearing needed to create space for parking during the construction of the parking lotlots diminishes tree cover and other natural increases the potential for erosion. Sedimentsvegetation that can help shade land and entering the waterway as a result of erosionmoderate temperatures. can smother habitat and stress aquatic organ­ isms. The turbidity created from the sedi­The environmental impacts of the HIE are mentation can disrupt an aquatic ecosystemvaried. Hotter temperatures can lead to by diminishing light transmission, reducingmore CO2 emissions due to increased energy plant growth, altering food supplies, interfer­demand to cool neighboring buildings.5 HIE ing with navigation, decreasing spawningcan also increase smog, and subsequently habitat, and reducing shelter.exacerbate pulmonary and cardiovascularhealth problems. During rain events, paved The contaminants in parking lot runoff alsosurfaces can transfer heat to runoff, increas­ pose a risk to wildlife. Toxic substances froming the temperature of receiving waters. This contaminated ground and surface water sup­warmer water can be detrimental to the natu­ plies have the potential to bioaccumulate inral habitats of fish and other aquatic life. the tissue of fish and other organisms in the wildlife food chain. They can also accumulateWaste Impacts in sediments, posing risks to bottom feedingThe traditional production and application organisms and their predators.of asphalt relies heavily on the use of virgin The impact of parking lots on water suppliesstone and aggregate and non-renewable, affects local ecology. Unnaturally low streampetroleum-based materials. Use of fresh flows as a result of decreased infiltrationasphalt in parking lot construction creates a can negatively impact deep water and swiftlost opportunity for reusing waste products, flowing habitats. Impaired water quality, andsuch as recycled asphalt, which would reduce increased volume and velocity of runoff, canthe amount of material sent to landfills lead to habitat loss, stress aquatic species,and increase the amount of virgin materi­ and have an overall negative effect on bio­als conserved. The use of recycled asphalt is logical diversity in abutting areas.common in the construction of roads, buthas yet to become prevalent in parking lot Decrease In Greenspaceconstruction. Greenspace is a finite resource with a wideDisturbance of Habitat and Local range of intrinsic values, including conserva­Ecology tion, recreation, and agricultural purposes, as well as its scenic qualities and contribution toTraditional parking lots can have a host of the overall character of a city or town. Propernegative impacts on adjacent habitat and CHAPTER 1—Impacts of Parking Lots 4
  • 8. management of greenspace is essential to ing walking and bicycling, and encouragesachieving and maintaining sustainable com­ automobile travel, disconnecting communi­munities. Nevertheless, greenspace areas are ties and decreasing the habitability of citiescommonly paved to accommodate demand and towns. The resulting increase in vehiclefor parking. For example, it is estimated that miles traveled and the associated high levels30 to 40 percent of a typical American down­ of mobile source air emissions exacerbatetown is used for parking spaces.6 air quality issues, and contribute to global climate change.Ineffective local government zoning restric­tions also result in the creation of larger areas COSTS OF PARKING LOTSof paved surface than necessary to meet theparking demand. Many municipalities require Beyond their environmental impacts, parkinga minimum number of parking spaces per lots have economic and social costs relateddevelopment project, often forcing devel­ to their construction—costs that are oftenopers to build more spaces than needed much higher than consumers realize. More­to meet actual demand. For instance, com­ over, parking costs are shouldered by manymercial parking lots frequently have 60 to stakeholders, including developers, local70 percent vacancy rates.7 Parking stall sizes governments, parking users, and communityrequired by zoning can also be larger than members. Below we describe the types ofnecessary, eliminating opportunities to alter costs related to parking lot construction, asparking lot configuration designs to achieve well as who pays.higher car capacity and minimize impervious On-site Costssurface area. On-site costs include the construction, opera­Conventional parking lots are often viewed as tion, maintenance, and disposal of materialsunattractive, hostile, and sometimes unsafe needed to develop and maintain parking lots,areas. In contrast, green parking lots with including paving materials and infrastructureurban greenscaping provide aesthetic ben­ such as gutters and curb cuts. In addition,efits, including privacy and noise reduction, on-site costs include the cost of parking lotto landowners and to communities. These landscaping that, depending on the shrubs,benefits are lost when conventional parking trees, and turf chosen, vary in their need forlot construction and paving techniques are mowing, pruning, and irrigation. These costsused. are typically paid by developers, althoughUrban Sprawl local governments sometimes subsidize infrastructure costs. HIE can add to parkingUrban sprawl and prevailing low-density lot user costs, by decreasing an automobile’sdevelopment patterns characterized by free, value by quickening the deterioration of theplentiful parking reinforce dependence on vehicle’s paint, plastics, and tires while onautomobiles for commuting to work, shop­ the lot. HIE can also shorten the life of theping, and social activities. Thus, conven­ pavement, causing it to become brittle andtionally designed parking is an enabler of weak (a cost to parking lot owners); and canurban sprawl. Conventional parking creates increase the energy costs of adjacent build-barriers to alternative transportation, includ­ Green Parking Lot Resource Guide—February 2008 5
  • 9. ings due to the hotter air temperatures (a Distributional Issuescost to the building owner and potentially to Parking lots provide a value to consumersthird parties). who use them, but result in negative im­Infrastructure Costs pacts for neighbors and other community members who do not use them. CommunityLocal governments bear the brunt of infra­ members would be better served by almoststructure costs related to parking. The high any other land use, particularly in cases ofvolume and velocity of polluted run-off from excessive sizing of paved areas, which canparking lots can stress stormwater man­ reduce adjacent property values.agement systems and hasten the need forrepairs, upgrades, and expansions to handle Community Development Costswater flow and treat runoff. Flooding caused Parking lots and associated sprawl decrease aby runoff can also degrade bridges, roads, community’s habitability, livability, and senseand other parts of a city’s infrastructure. of identity, a cost to all community members.Additionally, groundwater shortages due to Unattractive expanses of pavement placeddisruption of the water cycle can increase in front of buildings create voids and discon­the frequency, and thus cost, of pumping nectedness, discouraging pedestrian-friendlygroundwater. communities and alternative methods ofOpportunity Costs transport. The presence of multiple conven­ tional parking lots can also signal develop­Parking lots consume large areas of open ers that a community accepts urban sprawlspace that could otherwise be used for development. This signal can create a cyclicalalternative, higher value purposes, such as effect on a community’s future developmentparks, wildlife habitat, recreation, agriculture, patterns. Subsequent developments in thesehousing or other businesses. Building park­ areas are far more likely to have a similar pat­ing instead of other types of development tern of urban sprawl, further disconnectingcould reduce the property tax base, a cost the link with any older non-sprawl develop­to local governments and local taxpayers. ment, and eroding or precluding uniqueEnforced minimum parking requirements characteristics that establish a community’sdo not benefit developers either. They limit sense of place.the development potential of land; the moreparking spaces that are required, the less landavailable for more profitable uses. This can becostly because parking is relatively expensiveto construct and yields little return, or noreturn where parking is free. CHAPTER 1—Impacts of Parking Lots 6
  • 10. CHAPTER 2“GREEN” PARKING LOT TECHNIQUESI nnovative approaches to planning and of transport, through company support or design can greatly mitigate many of the subsidies. Another alternative is for mu­ negative impacts of parking lots, includ­ nicipalities to institute an optional fee thating diminished recharge of groundwater, developers can pay towards an appropriatehigh rates of stormwater runoff, and non- municipal fund, such as a traffic mitigationpoint source pollution, by decreasing imper­ fund, in lieu of meeting minimum parkingvious surface area, protecting water quality, requirements.8reducing stormwater management and Depending on the site, developers may notmaintenance costs, and increasing aesthetic opt for constructing less parking because itvalue. Below, we introduce green parking lot may make a site less marketable. A techniquetechniques, many of which are described in applicable in this case would be to set park­detail in subsequent chapters. ing maximums and/or area wide parkingPLANNING ASPECTS restrictions, which would limit the number of spaces allowed across a larger area, eve­Local planners regularly reinforce car depen­ ning the playing field for the marketability ofdence through zoning bylaws that, although sites in the area.meant to meet a community’s parking needs,can result in an oversupply of parking. As a Beyond reducing the number of parkingresult, cities and towns are increasingly trying spaces required, municipalities and develop­new approaches to parking management ers can also encourage practices that reducethat allow for greater flexibility and adapt­ stall dimensions by creating more compactability by determining parking space num­ car spaces and realistic stall size require­bers on a project-specific basis, rather than ments. Some local zoning laws currentlythrough a one-size-fits-all regulation. require unnecessarily large stall dimensions that are bigger than even the largest SUV.9One such technique is to reduce minimum In many cases smaller, more realistic, stallparking requirements based on project sizes would be sufficient while reducing thelocation or demographics. For example, local amount of disturbed land and imperviousgovernments can encourage projects that are surface associated with a project.located near public transportation to reducethe demand for parking spaces. Adaptations Improving the aesthetic of the parking lot isof this technique include municipalities also a central technique in green parking lots.allowing a reduction in the minimum park­ For instance, placing a parking lot behind aing requirements in return for a developer/ building rather than in front of it creates aemployer agreeing to implement a transpor­ more inviting and pedestrian-friendly envi­tation demand management program to en­ ronment. Reducing the number of curb cutscourage employees to use alternative modes also decreases the frequency of pedestrian/ Green Parking Lot Resource Guide—February 2008 7
  • 11. traffic interaction, thus making for a morepedestrian-accessible area. These practicesaim to improve the character of the develop­ment while maintaining accessibility to thelot. Additionally, parking lots can be dividedinto two or more parking areas, again project­ing a more visually welcoming appearance. Strategically sloped vegetated strips are a better option than conventional grassy parking islands for collecting and filtering runoff.The impact of locating a parking lot at thefront of a building can be mitigated by by 25-30 percent compared to conventionalproviding ample space between the lot and approaches.10the road, and then creating a buffer with Stormwater BMPs include structural controlslandscaping, fencing, or a wall. Landscaping and bioengineering techniques designed toinside the parking lot is also an important facilitate natural water cycling processes (i.e.technique. Beyond making the parking lot evaporation, transpiration, and groundwatermore visually pleasing, vegetation and land­ recharge) by capturing, filtering, infiltrating,scaping (including trees) around and inside and/or storing stormwater. Componentsthe parking lot reduce HIE and help to absorb of these soil- and plant-based systems canCO2 emissions. Landscaping is discussed carry out one or more of the aforementionedbelow. functions, including some that store water forChapter 3 provides detailed information on various durations (from 24 hours to perma­green parking planning. nent storage). Examples of BMPs include swales, vegetated buffer strips, and bioreten­ON-SITE STORMWATER tion areas.MANAGEMENT Unlike traditional stormwater managementInnovative stormwater management strate­ systems designed only for efficiency in storm-gies are increasingly being incorporated into water removal, which can lead to negativeparking lot design as part of the overarching downstream effects, BMPs represent a shiftconcept of Low Impact Development (LID). towards a sustainable approach to storm-LID stormwater techniques (also known as water management. Thus, in the context ofBest Management Practices, or BMPs) man­ parking lots, BMPs add value by minimizingage stormwater on-site, reducing negative environmental impacts of runoff, and oftenimpacts on receiving waters and municipal lower site development costs while improv­stormwater management systems, and ing aesthetics.decreasing the need for costly infrastruc­ture such as pipes, gutters, and curbs. Done Chapter 4 provides detailed information onon a small-scale, these controls attempt to greener stormwater management and BMPs.mimic the pre-development ecological andhydrological processes of an area and canreduce stormwater and site developmentdesign, construction, and maintenance costs CHAPTER 2—”Green” Parking Lot Techniques 8
  • 12. PARKING SURFACE MATERIAL economical for developers than incurringSELECTION the rising costs in some states for disposal of construction, demolition, and clearing debrisThe negative impacts associated with large in landfills.impervious surface areas in parking lots canbe reduced through the use of new perme­ Chapter 5 provides detailed information onable materials as substitutes for pavement. greener choices for parking surface materials.A number of paving substitutions have beendeveloped to reduce the range of environ­ LANDSCAPING AND IRRIGATIONmental impacts associated with the use of Green parking lot techniques work to mini­pavement. Types of permeable and semi­ mize the amount of land cleared for construc­permeable alternative pavers include gravel, tion, conserving as much of a site’s naturalcobble, concrete, wood mulch, brick, open vegetation and open space as possible,jointed pavers filled with turf or aggregate, and retaining habit for local wildlife. Whenturf blocks, natural stone, and pervious designing a parking lot area, landscapersconcrete. can use native trees and shrubs rather thanBased on a site’s characteristics (i.e. traffic non-indigenous species, which are more suit­volume, soil type, climate etc.), alternative able to local climates and, therefore, requirepavers may not be an option for the entire less irrigation. The benefits of increasing thesurface of primary parking areas.11 However, amount of greenscape in and around park­in many cases, the aisles and driveways can ing areas include reduction of CO2 in the air;be constructed using conventional pave­ improved stormwater runoff managementment, while alternative pavers can be used in including water storage; increases aquiferparking stalls, crosswalks, and overflow lots. recharge and flood protection; and increasedAlternative pavers slow the flow of runoff, human comfort through mitigation of HIEs.allowing it to filter into the soil, sustaining an Wetlands preservation or creation is particu­area’s natural hydrological cycle, and in some larly beneficial, as they can act as naturalcases, allowing microbes to break down con­ bioretention basins, providing water qualitytaminants before entering the soil layer. improvements, flood protection, and ero­ sion control. Wetlands also provide excellentOpportunities for materials recycling ex­ habitat for local avian and fish species, andist in the management and construction of are invaluable for water storage; one acre ofparking lots. For example, the use of recycled wetlands can store over million gallons ofasphalt in parking lot construction is not only water.12environmentally beneficial, but can makeeconomic sense. Other environmentally pref­ Chapter 6 provides detailed information onerable materials, such as recycled rubberized green parking lot landscaping and irrigation.asphalt, may also be used in parking lot con­struction. Recycling materials can be more Green Parking Lot Resource Guide—February 2008 9
  • 13. CHAPTER 3PLANNING ASPECTSP arking lot design and parking avail­ quantity of spaces in a parking lot. It is these ability are vital to transportation regulations that manage a community’s park­ management throughout the United ing capacity, and thus a large amount of itsStates. Parking availability may determine a impervious surface area.customer’s willingness to visit a business, and Zoning requirements for developers toit is often a sought after feature in urban resi­ provide off-street parking first began in thedential areas. However, parking lots should 1930s as a solution to an on-street parkingbe designed efficiently so that spaces are shortage. Over the years, off-street parkingused frequently and not left empty a majority requirements expanded in response to theof the time. When developing a parking lot, a population’s dependence on automobiles.number of factors combine to determine the Today, according to the U.S. Department oflot’s size, layout, and design. These decisions, Transportation, 87 percent of trips of lessmade during the planning stages of a devel­ than 50 miles are made by personal motoropment, can transform a parking lot from a vehicles.13 Americans have become accus­sparsely landscaped expanse of impervious tomed to the availability of free parking andpaving to a space that is more aesthetically automobile travel, rather than public transitpleasing, land efficient, and community and or other alternative methods, even for veryenvironmentally friendly. short distance trips. Increased parking avail­Local governments can use better park­ ability encourages more driving, more drivinging planning as a tool to promote infill and requires more parking, and so on.smart growth developments while reducing One of the most important local parkingthe direct environmental impact of park­ ordinances addresses minimum space re­ing. In many cases, revisions to zoning and quirements, or parking ratios. Typically, localother parking ordinances may be needed to governments require developers to constructachieve better parking planning. This chap­ the minimum number of parking spacester provides a summary of parking planning needed to satisfy peak demand. These mini­considerations that have environmental mum parking regulations often result in animplications, including municipal parking oversupply of parking. One study found thatlot regulations, parking lot aesthetics and the average parking supply at worksites is 30design, and the connection between parking percent greater than peak parking demand.14and smart growth. In many instances, minimum parking require­MUNICIPAL PARKING ments are inflexible to adaptation or vari­REQUIREMENTS ances. Also, the methods to determine these minimum parking requirements are oftenIn most urban and suburban areas, a num­ excessive and over-generalized, leading to anber of zoning laws govern the layout and oversupply of parking.15 In addition, although CHAPTER 3—Planning Aspects 10
  • 14. municipalities regulate the minimum number City of San Francisco, where city plannersof parking spaces, they typically do not put eliminated minimum parking require­a cap on the maximum. Thus, developers ments for development within a half milecan frequently construct even more than the of train stations and one-quarter mile ofrequired minimum, which is often the case major public transit routes.17at large retail developments, leading to a Municipalities can also consider the landfurther surplus in supply. uses in the surrounding area. For instance,In addition to requirements for the number it is possible that existing nearby develop­of spaces in a parking lot, regulations for the ment and parking may already providesize of each space are also common. Some some of the parking necessary to sup­local zoning laws require unnecessarily large port a new development. Mixed usedstall dimensions that are bigger than even developments often have natural parkingthe largest SUV.16 In many cases, smaller flexibility; an office where peak parkingstall sizes would satisfy parking needs while demand occurs during the day can sharereducing impervious surface, and the entire the same parking spaces with restaurants,footprint, of the parking lot. entertainment venues, or residential units that have peak parking demands at nightRe-thinking Municipal Parking and on weekends. Shared parking is alsoRequirements an option for single use developments inThere are a number of planning alternatives mixed-use areas.18to minimum parking requirements that lead­ • Maximum Limits on Parking—Theing local governments throughout the United opposite of parking minimums, parkingStates are implementing to minimize land maximums limit the number of spacesdedicated to parking. These include reducing that a developer can construct, which isminimum parking requirements; assessing often determined by the development’sparking needs on an individual project basis square footage. Portland, Oregon is onerather than using a generic formula; en­ city that has successfully implementedcouraging shared parking; and establishing the use of parking maximums. Benefitsparking maximums, area wide parking caps, of such a policy include open spacein-lieu parking fees, and reduced parking preservation, reduction in imperviousspace dimensions. surface area, traffic congestion reduction,• Reduced minimum parking require­ promotion of alternative transport, and ments—Parking requirements should the development of pedestrian-friendly be determined on a project-by-project urban design. For developers, such limits basis instead of by formula, taking into mean lower parking lot construction consideration how a project’s location can costs.19 Similar policies include setting shape parking needs. This approach may both a parking minimum and maximum, decrease the required parking capac­ or determining a median parking ratio. ity where there is accessibility to public • Area wide parking caps—Municipalities transportation and/or a high level of foot can control the amount of parking by and bike traffic. Such was the case for the Green Parking Lot Resource Guide—February 2008 11
  • 15. setting limits on the total amount of park­ stalls to achieve the greatest car capacity, ing spaces allowed in a certain area. This again reducing the amount of land neces­ strategy is being used in major U.S. cities sary for the lot. including Boston and San Francisco. Such regulations require greater research and PARKING LOT PLACEMENT AND planning efforts by the city or town to AESTHETICS ensure that the parking cap is appropriate Parking lots have been described as “sterile, and reasonable, but if done properly, it unattractive environments that deaden city can be very successful in minimizing the and suburban streets alike, further isolate land area used for parking and encourag­ users and preclude lively pedestrian-friendly ing use of public transportation. This op­ streets.”24 Although all parking lots do not tion is appropriate for areas with adequate match this description, many are eyesores access to public and alternative transpor­ that inhibit the usability and walkability of tation, as well as desirable location that an area. Several techniques can be incorpo­ would outweigh the perceived drawbacks rated into the design and layout of a parking of more limited parking.20 lot to improve aesthetics and help connect• In-Lieu Parking Fees—Towns such as parking lots to community design. This not Berkeley, California, Lake Forest, Illinois only benefits the user, but also the organi­ and Orlando, Florida incorporated systems zation or business adjacent to the lot, as a of in-lieu parking fees. This optional fee more pleasing atmosphere will help draw in is offered to developers by municipalities the public. Plantings around the perimeter, in-lieu of meeting minimum parking re­ especially trees and shrubs, can screen the lot quirements. This fee is typically allocated from passer-bys and break-up the otherwise to an appropriate municipal fund, such as continuous strip of asphalt and cars from a traffic mitigation fund.21 An alternative the street to the parking lot. This can also be under the in-lieu system is that in return achieved through the use of fencing or a wall. for the developer’s fee, the city provides Vegetation can also be used to divide one existing centralized, off-site parking to the large lot into two or more smaller lots, again new development’s tenants and visitors.22 increasing the site’s visual appeal. Equally important, landscaping within the lot pro­• Reduced stall size requirements— vides an environmental benefit by decreasing Adjusting a local government’s stall size dust, wind, noise, glare and air pollution; and requirements may reduce impervious sur­ minimizing heat island effect.25 face coverage as well. Alternatives include creating a certain number of compact The placement of a parking lot is a simple, car spaces and/or limiting stall dimen­ yet fundamental feature that can improve a sions to feasible sizes. For example, in the development’s attractiveness. A majority of town of Needham, Massachusetts, up to parking lots are placed in the front of build­ 50 percent of off-street parking can be ings, between buildings and streets, requiring reduced dimension spaces designed for pedestrians and bicyclists to cross expanses compact cars.23 If possible, developers can of parking in order to enter a building. Alter­ also adapt the layout and angle of parking natively, parking lots could be placed at the CHAPTER 3—Planning Aspects 12
  • 16. rear of a building, increasing the intercon- States, and promoting sustainable land use nectedness between pedestrians and the patterns. With many cities designed aroundbuilt environment. This simple zoning change use of the automobile, planners are oftenis incredibly effective in shifting the orienta­ presented with the conflicting challenge oftion of a streetscape from cars to pedestrians. promoting smart growth development whileThis also helps give the community a greater supporting the parking needs of a popula­sense of place and interconnectedness. In tion. Green parking planning approachesrecognition of such benefits, the City of Fort support smart growth by creating moreCollins, Colorado requires that no more than sustainable land use patterns and decreasing50 percent of the parking for a retail devel­ the environmental impacts of conventionalopment be located between the principle parking lot development. By promoting andbuilding and the primary abutting street.26 supporting alternative transport and com­Limiting the number of curb cuts also makes muting, local governments may reduce thea parking lot more pedestrian friendly and parking needs.inviting. Furthermore, by minimizing the A concept linked to smart growth is “transit­number of vehicular entries to parking areas, oriented development,” defined as develop­pedestrian mobility is improved, and pedes­ ment placed within close proximity of publictrian/traffic is minimized. transportation, designed to create walkableLINKING PARKING TO communities and alleviate traffic conges­SMART GROWTH tion and environmental impacts caused by urban sprawl. When building parking lots,Smart Growth is a state and local government local governments can encourage or requireplanning movement aimed at improving the developers to incorporate features that helplong-term habitability and sustainability of reduce automobile reliance, such as bicyclecities and towns by minimizing environmen­ racks. Employers can support use of alterna­tal impacts, improving human health, build­ tive transport options by subsidizing the costing a sense of community, creating walkable of public transit, encouraging participationneighborhoods, promoting traditional and in a commuting program, and/or providingalternative transport, and preserving open shower facilities on-site so that staff can bikespace. Most fundamentally, smart growth to work.entails moving away from the urban sprawldevelopment pattern common in the United Green Parking Lot Resource Guide—February 2008 13
  • 17. CHAPTER 4STORMWATER MANAGEMENTA pivotal component of green park­ project alone can be minimal, but multiplied ing lots is the inclusion of innova­ by the current, and growing, number of tive stormwater management commercial and residential parking lots, thetechniques, often referred to as stormwater combined effect of stormwater runoff has be­“best management practices” (BMPs). BMPs come the leading cause of non-point sourceare practices, techniques, and measures pollution to our waterbodies.29that prevent or reduce water pollution from As discussed in Chapter 2, the environmen­non-point sources (i.e. runoff ) using the most tal effects of increased volume and velocityeffective and practicable means available.27 of stormwater include not only diminishedStormwater management BMPs often include water quality in surrounding waterbodies,engineered, on-site systems that, when but also:coupled with reduction of impervious surfacearea, can help significantly reduce detrimen­ • Degradation of stream channels resultingtal environmental effects and infrastructure erosion and sedimentation;burden from stormwater runoff. • Minimized groundwater recharge, whichIncreased development and conventional can diminish water flow in the dry weath­stormwater systems have significantly er, and lead to poorer water quality duringchanged the characteristics of stormwater low flows;flow from land into receiving waters. Accord­ • Higher water temperatures, whiching to the Natural Resources Defense Council, negatively impact aquatic organisms andthe amount of rain converted to runoff under plants; andnatural conditions is less than ten percent ofthe rainfall volume.28 However as more devel­ • More frequent and severe flooding.30opment occurs, rainwater or snow melt that This chapter provides an overview of greenwould have infiltrated into the soil, evapo­ parking lot stormwater management BMPsrated into the air, or been absorbed by plants, that can help mitigate these impacts, in­instead flows quickly off of the pavement as cluding information on pollutant removalstormwater runoff. Moreover, conventional efficiency and cost considerations.stormwater management exacerbates thisproblem. Conventional parking lot stormwa­ GREEN PARKING LOT STORMWATERter management typically consists of costly MANAGEMENT TECHNIQUESsystems of man-made drains, pipes, gutters,storm ponds, and paved channels that direct Green parking lots offset environmental im­runoff from impervious lots into storm drains pacts of parking by using on-site stormwaterand neighboring waterbodies. The environ­ infrastructure that more closely mimics themental ramifications of one development natural water cycle, and manages stormwater CHAPTER 4—Stormwater Management 14
  • 18. through effective rainfall retention, pollutant ter runoff, and often are incorporated toremoval, and water infiltration. Although still pre-treat and remove sediment beforein the early stages of wide-spread implemen­ water enters infiltration devices such astation, cities and towns are recognizing the bioretention areas.34 Other benefits in­benefits of stormwater BMPs, and many have clude protection of riparian areas, habitatintroduced both voluntary and mandatory creation, and streambank stability.policies for their inclusion in development Vegetated filter strips are frequently usedprojects.31 in combination with riparian buffers, an­Some of the most commonly used structural other common BMP, to increase pollutantBMPs are described below. It also should be removal effectiveness. Riparian buffersnoted that incorporating BMPs is not lim­ are vegetated strips along waterways thatited to new development. As illustrated by trap and filter contaminants, encouragethe case study of building a rain garden at infiltration, and slow stormwater flow.Bloedel Donovan Park in this chapter, exist­ They also help to preserve streambanking parking lots can be retrofitted to include stability.them. • Bioretention Areas (Rain Gardens)• Swales One of the more well-know BMPs, biore­ Swales are open channels or depressions tention treatment areas (a.k.a., rain with dense vegetation used to transport, gardens) consist of a grass buffer strip, decelerate, and treat runoff. In parking shallow ponding area, organic layer, plant­ lots, they are designed to help direct ing soil, and vegetation. These areas are water into bioretention areas. Swales can typically used in parking lot islands. Unlike come in the form of a grassed channel, dry swales, bioretention areas are well-suited swale, or wet swale. They can be used in for parking lots in denser, urban areas most climatic regions of the United States, with less available open space. but may be unsuitable for densely urban • Dry Detention Basins areas as they require a large amount of pervious surface area.32 A dry detention basin is a vegetated basin with controlled outlets, designed to• Vegetated Filter Strips/Riparian detain runoff (lowering flows and reduc­ Buffers ing velocity) for a short amount of time Vegetated filter strips are flat pieces of (e.g. 24 hours or less), partially removing land with low slopes, which are designed pollutants before the water is discharged. to encourage natural sheet flow of storm- This helps limit flooding and other storm- water as opposed to channeled runoff. water impacts, such as stream channel Vegetated filter strips are well suited for erosion and wildlife habitat destruction. low-density development or areas with Dry extended detention basins are better less concentrated amounts of runoff.33 suited for pollutant removal than standard They function by using soil and vegeta­ dry detention basins because they retain tion to remove pollutants from stormwa­ the water for an “extended” period of time Green Parking Lot Resource Guide—February 2008 15
  • 19. (i.e., up to 48 hours). They are effective and filled with stone to form a subsurface at treating certain runoff contaminants, basin, where water is stored until it infil­ particularly those contained in spring trates into the soil. This system greatly re­ and winter runoff in colder climate areas. duces the volume of runoff, and is particu­ However, because water temperature larly good for groundwater recharge as it increases while in this type of system, dry allows a significant amount of rainwater to detention basins discharge warmer than infiltrate. Both of these BMPs are consid­ natural water into waterbodies, which ered effective for pollutant removal when should be taking into consideration. Both used in conjunction with a pre-treatment dry detention and dry extended detention BMP such as a swale. However, potential basins are normally dry between storm drawbacks include higher failure rates events, thus giving them their name.35 due to improper design and maintenance, limited site applicability, and increased• Wet Retention Basins sediment clogging.38 Wet retention basins are designed to cap­ Porous pavement is another type of infil­ ture, filter, store, and infiltrate storwmater, tration technique used in green parking and have storage capacity adequate for lots; as it is also an asphalt alternative, it flood volumes of water. Because they have is discussed in Chapter 5: Parking Surface the capacity to store a permanent pool of Materials. water, wet basins can be very effective for water control, and can provide the bene­ • Constructed Wetlands fits of aesthetic value and wildlife habitat, Constructed wetlands are designed to both terrestrial and aquatic. Although not capture, filter, and store stormwater simi­ suitable for smaller areas because of their lar to a wet retention basin. However, they size, when applicable, retention basins are also contain a large quantity of wetland a very effective BMP.36 vegetation and have wetland channels.• Infiltration Systems Although they are not built to replicate all of the ecological functions of wetlands, Infiltration systems are designed to constructed wetlands help simulate the capture and retain stormwater runoff, natural water cycle, recharge groundwa­ allowing water to gradually infiltrate into ter, remove pollutants, reduce erosion, the ground over a period of hours or days, and provide wildlife habitat. They are depending on the design.37 Two common considered to be a very effective pollutant infiltration systems used in green parking removal option.39 Constructed wetlands lots are infiltration basins and infiltration have a few limitations; they are not ap­ trenches. An infiltration basin is an open plicable in arid climates and, due to their depression that covers a relatively large large size, they are not suitable for dense area. It is constructed to work in conjunc­ urban areas. tion with filter strips or swales, which help direct runoff from a parking surface into It is not necessary for developers to in­ the basin. Infiltration trenches are shallow corporate all available green stormwater excavated ditches lined with filter strips techniques into a project; rather, they should CHAPTER 4—Stormwater Management 16
  • 20. determine those useful for specific site condi­ source of pollutants in parking lot runoff, in­tions. Considerations should include all fac­ cluding antifreeze, oil, hydrocarbons, metalstors that affect the amount, speed, and pol­ from wearing break linings, rubber particleslutant loadings of runoff: soil type, the slope from tires, nitrous oxide from car exhausts,and landscape of the site, amount of impervi­ and grease. Other polluting materials includeous surface, local precipitation patterns, and pesticides, fertilizers, litter, pet waste, dirt,rainfall surface retention.40 Carefully choos­ and sand.45ing the appropriate BMP(s) is important to One of the main goals of a green parking lotavoid any secondary environmental impacts is to decrease pollutant levels in stormwatercaused by the use of an inappropriate BMP. runoff as much as possible before it enters aBMPs should address peak discharge, runoff waterbody. Exhibit 1 shows a range of pol­volume, infiltration capacity, base flow levels, lutant removal efficiencies for selected BMPs.ground water recharge, and maintenance of Understanding the effectiveness of each BMPwater quality, so that they are ideally man­ for pollutant removal is a complex undertak­aged in the pre-development stormwater ing because pollutant removal is affected byfiltration conditions of the site.41 a large number of variables. Fundamentally,It should be noted that BMPs are helping to removal effectiveness depends on: 1) BMPmeet the Clean Water Act’s mandate to “re­ type, 2) the quantity of runoff treated, andstore and maintain the chemical, physical and 3) the type of pollutant being removed.46biological integrity of the Nation’s waters”.42 Variation in one of these factors can affectBy 2025 the U.S. population is predicted to a BMP’s efficiency. For example, infiltrationgrow 22 percent, which could mean an ad­ trenches show a high pollutant removal ef­ditional 68 million acres of development, a ficiency for pathogens, but much lower forgood fraction of which will be dedicated to phosphorus. However, these effectivenessparking.43 Thus, BMPs may play a larger role ranges can vary based on the climate, soil,in the future to mitigate non-point water and land type of a particular site. Infiltra­pollution. tion trenches may be less effective in colder climates when surface waters freeze and can­BMP POLLUTANT REMOVAL AND not allow runoff to flow into them, a limita­EFFECTIVENESS tion that can be partially remedied throughStormwater can carry a number of harmful proper design and maintenance, but may stillpollutants, and is the prime contributor to reduce pollutant removal effectiveness.47non-point source pollution. Runoff contami­ As seen in Exhibit 1, not all BMPs have a highnants can originate from a variety of sources, level of pollutant removal effectiveness.including the paving materials used to build Instead, they serve other roles in control­the parking lots. Recently, the USGS pin­ ling the impacts of runoff. This is the case forpointed parking lot sealants as a large source dry detention basins, which serve to reduceof non-point source pollution, specifically peak discharges of stormwater to neighbor­polycyclic aromatic hydrocarbons (PAHs), a ing waterbodies, as well as limit erosion andknown carcinogen that can be toxic to fish downstream flooding.and wildlife.44 Automobiles are also a major Green Parking Lot Resource Guide—February 2008 17
  • 21. EXHIBIT 1: BMP EFFECTIVENESS Typical Pollutant Removal Efficiency (percentage) BMP Type Suspended Nitrogen Phosphorus Pathogens Metals Solids Dry Detention Basins 30-65 13-45 15-45 <30 15-45 Retention Basins 50-80 30-65 30-65 <30 50-80 Constructed Wetlands 50-80 <30 15-45 <30 50-80 Infiltration Basins 50-80 50-80 50-80 65-100 50-80 Infiltration Trenches/ 50-80 50-80 15-45 65-100 50-80 Dry Wells Grassed Swales 30-65 15-45 15-45 <30 15-45 Vegetated Filter Strips 50-80 50-80 50-80 <30 30-65 Source: U.S. EPA, 1993, Handbook Urban Runoff and Pollution Prevention Planning, EPA-625-R-93-004, taken from Purdue Uni­ versity Engineering Department’s Long-Term Hydrologic Impact Assessment (L-THIA): http://cobweb.ecn.purdue.edu/~sprawl/ LTHIA7/lthia/lthia_index.htm.BMP COST CONSIDERATIONS constructing a BMP considerably because of excavation costs.Innovative structural stormwater BMPs aremore effective than conventional storm- Another significant variable in the compara­water management in removing pollutants tive cost of BMPs is the value of land; in areasand maintaining the environmental quality where real estate prices are high, construct­of a site. However, because some of these ing a BMP may take up too much space to betechniques are relatively new and have not cost effective.49 BMPs operation and mainte­achieved market penetration, it is not clear nance costs can also be significant. The long-their costs compare to conventional storm- term cost to maintain certain, more complex,water management approaches.48 Calculating stormwater BMPs over a 20-25 year periodthe cost-effectiveness of a stormwater BMP can be close to its initial construction cost.50is a very site-specific endeavor, and current However, some BMPs, such as swales andcost information is limited and inconsistent. bioretention areas, are less expensive to buildThe main factors affecting the relative costs than their conventional counterparts of pipeof BMPs include the cost of land, engineering and gutter systems. These BMPs can decreaseand design, permitting, construction, and development costs by reducing or eliminat­operation and maintenance. These costs can ing the high cost of conventional stormwatervary greatly due to individual site characteris­ infrastructure such as piping, gutters, andtics such as climate, topography, government drains, as well as reduced long-term mainte­regulations, soil type, time of year of con­ nance costs for such systems. Furthermore,struction, drainage, accessibility of equip­ some BMPs, such as constructed wetlands,ment, and economics of scale. For instance, may increase the property value by creat­very rocky soils may increase the cost of ing a water feature and vegetation that has CHAPTER 4—Stormwater Management 18
  • 22. high aesthetic value. Developers may also protect the health of waterbodies, but alsogain from local government incentives that because they can avoid long-term costs.encourage incorporating structural stormwa­ Without stormwater BMPs, many waterbod­ter BMPs. For instance, the City of Portland, ies and water infrastructure may deteriorate.Oregon will give up to a 35 percent discount Taxpayers bear the cost burden to slowoff its stormwater utility fee to properties or repair damage caused by downstreamwith on-site stormwater management.51 In flooding, stream and aquatic habitat dete­addition, some costs are tax deductible, and rioration, and repairs and upgrades to wornoperating costs may be fully deductible as town stormwater infrastructure systems, allexpenses in the year they are incurred.52 of which are very expensive and time-con­ suming.53 Infrastructure costs associated withAlthough the costs of BMPs vary by site and stormwater management and how greentype, they are almost always a good invest­ parking can help mitigate these costs arement from the perspective of local govern­ discussed further in Chapter 7.ments and taxpayers, not only because they Green Parking Lot Resource Guide—February 2008 19
  • 23. CASE STUDY 1: STORMWATER BEST MANAGEMENT PRACTICES (BMP)BLOEDEL DONOVAN PARK, BELLINGHAM, WASHINGTON54Stormwater runoff in Bellingham, Washing­ton, like much of the U.S., is a foremost waterquality issue. The Washington Department ofEcology estimates that roughly one-third ofthe state water bodies with pollution relatedproblems are impaired because of stormwa­ter runoff impacts. In an effort to protect thereceiving waters of nearby Lake Whitcomfrom such impacts, City of Bellingham of­ficials chose to retrofit stormwater manage­ment at the heavily used Bloedel DonovanPark parking lot. Rather than choosing aconventional technique, they elected to buildan innovative rain garden to manage storm- The raingarden in Bloedel Donovan Park helps protect the water quality in nearby Lake Whatcom, and recharge groundwater supplies.water on-site. of drain rock, and topped with a layer ofDESIGN AND CONSTRUCTION fabric to constrain the sand and restrictDesigned on a 550 square-foot section of the any plants from growing through. Anparking lot near the catch basin, the park’s 18- to 24-inch layer of sand composed ofrain garden supports runoff from 80 parking twenty percent organic materials is thespaces and two parking lanes. To meet water top layer .quality guidelines, the rain garden was also • Landscaping—For landscaping, the citydesigned to treat 91 percent of the runoff chose native plants that could survive thefrom a 50-year storm event. Aspects of its year-round climatic conditions of the site.construction included: This included plants that prefer wet soil,• Site excavation—From site topography but could also tolerate drought. and soils logs, the city determined the maximum allowable depth for water to EXHIBIT 2: CASE STUDY INITIAL pond in the rain garden. Under a 50-year COST COMPARISON storm event, the depth should be no more Conventional stormwater than six-feet. Thus, the site was excavated technique $52,800 three to four feet. (4,400 ft3 wet vault)• Layering of materials—The rain garden Rain Garden $12,820 is composed of three layers of non-woven Cost Savings $39,980 geotextile fabric alternated with six inches CHAPTER 4—Stormwater Management 20
  • 24. COST AND POLLUTANTS REMOVAL in-ground storage and treatment stormwa­EFFECTIVENESS ter system (see Exhibits 2 and 3). This was achieved through reduced construction andThe benefits from incorporating this rain equipment costs, as well as reduced laborgarden are numerous. It adds aesthetic value costs from the relative ease of installation,to the site, increases wildlife habitat, and is a some of which was accomplished by volun­highly effective BMP for treating stormwater teer landscaping help. These costs savings dorunoff. According to officials at the Belling­ not include future regular maintenance costs.ham Public Works Department’s, monitoringshows that approximately 80 percent of total A more detailed case study of the city ofrunoff is captured by the rain garden, with Bellingham’s rain garden can be foundoverflows running through media filtration on the Puget Sound Action Team’s Weband then another infiltration bed. Further­ site at www.psat.wa.gov/Publications/more, Bellingham saved 70 percent in initial Rain_Garden_book.pdf.costs compared to installing a conventional EXHIBIT 3: COST FOR BLOEDEL DONOVAN PARK RAINGARDEN Labor $3,600 Vehicle use 1,900 Amended soil 1,650 Concrete 1,200 Asphalt 1,200 PVC/grates/catch basins/fabric/other misc. 1,000 Washed rock 805 Excavator rental (1.5 days) 500 Plants 400 Debris Removal 300 WCC crew planting time 265 Total Cost $12,820 Green Parking Lot Resource Guide—February 2008 21
  • 25. CHAPTER 5ALTERNATIVE PARKING SURFACE MATERIALST he majority of parking lots are made Permeable pavements provide a sustainable of a combination of asphalt concrete, alternative to the conventional asphalt and the most widely used paving material concrete parking materials widely used today.in the United States, and aggregates such as Permeable pavements are a broadly definedsand, gravel, or crushed stone. Conventional group of pervious paving options that allowpavement is an impervious, heat absorb­ natural infiltration rates of stormwater intoing material that collects stormwater on its the soil through certain design techniquessurface, and does not allow it to filter into the and material substitutions.58 For this reason,soil, inhibiting the natural water cycle. As a re­ like many of the techniques mentioned insult, parking lots must be designed to quickly Chapter 4, permeable pavements are consid­remove the water that gathers during storms ered a best management practice (BMP) forby channeling it off the lot via means such stormwater management. However, perme­as gutters, drains, and pipes. The stormwater able pavement should be used in combina­is directed into receiving water bodies at tion with other BMP techniques to magnifyunnaturally high rates, causing a number of benefits and provide back-up systems in caseadverse impacts including increased down­ of BMP failure.59 Two basic types of perme­stream flooding, combined sewer overflow able paving designs exist: 1) porous pave­events, diminished groundwater supplies, ment and 2) alternative pavers. This chapterstreambank erosion, and non-point source describes these permeable pavement alterna­water pollution from runoff contaminated by tives, considering their functionality, infiltra­vehicular residues and other pollutants. tion and pollutant removal effectiveness, and cost implications.To combat several of the negative impactsof conventional parking lot paving, develop­ POROUS PAVEMENTers are increasingly incorporating modestchanges, such as using light colored concrete Porous pavement is a permeable pavementinstead of asphalt to reduce heat-island surface, often built with an underlying stoneeffect, or using recycled rather than virgin reservoir, which temporarily stores storm-asphalt to reduce emissions and natural re­ water before it infiltrates into the underlyingsource consumption. For example, 80 percent soil.60 Porous pavement works by eliminatingof asphalt pavement removed each year the finer aggregates typically used in con­during widening and resurfacing projects is ventional paving, and binding the remain­reused, with contractors typically incorpo­ ing aggregates together with an asphalt orrating up to 20 percent recycled material in Portland cement binder. By eliminating finerconcrete mixes.55, 56 However, these changes aggregates, a less dense material is createddo not address the fundamental problem of that allows stormwater to seep through. Theparking lot impermeability.57 underlying stone bed is designed with an overflow control structure, helping to ensure CHAPTER 5—Alternative Parking Surface Materials 22
  • 26. that water does not rise to the pavement significant downstream benefits.66 Althoughlevel. Stormwater settles in the empty spaces porous pavement looks very similar to con­of the storage bed, infiltrating over time into ventional pavement, it is a far more sustain­the subgrade soils—a process similar to an able alternative, considered by experts to beinfiltration basin.61 the most effective and affordable technique for addressing stormwater managementThe most common types of porous pavement from development.67are porous asphalt and pervious concrete,which are very similar in their design and Porous pavements typically have a greaterapplicability. spectrum of uses than alternative pavers (discussed below), as porous pavement• Porous Asphalt—Developed by the can be applied to both low vehicular traffic Franklin Institute in the 1970s, porous areas and some medium traffic areas. Porous asphalt consists of an open-grade coarse pavements also have been used in a few high aggregate, bonded together by a typical traffic areas, including some highway applica­ asphalt cement in which fine aggregates tions, because the product can provide better have been reduced or eliminated, allow­ traction than conventional pavement and ing water to move through the small voids reduce hydroplaning.68 Ongoing research is created.62 Porous asphalt can be used in working to improve its highway applicability all climates where conventional asphalt is through the use of additives and binders.69 suitable.63 In addition, porous asphalt may help reduce• Pervious Concrete—Pervious concrete noise levels from tires on pavement. In a was developed by the Florida Concrete study measuring acoustical properties of Association. It typically contains a mixture pavement types, porous asphalt was shown of Portland cement; uniform, open-graded to have lower noise levels than conventional coarse aggregate; and water. There is at hot mix asphalt.70 least 15 percent more void space in pervi­ ous concrete compared to conventional ALTERNATIVE PAVERS pavements.64 Pervious concrete can be Alternative pavers, also known as perme­ more durable than porous asphalt, par­ able pavers or unit pavers, are interlocking ticularly in hot weather. However, the State concrete blocks or synthetic fibrous grids of Pennsylvania’s Department of Environ­ with open areas filled with grass, sand, or mental Protection has noted that in colder gravel. Unlike concrete or asphalt poured-in­ northern and mid-Atlantic climates, porous place paving surfaces, alternative pavers are concrete parking lots should always be separate units laid out on a prepared base.71 designed with a stone subbase for storm- When built with a storage bed infiltration water management, and should not be system, alternative pavers function similarly placed directly onto a soil subbase.65 to porous paving systems. The voids betweenThe manufacturing process for porous pave­ the interlocked pavers allow stormwater fromment has the same environmental and health a parking lot’s surface to collect and thenimpacts as the process for conventional pav­ seep into the storage bed, which is made ofing materials, but porous pavement exhibits sand or crushed stone. The water then gradu- Green Parking Lot Resource Guide—February 2008 23
  • 27. ally infiltrates over time into the subgrade last 15 to 20 years, a length similar to con­soils. In addition to stormwater management, ventional asphalt concrete pavement, whichthe storage bed also provides added struc­ requires resurfacing after 20 years on aver­tural support to the pavers.72 As with porous age.78 However, a number of factors need topavements, the most beneficial element of be assessed when determining whether a sitealternative pavers is the reduction or elimina­ is suitable for a permeable paving system, in­tion of stormwater impacts.73 cluding: slope, traffic volume, subgrade, land use, soil, infiltration and drainage characteris­A number of alternative paver options are on tics, and groundwater conditions.79the market, including but not limited to: Turf-stone®, UNI Eco-Stone®, Checkerbox®, Grass­ Compared to conventional asphalt surfacepave2®, and Gravelpave2®. Of the alternative installation and design, features such as sub-paver options, grass paving systems are the grade, soil type, and installation requirementsmost permeable. However, they have more are more complicated for permeable pavinglimited applicability because grass cannot systems.80 For example, soil, including itssurvive daily traffic; thus, grass-based systems type, porosity, and stability, is considered oneare typically used for emergency fire lanes or of the most important factors to determinetemporary overflow parking areas.74 Pavers site suitability. According to the New Yorkshould be filled with fine gravel or other per­ State Stormwater Design Manual, developersmeable materials when more frequent park­ must ensure that soils are permeable enoughing is expected.75 It should also be noted that to carry out adequate infiltration by consider­certain types of alternative pavers, including ing the natural qualities of a soil type as wellblock, grid pavers, and gravel, are not always as past land uses, because previous grading,suitable for handicap accessible areas.76 filling, compaction, and other disturbances of the land can alter soil infiltration qualities.DESIGN AND INSTALLATION Underlying soils should have a minimum infil­CONSIDERATIONS tration rate of 0.5 inches per hour to accom­A number of uses for permeable pavement modate stormwater volumes, and knowledgeexist beyond new, whole parking lot con­ of the organic matter content of the soil isstruction projects. One option for high traffic also important in determining its pollutantparking lots is to design a hybrid parking lot removal capabilities.81combining permeable pavement parking Permeable pavement is meant to treat smallspots with more conventional paving in the storm events, which can range from 0.5 to 1.5aisles.77 In addition, permeable pavements inches. A site must be designed with an ad­can be used during parking lot retrofits and equate ratio of infiltration area to imperviousreplacements. area, and the soil should have a permeabilityAccording to the U.S. Department of Trans­ of between 0.5 and 3.0 inches per hour inportation, permeable pavements must be order to adequately handle stormwater.82 Oc­properly sited, designed, and installed in casionally, exceptions can be made to alloworder to function fully over their life span. If for permeable paving when sites do not meetplanned correctly, permeable pavements can certain criteria. For instance, permeable pave- CHAPTER 5—Alternative Parking Surface Materials 24
  • 28. ment can be used in soils with low porosity that if properly installed, success rates for aif a discharge pipe is installed to run from a permeable paving system, particularly po­storage area to a conventional stormwater rous asphalt, can be much higher than earliersystem. This modified system will still treat installations using these materials.88stormwater from small and medium storms,but also will prevent flooding during large MAINTENANCE OF PERMEABLEstorm events.83 PAVEMENTPorous pavement and alternative pavers In the past, studies indicated that permeablealone are not an appropriate BMP to combat pavement applications had a high failureextreme flooding events in channels and rate, due not only to improper siting, butriverbanks. It is recommended that a BMP de­ also poor maintenance. Failure of a perme­signed specifically to control high waterflows, able paving system means that the surfacesuch as a dry detention pond, should be used becomes impervious and behaves like con­in conjunction with porous pavement. This ventional asphalt, yet typically without theapproach is required by some local govern­ fully developed system of piping and guttersments as part of flood protection design used to manage runoff on conventional park­criteria.84 ing surfaces. However, with correct mainte­ nance, permeable pavement can retain itsPermeable pavement should not be used permeability, and be a successful stormwaterin parking lot areas with high volumes of management option.89sediment-laden runoff, high traffic volume,high dust areas, and/or heavy equipment The level of maintenance necessary totraffic.85 Clogging is the main cause of a maintain permeable pavement lots varies.system malfunction that can result from poor Alternative pavers such as concrete grid pav­siting of the permeable pavement system. ers and plastic modular blocks will requireDuring construction, developers can prepare less maintenance because they do not clogfor possible clogging by installing a perim­ as easily as porous asphalt and permeableeter trench connected to the stone reservoir concrete. Location also impacts the amountto treat overflow should the surface clog.86 of maintenance, as areas receiving moreOther common problems to avoid include: sediment will require more maintenance. For example, a parking lot with higher traffic vol­• Compaction of underlying soil, such as umes will tend to require more maintenance through the use of heavy equipment. because of the resulting increased quantities• Contamination of stone sub-base with of soil and particulates brought onto the lot. sediment. Although the new soil alone will not neces­ sarily clog the pavement’s voids, if ground in• Tracking of sediment onto pavement.87 repeatedly by tires, clogging can occur.90,91Like other best management practices, when Regular maintenance can avoid clogging ofpermeable paving systems fail, it is frequently permeable paving systems. Facilities manag­due to mistakes made during the design and ers are generally advised to high pressureconstruction process. Recent studies note hose and then vacuum porous pavement a Green Parking Lot Resource Guide—February 2008 25
  • 29. minimum of two to four times a year, de- may lead to contamination of the ground-pending on the system. This should remove water. This includes prohibiting constructionany dislodged sediment and particulate vehicles or hazardous material carriers frommatter from the site.92 Exhibit 4 provides an using the lot.95 Finally, because these types ofexample of typical permeable pavement parking lots have unique maintenance needs,maintenance activities. land owners must ensure that individualsEXHIBIT 4: MAINTENANCE ACTIVITIES FOR PERMEABLE PAVEMENTPARKING LOTS Maintenance Activity Scheduling Ensure paved area is clear of sediments As needed Mow upland and adjacent areas, and seed bare areas Monthly Ensure paved area is clear of debris Monthly Monthly and after Monitor that paved area dewaters between storms storms >0.5 inches Vacuum sweep routinely to keep surface free of sediments 3 to 4 times a year Clean inlets draining to the subsurface bed Biannually Inspect the paved surface for deterioration Annually Source: Adapted from New York State Department of Environmental Conservation, (2007), New York State Stormwater Design Manual—Chapter 9, : www.dec.ny.gov/chemical/29072.html.Clogging can also be avoided through responsible for parking lot maintenance, suchmonitoring activities on and around the lot, as the facilities manager, are properly trainedincluding: and prepared to handle the lot’s maintenance• Never using sand or gravel to address needs. icy conditions on porous pavements, although salt may be used on porous Cold Climate Considerations asphalt, and commercial deicers may be In cold weather regions, specific activities used on porous concrete.93 are necessary to properly maintain a perme­• Ensuring that the surface is not sealed or able pavement parking lot. The underlying repaved with a non-porous material. stone bed of permeable paving systems often absorbs and retains heat, causing faster snow• Maintaining planted areas adjacent to melt which leads to less snow accumulation. porous pavement to prevent soil washout However, snow may still accumulate, espe­ onto the pavement.94 cially during heavier storms. When treatingSigns should also be posted around the lot to it, abrasive materials such as sand should notprevent harmful activities such as resurfacing, be used on or near the pavement, as it willthe use of abrasives, and any activities that quickly clog the surface. As noted above, salt CHAPTER 5—Alternative Parking Surface Materials 26
  • 30. can be used as a deicer on the porous pave­ INFILTRATION & POLLUTANTment, though nontoxic, organic deicers are REMOVAL EFFECTIVENESS OFpreferable because the chlorides in salt can PERMEABLE PAVEMENTSmigrate into the groundwater.96 With porouspavement, some sites have found that light Permeable paving coupled with a subsurfaceplowing reduces the need for salt, as the storage bed can capture and manage storm-remaining snow quickly drains into the mate­ water from small, frequent rainfall events,rial.97 When plowing snow, operators should which accounts for between 30 and 50set the blade slightly higher than usual (i.e., percent of annual precipitation on average.102one inch), as to not damage the material. This In addition, this combination can be very ef­will avoid the blade catching the edge of a fective at removing stormwater pollutants.block or paving and damaging its surface. Infiltration EffectivenessSigns should be posted to reinforce plowingrequirements.98 Finally, frost heave can occur Permeable pavement, when properly de­if infiltrating runoff freezes below the surface, signed and maintained, can eliminate almosthowever porous pavement can be designed all surface runoff from low intensity storms.103to avoid this issue.99 As mentioned before, proper siting and maintenance of permeable parking areas areRepairs critical to maintaining high surface infiltra­According to Cahill Associates, a leading tion rates.104 Data on infiltration rates varysustainable stormwater management design widely according to design characteristicsfirm, potholes in porous pavement are very and underlying soils, however, research indi­rare. However, settling might occur if any soft cates that an average of 50 percent of annualspots in the subgrade are not addressed dur­ rainfall on porous pavement infiltrates, withing construction. Even after 20 years, a well- reported infiltration rates reaching as high asmaintained porous surface can show little if 80 percent.105 Infiltration rates can decline toany cracking or potholes.100 Many alternatives a certain extent over time, again dependingare available for repairing damaged porous on design, installation, maintenance, and sitepavement and alternative pavers. In general, characteristics such as sediment loads.106areas less than 50 square feet can be patched Pollutant Removal Effectivenessby using either a porous mix or standardpavement because the loss of porosity to Limited data indicate that permeable pave­a small spot is insignificant to the overall ment systems have high removal rates forstormwater management function. If an area many pollutants, including total suspendedgreater than 50 square feet is damaged, an solids, metals, oils, and grease.107 However,engineer should be consulted to design an pollutant removal is not effective for largerappropriate patch.101 storms with rainfall greater than one-inch, or with high rainfall intensity.108 Green Parking Lot Resource Guide—February 2008 27
  • 31. Porous Pavement lower. Also, motor oil was detected in 89 per­Studies of porous pavement performance cent of the runoff samples from conventionalshow that they can effectively trap soluble asphalt, while no motor oil was detected inpollutants, which are then absorbed or any samples that infiltrated through sectionsbroken down in the underlying soil layers. Ex­ of alternative pavers.111hibit 5 depicts the range of pollutant removal Another study researched driveways con­effectiveness for porous pavement, showing structed of conventional asphalt versusa removal effectiveness of at least 65 percent permeable pavers to compare their runofffor suspended solids, nitrogen, pathogens, depths, infiltration rates, and pollutant con­and metals; and at least 30 percent of phos­ centrations over two years. The study foundphorus.109 that the mean weekly runoff rate for conven-EXHIBIT 5: POROUS PAVEMENT POLLUTANT REMOVAL EFFICACY Typical Pollutant Removal (percentage) BMP Type Suspended Nitrogen Phosphorus Pathogens Metals Solids Porous Pavement 65-100 65-100 30-65 65-100 65-100 Source: U.S. EPA, 1993, Handbook Urban Runoff and Pollution Prevention Planning, EPA-625-R-93-004, taken from Purdue Uni­ versity Engineering Department’s Long-Term Hydrologic Impact Assessment (L-THIA): http://cobweb.ecn.purdue.edu/~sprawl/ LTHIA7/lthia/lthia_index.htm.Alternative PaversAlternative paver systems have been shown tional asphalt was over three times that ofto be just as effective as porous pavement the permeable pavers. In addition, they foundin removing pollutants. A study from the that pollutant concentrations in runoff fromUniversity of Washington conducted to the permeable pavers were substantially lessdetermine the long-term effectiveness of than from the conventional asphalt, as shownpermeable pavements as a stormwater in Exhibit 6.112management strategy showed significant As with other stormwater infiltration BMPs,pollutant removal rates. Researchers com­ developers must take measures to mitigatepared the effectiveness of four permeable any possible groundwater contamination atpavement types and conventional asphalt a permeable pavement site. Permeable pav­over six-years.110 They found that runoff from ing should not be used to treat stormwaterthe conventional asphalt had significantly “hotspots,” areas where land uses or activitieshigher concentrations of measured pollutants have the potential to generate highly con­(i.e. motor oil, copper, zinc) compared to the taminated runoff. These areas include: com­alternative paver surfaces. Concentrations of mercial nurseries, auto recycling and repaircopper in runoff from alternative pavers were facilities, vehicle service and maintenanceroughly 80 percent lower than those found areas, fueling stations, high-use commercialin the runoff from conventional asphalt, and parking lots, and marinas.113zinc concentrations were at least 40 percent CHAPTER 5—Alternative Parking Surface Materials 28
  • 32. EXHIBIT 6: STUDY EXAMPLE: STORMWATER RUNOFF COMPARISON INJORDAN COVE, CT Conventional Asphalt Permeable Pavement Pollutant (mg/l) (mg/l) TSS 47.8 15.8 NO2-N 0.6 0.2 NH3-N 0.18 0.05 TP 0.244 0.162 Cu 18 6 Pb 6 2 Zn 87 25 Source: Hinman, C., (2005), Low Impact Development Technical Guidance Manual for Puget Sound, Puget Sound Action Team, publication number PSAT 05-03: www.psat.wa.gov/Publications/LID_tech_manual05/lid_index.htm.COST CONSIDERATIONS percent more than conventional asphalt pav­ ing.114 Finally, Cahill Associates maintains thatThe costs for permeable pavement systems the cost of a porous pavement installation isvary depending on site specifications and the roughly the same as the cost of a convention-type of system being used. In general, the al asphalt parking lot.115 The costs for alterna­cost to install alternative pavers or porous tive pavers are more difficult to estimate, aspavements alone are higher than conven­ they fluctuate widely depending on type andtional asphalt paving, which costs between manufacturer.116 In general, larger parking$0.50 to $1.00 per square-foot. Sources dis- lots utilizing alternative pavers will incur aagree on the average initial costs for perme­ lower overall unit cost per space.able pavement. Exhibit 7 provides an initialcost comparison of pavement options from The overall cost-effectiveness of perme­the NY State Stormwater Design Manual. able pavement can only be fully assessed byHowever, another source notes that porous considering its typical use in concert withasphalt, with additives, costs from 10 to 20 other stormwater BMPs. Specifically, the cost-EXHIBIT 7: PARKING SURFACE INITIAL COST COMPARISON CHART Pavement Type Cost per Ft2 (Installed) Conventional Asphalt $0.50 to $1.00 Permeable Concrete $1.50 to $5.75 Grass/Gravel Pavers $2.00 to $6.50 Interlocking Concrete Blocks $5.00 to $10.00 Source adapted from New York State, New York State Stormwater Design Manual: www.rpi.edu/~kilduff/Stormwater/ permpaving1.pdf. Green Parking Lot Resource Guide—February 2008 29
  • 33. competitive nature of permeable pavement the need for land-intensive BMPs such as drysystems lies in their success when combined extended detention or wet retention ponds.with other BMPs or subsurface drainage This fact produces additional cost advantagesto create a well-designed and sustainable for permeable pavement over conventionalstormwater management system. Prop­ asphalt in locations with high land prices.118erly designing and installing such a system Maintenance costs should also be factored inrequires a high level of labor and expertise, when considering the costs of a permeableas well as material costs, including excavation paving system. If not designed and main­for deep underlying stone bed and the use of tained properly, porous pavement’s effectivegeotextile fabric. However, these higher ini­ lifespan may be shortened due to potentiallytial costs are offset by reductions in the need high risks of clogging.119 Some studies sug­for expensive traditional “hard” stormwater gest that the cost of vacuum sweeping on amanagement of pipes, gutters, and drains new permeable lot may be considerable if therelative to parking lots made of conventional landowner does not already perform vacuumasphalt pavement. When these savings are sweeping operations. However, one studyincorporated, overall project costs are often estimates the annual maintenance cost for areduced.117 Also, when used in combination porous pavement parking lot at $200 per acrewith other smaller techniques, such as biore­ annually, which includes regular inspections,tention cells, vegetated swales, or vegetated as well as jet hosing and vacuum sweeping.120filter strips, permeable pavement reduces CHAPTER 5—Alternative Parking Surface Materials 30
  • 34. CASE STUDY 2: PARKING SURFACE ALTERNATIVESHEIFER INTERNATIONAL, LITTLE ROCK, ARKANSASIn 2006, Heifer International, a non-profit sus­tainable community development organiza­tion located in Little Rock, Arkansas, designedan environmentally-friendly parking plaza tocomplement their new green building head­quarters. A first of its kind in Arkansas, thisproject serves as a model for other organiza­tions considering a green parking lot. Heifer’sparking plaza encompasses numerous greenparking lot techniques including the use ofmore sustainable materials to minimize im­pervious surface, reduce runoff, reduce virgin Heifer International’s World Headquarters: a green building with a greenwater use, and incorporate recycled content. parking lot.Heifer evaluated a variety of paving options • Gravel Pave system—Used for the park­when selecting materials for their green ing stalls, thirty thousand square feet ofparking lot. Unlike a conventional lot, which Heifer’s parking plaza are covered by amost likely would be constructed primarily gravel pave system. The stalls are construct-of asphalt, Heifer chose three types of paving ed using 100 percent recycled materialmaterials that provide environmental ben­ (90 percent post-industrial and 10 percentefits over asphalt. post-consumer). At a unit cost of $4.75 per square foot, this gravel pave portion of the• Concrete—The high traffic aisles and lot cost a total of $142,500. Maintenance driveway of the Heifer lot are paved with is minimal, requiring roughly eight hours a concrete rather than asphalt. Overall, it month at a cost of $160 per month. covers an 86,000 square-foot area, at a cost of $5.75 per square foot, or $494,500. • Brick pavers—Recycled brick pavers The concrete base contains 90 percent were used to form a decorative driveway recycled cement and its top layer is made centerpiece, and cover the smallest part of of locally produced concrete.121 Because it the lot (2,500 ft2) at a total cost of $34,418. is a light colored and highly reflective sur- Heifer minimized the cost for the pav­ face, concrete helps minimize heat island ers by reusing bricks from buildings that effect (HIE) at the Heifer site. Coupled with previously occupied the site. Heifer em- the extreme humidity in the Little Rock ployees also volunteered to help clean a region where Heifer is located, this HIE can number of the bricks so they could be re- be stifling. However the use of concrete used. The total cost for the pavers includes for paving has been shown to produce a additional labor, beyond the volunteer 20ºF reduction in surface temperatures hours, to clean bricks and construct the compared to asphalt.122 centerpiece. Heifer has yet to incur any maintenance costs for this area. Green Parking Lot Resource Guide—February 2008 31
  • 35. All of the parking lot materials used in the net increase in emissions or resource use. ForHeifer lot were purchased from local deal­ instance, Heifer’s green parking lot used moreers within 500 miles of the site, supporting water than an asphalt parking lot would havethe local economy and reducing emissions because of the greater water inputs requiredassociated with transportation of purchased in the recycling of concrete pavement com­materials. pared to the production of asphalt pavement.UPSTREAM BENEFITS By applying estimates of the economic value of reduced human health and ecologicalUpstream environmental benefits were real­ impacts from avoiding emissions, theseized through Heifer’s use of recycled concrete upstream benefits were then monetized.and other recycled materials, instead of using Reliable estimates of economic value are notvirgin asphalt, in the construction of their lot. available for carbon dioxide (CO2) emissions.These benefits include reduced air emissions However, by applying estimates for the value(associated with the production of asphalt), of reducing sulfur dioxide (SO2) and particu­reduced transportation emissions (from pur- late matter (PM10) emissions, a range of mon-EXHIBIT 8: UPSTREAM BENEFITS OF THE HEIFER PARKING LOT124 Energy Water Use Tons Hazardous Waste (MMBtu) (gallons) CO2 NOX PM10 SO2 Generated 668.3 -116 20.9 -0.89 0.72 25.3 20.7chasing locally produced materials), reduced etary values related to Heifer’s reductions canenergy use, and reduced hazardous waste be shown (see Exhibit 9).125generation related to the production of virginmaterials. Heifer’s goal in building its parking plaza was to minimize impacts to the environmentModeling was used to estimate any upstream while handling a large volume of site traffic.benefits from the construction of Heifer’slot.123 The resulting analysis (see Exhibit 8) A more detailed case study of Heifer Inter­shows a clear overall positive net benefit national’s green parking lot can be foundfrom the construction of Heifer’s lot, although on the U.S. EPA’s Web site at www.epa.gov/results for some individual metrics indicate a earth1r6/6sf/bfpages/bfheifer.html.EXHIBIT 9: VALUE OF UPSTREAM AIR EMISSIONS BENEFITS FOR HEIFER LOT Monetized Upstream Benefit Air Emission Low High SO2 $43,044 $455,760 PM10 $7,170 $71,700 CHAPTER 5—Alternative Parking Surface Materials 32
  • 36. CASE STUDY 3: PARKING SURFACE ALTERNATIVES UNIVERSITY OF RHODE ISLAND, KINGSTON, RHODE ISLAND126 OVERVIEW In 2002 and 2003, the University of Rhode (URI) constructed two parking lots at their Kingston, Rhode Island campus to meet parking demands from new University development and commuting students. The parking lots were located within the town’s groundwater protection overlay district, the University’s wellhead protection area, and also within the Pawcatuck sole source aquifer. These lots would increase parking capacity by 1,000 spaces, spread over seven acres of land (see areas highlighted in red in Photo 1). Rainwater infiltrates the porous asphalt (left), but accumulates on adjacent road paved with conventional material (right). However, because the lots were located in an ecologically sensitive area already covered by In addition, project managers were also an estimated thirty percent impervious sur­ interested in avoiding any potential impacts face, the University desired an environmen­ to groundwater supplies.127 The University tally protective option than would combat determined that a permeable asphalt surface stormwater issues more effectively than con­ would help control runoff quantities as well ventional paving surfaces. The University’s as potentially limit pollutants entering sur­ main stormwater concern was to decrease face and groundwater supplies. runoff quantities to protect a nearby stream In addition to using permeable asphalt, considered impaired due to low water flows. landscaped islands were designed as biofil­ tration areas to provide a secondary route of infiltration during large storm events or pavement clogging. Also, the University took precautions to avoid clogging the permeable pavement by planting trees and grass around the parking lot perimeter, which limits wind­ blown dust from nearby agricultural areas and controls soil erosion. An emergency spill­ way was also constructed to direct overflow to recharge beds in the extremely unlikely event that the permeable asphalt and biofil­ tration areas both clog.URI’s permeable parking lots - The two original permeable asphalt parkinglots built in 2002 and 2003 are outlined in red. The 2005 parking lot exten­sion is outlined in green. Green Parking Lot Resource Guide—February 2008 33
  • 37. COST CONSIDERATIONS meable asphalt layer was not infiltrating properly because the binder had becomeThe total construction costs for the two park­ separated from the asphalt. Projecting lots was just over $3 million, or $3,000 per consultants recommended an improvedparking space, which is considered compara­ polymer mixture, new to the market, thatble to conventional parking lots of equal size. would prevent the separation and elimi­Costs included site preparation, barn demoli­ nate the infiltration problem.tion, materials, lighting, drainage, landscap­ing, monitoring wells, post-construction in­ • Pollutant removalspections, and design fees that were roughly The University is currently monitoring theten percent of the total cost. URI’s costs pollutant removal and runoff level fromincluded non-typical items such as removal the lots. They found a 90 percent retentionof stone masonry walls, and installation of of zinc and copper. However, the perme­security cameras and emergency telephones. able asphalt was not as effective in captur­Without these additions, installation would ing other pollutants, including organichave been cheaper. On average, installation pollutant such as PAHs, and inorganicruns between $2,200 and $2,750 for porous pollutant such as nitrate and phosphate.pavements such as permeable asphalt. This is due to clogging, as well as the type of geotextile fabric used in the project,INCORPORATING LESSONS LEARNED which was found to prevent an even flowIn the few year since they constructed the of water into the subsurface.two permeable asphalt parking lots, URI has In the summer of 2005, the larger of the twobeen monitoring their success in managing permeable asphalt parking lots was expand­and filtering stormwater. As a new technolo­ ed by another 800 spaces. When planninggy, they noted several areas for improvement. this expansion, the University was able to• Clogging incorporate improvements to their design based on lessons learned from the original Overall, these parking lots were successful two parking lots. Design changes included from a hydrological perspective. However, use of the polymer mixture to prevent sepa­ some clogging was observed in the higher ration of the binder, fewer and wider biofiltra­ traffic areas of the lot. Clogging also tion islands, and curb cuts for water entry to occurred in one corner of the lot where the biofiltration islands. Maintenance issues plowed snow was stockpiled during the regarding snow removal were also addressed. winter, which reduced infiltration due to sediment build-up. This is an indication Further information on the University of that plow blades were not raised to the Rhode Island’s permeable asphalt parking required height, an issue that also caused lots can be found at www.uri.edu/ce/wq/ surface defects to the lot. NEMO/Publications. Excavation of the lot during construction of a sidewalk also revealed that the per- CHAPTER 5—Alternative Parking Surface Materials 34
  • 38. CHAPTER 6LANDSCAPING AND IRRIGATIONI n the majority of parking lots across • Reduce damage from stormwater, and the country, landscaping does not vary • Improve habitat and increase according to geographic location. It is biodiversity.130typically designed using conventional turfgrass, such as Kentucky Bluegrass, and com­ This chapter provides an overview of naturalmon popular ornamental plantings. However, landscaping and irrigation techniques suitablebecause these plants are often not native for green parking lots. It describes the differ­to areas where they are being used, regu­ ence in irrigation and maintenance require­lar maintenance is required to keep them ments for natural landscaping compared tohealthy. Sustaining this greenery requires conventional landscaping, the benefits ofirrigation systems and potable water use to natural landscaping, and cost considerations.supplement rainfall, chemical applications ofpesticides and fertilizers, and ongoing lawn OVERVIEW OF NATURALmaintenance (e.g., mowing).128 Irrigation and LANDSCAPING AND IRRIGATIONchemical use contribute to degradation of Natural Landscapingwater quality and aquatic habitat in receiving Considerations and Vegetationwaters, decreased water supplies, increased Conservationstormwater runoff, declining biodiversity, andair pollution. Mowing and other maintenance Natural landscape design, sometimesactivities are a significant air pollution con­ referred to as native or sustainable landscap­cern; for example, in one hour a lawn mower ing, uses plant species indigenous to a regionemits as much pollution as a car driving 350 pre-European settlement. Because thesemiles.129 With proper planning, landowners native plant species have evolved in the localcan avoid these impacts by utilizing “natural environment, maintaining them is relativelylandscaping” approaches. easy—they are more resistant to local pests, they are better suited to survive on naturalNatural landscaping involves creating a low- rainfall, and they are adapted to live in localmaintenance landscape in and around a park­ soil types. These heartier plants also provideing lot using native plants and water-efficient habitat for local native wildlife species thatirrigation techniques. A vital component of they co-evolved with—a symbiotic relation­green parking lots, natural landscaping can: ship that is the foundation for our native• Reduce landscape installation and main­ ecosystems and biodiversity.131 tenance costs, A feasible and intelligent approach for most• Limit harmful chemical pollution (i.e. development sites, natural landscaping also pesticides, fertilizers), supports sustainable development strategies such as Low Impact Development (LID) and• Reduce potable water use and pollutant Smart Growth, and is a vital component to air emissions, Green Parking Lot Resource Guide—February 2008 35
  • 39. many stormwater Best Management Practic­ amount of turf to only those areas necessaryes (BMPs). For example, some of the bioreten­ for practical purposes.tion approaches described in Chapter 4, suchas vegetated swales and rain gardens, are Irrigation Requirements forbased on natural systems and intended to Natural Landscapingfunction as they would have in absence of de­ As mentioned above, a key difference be­velopment.132 BMPs rely on native plants for tween conventional and natural landscapingadded efficiency in retention, infiltration and is water use requirements. Conventional land­transpiration, and cleansing.133 See Chapter 4 scaping consumes large quantities of waterfor more information on BMPs. to sustain non-native species, which typicallyDevelopers must take a number of factors cannot withstand local conditions as well asinto consideration when planning and de­ native varieties. For instance, the popular turfsigning natural landscaping. Natural land­ species Kentucky Bluegrass typically requiresscaping involves more than new plantings of in excess of 40 inches a year of precipitationnative species; an important step to consider to thrive.136 This is above annual rainfall levelsbefore construction even begins is retaining for many states, particularly in Western partsas much of the existing native landscaping as of the country. According to the U.S. Depart­possible at a site. By preserving existing vege­ ment of Energy, native and other climatetation, developers can minimize the need for appropriate landscaping can reduce irriga­new landscaping, and limit site disturbance. tion water use by at least 50 percent.137 ThisIf the location of existing vegetation is not was the case for Heifer International’s greensuitable, it is preferable to relocate it on-site parking lot (see case study at the end of therather than dispose of it during construction. chapter), where the landscaping requires noAnother option is to remove native plants additional irrigation under normal conditions.from sites scheduled for construction; some Typically, native plants require irrigation onlyvolunteer organizations will retrieve plants when they first take root.138from construction sites to later replant at In most cases the water source for conven­other locations.134 tional irrigation is the same potable drinkingLandscaping choices should be compatible water used inside buildings, applied gener­with individual site characteristics including ously by inefficient spray irrigation systems.topography, soil, drainage patterns, and sun In many developments, these irrigationexposure.135 It is important to select site- systems are programmed to turn on auto­appropriate plants when bringing native matically, and do not take fluctuating rainfalllandscaping in from off-site; as such, consult­ amounts or soil moisture into account. Ining a local landscape designer with native contrast, natural landscaping fosters smarterplant knowledge is recommended. irrigation practices, through water-efficient planting, mulching, rainwater harvesting, andAlthough native landscaping is feasible for water-efficient irrigation technology.most sites, in cases where it is not feasible oris otherwise not utilized, developers should Efficient Irrigation Technology139choose low-water use plants and limit the Efficient irrigation technology is essential to CHAPTER 6—Landscaping and Irrigation 36
  • 40. conserving water, and a number of options properly schedule sprinkler use; and zoningare available to help landowners save money systems that focus on the water needs ofthrough less wasteful practices. A fundamental each plant grouping.143problem of conventional irrigation is over-watering. Not only does over-watering reduce Efficient Irrigation Procedureswater supplies and increase runoff amounts, The basic practices of landscaping, includingbut it also can result in plant diseases such as plant layout and irrigation scheduling, arefungus, and in the excessive growth of weeds also vital to natural landscaping.and pests. Over-watering also results in weakplant growth that in turn precipitates the need • Seasonal influences—When scheduling for additional maintenance.140 irrigation, it is important to understand the seasonal variations and changingIf landscaping is watered at a less frequent weather conditions. In some regions ofand more appropriate rate, plants will the country, water requirements can varydevelop deeper roots and become healthier considerably depending on the season.overall.141 Recommended alternatives to thetraditional sprinkler method, which often • Time of day—It is also important toover-waters landscaping, include soaker consider the time of day when irrigationhose, drip, or subsurface irrigation. is taking place. Watering is more effective during early morning hours or early inDrip irrigation in particular is a water conser­ the evening, when temperature and windvation technology that is gaining popularity. speeds are typically lower, thus reducingUsed in the past to conserve water in arid evaporation water loss.144areas, its use has expanded with heightenedawareness of resource conservation and • Weather conditions—Weather condi­ environmental sustainability. Drip irrigation tions and weather forecasts should beis a system of tubing with small holes that incorporated into irrigation planning. Useallows water to drip out onto the root zone of system override devices when it is raining,plants, providing more targeted and uniform and try to program irrigation to avoid daysirrigation. Such systems can run on recycled when rain is forecast. In addition, wateringwater, and can be an option for temporary on windy days means that the water mayuse to establish native plants. Should a sprin­ not reach targeted areas or may be blownkler system be selected, low-flow sprinkler onto paved areas.systems that release water slowly and close Mulching helps keep moisture in the soil andto the ground are preferable to sprinklers allows rainfall and irrigation water to betterthat emit mist, which easily evaporates.142 penetrate the root system. Landscapers rec­Other examples of efficient irrigation tech­ ommend that roughly three inches of organicnology include soil tensiometers, which de­ mulch be applied over trees and shrubs roots,termine when the soil is dry and gauge water and in plant beds. This also helps moderateneeds; rain or moisture sensors that can shut soil temperature, minimize evaporation, andoff automated irrigation systems during rain; reduce erosion and weeds. In addition, whenirrigation timers with manual overrides to mulch decomposes, it increases the organic Green Parking Lot Resource Guide—February 2008 37
  • 41. content of the soil.145 Lastly, the layout of are established. The primary environmentalnatural landscaping is important to efficient benefits of incorporating natural landscapingirrigation. By grouping plants with similar wa­ into parking lots are described below.ter needs together, a dedicated irrigation lineor valve can be used to apply the appropriate Decreased Non-Point Sourceamount of water at the correct frequency.146 Pollution The U.S. EPA’s 2004 Conference on Landscap­Rainwater Harvesting and ing with Native Plants found that landscapingRecycled Water147 with native plants may help reduce non-pointTo conserve water, natural landscaping also source pollution reduction in the followingincludes the use of collected rainwater or ways:recycled wastewater for irrigation. These are • The need for fertilizers and pesticides toboth preferred alternatives to using potable maintain conventional landscapes (i.e. turfwater, which is a finite natural resource. grass) can often be eliminated with nativeMoreover, potable water treatment man­ vegetation.agement requires energy use for desalting,pumping, pressurizing, groundwater extrac­ • Through direct uptake of nutrients, nativetion, conveyance, and treatment.148 plants may reduce the impact of fertilizer elements (i.e. nitrogen and phosphorous)Reuse of rainwater is a good option because it that would otherwise contaminate wateris “not chlorinated and is mildly acidic, which sources.152 Fertilizer contributes to ap­helps plants take up important minerals.”149 proximately 80 percent of nutrient loadsContainers, such as cisterns or rain barrels, can in the springtime.153be used to collect and store water from roofcatchment areas. Rainwater can also be har­ • Native plants may create sub-soil condi­vested from an underground storage system, tions that help reduce levels of nitratewhich is then pumped to the irrigation system. entering water supplies via facilitation.154In addition to rainwater harvesting, certain • Native plants are capable of filtering othertypes of non-potable water, if treated properly, impurities from stormwater runoff, such ascan be used as well for irrigation. For instance, salt and automobile deposits (i.e., oil).water recycled from wastewater, also knownas irrigation quality or reclaimed water, can be The over-application of fertilizers andtreated and, although not suitable for drinking, pesticides can lead to other detrimentalis very useful for irrigation. environmental impacts beyond non-point source pollution. Less than 10 percent ofENVIRONMENTAL BENEFITS OF insects actually harm plants, yet inappropri­USING NATURAL LANDSCAPING AND ate pesticide use harms non-target insectsASSOCIATED IRRIGATION that are beneficial to the environment, it canCompared to conventional landscaping de­ also harm wildlife.155 Overuse of fertilizers cansign, natural landscaping can offer substan­ exacerbate insect diseases as well as promotetial environmental benefits by minimizing ir­ unnecessary plant growth, which in turnrigation and maintenance needs once plants increases maintenance needs.156 CHAPTER 6—Landscaping and Irrigation 38
  • 42. An innovative natural landscaping approach industrial developments. Xeriscaping is ato pest management, called “integrated pest collection of sustainable landscaping designmanagement,” is a low chemical approach principles incorporating the use of nativeto landscape maintenance. Rather than or other water efficient plants.160 Anotheremphasizing the use of harsh chemicals, it example is Las Vegas, Nevada, where a cityincorporates materials composed of natu­ ordinance limits the amount of turf on newrally occurring compounds, and promotes landscapes to no more than 50 percent.161natural landscaping design and maintenancepractices. According to the U.S. Department Reduced Air Pollutionof Energy, integrated past management Reduced maintenance from native landscap­“demonstrably creates a better environment ing can improve air quality:for plants as time passes.”157 • Locally, through reduced smog and airWater Conservation toxics;Water conservation is one of the primary • Regionally, through the reduction of acidbenefits of a natural landscaping approach. rain caused by nitrogen oxide (NOX) andUsing native plants in landscaping helps con­ sulfur dioxide (SO2) emissions; andserve water because once established, native • Globally, by combating greenhouse gasplants often do not need supplemental wa­ emissions.162tering beyond local rainfall amounts.158 Thisis not the case for conventional landscaping It is estimated that for every 10 days ofwhere, for instance, the watering schedule maintenance required for a traditional turffor turf landscaping is estimated at 1 inch of landscape area, a natural designed area onlywater over the entire area, for 30 applications requires one day.163 This greatly minimizesper year.159 The water conservation ben­ the need to run maintenance equipmentefits become even greater when harvested such as lawn mowers, leaf blowers, and weedrainwater or recycled wastewater are used for wackers, which typically run on gasoline andirrigation rather than potable water. emit carbon dioxide (CO2) and other air pol­ lutants. For example, the use of lawn equip­With water shortages seen in many commu­ ment in just the Chicago region produces 50nities throughout the country, native land­ tons of volatile organic compounds (VOCs)scaping is a sensible approach to preserving every day in the summertime.164water. Local governments in states such asNorth Carolina, Texas, and California have Reduced Erosion andadopted natural landscaping ordinances, Sedimentationinnovative rate structures, and wastewaterreuse plans to address water shortages. For Natural landscaping in parking lots also helpsexample, Santa Monica, California requires minimize the erosion and sedimentationthe use of a particular water-efficient land­ impacts of development. The deep root sys­scaping strategy called “xeriscaping” for all tems of native plants stabilize soils and helplandscapes installed in new commercial and prevent wind and water erosion along deten- Green Parking Lot Resource Guide—February 2008 39
  • 43. tion basin edges and streambanks.165 This is the variety of life. Defined as “the variabilityparticularly true of plants that were on-site among living organisms from all sources in­pre-construction and preserved. Native plant­ cluding…terrestrial, marine and other aquat­ings can also help remove sediments from ic ecosystems, and the ecological complexesrunoff through filtration, again helping to of which they are part,” biodiversity is thepreserve water quality and aquatic habitat.166 diversity within species, between species and of ecosystems.170 Conventional landscapingReduced Heat Island Effect can negatively affect biodiversity of species atAs discussed in Chapter 1, heat island effect various levels when native plants species are(HIE) occurs in urban areas when the com­ replaced with homogenous, exotic, ornamen­bined effect of heat-absorbing surfaces, such tal species. This “monoculture” limits genetic,as asphalt, leads to higher air and surface species, and ecosystem diversity.temperatures. HIE can increase temperatures The diversity of our flora and fauna is an in­between 2 to 8ºF on average during the sum­ valuable resource from an environmental andmer.167 The greatest temperature increases are human health perspective. Ecosystems thattypically seen in areas with less vegetation contain a diversity of native plant and animaland high amounts of urban development. species better provide “ecosystem services”Vegetation, especially trees, can help reduce to humans, such as water and air purifica­HIE, by providing shading to paved areas. For tion.171 Native plants also support a healthierexample, a NASA study on the Madison Square environment by providing food and shelterMall in Huntsville, Alabama found that the for wildlife. In addition, some exotic plantstemperature in the middle of the parking lot can become invasive species, smothering na­on a summer day was 120ºF, while the temper­ tive plants or overrunning their habitat, againature at a small tree island in the parking lot affecting the plant population and the chainwas only 89ºF. For every additional tree canopy of species dependent upon it.cover temperatures can often be reduced by1º F. Vegetation can also indirectly cool parking COST EFFECTIVENESS OF USINGareas though transpiration, and soil also cools NATURAL LANDSCAPINGthrough water evaporation.168 A common perception is that natural land­Because of its cooling capabilities, landscap­ scaping is more costly than conventionaling also plays a role in reducing building landscaping. However, cost/benefit modelingenergy use and associated CO2 air emissions. and case studies have shown that naturalHotter temperatures from HIE can lead to landscaping can be more cost-effective in theincreased energy demand to cool buildings long term—for both communities and landlocated near heat absorbing surfaces such as owners.172 Reduced costs result from de­parking lots. By reducing HIE, it is estimated creased energy use, forestalled infrastructurethat plantings close to buildings can reduce upgrades, and lower land maintenance costs.air conditioning costs by 5 to 20 percent.169 For example, one study found that landown­ ers can save between $270 and $640 dollarsEnhanced Biodiversity per acre by preserving the native landscapeBiological diversity, or biodiversity, is literally of their open land instead of creating a CHAPTER 6—Landscaping and Irrigation 40
  • 44. conventional, tuft-based, landscape. Savings sustainable landscaping versus conventional can also be realized during the installation landscaping.of natural landscaping. It can be between By using a simple payback calculation, the$4,400 and $8,850 less expensive per acre for above example demonstrates that the coststhe installation of natural landscaping than for the native landscaping are recoveredfor turf grass.173 within the first year because of significantlyOf all the potential sources of costs savings lower maintenance costs.174 As a generalfrom natural landscaping, reduced main­ rule, annual maintenance costs for naturaltenance leads to the greatest savings. As landscaping are approximately 10 percent ofdiscussed throughout this chapter, natural conventional landscaping.175landscaping requires less maintenance and Other economic benefits of natural landscap­labor expenditures, such as less irrigation, ing include local government and commu­mowing, weeding, and fertilizer/pesticide ap­ nity cost-savings from avoided infrastructureplication. Decreased irrigation is a major part and/or water supply upgrades associatedof these savings, as is seen in the case of Heifer with stormwater runoff, which can lead toInternational (see following case study). flooding, pollution, groundwater rechargeEXHIBIT 10: INSTALLATION, MAINTENANCE, AND INCREMENTAL COSTSOFSUSTAINABLE VS. CONVENTIONAL LANDSCAPE AREA(LANDSCAPE AREA = 8,000 SQUARE FEET) Site Design and Total Maintenance Installation Implementation ($/year) Native Planting $3,673 $184 $272 Traditional Turf $1,224 $61 $3,318 Cost Difference (Native $2,449 $123 -$3,046 minus Traditional) Source: Estimate of landscape area includes 1-acre (43,560 ft2) lot with 25,200 square foot parking area and 10,082 ft2 building footprint. For more information see U.S. Department of Energy, (2003), The Business Case for Sustainable Design in Federal Facilities—Appendix D, http://www1.eere.energy.gov/femp/sustainable/sustainable_federalfacilities.html.An example of the overall maintenance sav- deficits, and damage to stream ecology.176ings, including water savings, is presented in Reduced infrastructure burden is discussedthe following comparison produced by the in Chapter 7. In addition, communities oftenU.S. Department of Energy. In this example, pay to eradicate algae blooms caused by ex-costs are compared for a one-acre site (in- cess fertilizing, a cost avoided by widespreadcluding a 50 to 75 space parking area) using use of native landscaping.177 Green Parking Lot Resource Guide—February 2008 41
  • 45. CASE STUDY 4: LANDSCAPING AND IRRIGATIONHEIFER INTERNATIONAL, LITTLE ROCK, ARKANSASIn 2006, Heifer International, a non-profit sus­tainable community development organiza­tion located in Little Rock, Arkansas, designedan environmentally-friendly parking plaza tocomplement their new green building head­quarters. A first of its kind in Arkansas, thisproject serves as a model for other organiza­tions considering utilizing green parking lottechniques. One highlight is Heifer’s use ofnative landscaping and irrigation methods,which reduce potable water use and providehabitat for local species. By using native landscaping around its parking lot, Heifer International supportsThe innovative landscaping and irrigation the local ecosystem and conserves water.surrounding Heifer International’s parking lot thirds reduction in water demand comparedprovides a variety of environmental benefits. to a conventional parking lot scenario withThe grasses, plants, trees, and wildflowers standard landscaping. By using recycled wa­used throughout much of the site are indig­ ter, native plants, and water conserving irriga­enous, and do not require pesticides. They tion, Heifer is conserving 520,000 gallons ofalso offer food and shelter to native wildlife, potable water, and saving $65,343, annually.and help create a more visually pleasingaesthetic. Under natural rainfall events, the Currently Heifer has six irrigation zones, fourspecies planted in the lot should be able to that use drip irrigation and two that use con-sustain themselves with little irrigation. In ventional sprinkler irrigation.fact, in a normal rainfall year, the landscape • Drip Irrigation—Heifer has four drip-will require irrigation only once a week. zones for irrigating native trees and shrubsBecause Heifer used a combination of native on the site. Each releases 0.9 gallons perseeding and sod, their parking lot requires hour, using a total of approximately 2,000less irrigation than a conventional lot using gallons of water per week. The total costall sod and non-native landscaping. In a typi­ for the drip irrigation system was $79,000.cal, non-drought year, Heifer’s closed loop • Sprinkler Irrigation—Heifer has twostormwater system will provide 100 percent spray-zones for irrigating the sod portionsof the water necessary to irrigate vegeta­ of the lot. These conventional pop-uption throughout the lot, eliminating use of spray heads produce approximately 25municipal water for this purpose. Heifer uses gallons of water per minute per zone, us-approximately 5,000 gallons of irrigation ing a total of approximately 3,000 gallonswater per week, or 260,000 gallons annually, of water per week. The total cost for theto irrigate its grounds. According to their sprinkler irrigation system was $42,000.landscape architect, this represents a two- CHAPTER 6—Landscaping and Irrigation 42
  • 46. Heifer supported this sustainable landscap- aesthetics of the parking lot, reduced heat ing by amending the soil with compost, island effect, and supported wildlife habitat.which helps increase nutrient retention, For more information on Heifer Internation­decrease irrigation needs, and improve soil al’s green parking lot, including their sustain­and plant health. They went beyond the City able landscaping techniques, please vist theof Little Rock’s parking ordinance by planting U.S. EPA’s green building Web site at: www.80 trees (63 more than the city requires) and epa.gov/earth1r6/6sf/bfpages/bfheifer.html.landscaped a far larger area within the lotthan required. These actions improved the Green Parking Lot Resource Guide—February 2008 43
  • 47. CHAPTER 7REDUCED INFRASTRUCTURE BURDENT his resource guide has explored • The Environmental Council of States how components of a green park­ (ECOS) ing lot, including stormwater best In 2007, ECOS’ Green Infrastructuremanagement practices, innovative planning Resolution (07-10) encouraged the usepolicies, and native landscaping, can be of green infrastructure to mitigate sewerused in combination to sustainably manage overflows and protect public health andstormwater at individual sites. The ultimate the environment.179potential of these practices, however, lies inscaling them up to the neighborhood, town, • The U.S. Conference of Mayorsor regional level, to reduce burden on the A 2006 Green Infrastructure Resolutioncurrent stormwater management infrastruc­ from the U.S. Conference of Mayors recog­ture, and plan for sustainable future growth. nized that “green infrastructure naturallyThis “green infrastructure” approach encom­ manages stormwater, reduces floodingpasses planning for parking lots, housing risk and improves air and water quality,developments, roads, and other stormwater thus performing many of the same func­related infrastructure. Defined by the EPA tions as traditional building infrastructure,as techniques that “utilize natural systems, often at a fraction of the cost.”180or engineered systems that mimic naturallandscapes, to capture, cleanse, and reduce The need for scaling up green infrastructurestormwater runoff using plants, soils, and is pressing. It is estimated that nearly 25microbes,” green infrastructure is an approach million acres of impervious surface cover thethat is being endorsed by U.S. federal, state continental United States, and that approxi­and local government entities, including: mately 70 million acres of land will be newly developed in the United States by the year• The U.S. Environmental Protection 2025. By 2030, 50 percent of the built envi­ Agency (EPA) and national stakeholders ronment will have been constructed since In 2007, EPA and four major national 2000.181 Such growth will increase strain on groups (National Association of Clean Wa­ existing municipal stormwater management ter Agencies, Natural Resources Defense systems by adding more impervious surface Council, Low Impact Development Center, area and higher volumes of runoff. In many and Association of State and Interstate areas of the country, these systems are al­ Water Pollution Control Administrators) ready critically strained and are saddled with signed an agreement to promote the use a backlog of deferred maintenance. A green of green infrastructure to reduce stormwa­ infrastructure approach can minimize runoff ter runoff and sewer overflows.178 volumes, and reduce the combined burden on municipal stormwater and wastewater infrastructures.182 CHAPTER 7—Reduced Infrastructure Burden 44
  • 48. REGIONAL STORMWATER AND major component.186 For example, Portland,WASTEWATER IMPACTS Oregon is a leader in integrating innovative environmental technology into its city plan­As outlined in previous chapters, stormwater ning and policies. The city’s building codesrunoff can cause a number of serious prob­ require on-site stormwater managementlems including water pollution, flooding, for all new construction projects, and theirgroundwater recharge deficits, and damage stormwater manual encourages the use ofto stream ecology.183 These impacts translate best management practices.187 A number ofinto high costs to municipalities, and using smaller cities and towns have also startedconventional methods alone to control them to embrace green infrastructure planning.can be an expensive use of public funds. This In Kansas City, Missouri, planners are imple­is particularly true in regions of the country menting the 10,000 Rain Garden Initiative,with older infrastructure, including the Pacific which will create 10,000 such gardens toNorthwest, Northeast, and Great Lakes. In help the city achieve its 20-year Wet Weatherthese regions, stormwater is often channeled Solutions Program. This is one of the largestinto the same pipes as sewage (i.e., combined infrastructure projects in the city’s history.188sewers). With large areas of impervious sur­face and development, heavy rain events can COST EFFECTIVENESSpush these combined pipes beyond capacity,causing them to overflow. These “combined Looking at stormwater management fromsewer overflows,” or CSOs, result in large a regional or watershed scale is importantamounts of untreated waste overflowing into when considering costs. The piping, channels,waterways, making them a primary source of and treatment plants of a traditional storm-pollution for many water bodies. The Clean water infrastructure are expensive to build,Water Act requires that combined sewer sys­ operate, and maintain, and are not the mosttems be updated to prevent CSOs, however, effective way of controlling stormwater.189these upgrades are cost prohibitive for many The EPA’s Assistant Administrator for Watercities and towns.184 The EPA’s 2000 Clean has stated that:Watersheds Needs Survey estimates that $56 “Green infrastructure may save capitalbillion in capital investment nationally was costs associated with digging big tun­needed for CSO controls.185 nels and centralized stormwater ponds,The regional impact of stormwater runoff operations and maintenance expenses forand CSOs cannot be properly controlled by treatment plants, pipes, and other hardsporadic site-by-site controls, or large end­ infrastructure; energy costs for pumpingof-pipe conventional stormwater treatment water; and costs of wet weather treatmentalone. A coordinated, area-wide planning and repairing of stormwater and sewageeffort is required. Major cities throughout the pollution impacts, such as stream bankcountry, including Portland (Oregon), Seattle, restoration.”190Chicago, and Philadelphia, have started to Potential cost savings are important to com­invest in land use planning and infrastructure munities throughout the United States thatdevelopment with green infrastructure as a are working to comply with federal storm- Green Parking Lot Resource Guide—February 2008 45
  • 49. water management regulations. According the water body, rather than piping it directly to an 2007 report evaluating the potential into the river. They found that, at a cost ofof a major storm water minimization pro­ less than $50,000 per year, the wetlands notgram, “the use of green infrastructure can only diminished stormwater flows, but alsohelp communities meet their overall water successfully removed pollutants from runoff,resource management goals and reduce the including 80 percent of suspended solids,costs (or free up funding for other uses such 70 percent of phosphorus, and 60 percentas land purchases) of constructing and main­ of oxygen depleting compounds and heavytaining engineered infrastructure including metals. The high efficacy of the wetlandspipes and treatment systems.”191 For example, made them a cost-effective strategy forin Kane County, Illinois, researchers estimated improving the river’s water quality.194 In Port­economic benefits of downstream stormwa­ land, Oregon, the City has found that adopt­ter management through green infrastruc­ ing a variety of green infrastructure tech­ture practices implemented upstream would niques over the course of a 10 year period hassave approximately $4 million, money that avoided over 1.2 billion gallons of runoff andwould otherwise have been spent on culvert has reduced CSO events by 10 percent.195replacement or upgrades for stormwater It is clear that stormwater management mustdiversion. When both flood reduction and in­ be elevated to a key urban planning andfrastructure savings are considered, the green policy issue as local governments seek toinfrastructure practices were found to be ap­ reduce stormwater impacts cost-effectively.proximately $300-$700 less expensive per de­ Promoting green infrastructure regionally orveloped acre.192 Portland, Oregon estimates watershed-wide will help control the cumula­its Green Streets stormwater infrastructure tive impact that stormwater from multipledesign saves 40 percent in costs compared to sources has on stormwater infrastructure.conventional stormwater infrastructure (also Even in cases where green infrastructuresee Green Streets case study at the end of this investments are not more cost-effective inchapter).193 the short-term, the long-term environmentalGreen infrastructure can be a cost effective and social benefits can be quite significantreplacement or complement for other water to livability and sustainability on a regionalquality improvement strategies. For example, scale. These benefits have been exploredfor 10 years, a demonstration project in the throughout this guide, and include enhancedRouge River area of Michigan has been utiliz­ groundwater recharge, pollution prevention,ing 14 acres of wetlands (two thirds of which increased carbon sequestration, HIE mitiga­are constructed) along the river’s banks to tion, improved air quality, and increasednaturally treat stormwater before it enters green space and wildlife habitat.196 CHAPTER 7—Reduced Infrastructure Burden 46
  • 50. CASE STUDY 5: REDUCED INFRASTRUCTURE BURDENGREEN STREETS PROGRAM—PORTLAND, OREGONFor over a decade, the City of Portland,Oregon has been pursuing new approachesto stormwater management. Known for itswet weather with the third highest numberof rainy days annually in the U.S., Portlandtypically averages 37 inches of rain a year.197Approximately 66 percent of the resultingstormwater runoff comes from streets andrights of way.198 For this reason, the Citycreated “Green Streets,” a city-wide land useplanning effort for stormwater managementfocused on transportation-related develop­ment (i.e. parking lots, streets). Defining aGreen Street as “one that uses vegetated One of many rain gardens being built throughout Portland as part of the city’sfacilities to manage stormwater runoff as its Green Streets program.source,” this program is part of a concert ofinitiatives that the city is undertaking to help surface runoff through the use of infiltrationthem reach their goal of removing 60 million basins. In 2006, this project was recognizedgallons of stormwater annually by 2011.199, 200 with the national American Society of Land- scape Architects Design Award.201 By startingAlthough city officials have been promoting with demonstration projects, the City wasa green streets theme for a number of years, able to monitor results and incorporate les­in 2005 an interdisciplinary team of area sons learned into more effective stormwaterexperts, including government officials, en- designs that could be replicated on a city­gineers, planners, landscape architects, and wide scale.202watershed managers refocused the programby taking a fresh look at opportunities for its In April 2007, the Portland City Council of-implementation. This multi-disciplinary ap­ ficially endorsed the enhanced Green Streetsproach provided the breadth of knowledge program by approving an innovative storm­necessary to properly address comprehensive water management plan comprised of a reso­stormwater management, and was invalu­ lution, report, and policy. The overarchingable to successfully implementing the Green goal of this program is to “comprehensivelyStreets program. address numerous city goals for neighbor- hood livability, sustainable development,In revamping the Green Streets program, increased green spaces, stormwater manage-Portland focused on learning through dem­ ment, and groundwater protection.”203 Theonstration projects. This includes a project on city council articulated several objectives forthe Portland State University campus built achieving this goal, including a neighbor-in 2005 to treat 8,000 square-feet of street hood planning initiative, further stakeholder Green Parking Lot Resource Guide—February 2008 47
  • 51. outreach, the pursuit of more funding mecha- For more information on the Portland, nisms, and ultimately the establishment of Oregon Green Streets program, please visit even more Green Streets. As a short term the Green Streets Web site at: objective, the City is planning on developing www.portlandonline.com/BES/index.500 additional Green Street projects to ad- cfm?c=44407&.dress combined sewer overflow issues.204 CHAPTER 7—Reduced Infrastructure Burden 48
  • 52. KEY RESOURCESPLANNING RESOURCES U.S. EPA, (2006), Parking Spaces/Community Places: Finding the Balance through SmartAmerican Rivers and SmartGrowth America, Growth Solutions, EPA 231-K-06-001: (2002), Paving Our Way to Water Short­ www.epa.gov/dced/pdf/ ages: www.smartgrowthamerica.org/ EPAParkingSpaces06.pdf. DroughtSprawlReport09.pdf. U.S. EPA, (2005), Using Smart Growth Tech­Boston Metropolitan Area Planning Council, niques as Stormwater Best Management (2006), Sustainable Transportation Toolkit: Practices, EPA 231-B-05-002: Parking: http://transtoolkit.mapc.org/. www.epa.gov/livability/pdf/Center for Neighborhood Technology, (2006), sg_stormwater_BMP.pdf Paved Over: Surface Parking Lots or Op­ U.S. EPA, (1999), Parking Alternatives: Mak­ portunities for Tax—Generating Sustain­ ing Way for Urban Infill and Brownfield able Development, November 2006: Redevelopment, EPA231-K-99-001. www.cnt.org/repository/PavedOver-Final.pdf.Gibbons, J. (1999), Parking Lots—Technical STORMWATER MANAGEMENT BMP Paper #5, University of Connecticut RESOURCES Nonpoint Education for Municipal Officials Chester County, Pennsylvania Water (NEMO) program: http://nemo.uconn.edu/ Resources Compendium, (2005), Water­ tools/publications/tech_papers/ shed Primer: http://dsf.chesco.org/water/ tech_paper_5.pdf. cwp/view.asp?a=3&q=607722.Litman, T., (2006), Parking Management: Community Design and Architecture, (2005), Strategies, Evaluation and Planning, Stormwater Guidelines for Green Dense Victoria Transport Policy Institute, April 25, Redevelopment, U.S. EPA: www.epa.gov/ 2006: www.vtpi.org/park_man.pdf. dced/pdf/Stormwater_Guidelines.pdf.Maryland Governor’s Office of Smart Growth, Kloss, C. and Calarusse, C. (2006), Rooftops (2005), Driving Urban Environments: to Rivers: Green Strategies for Controlling Smart Growth Parking Best Practices: Stormwater and Combined Sewer Over­ www.smartgrowth.state.md.us. flows, Natural Resources Defense Council:Shoup, D., (2005), The High Cost of Free Park­ www.nrdc.org/water/pollution/rooftops/ ing, APA Planners Press. contents.asp.Shoup, D., (1999), The Trouble with Minimum Minnesota Pollution Control Agency, (2000), Parking Requirements, Transportation Protecting Water Quality in Urban Areas: Research Part A, Vol. 33, pgs. 549-574: www.pca.state.mn.us/water/pubs/ www.vtpi.org/shoup.pdf. sw-bmpmanual.html. Green Parking Lot Resource Guide—February 2008 49
  • 53. Muthukrishnan, S. and Selvakumar, A., (2004), Wossink, A. and Hunt, B., (2003), An Evalua­ The Use of Best Management Practices tion of the Costs and Benefits of Structural (BMPs) in Urban Watersheds, U.S. En­ Stormwater Best Management Practices vironmental Protection Agency, EPA­ in North Carolina, North Carolina State 600-R-04-184. University: www.stormwaterauthority.org/ assets/Stormwater_BMP_Factsheet%20NAHB Research Center, Inc., (2003), The -%20NC.pdf. Practice of Low Impact Development, U.S. Department of Housing and Urban Devel­ NATURAL LANDSCAPING AND opment: www.huduser.org/publications/ IRRIGATION PDF/practlowimpctdevel.pdf. City of Chicago, (2003), A Guide to Storm-U.S. EPA, (2007), National Pollutant Discharge water Best Management Practices: www. Elimination (NPDES) Fact Sheets: cdfinc.com/CDF_Resources/Chicago%20 http://cfpub.epa.gov/npdes/ GuideTo%20Stormwater%20BMP.pdf. stormwater/menuofbmps/ index.cfm?action=factsheet_ Florida Department of Environmental Protec­ results&view=specific&bmp=75. tion, (2006), Water Best Management Practices, Florida Green Lodging Program:U.S. EPA, (2007), Polluted Runoff (Nonpoint www.treeo.ufl.edu/greenlodging/content/ Source Pollution) Web site: gr_h2o.htm. www.epa.gov/owow/nps/whatis.html. Illinois Conservation Foundation and Chi­U.S. EPA, (1999), Preliminary Data Summary cago Wilderness, (2005), Changing Cost of Urban Stormwater Best Management Perceptions: An Analysis of Conserva­ Practices, EPA-821-R-99-012, August 1999: tion Development: www.cdfinc.com/ www.epa.gov/waterscience/guide/ CDF_Resources/Cost%20Analysis%20 stormwater. -%20Part%201%20-%20Report%20-%20U.S. EPA, (1999), Storm Water Municipal Tech­ with%20Exec%20 nologies, EPA-832-F-99-019: Summary.pdf. www.epa.gov/owm/mtb/mtbfact.htm. North Carolina Department of EnvironmentWashington State Department of Ecology, and Natural Resources, (2005), Water (2004), Stormwater and Economic Devel­ Efficiency: Water Management Options, opment, 04-10-001: www.ecy.wa.gov/ Division of Pollution Prevention and Envi­ pubs/0410001.pdf. ronmental Assistance: www.p2pays.org/ ref/04/03102.pdf.Weiss, P., Gulliver, J., and Erickson, A., (2007), Cost and Pollutant Removal of Storm-Wa­ Pennsylvania Department of Environmental ter Treatment Practices, Journal of Water Protection, (2006), Pennsylvania Stormwa­ Resources Planning and Management, ter Best Management Practices Manual: Volume 133, Issue 3, pp. 218-229, May/ Chapter 5, 363-0300-002: www.dep.state. June 2007. pa.us/dep/deputate/watermgt/wc/sub- jects/stormwatermanagement/BMP%20 Manual/05_Chapter_Final_Draft.pdf. Key Resources 50
  • 54. State of California Energy Commission, (2005), Cahill, T. et al, (2005), Stormwater Manage­ California’s Water-Energy Relationship, ment with Porous Pavements, Govern­ CEC-700-2005-011-SF: www.energy. ment Engineering, March-April 2005, pp. ca.gov/2005publications/CEC-700-2005-011/ 14-19: www.govengr.com/ArticlesMar05/ CEC-700-2005-011-SF.PDF. porous.pdf.U.S. Department of Energy, (2006), Federal Diyagama, T., et al., (2004), Permeable Pave­ Energy Management Program—Water ment Design Guidelines - Draft, prepared Efficiency: http://www1.eere.energy.gov/ for North Shore City, EcoWater Solutions, femp/water/water_bmp3.html. and Rodney District: www.northshorecity. govt.nz/IDSM/IDSM2006/downloads/U.S. Department of Energy, (2001), Greening PDFs/Permeable_Pavement_Design_ Federal Facilities, second edition: Guidelines_Draft_092004.pdf. www.nrel.gov/docs/fy01osti/29267.pdf. Hinman, C., (2005), Low Impact DevelopmentU.S. EPA, (2004), Conference Summary, Technical Guidance Manual for Puget Landscaping with Native Plants: Exploring Sound, Puget Sound Action Team, publi­ the Environmental, Social and Economic cation number PSAT 05-03, p. 121: Benefits Conference December 6 - 7, 2004: www.psat.wa.gov/Publications/LID_tech_ www.epa.gov/greenacres/conf12_04/ manual05/lid_index.htm. conf_knwldge.html. Idaho Department of Environmental Quality,U.S. EPA, GreenScapes Web site Resource: (2005), Storm Water Best Management www.epa.gov/greenscapes/. Practices Catalog: www.deq.idaho.gov/U.S. EPA, Landscaping with Native Plants— water/data_reports/storm_water/catalog/ Greenacres Web site Resource: www.epa. sec_3/bmps/11.pdf. gov/greenacres//index.html#Benefits. Knox County, Tennessee, (2007), StormwaterU.S. EPA, (2003), Water-Efficient Landscaping: Management Ordinance, Volume 1 and 2: www.epa.gov/npdes/pubs/ http://knoxcounty.org/stormwater/. waterefficiency.pdf. New Jersey Department of EnvironmentalWolf, K., (2004), Trees, Parking, and Green Protection, (2004), New Jersey Stormwa­ Law: Strategies for Sustainability: www.ur­ ter Best Management Practices Manual: banforestrysouth.org/Resources/Library/ www.njstormwater.org/tier_A/pdf/ Citation.2004-07-14.1757/file_name. NJ_SWBMP_9.7.pdf.ALTERNATIVE PARKING SURFACE New York State Department of Environmen­MATERIALS tal Conservation, (2003), New York State Stormwater Management Design Manual,Brattebo, B. and Booth, D., (2003), Long-term with updated sections from 2007: stormwater quantity and quality perfor­ www.dec.ny.gov/chemical/29072.html. mance of permeable pavement systems, Water Research, 37, 4368-4376, November Pennsylvania Department of Environmental 2003. Protection, (2005), Draft Pennsylvania Green Parking Lot Resource Guide—February 2008 51
  • 55. Stormwater Best Management Manual: Administrator on Water, to USEPA Regional www.dep.state.pa.us/dep/deputate/ Administrators regarding Using Green watermgt/wc/subjects/ Infrastructure to Protect Water Quality in stormwatermanagement/BMP%20 Storm Water, CSO, Non-point Source and Manual/BMP%20Manual.htm. Other Water Programs, March 5, 2007.U.S. Department of Transportation, (2007), Kloss, C. and Calarusse, C., (2006), Rooftops Stormwater Best Management Practices to Rivers: Green Strategies for Controlling in an Ultra Urban Setting: www.fhwa.dot. Stormwater and Combined Sewer Over­ gov/environment/ultraurb/uubmp3p6.htm. flows, Natural Resources Defense Council: www.nrdc.org/water/pollution/rooftops/U.S. EPA, National Pollutant Discharge Elimi­ contents.asp. nation System (NPDES)—National Menu of Stormwater Best Management Practices U.S. EPA, (2007), Green Infrastructure Pro­ (i.e. Porous Pavement Fact Sheet, Alterna­ gram—A report evaluating the concept of tive Pavers Fact Sheet): http://cfpub.epa. a major storm water minimization pro­ gov/npdes/stormwater/menuofbmps/. gram, utilizing green infrastructure and related methods, prepared by PreparedREDUCED INFRASTRUCTURE BURDEN by Metropolitan Sewer District of GreaterCenter for Neighborhood Technology, (2007), Cincinnati et al: www.msdgc.org/ Green Infrastructure Performance: www. downloads/wetweather/greenreport/ cnt.org/repository/BMP-Performance.pdf. Files/Green_Report.pdf.City of Portland, Oregon Green Streets Program: U.S. EPA, (2007), National Pollutant Discharge Elimination System (NPDES): Environmen­ Green Streets Program Web site accessed tal Benefits of Green Infrastructure: at: www.portlandonline.com/BES/index. http://cfpub.epa.gov/npdes/ cfm?c=eeeah greeninfrastructure/information. Green Street Cross-Bureau Team Report – cfm#enviroben. Phase I, March 2006: www.portlandonline. U.S. EPA, (2007), National Pollutant Discharge com/shared/cfm/image.cfm?id=123793 Elimination Systems (NPDES): Green In­ Green Street Cross-Bureau Team Report— frastructure: http://cfpub.epa.gov/npdes/ Phase 2: www.portlandonline.com/ home.cfm?program_id=298. shared/cfm/image.cfm?id=153974. U.S. EPA, Report to Congress: Impacts andDunn, A. and Stoner, N., (2007), Green Light Control of CSOs and SSOs, Office of Water, for Green Infrastructure, The Environ­ EPA-833-R-04-001, August 2004. mental Forum, May/June 2007, reprinted Water Environment Research Foundation, by the Environmental Law Institute and (2007), Portland Oregon: Building a accessed at: www.epa.gov/npdes/pubs/ Nationally Recognized Program Through green_light_gi.pdf. Innovation and Research, accessed as:Grumbles, B.H., (2007), Memorandum from www.werf.org/livablecommunitires/stud­ Benjamin H. Grumbles, USEPA Assistant ies_port_or.html. Key Resources 52
  • 56. ENDNOTES Requirements, Transportation Research Part A, Vol. 33, pgs. 549-574.1 Van Metre, P. et al, (2006), Parking Lot Sealcoat: A Major 16 Ibid. Source of Polycyclic Aromatic Hydrocarbons (PAHs) in Urban 17 and Suburban Environments, USGS Fact Sheet 2005-3147, Halifax Regional Municipality, (2003), Parking Supply Man­ January 2006. agement Strategies, accessed at: www.halifax.ca/regional­ planning/publications/ParkingStrategies.pdf.2 N.Y. State Department of Transportation, (2003), Safety 18 Bulletin: Paving with Hot Mix Asphalt, SB-03-3, accessed U.S. EPA, (1999), Parking Alternatives: Making Way for Urban at: www.dot.state.ny.us/progs/safety/files/pavinghma. Infill and Brownfield Redevelopment, EPA231-K-99-001. pdf#search=%22fumes%20from%20hot%20mix%20as­ 19 Ibid. phalt%22. 20 Maryland Governor’s Office of Smart Growth, (2005),3 U.S. EPA, (1992), Cooling Our Communities, Driving Urban Environments: Smart Growth Parking Best GPO#055-000-00371-8, January 1992, accessed at: www. Practices, page 4, accessed at: www.smartgrowth.state. epa.gov, as cited in Pavement Busters Guide (2002), page md.us. 10, Victoria Transport Policy Institute. 21 Ibid.4 Gibbons, J., (1999), Pavements and Surface Materials, Tech­ 22 nical Paper #8, pg. 2, University of Connecticut Nonpoint U.S. EPA, (1999,) Parking Alternatives: Making Way for Urban Education for Municipal Officials (NEMO) program, accessed Infill and Brownfield Redevelopment, EPA231-K-99-001. at: http://nemo.uconn.edu/tools/publications/tech_papers/ 23 Boston Metropolitan Area Planning Council, (2006), Sustain­ tech_paper_8.pdf. able Transportation Toolkit: Parking, accessed at:5 Pomeranz, Melvin, Lawrence Berkeley National Laboratory, http://transtoolkit.mapc.org/ in June 2007. Benefits of Cooler Pavements, http://eetd.lbl.gov/HeatIs­ 24 Maryland Governor’s Office of Smart Growth, (2005), land/Pavements/Overview/index.html, Driving Urban Environments: Smart Growth Parking Best6 Miramontes, E.M. University of California at Berkeley, (1997), Practices, page 4, accessed at: www.smartgrowth.state. The Bay Area’s Love-Hate Relationship With The Motorcar, md.us. San Francisco Examiner, October 20, 1997, as cited in Gib­ 25 Gibbons, J., (1999), Parking Lots, Technical Paper #5, bons, J. (1999), Parking Lots, Technical Paper #5, page 2, University of Connecticut Nonpoint Education for Municipal University of Connecticut Nonpoint Education for Municipal Officials (NEMO) program, accessed at: http://nemo.uconn. Officials (NEMO) program, accessed at: http://nemo.uconn. edu/tools/publications/tech_papers/tech_paper_5.pdf. edu/tools/publications/tech_papers/tech_paper_5.pdf. 26 University of Connecticut Nonpoint Education for Municipal7 Benfield, F.K. et al, (1999), Once There Were Greenfields: Officials (NEMO) program, (1999), Parking Lots - Technical How Urban Sprawl is Undermining America’s Environment, Paper #5, accessed at: http://nemo.uconn.edu/tools/publi­ Economy, and Social Fabric, Natural Resources Defense cations/tech_papers/tech_paper_5.pdf. Council (NRDC), as cited in Paving Our Way to Water Short­ 27 ages, NRDC, American Rivers, Smart Growth America, 2002, Minnesota Pollution Control Agency, (2000), Protecting page 6. Water Quality in Urban Areas, accessed at: www.pca.state. mn.us/water/pubs/sw-bmpmanual.html.8 Maryland Governor’s Office of Smart Growth (2005) Driving 28 Urban Environments: Smart Growth Parking Best Practices, Kloss, C. and Calarusse, C., (2006), Rooftops to Rivers: Green page 4, accessed at: www.smartgrowth.state.md.us. Strategies for Controlling Stormwater and Combined Sewer Overflows, Natural Resources Defense Council, accessed at:9 Ibid. www.nrdc.org/water/pollution/rooftops/contents.asp.10 Maryland Governor’s Office of Smart Growth, (2005), 29 Muthukrishnan, S. and Selvakumar, A., (2004), The Use of Driving Urban Environments: Smart Growth Parking Best Best Management Practices (BMPs) in Urban Watersheds, Practices, page 23, accessed at: www.smartgrowth.state. U.S. Environmental Protection Agency, EPA-600-R-04-184. md.us. 30 Ibid.11 Permeable pavers should not be used for the aisles and 31 main (primary) vehicle travel areas in high traffic lots Ibid. because they are not strong enough to withstand constant 32 U.S. EPA, (2007), National Pollutant Discharge Elimination weight and use, however in most cases they would be ideal (NPDES)—Grassed Swales Fact Sheet, accessed at: http:// for use in parking stalls, crosswalks, or overflow (i.e. second­ cfpub.epa.gov/npdes/stormwater/menuofbmps/index. ary) parking areas. cfm?action=factsheet_results&view=specific&bmp=75.12 U.S. EPA, (2001), Functions and Values of Wetlands, EPA 33 Muthukrishnan, S. and Selvakumar, A., (2004), The Use of 843-F-01-002c, September 2001, accessed at: www.epa. Best Management Practices (BMPs) in Urban Watersheds, gov/owow/wetlands/pdf/fun_val.pdf. U.S. Environmental Protection Agency, EPA-600-R-04-184.13 Shoup, D., (2005), The High Cost of Free Parking, APA Plan­ 34 NAHB Research Center, Inc., (2003), The Practice of Low Im­ ners Press, pages 2-3. pact Development, U.S. Department of Housing and Urban14 Litman, T., (2002), Pavement Busters guide, Victoria Trans­ Development, accessed at: www.huduser.org/publications/ port Policy Institute, accessed at: www.vtpi.org/pavbust.pdf PDF/practlowimpctdevel.pdf. in June 2007. 35 Muthukrishnan, S. and Selvakumar, A., (2004), The Use of15 Standards are typically determined by referring to the Best Management Practices (BMPs) in Urban Watersheds, Institute of Transportation Engineers guidance documents U.S. Environmental Protection Agency, EPA-600-R-04-184. or by researching the requirements of surrounding towns. 36 ibid. Shoup, D., (1999), The Trouble with Minimum Parking Green Parking Lot Resource Guide—February 2008 53
  • 57. 37 54 ibid. Information for this case study was obtained from: LaCroix,38 R., et al, (2004), Reining in the Rain: A case study of the city U.S. EPA, (2007), National Pollutant Discharge Elimination of Bellingham’s use of rain gardens to manage stormwater, (NPDES) - Grassed Swales Fact Sheet, accessed at: http:// accessed at: www.psat.wa.gov/Publications/Rain_Garden_ cfpub.epa.gov/npdes/stormwater/menuofbmps/index. book.pdf and personal communication with Bill Reilly, City cfm?action=factsheet_results&view=specific&bmp=75. of Bellingham Public Works Department.39 Muthukrishnan, S. and Selvakumar, A., (2004), The Use of 55 King County Environmental Purchasing Program, (2007), Best Management Practices (BMPs) in Urban Watersheds, Recycled Asphalt Fact Sheet, King County, Washington, ac­ U.S. Environmental Protection Agency, EPA-600-R-04-184. cessed at: www.metrokc.gov/procure/green/asphalt.htm#1.40 Community Design and Architecture, (2005), Stormwater 56 U.S. EPA, (2005), EPA Lessons Learned Paper – Heifer Inter­ Guidelines for Green Dense Redevelopment, U.S. EPA, ac­ national, page 5. cessed at: www.epa.gov/dced/pdf/Stormwater_Guidelines. 57 pdf. Similarly, the new paving product RESINPAVE™ is manu­41 factured from renewable resources, contains no petroleum Minnesota Pollution Control Agency, (2000), Protection ingredients, and is highly reflective. However, it too is Water Quality in Urban Areas, March 1, 2000, accessed at: impervious, and is also still in experimental stages. www.pca.state.mn.us/water/pubs/sw~bmpmanual.html. 58 42 New York State Department of Environmental Conservation, Washington State Department of Ecology, (2004), Storm- (2007), New York State Stormwater Design Manual - Chapter water and Economic Development, 04-10-001, accessed at: 9, accessed at: www.dec.ny.gov/chemical/29072.html. www.ecy.wa.gov/pubs/0410001.pdf. 59 43 U.S. EPA, (2007), National Pollutant Discharge Elimination Kloss, C. and Calarusse, C., (2006), Rooftops to Rivers: Green System (NPDES) – Porous Pavement Fact Sheet, accessed at: Strategies for Controlling Stormwater and Combined Sewer http://cfpub.epa.gov/npdes/stormwater/menuofbmps/in­ Overflows, Natural Resources Defense Council, accessed at: dex.cfm?action=factsheet_results&view=specific&bmp=71. www.nrdc.org/water/pollution/rooftops/contents.asp. 60 44 Ibid. Van Metre, P. et al, (2006), Parking Lot Sealcoat: A Major 61 Source of Polycyclic Aromatic Hydrocarbons (PAHs) in Urban New Jersey Department of Environmental Protection, and Suburban Environments, USGS Fact Sheet 2005-3147, (2004), New Jersey Stormwater Best Management Practices January 2006. Manual, accessed at: www.njstormwater.org/tier_A/pdf/45 NJ_SWBMP_9.7.pdf. U.S. EPA, (2007), Polluted Runoff (Nonpoint Source Pollu­ 62 tion) website, accessed at: www.epa.gov/owow/nps/whatis. U.S. EPA, (2007), National Pollutant Discharge Elimination html. System (NPDES) – Porous Pavement Fact Sheet, accessed at:46 http://cfpub.epa.gov/npdes/stormwater/menuofbmps/in­ Muthukrishnan, S. and Selvakumar, A., (2004), The Use of dex.cfm?action=factsheet_results&view=specific&bmp=71. Best Management Practices (BMPs) in Urban Watersheds, 63 U.S. Environmental Protection Agency, EPA-600-R-04-184. Pennsylvania Department of Environmental Protection,47 (2005), Draft Pennsylvania Stormwater Best Management U.S. EPA, (1999), Storm Water Technology Fact Sheet Infiltra­ Manual, Section 6 - Comprehensive Stormwater Manage­ tion Trench, EPA-832-F-99-019, accessed at: www.epa.gov/ ment: Structural BMPs, accessed at: www.dep.state.pa.us/ owm/mtb/infltrenc.pdf. dep/subject/advcoun/stormwater/Manual_DraftJan05/48 Wossink, A. and Hunt, B., (2003), An Evaluation of the Costs Section06-StructuralBMPs-part1.pdf and Benefits of Structural Stormwater Best Management 64 Knox County, Tennessee, (2007), Stormwater Management Practices in North Carolina, North Carolina State University, Ordinance, Volume 2 (technical guidance), accessed at: accessed at: www.stormwaterauthority.org/assets/Storm- http://knoxcounty.org/stormwater/volume2.php. water_BMP_Factsheet%20-%20NC.pdf. 65 49 Pennsylvania Department of Environmental Protection, U.S. EPA, (1999), Preliminary Data Summary of Urban (2005), Draft Pennsylvania Stormwater Best Management Stormwater Best Management Practices, EPA-821-R-99-012, Manual, Section 6 - Comprehensive Stormwater Manage­ August 1999, accessed at: www.epa.gov/waterscience/ ment: Structural BMPs, accessed at: www.dep.state.pa.us/ guide/stormwater. dep/subject/advcoun/stormwater/Manual_DraftJan05/50 Muthukrishnan, S. and Selvakumar, A., (2004), The Use of Section06-StructuralBMPs-part1.pdf Best Management Practices (BMPs) in Urban Watersheds, 66 Frazer, L., (2006), Paving Paradise: The Peril of Impervious U.S. Environmental Protection Agency, EPA-600-R-04-184. Surfaces, Environ Health Perspect. 2006 Jan;114(1):A21.51 Kloss, C. and Calarusse, C., (2006), Rooftops to Rivers: Green 67 Cahill, T. et al, (2005), Stormwater Management with Porous Strategies for Controlling Stormwater and Combined Sewer Pavements, Government Engineering, March-April 2005, Overflows, Natural Resources Defense Council, accessed at: pp. 14-19, accessed at: www.govengr.com/ArticlesMar05/ www.nrdc.org/water/pollution/rooftops/contents.asp. porous.pdf.52 Wossink, A. and Hunt, B., (2003), An Evaluation of the Costs 68 U.S. EPA, (2007), National Pollutant Discharge Elimination and Benefits of Structural Stormwater Best Management System (NPDES) – Porous Pavement Fact Sheet, accessed at: Practices in North Carolina, North Carolina State University, http://cfpub.epa.gov/npdes/stormwater/menuofbmps/in­ accessed at: www.stormwaterauthority.org/assets/Storm- dex.cfm?action=factsheet_results&view=specific&bmp=71. water_BMP_Factsheet%20-%20NC.pdf. 69 53 Pennsylvania Department of Environmental Protection, Chester County, Pennsylvania Water Resources Compen­ (2005), Draft Pennsylvania Stormwater Best Management dium, (2005), Watershed Primer Part 4: Land Use impacts Manual, Section 6 - Comprehensive Stormwater Manage­ and Watershed Economics, accessed at: http://dsf.chesco. ment: Structural BMPs, accessed at: www.dep.state.pa.us/ org/water/cwp/view.asp?a=3&q=607722. dep/subject/advcoun/stormwater/Manual_DraftJan05/ Section06-StructuralBMPs-part1.pdf. Key Resources 54
  • 58. 70 McDaniel, R., (2004), Field Evaluation of Porous Asphalt dex.cfm?action=factsheet_results&view=specific&bmp=71. Pavement – Research Summary, Purdue University, 84 Knox County, Tennessee, (2007), Stormwater Management accessed at: http://meweb.ecn.purdue.edu/~sqdh/ Ordinance, Volume 2 (technical guidance), accessed at: SQDH2004_3/RS%20McDaniel%20Porous%20Asphalt.pdf. http://knoxcounty.org/stormwater/volume2.php.71 Idaho Department of Environmental Quality, (2005), Storm 85 New York State Department of Environmental Conservation, Water Best Management Practices Catalog, accessed at: (2007), New York State Stormwater Design Manual - Chap­ www.deq.idaho.gov/water/data_reports/storm_water/ ter 9, accessed at: www.dec.ny.gov/chemical/29072.html. catalog/sec_3/bmps/11.pdf. 86 72 Ibid. New Jersey Department of Environmental Protection, 87 (2004), New Jersey Stormwater Best Management Practices Pennsylvania Department of Environmental Protection, Manual, accessed at: www.njstormwater.org/tier_A/pdf/ (2005), Draft Pennsylvania Stormwater Best Management NJ_SWBMP_9.7.pdf. Manual, Section 6 - Comprehensive Stormwater Manage­73 ment: Structural BMPs, accessed at: www.dep.state.pa.us/ U.S. EPA, (2007), National Pollutant Discharge Elimina­ dep/subject/advcoun/stormwater/Manual_DraftJan05/ tion System (NPDES) – Alternative Pavers Fact Sheet, Section06-StructuralBMPs-part1.pdf. accessed at: http://cfpub.epa.gov/npdes/storm­ water/menuofbmps/index.cfm?action=factsheet_ Cahill, T. et al, (2005), Stormwater Management with Porous results&view=specific&bmp=134. Pavements, Government Engineering, March-April 2005,74 pp. 14-19, accessed at: www.govengr.com/ArticlesMar05/ Idaho Department of Environmental Quality, (2005), Storm porous.pdf. Water Best Management Practices Catalog, accessed at: 88 www.deq.idaho.gov/water/data_reports/storm_water/ U.S. EPA, (2007), National Pollutant Discharge Elimination catalog/sec_3/bmps/11.pdf. System (NPDES) – Porous Pavement Fact Sheet, accessed at:75 http://cfpub.epa.gov/npdes/stormwater/menuofbmps/in­ Idaho Department of Environmental Quality, (2005), Storm dex.cfm?action=factsheet_results&view=specific&bmp=71. Water Best Management Practices Catalog, accessed at: 89 www.deq.idaho.gov/water/data_reports/storm_water/ Ibid. catalog/sec_3/bmps/11.pdf. 90 New York State Department of Environmental Conservation,76 New York State Department of Environmental Conservation, (2007), New York State Stormwater Design Manual - Chap­ (2007), New York State Stormwater Design Manual - Chap­ ter 9, accessed at: www.dec.ny.gov/chemical/29072.html. ter 9, accessed at: www.dec.ny.gov/chemical/29072.html. 91 Pennsylvania Department of Environmental Protection,77 Idaho Department of Environmental Quality, (2005), Storm (2005), Draft Pennsylvania Stormwater Best Management Water Best Management Practices Catalog, accessed at: Manual, Section 6 - Comprehensive Stormwater Manage­ www.deq.idaho.gov/water/data_reports/storm_water/ ment: Structural BMPs, accessed at: www.dep.state.pa.us/ catalog/sec_3/bmps/11.pdf. dep/subject/advcoun/stormwater/Manual_DraftJan05/78 Section06-StructuralBMPs-part1.pdf. US Department of Transportation, (2007), Stormwater Best 92 Management Practices in an Ultra Urban Setting, accessed New Jersey Department of Environmental Protection, at: www.fhwa.dot.gov/environment/ultraurb/uubmp3p6. (2004), New Jersey Stormwater Best Management Practices htm. Manual, accessed at: www.njstormwater.org/tier_A/pdf/79 NJ_SWBMP_9.7.pdf. Diyagama, T., et al. ,(2004), Permeable Pavement Design 93 Guidelines - Draft, prepared for North Shore City, EcoWater Pennsylvania Department of Environmental Protection, Solutions, and Rodney District, accessed at: www.northsho­ (2005), Draft Pennsylvania Stormwater Best Management recity.govt.nz/IDSM/IDSM2006/downloads/PDFs/Perme­ Manual, Section 6 - Comprehensive Stormwater Manage­ able_Pavement_Design_Guidelines_Draft_092004.pdf. ment: Structural BMPs, accessed at: www.dep.state.pa.us/80 dep/subject/advcoun/stormwater/Manual_DraftJan05/ US Department of Transportation, (2007), Stormwater Best Section06-StructuralBMPs-part1.pdf. Management Practices in an Ultra Urban Setting, accessed 94 at: www.fhwa.dot.gov/environment/ultraurb/uubmp3p6. Ibid. htm. 95 Ibid.81 New York State Department of Environmental Conservation, 96 Pennsylvania Department of Environmental Protection, (2007), New York State Stormwater Design Manual - Chap­ (2005), Draft Pennsylvania Stormwater Best Management ter 9, accessed at: www.dec.ny.gov/chemical/29072.html. Manual, Section 6 - Comprehensive Stormwater Manage­82 Cahill, T. et al, (2005), Stormwater Management with Porous ment: Structural BMPs, accessed at: www.dep.state.pa.us/ Pavements, Government Engineering, March-April 2005, dep/subject/advcoun/stormwater/Manual_DraftJan05/ pp. 14-19, accessed at: www.govengr.com/ArticlesMar05/ Section06-StructuralBMPs-part1.pdf. porous.pdf. New York State Department of Environmental Conservation, U.S. EPA, (2007), National Pollutant Discharge Elimination (2007), New York State Stormwater Design Manual - Chap­ System (NPDES) – Porous Pavement Fact Sheet, accessed at: ter 9, accessed at: www.dec.ny.gov/chemical/29072.html. http://cfpub.epa.gov/npdes/stormwater/menuofbmps/in­ 97 Cahill, T. et al, (2005), Stormwater Management with Porous dex.cfm?action=factsheet_results&view=specific&bmp=71. Pavements, Government Engineering, March-April 2005, New York State Department of Environmental Conservation, pp. 14-19, accessed at: www.govengr.com/ArticlesMar05/ (2007), New York State Stormwater Design Manual - Chap­ porous.pdf. ter 9, accessed at: www.dec.ny.gov/chemical/29072.html. 98 New York State Department of Environmental Conservation,83 U.S. EPA, (2007), National Pollutant Discharge Elimination (2007), New York State Stormwater Design Manual - Chap­ System (NPDES) – Porous Pavement Fact Sheet, accessed at: ter 9, accessed at: www.dec.ny.gov/chemical/29072.html. http://cfpub.epa.gov/npdes/stormwater/menuofbmps/in­ Green Parking Lot Resource Guide—February 2008 55
  • 59. 99 U.S. EPA, (2007), National Pollutant Discharge Elimination dex.cfm?action=factsheet_results&view=specific&bmp=71. System (NPDES) – Porous Pavement Fact Sheet, accessed at: 114 Pennsylvania Department of Environmental Protection, http://cfpub.epa.gov/npdes/stormwater/menuofbmps/in­ (2005), Draft Pennsylvania Stormwater Best Management dex.cfm?action=factsheet_results&view=specific&bmp=71. Manual, Section 6 - Comprehensive Stormwater Manage­100 Cahill, T. et al, (2005), Stormwater Management with Porous ment: Structural BMPs, accessed at: www.dep.state.pa.us/ Pavements, Government Engineering, March-April 2005, dep/subject/advcoun/stormwater/Manual_DraftJan05/ pp. 14-19, accessed at: www.govengr.com/ArticlesMar05/ Section06-StructuralBMPs-part1.pdf. porous.pdf. 115 Cahill, T. et al, (2005), Stormwater Management with Porous101 Pennsylvania Department of Environmental Protection, Pavements, Government Engineering, March-April 2005, (2005), Draft Pennsylvania Stormwater Best Management pp. 14-19, accessed at: www.govengr.com/ArticlesMar05/ Manual, Section 6 - Comprehensive Stormwater Manage­ porous.pdf. ment: Structural BMPs, accessed at: www.dep.state.pa.us/ 116 Pennsylvania Department of Environmental Protection, dep/subject/advcoun/stormwater/Manual_DraftJan05/ (2005), Draft Pennsylvania Stormwater Best Management Section06-StructuralBMPs-part1.pdf. Manual, Section 6 - Comprehensive Stormwater Manage­102 New York State Department of Environmental Conservation, ment: Structural BMPs, accessed at: www.dep.state.pa.us/ (2007), New York State Stormwater Design Manual - Chapter dep/subject/advcoun/stormwater/Manual_DraftJan05/ 9, accessed at: www.dec.ny.gov/chemical/29072.html. Section06-StructuralBMPs-part1.pdf.103 117 Hinman, C., (2005), Low Impact Development Technical New York State Department of Environmental Conservation, Guidance Manual for Puget Sound, Puget Sound Action (2007), New York State Stormwater Design Manual - Chapter Team, publication number PSAT 05-03, accessed at: www. 9, accessed at: www.dec.ny.gov/chemical/29072.html. psat.wa.gov/Publications/LID_tech_manual05/lid_index. 118 Pennsylvania Department of Environmental Protection, htm. (2005), Draft Pennsylvania Stormwater Best Management104 Bean, E., et al, (2007), Field Survey of Permeable Pavement Manual, Section 6 - Comprehensive Stormwater Manage­ Surface Infiltration Rates, J. Irrig. and Drain. Engrg., Volume ment: Structural BMPs, accessed at: www.dep.state.pa.us/ 133, Issue 3, pp. 249-255, May/June 2007. dep/subject/advcoun/stormwater/Manual_DraftJan05/105 Section06-StructuralBMPs-part1.pdf. U.S. EPA, (2007), National Pollutant Discharge Elimination 119 System (NPDES) – Porous Pavement Fact Sheet, accessed at: U.S. EPA, (2007), National Pollutant Discharge Elimina­ http://cfpub.epa.gov/npdes/stormwater/menuofbmps/in­ tion System (NPDES) – Alternative Pavers Fact Sheet, dex.cfm?action=factsheet_results&view=specific&bmp=71 accessed at: http://cfpub.epa.gov/npdes/storm­ water/menuofbmps/index.cfm?action=factsheet_ Hinman, C., (2005), Low Impact Development Technical results&view=specific&bmp=134 Guidance Manual for Puget Sound, Puget Sound Action 120 Team, publication number PSAT 05-03, p. 121, accessed at: New York State Department of Environmental Conservation, www.psat.wa.gov/Publications/LID_tech_manual05/lid_in­ (2007), New York State Stormwater Design Manual - Chapter dex.htm. 9, accessed at: www.dec.ny.gov/chemical/29072.html.106 121 Hinman, C., (2005), Low Impact Development Technical Another option is to also include coal ash in the concrete, Guidance Manual for Puget Sound, Puget Sound Action which improve its strength and durability while using a Team, publication number PSAT 05-03, accessed at: www. recycled material. Heifer explored this, but chose other psat.wa.gov/Publications/LID_tech_manual05/lid_index. sustainable options for their lot based on preference and htm. budget.107 122 Cahill, T. et al, (2005), Stormwater Management with Porous Wade, B., (2000), Putting the freeze on heat islands, Ameri­ Pavements, Government Engineering, March-April 2005, can City & County, 115, 2, 30, page 2, Feb 2000. pp. 14-19, accessed at: www.govengr.com/ArticlesMar05/ 123 Calculated using the PaLATE model, a lifecycle assessment porous.pdf. tool created to derive the environmental and economic108 New York State Department of Environmental Conservation, effects of paved surfaces. Information on the PaLATE model (2007), New York State Stormwater Design Manual - Chapter can be found at: www.ce.berkeley.edu/~horvath/palate. 9, accessed at: www.dec.ny.gov/chemical/29072.html. html.109 124 Knox County, Tennessee, (2007), Stormwater Management Mercury (Hg) emissions were modeled by PaLATE, but were Ordinance, Volume 2 (technical guidance), accessed at: not mentioned here because the emissions difference was http://knoxcounty.org/stormwater/volume2.php. negligible.110 125 Turfstone®, UNI Eco-Stone®, Grasspave2®, and Gravelpave2® U.S. Office of Management and Budget, (2005), Draft 2005111 Report to Congress on the Costs and Benefits of Federal Brattebo, B. and Booth, D., (2003), Long-term stormwater Regulations, Appendix B and U.S. Office of Management quantity and quality performance of permeable pavement and Budget, Circular A-94: Guidelines and Discount Rates systems, Water Research, 37, 4368-4376, November 2003. for Benefit-Cost Analysis of Federal Programs, accessed at:112 Hinman, C., (2005), Low Impact Development Technical www.whitehouse.gov/omb/circulars/a094/a094.pdf on Guidance Manual for Puget Sound, Puget Sound Action January 10, 2007. Team, publication number PSAT 05-03, accessed at: www. It should be noted that the values shown here are based on psat.wa.gov/Publications/LID_tech_manual05/lid_index. national averages. htm.113 The high end of this range represents values associated U.S. EPA, (2007), National Pollutant Discharge Elimination with avoided emissions in areas with severe air quality System (NPDES) – Porous Pavement Fact Sheet, accessed at: impairment, and are likely too high to apply to the Little http://cfpub.epa.gov/npdes/stormwater/menuofbmps/in­ Rock area, which is in attainment with federal PM10 and SO2 Key Resources 56
  • 60. standards, as well as all other air quality standards. Query Building Sciences, (2007), Whole Building Design Guide, of EPA Air Data, January 21, 2006: www.epa.gov/air/data/ accessed at: www.wbdg.org/tools. nonat.html?st~AR~Arkansas. 140 Florida Department of Environmental Protection, (2006),126 Sources for this case study include: McNally, C., et al, Water Best Management Practices, Florida Green Lodging (2003), The University of Rhode Island’s Permeable Parking Program, accessed at: www.treeo.ufl.edu/greenlodging/ Lots: A case Study of Alternative Pavement Materials, ac­ content/gr_h2o.htm. cessed at: www.uri.edu/ce/wq/NEMO/Publications/PDFs/ 141 Ibid. PP.URICaseStudy.pdf; and the 2005 update to this docu­ 142 ment located at www.uri.edu/ce/wq/NEMO/Publications/ U.S. Department of Energy, (2006), Federal Energy Manage­ index.htm. ment Program – Water Efficiency, accessed at: http://www1.127 eere.energy.gov/femp/water/water_bmp3.html. URI also does not permit commercial and industrial vehicles 143 on this lot because of groundwater contamination con­ Ibid. cerns, and to avoid compaction of the pourous bituminous 144 Florida Department of Environmental Protection, (2006), asphalt. Water Best Management Practices, Florida Green Lodging128 Potable water is defined by the US EPA as water suit­ Program, accessed at: www.treeo.ufl.edu/greenlodging/ able for drinking or cooking purposes from both health content/gr_h2o.htm. and aesthetic considerations. (Office of Environmental 145 Ibid. Information, (2007), Ecoview Glossary, accessed at: http:// 146 iaspub.epa.gov/trs/trs_proc_qry.navigate_term?p_term_ San Mateo County, (2007), Recycle Works – Landscape id=291323&p_term_cd=TERMDIS). Plantings, accessed at: www.recycleworks.org/greenbuild­129 ing/sus_plantings.html. Romero, M. and Hostetler, M., (2007), Policies that Address 147 Sustainable Landscaping Practices, Circular 1519, University As with high-efficiency irrigation technology, developers of Florida, accessed at: http://edis.ifas.ufl.edu/UW253. can also acquire LEED WE Credit-1.1 by recycling rainwater130 or using recycled wastewater to reduce potable water U.S. EPA, (2005), The Natural Landscaping Alternative: consumption by fifty percent over conventional means; An Annotated Slide Collection, from Green Landscaping: or through LEED WE Credit-1.2 by using only captured Greenacres Natural Landscaping Tool Kit, accessed at: www. rainwater or recycled water to eliminate all potable water epa.gov/greenacres/tooltestkit/gallary/index.html. use for site irrigation (except for initial watering of plants).131 San Mateo County, (2007), Recycle Works – Landscape National Institute of Building Sciences, (2007), Whole Build­ Plantings, accessed at: www.recycleworks.org/greenbuild­ ing Design Guide, accessed at www.wbdg.org/tools. ing/sus_plantings.html. 148 State of California Energy Commission, (2005), Califor­132 Pennsylvania Department of Environmental Protection, nia’s Water-Energy Relationship, CEC-700-2005-011-SF, (2006), Pennsylvania Stormwater Best Management accessed at: www.energy.ca.gov/2005publications/ Practices Manual: Chapter 5 - Non Structural BMPs, CEC-700-2005-011/CEC-700-2005-011-SF.PDF. 363-0300-002, accessed at: www.dep.state.pa.us/dep/ 149 Milwaukee Metropolitan Sewerage District, (2007), State deputate/watermgt/wc/subjects/stormwatermanagement/ of the Art Report Draft, accessed at: www.mmsd.com/ BMP%20Manual/05_Chapter_Final_Draft.pdf. wqi/2020Plan/SR_04.pdf.133 Illinois Conservation Foundation and Chicago Wilderness, 150 U.S. EPA, (2004), Conference Summary, Landscaping with (2005), Change Cost Perceptions: An Analysis of Conserva­ Native Plants: Exploring the Environmental, Social and Eco­ tion Development, accessed at: www.cdfinc.com/CDF_Re­ nomic Benefits Conference December 6 - 7, 2004, accessed sources/Cost%20Analysis%20-%20Part%201%20-%20 at: www.epa.gov/greenacres/conf12_04/conf_knwldge. Report%20-%20with%20Exec%20Summary.pdf. html.134 King County Department of Natural Resources (2007) Na­ 151 Ibid. tive Plant Salvage Program, accessed at: http://dnr.metrokc. 152 gov/wlr/pi/salopps.htm. Ibid.135 153 City of Chicago, (2003), A Guide to Stormwater Best Man­ Muthukrishnan, S. et al, (2004), The Use of Best Manage­ agement Practices, accessed at: www.cdfinc.com/CDF_Re- ment Practices (BMPs) in Urban Watersheds, U.S. EPA, sources/Chicago%20GuideTo%20Stormwater%20BMPs.pdf. EPA/600/R-04/184, accessed at: www.epa.gov/ORD/136 NRMRL/pubs/600r04184/600r04184.pdf. U.S. Department of Energy, (2006), Federal Energy Manage­ 154 ment Program – Water Efficiency, accessed at: http://www1. Ibid. eere.energy.gov/femp/water/water_bmp3.html. 155 U.S. EPA, (2004), Conference Summary, Landscaping with137 Ibid. Native Plants: Exploring the Environmental, Social and Eco­138 nomic Benefits Conference December 6 - 7, 2004, accessed San Mateo County, (2007), Recycle Works – Landscape at: www.epa.gov/greenacres/conf12_04/conf_knwldge. Plantings, accessed at: www.recycleworks.org/greenbuild­ html. ing/sus_plantings.html. 156 139 Florida Department of Environmental Protection, (2006), By using high efficiency irrigation technology, developers Water Best Management Practices, Florida Green Lodging can acquire LEED Water-Efficiency (WE) Credit 1.1 if they Program, accessed at: www.treeo.ufl.edu/greenlodging/ reduce potable water consumption for irrigation by fifty content/gr_h2o.htm. percent over conventional means. In addition, they can also 157 achieve LEED WE Credit 1.2 by not installing a permanent U.S. Department of Energy, (2001), Greening Federal landscape irrigation system, which is the highest goal of Facilities, second edition, accessed at: www.nrel.gov/docs/ water efficient natural landscaping. National Institute of fy01osti/29267.pdf. Green Parking Lot Resource Guide—February 2008 57
  • 61. 158 176 U.S. EPA, (2004), Conference Summary, Landscaping with U.S. EPA, (2004), Conference Summary, Landscaping with Native Plants: Exploring the Environmental, Social and Eco­ Native Plants: Exploring the Environmental, Social and Eco­ nomic Benefits Conference December 6 - 7, 2004, accessed nomic Benefits Conference December 6 - 7, 2004, accessed at: www.epa.gov/greenacres/conf12_04/conf_knwldge. at: www.epa.gov/greenacres/conf12_04/conf_knwldge. html. html.159 177 U.S. Department of Energy, (2001), Greening Federal Ibid. Facilities, second edition, accessed at: www.nrel.gov/docs/ 178 Dunn, A. and Stoner, N., (2007), Green Light for Green fy01osti/29267.pdf. Infrastructure, The Environmental Forum, May/June 2007,160 North Carolina Department of Environment and Natural reprinted by the Environmental Law Institute and accessed Resources, (2005), Water Efficiency: Water Management at: www. Epa.gov/npdes/pubs/green_light_gi.pdf. Options, Division of Pollution Prevention and Environmental 179 U.S. EPA, (2007), National Pollutant Discharge Elimination Assistance, accessed at: www.p2pays.org/ref/04/03102.pdf. Systems (NPDES): Green Infrastructure, accessed at: http://161 U.S. EPA, (2003), Water-Efficient Landscaping, accessed at: cfpub.epa.gov/npdes/home.cfm?program_id=298. www.epa.gov/npdes/pubs/waterefficiency.pdf. 180 U.S. EPA, (2007), National Pollutant Discharge Elimination162 U.S. EPA, (2007), Landscaping with Native Plants, accessed System (NPDES): Green Infrastructure – General Informa­ at: www.epa.gov/greenacres//index.html#Benefits. tion, accessed at: http://cfpub.epa.gov/npdes/greeninfra­163 structure/information.cfm U.S. Department of Energy, (2003), The Business Case for 181 Sustainable Design in Federal Facilities – Appendix D, ac­ Ibid. cessed at: http://www1.eere.energy.gov/femp/sustainable/ 182 Kloss, C. and Calarusse, C., (2006), Rooftops to Rivers: Green sustainable_federalfacilities.html. Strategies for Controlling Stormwater and Combined Sewer164 U.S. EPA, (2004), Conference Summary, Landscaping with Overflows, Natural Resources Defense Council, accessed at: Native Plants: Exploring the Environmental, Social and Eco­ www.nrdc.org/water/pollution/rooftops/contents.asp. nomic Benefits Conference December 6 - 7, 2004, accessed 183 U.S. EPA, (2004), Conference Summary, Landscaping with at: www.epa.gov/greenacres/conf12_04/conf_knwldge. Native Plants: Exploring the Environmental, Social and Eco­ html. nomic Benefits Conference December 6 - 7, 2004, accessed165 City of Chicago, (2003), A Guide to Stormwater Best Man­ at: www.epa.gov/greenacres/conf12_04/conf_knwldge. agement Practices, accessed at: www.cdfinc.com/CDF_Re- html. sources/Chicago%20GuideTo%20Stormwater%20BMPs.pdf. 184 Kloss, C. and Calarusse, C., (2006), Rooftops to Rivers: Green166 U.S. EPA, (2004), Conference Summary, Landscaping with Strategies for Controlling Stormwater and Combined Sewer Native Plants: Exploring the Environmental, Social and Eco­ Overflows, Natural Resources Defense Council, accessed at: nomic Benefits Conference December 6 - 7, 2004, accessed www.nrdc.org/water/pollution/rooftops/contents.asp. at: www.epa.gov/greenacres/conf12_04/conf_knwldge. 185 U.S. EPA, Report to Congress: Impacts and Control of CSOs html. and SSOs, Office of Water, EPA-833-R-04-001, August 2004167 U.S. EPA, (1992), Cooling Our Communities, as cited in Kloss, C. and Calarusse, C., (2006), Rooftops to GPO#055-000-00371-8, January 1992, accessed at: www. 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