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Chapter 3. Controlling Urban Runoff 3-110 

## 4

. Urban Runoff Management for the Redevelopment Secto r 1

3. 

### The implementation measures listed in Section 2 for reducing runoff 2 

### volume are expanded in this section because 4.1 Introduction 3 It has been estimated that about 50 percent of the importance of addressing redevelopment 4 residential, commercial, and industrial buildings p resent in the restoration of year 2030 will be 5 constructed between 2000 and 2030 (Brookings Institute 2004) , creating opportunities for water 6 quality improvements that our cities must s eize if we are to achieve the goals of restoring the 7 Chesapeake Bay or any other urban waterbodies. 8 The implementation measures specifically applicable to redevelopment (repeated waters

. As 9 redevelopment projects occur over several decades , pollutant disch arges for developed areas can 10 be gradually reduced as pr actices are installed to incrementally improve the quality of runoff 11 from Section 2) are below existing, untreated developed land

. 12 Implementation Measure: Develop and implement redevelopment programs that identify opportunities for a range of types and sizes of red evelopment projects to mitigate water resource impacts that

• Establish appropriate redevelopment stormwater perf ormance standards consistent with the goal of restoring predevelopment hydrology with regard to the temperature, rate, volume and duration of flow, or more restrictive if needed for site-specific water quality protection

• Include development of an inventory of appropriate mitigation practices (e.g. permeable pavement, infiltration practices, green roofs) that will be encouraged or required for implementation at redevelopment sites that are smal ler than the applicability threshold

• Include site assessment to determine appropriate GI /LID practices

• Review codes and ordinances and modify as appropria te to allow and encourage GI/LID practices

• Implement GI/LID demonstration projects

• Incentivize early adopters of GI/LID practices

• Maximize urban forest canopy to reduce runoff

• Conduct soil analyses and amend compacted urban soi ls to promote infiltration Redevelopment : The process whereby an existing development is ad aptively reused, rehabilitated, restored, renovated, or expa nded, which results in disturbance or clearing of a defined footprint at the site

.
It has been estimated that about 50 percent of the residential, commercial, and industrial 13 buildings present in the year 2030 will be construc ted between 2000 and 2030 (Brookings 14 Institute 2004) , creating opportunities for water quality improvements that our cities must seize if 15 we are to achieve t he goals of restoring the Chesapeake Bay or other u rban waters

. As 16 redevelopment projects occur over several decades , pollutant discharges for developed areas can 173/15/20 2

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Chapter 3. Controlling Urban Runoff 3-111 be gradually reduced as pr actices are installed to incrementally improve the quality of runof f 1 from existing, untreated developed land

. 2 Sound redevelopment practices incorporate principle s of smart growth and sustainable 3 development (USEPA 2005, 2006). LID practices insta lled at redevelopment projects in 4 catchments that are served by combined sewer system s can help reduce the frequency and 5 magnitude of combined sewer overflows (CSOs) to riv ers and estuaries (Limnotech 2007). 6 Well-planned redevelopment is necessary for many re asons other than just water quality, 7 prompting a growing number of redevelopment project designers and communities to develop 8 holistic approaches for achieving water quality imp rovements in the redevelopment process in 9 combination with other social, economic, and enviro nmental factors. Water quality programs are 10 an important component of a healthy, vibrant, livab le, and environmentally sound community 11 and are a key factor to consider in a redevelopment project. 12 Encouraging redevelopment, rather than Greenfield d evelopment, promotes 13

• Land use efficiency 14

• Improves the quality of life in urban areas 15

• Optimizes use of existing public infrastructure 16

• Provides a tax base to enable maintenance of existi ng public infrastructure 17 LID and green infrastructure stormwater requirement s create an excellent opportunity to 18 facilitate mitigation of the effects of past develo pment at the site or watershed scale, and to 19 address other societal objectives. 20



### 4.2 Challenges and Opportunities in the Redevelopment S ector

. 21 Redevelopment projects require innovative, cost-eff ective, LID solutions to overcome challenges 22 such as the following: 23
Site Constraints . Most infill and redevelopment projects are small in area, highly 24 impervious, and have existing utilities and infrast ructure, all of which constrain the use of 25 some traditional stormwater practices, particularly those that rely on infiltration through 26 vegetative practices. 27 High Trash Loads . Runoff from highly urban watersheds is often seve rely polluted and 28 contains a high load of trash, litter, debris and g ross solids (COB 2006), which can 29 interfere with the performance of stormwater practi ces and creates the need for more 30 frequent practice maintenance. 31 Compacted and Polluted Soils . Soils have been graded, eroded, and reworked by p ast 32 development, often resulting in compaction such tha t runoff cannot be effectively 33 infiltrated. In severe cases, legacy problems from past industrial and municipal activity 34 have created brownfields that must be capped to prevent infiltration from l eaching 35 pollutants or contaminating soils (USEPA 2008 a ). For those sites with compacted or 36 polluted soils, using infiltration practices might be limited. Example case studies are 373/15/20 2

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Chapter 3. Controlling Urban Runoff 3-112 provided at EPA’s Brownfields Program 1 ( http://www.epa.gov/brownfields/tools/swcs0408.pdf http://www .epa.gov/brownfields/too 2 ls/swcs0408.pdf ) 3
Natural Stream Network is Altered or Buried . Urbanization has severely altered, reduced 4 or eliminated the natural stream network (NRC 2008) . The urban stream system that 5 remains is often highly degraded and altered in siz e and shape, and most development 6 projects discharge to existing storm drain pipes or conveyance channels rather than 7 streams. 8 Feasibility and Cost of Compliance . The cost of stormwater practices at redevelopment 9 projects in highly urban settings is often more exp ensive than in new development 10 projects in greenfield settings, where more surface land is available for the practices 11 (Schueler 2007). 12 Redevelopment Should Focus on Both Source Control ( Pollution Prevention) and LID. 13 Almost without exception, most redevelopment sites in the Chesapeake Bay watershed 14 and elsewhere in the nation often discharge to rece iving waters that are listed as water 15 quality impaired and require pollutant reductions t hrough TMDLs for a range of 16 pollutants, including bacteria, trash, nutrients, m etals and hydrocarbons. All these varied 17 sources should be addressed in redevelopment. 18
Smart Growth Considerations. High-density land development is an essential elem ent of 19 smart growth, green infrastructure, and sustainable cities. Therefore, it is important that 20 managers select stormwater practices that will be c onsistent with those important 21 redevelopment principles. 22 Because of those constraints, many urban communitie s in the Chesapeake Bay watershed (and 23 elsewhere in the nation) have historically waived, relaxed, or otherwise reduced stormwater 24 requirements for redevelopment projects. That has c ontributed to the continuing deterioration of 25 urban waters. However, in recent years, stormwater managers have taken a more creative 26 approach to treating stormwater from the redevelopm ent sector that reflects the following 27 opportunities: 28 New Redevelopment Practices. In the past decade, considerable research has been 29 conducted, demonstrations made, and experience gain ed—all of which demonstrate that a 30 variety of LID practices can be used that are speci fically adapted for highly urban areas 31 (such as expanded tree boxes, green roofs, and permeable pavements , and flexible rubber 32 sidewalk sections allowing for less destructive tre e root growth ). The new practices 33 emphasize the sustainable use of stormwater as part of green buildings and green 34 infrastructure. In addition, the new practices prom ote larger sustainability objectives such 35 as increased energy efficiency and water conservati on, greater building longevity, 36 community greening, safer and more walkable communi ties, and more creative 37 architectural solutions. 38 Green Building and Sustainability Movement . Designers are seeking LEED certification 39 for their buildings, and points are awarded for usi ng innovative stormwater practices. 40 Other certification systems such as the Sustainable Sites Initiative (ASLA 2009) reward 413/15/20 2

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Chapter 3. Controlling Urban Runoff 3-113 effective stormwater solutions for the entire site and not just the building itself. Together, 1 such certification systems provide powerful incenti ves to create innovative stormwater 2 solutions for redevelopment projects. 3 Municipal Leadership on Green Infrastructure . Cities have found that a green approach 4 to designing their streets, parking lots, and build ings can provide multiple benefits in the 5 urban setting and have retrofitted their infrastruc ture designs and building codes to allow 6 for green streets and streetscapes, urban forestry, and landscaping areas to treat 7 stormwater (COE 2005; COPH 2008; COPO 2008; SMC 200 9). 8 Alternative Strategy to Abate CSOs . Traditionally, most approaches to reduce the effe cts 9 of CSOs have relied on extensive mitigation structu res such as deep tunnels and swirl 10 concentrators to store and treat the overflows. In recent years, however, several cities 11 have realized that using LID practices on both the existing and redevelopment sectors can 12 sharply reduce the stormwater inflows into CSOs, an d more importantly, greatly reduce 13 the frequency and magnitude of overflow events (Lim notech 2007). For example, most 14 residents in Southeast Portland, Oregon, are ready and willing to support an ambitious 15 program to manage stormwater using a sustainable, o r as they often prefer, a natural 16 approach. Residents have a strong orientation towar d sustainable living, particularly 17 around walk/bike-friendly streets and organic and w ater-wise gardening (Campbell 18 DeLong Resources, Inc., 2008). The practical benefi t is that applying LID practices can 19 help reduce the large capital costs associated with CSO abatement. For example, the City 20 of Philadelphia is envisioning embarking on an ambitious project to implement LID 21 practices to reduce the reliance on underground inf rastructure ( COPH City of 22 Philadelphia , 2009). 23 Other examples of cities that are using LID practic es as an integral element of their CSO 24 abatement projects include Washington, DC; Portland , Oregon; and Milwaukee, Wisconsin. In 25 New York City, the Riverkeeper report Sustainable Raindrops: Cleaning New York Harbor by 26 Greening the Urban Landscape evaluates the costs and benefits of using green 27 infrastructure/LID to help mitigate CSOs ( http://www.riverkeeper.org/about28 us/publications/reports ). Riverkeeper estimates that for $1,000 invested i n the Department of 29 Environmental Protection’s end-of-pipe projects, CS Os might decrease by 2,400 gallons per 30 year. By comparison, the same $1,000 investment in : 31

• Green streets could decrease CSOs by 14,800 gallons 32

• Street trees could decrease CSOs by 13,170 gallons 33

• New green roofs could decrease CSOs by 810 gallons; retrofitted green roofs could 34 decrease CSOs by 865 gallons; and incentivized gree n roofs could decrease CSOs by 35 12,000 gallons 36

• Rain barrels could decrease CSOs by 9,000 gallons 37 That indicates the value of incorporating LID pract ices in redevelopment. 383/15/20 2

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Chapter 3. Controlling Urban Runoff 3-114 

### 4. 1 Establish 3 Stormwater Performance Standards G oals for the 1 

### Redevelopment Sector Consistent with the Goal 2


### A number

of Restoring Predevelopment Hydrology 3 For all redevelopment sites, establish the means of determining compliance with the different 4 numeric performance standard goals have been established for runoff volume reduction or 5 pollutant reduction. stormwater management in the redevelopment sector, as described below: 6 The federal government is leading by example by req uiring runoff volume reduction that would 7 either be equivalent to that of predevelopment hydr ology, or as a default depth, from the 95 th 8 percentile rainfall event. That requirement applies for redevelopment projects at federal facilities 9 and lands nationwide, and is described in U.S. DoD (2009) and USEPA (2009b). It is derived 10 from section 438 of the 2008 Energy Independence an d Security Act. In the Chesapeake Bay 11 watershed, that LID requirement would apply to abou t 1.5 to 1.9 inches of rainfall, depending on 12 where the project is in the watershed. 13

• Several cities such as the District of Columbia, Ph iladelphia , Los Angeles and sta t es such 14 as Pennsylvania and New Jersey promote sustainable stormwater management and have 15 established their own requirements for run off reduction for redevelopment sites that meet 16 or exceed those required by the state. 17



### 4. 2 4 Stormwater Management Practices for Redevelopment 18 A unique set of practices are commonly used to redu ce runoff and pollutant loads from the 19 redevelopment sector, as shown in Table 3-42. The p ractices can be applied to address untreated 20 impervious or pervious areas in the redevelopment s ector. 21

Table 3 4 -42: Example practices for addressing Practices for Addressing the redevelopment 22 sector Redevelopment Sector 23 Treat impervious cover Manage pervious areas Green Roofs Rainwater Harvesting, including Blue Roofs Foundation Planters Permeable Pavers Expanded, Compaction-protected Tree Pits Flexible Rubber Sidewalk Sections for Tree Pits Urban Bioretention Bioretention Conserve and Restore Natural area Remnants Soil Amendment and Restoration Reforestation Conservation Landscaping Turf Management Impervious Cover Reduction Create Functional Bioretention from Elevated Parking Lot Islands and Traffic Medians Note: Where surface area is available, typical on-s ite LID stormwater practices from the new developme nt sector can be used to comply . In addition, when feasible on-site practices are not capable of achieving full attainment of predevelopment hydrology, restoration practices fro m the existing development areas may help in mitiga tion. For more detailed information on each practice, please consult the practice profile sheets in Section 6 of this Guide3/15/20 2

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Chapter 3. Controlling Urban Runoff 3-115 Key considerations in applying these practices are as follows: 1

• Use a Roof to Street Design Approach. Break the site into smaller drainage areas with a 2 unique LID solution for each area (e.g., roofs, ped estrian areas, streets, open space and 3 parking lots). In that manner, stormwater managemen t is directly integrated into the 4 design of buildings, parking lots, hardscapes, open spaces, landscaping, and streetscapes. 5 That avoids the need for underground structures or consumption of costly surface real 6 estate for stormwater practices. The basic approach includes 7

– Managing rooftop runoff through green roofs, water harvesting, disconnection, or 8 storage and release from foundation planters 9

– Minimizing surface parking or designing designed surface parking to reduce, store, 10 and treat stormwater using permeable pavements, bio retention, or biofiltration s and 11 filters (see SMC 2009) 12

– Designing urban hardscapes such as plazas, courtyar ds, and pedestrian areas to store, 13 filter, and treat runoff using permeable pavers (wi th storage in the void space of 14 underlying gravel), stormwater planters, and amenit y bioretention areas 15

– Ensuring that all pervious and landscaping areas in the redevelopment project are 16 designed for effective stormwater treatment using p ractices such as soil restoration, 17 reforestation, and bioretention 18

– Designing the streetscape to maximize the capture a nd re use of stormwater runoff by 19 using expanded tree pits, street bioretention, curb cut extensions, and other green 20 street

methods (see COPO 2008; COPH 2008; and SMC 2009) 21 An example of such a design approach is the redevel opment of an office building at 1050 22 K Street, NW, Washington, DC, in the downtown busin ess district, shown in Figure 3-18. 23 Figures 3-19 and 3-20 provide additional redevelopm ent examples. 24

• Reduce Real Impervious Cover . Ensure that pervious cover performs hydrologicall y as if 25 it were an undisturbed pervious area. Deep tilling and amending soils with compost and 26 other materials can increase porosity and water hol ding capacity. In many cases, runoff 27 from rooftops can be effectively disconnected and d rained over such improved pervious 28
areas. 29

• Identify and Treat Hotspot-Generating Areas . Require that contributing drainage areas 30 from stormwater hotspots be isolated from the remainder of the site (usuall y by grading 31 and drainage) so that the runoff can be fully treat ed to prevent toxic discharges to surface 32 water or groundwater. 33

• Adapt LID to Urban Design . Adapt principles such as Better Site Design (CWP 1998) to 34 urban environments. Examples include innovative urb an parking management solutions 35 (COE 2005), municipal green street specifications ( SMC 2009), context-sensitive road 36 design standards providing stormwater treatment in the right-of-way (MC 2008), and 37 modifications to traditional streetscape standards to use street trees as a stormwater 38 filtering device (COPO 2008; Cappiella et al. 2006 ; Stormwater Magazine March/April 39 2010 ). 403/15/20 2

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Chapter 3. Controlling Urban Runoff 3-116 The potential for green infrastructure to mimic nat ural systems even in the densest of cities is demonstrated at 1050 K Street—a LEED Gold-certified office building in the heart of Washington, DC, on the site of a former parking lot. The site had been 97 percent impervious. The project design reduced impervious area to 67 percent. Runoff from the prop erty occurs only in a major storm event because of the green infrastructure practices employed in the building design:

• Two tiers of green roofs retain rainwater falling on the rooftop

• Three bioretention cells in the building plaza ret ain and treat runoff from adjacent impervious areas

• A 5,000-gallon cistern beneath the building comple ments these features by storing any stormwater that cannot be retained.

• All irrigation water is from the cistern, reducing building water consumption and maintaining cistern storage capacity. This suite of green infrastructure practices provid es stormwater benefits, an urban oasis for the tena nts and passers-by, and a competitive advantage for the building owners (Lanier 2007).

Figure 3-18. Redevelopment stormwater retrofits at 1050 K Street, Washington, DC. 1 Photos, courtesy Lu Gay Lanier, The Timmons Group3/15/20 2

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Chapter 3. Controlling Urban Runoff 3-117 1 In 2009 Manassas Park, Virginia, expanded the eleme ntary school, using an existing impervious parking lot as the site. The new school incorporate s many natural educational features, a historic sit e, and functional stormwater features. Native plants a nd no-mow meadow grasses are used to enhance the educational experience. The post-development ru noff is slightly lower than predevelopment conditions. See a video highlighting the features a t http://vimeo.com/chesapeakebay

. A 75,000-gallon rainwater cistern, built to potable water standards, collects rainwater from the entir e rooftop area and is used for toilet flushing and ir rigation. It is estimated to conserve 1.3 million g allons of water per year. An outdoor classroom with semicircu lar, stepped seating doubles as a stormwater bioretention cell.3/15/20 2

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Chapter 3. Controlling Urban Runoff 3-118 1 Figure 3-19. Manassas Park Elementary School. 2 In 2009 Manassas Park, Virginia, expanded the eleme ntary school, using an existing impervious parking lot as the site. The new school incorporate s many natural educational features, a historic sit e, and functional stormwater features. Native plants a nd no-mow meadow grasses are used to enhance the educational experience. The post-development ru noff is slightly lower than predevelopment conditions. See a video highlighting the features a t http://vimeo.com/chesapeakebay

. A 75,000-gallon rainwater cistern, built to potable water standards, collects rainwater from the entir e rooftop area and is used for toilet flushing and ir rigation. It is estimated to conserve 1.3 million g allons of water per year. An outdoor classroom with semicircu lar, stepped seating doubles as a stormwater bioretention cell.3/15/20 2

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Chapter 3. Controlling Urban Runoff 3-119 1 The Yorktown project serves as a model for resident ial and business communities demonstrating how green roofs and other stormwater management designs can be implemented to improve water quality, decrease erosive stormwater, and conserve flora and wildlife resources in the Chesapeake Bay watershed. In designing the green roof, structural concerns re lative to the 30-year-old building were a major fac tor in the decision to use a lightweight building syste m incorporating waterproofing, root barrier, water retention, and drainage system in one layer. The 15 pound/square foot capacity had to include all weight associated with the waterproofing, growing m edia, water retention system, and mature vegetation (fully saturated and fully hydrated). Th e project, including membranes cost $12 per square foot (sf) (for a 4,700-sf green roof system). It is estimated that the green roof provides a 20 p ercent reduction in cooling cost and should enjoy a life expectancy of more than 40 years. Initial reports c onfirm that 80 percent of the annual rainfall is retained on the roof, via a hydrogel technology alo ng with the design of the porous growing media. Other storm water management features consist of ra in gardens, a bioswale, and a federally protected biohabitat.3/15/20 2

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Chapter 3. Controlling Urban Runoff 3-120 1 Figure 3-20. Yorktown Square Condominiums, Falls Ch urch, Virginia. 2



### 4. 2.1 5 Practice Integration and Assessment Tools 3 Effective application of the roof-to-street design approach in the redevelopment sector requires 4 creative integration of stormwater practices in bui ldings, courtyards, streetscapes, and parking 5 lots. Multiple practices are used to treat and redu ce runoff from small and different urban 6 surfaces , using a treatment train approach to help ensure t he best performance. Redevelopment 7 programs should identify opportunities for a range of types and sizes of redevelopment projects. 8 Practices should be identified that can be encourag ed or required for implementation at sites even 9 below applicability area thresholds

. 10 Several tools have been developed to track progress in meeting the performance standards for the 11 redevelopment sector , and optimize the best and to identify most cost-effective combination s of 12 practices at the site. Such tools include the follo wing: 13

• A series of spreadsheets that allow the user to bre ak the site into smaller drainage areas 14 and size and optimize the most appropriate practice s for them. For example Emeryville, 15 California (COE 2005), developed a spreadsheet-base d calculator to determine the proper 16 size of stormwater treatment devices for new develo pment projects 17 (see http://ca-emeryville.civicplus.com/DocumentView.asp x?DID=109 ). Virginia 18 The Yorktown project serves as a model for resident ial and business communities demonstrating how green roofs and other stormwater management designs can be implemented to improve water quality, decrease erosive stormwater, and conserve flora and wildlife resources in the Chesapeake Bay watershed. In designing the green roof, structural concerns re lative to the 30-year-old building were a major fac tor in the decision to use a lightweight building syste m incorporating waterproofing, root barrier, water retention, and drainage system in one layer. The 15 pound/square foot capacity had to include all weight associated with the waterproofing, growing m edia, water retention system, and mature vegetation (fully saturated and fully hydrated). Th e project, including membranes cost $12 per square foot (sf) (for a 4,700-sf green roof system). It is estimated that the green roof provides a 20 p ercent reduction in cooling cost and should enjoy a life expectancy of more than 40 years. Initial reports c onfirm that 80 percent of the annual rainfall is retained on the roof, via a hydrogel technology alo ng with the design of the porous growing media. Other storm water management features consist of ra in gardens, a bioswale, and a federally protected biohabitat.3/15/20 2

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Chapter 3. Controlling Urban Runoff 3-121 Department of Conservation and Recreation (VA DCR 2 009) developed a spreadsheet1 based tool to estimate stormwater volume reduction and pollutant removal (see 2 www.dcr.virginia.gov/lr2f.shtml ). 3

• Philadelphia uses a series of checklists and worksh eets to achieve the same purposes 4 (COPH 2008) (see 5 www.phillyriverinfo.org/PWDDevelopmentReview/Requir ementsLibrary.aspx#www.phi 6 llywatersheds.org/what_were_doing/documents_and_dat a/cso_long_ term_control_plan )

. 7 Urban communities in the Chesapeake Bay watershed a nd elsewhere should adapt and modify 8 such integration tools to meet their unique redevel opment conditions. 9 Designers might also maximize stormwater LEED point s to obtain green building certifications 10 or use the performance benchmarks for sustainable s tormwater initiatives (ASLA 2009). See the 11 example in Figure 3-21. 12

13 The Eastern Village Condominiums structure is a red evelopment of a former office building that has been transformed into 56 condominium units in a thr iving urban community. It is the first LEEDcertified cohousing structure. Before construction, the site was more than 90 percent impervious while the new design decreased the imperviousness o f the site to 54 percent. Practices installed at the site include a green roof, a vegetated courtyar d, and rain barrels.

Roof area: 12,330 sf Planted area: 8,000 sf Cost: $36/sf (2006)3/15/20 2

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Chapter 3. Controlling Urban Runoff 3-122 1 Figure 3-21. Eastern Village Cohousing Condominiums HOA, Silver Spring, Maryland 2



### 4.3 Site Evaluations 3


### Site evaluations should be conducted to determine t he 4 

### appropriateness of infiltration practices. Soils sh ould be 5 

### evaluated to 4.6 Programmatic Practices for the R edevelopment 6 

### S ector 7 T he following recommend ations help a ddress redevelopment program implementation: 8 Defi ne Redevelopment

. C lear ly defin e redevelopment and the minimum land area 9 trigger ing stormwater requirements. 10
Establish Redevelopment Stormwater Performance Standards. E stablish a defined 11 performance standard for runoff volume reduction or pollutant reduction for all 12 redevelopment sites. If it is technically infeasible to achieve predevel opment hydrology 13
on

- site, provide an offset or a mitigation fee if full compliance is not possible. Use f unds 14 from the offse ts to finance stormwater retrofit and restoration p rojects elsewhere in the 15 sub watershed. 16 The Eastern Village Condominiums structure is a red evelopment of a former office building that has been transformed into 56 condominium units in a thr iving urban community. It is the first LEEDcertified cohousing structure. Before construction, the site was more than 90 percent impervious while the new design decreased the imperviousness o f the site to 54 percent. Practices installed at the site include a green roof, a vegetated courtyar d, and rain barrels.

Roof area: 12,330 sf Planted area: 8,000 sf Cost: $36/sf (2006)3/15/20 2

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Chapter 3. Controlling Urban Runoff 3-123 Conduct Site Investigations

. E valuate soil conditions and determine whether the site is subject to 1 brownfield remediation. Stormwater designers can us e the assessments to determine if 2 stormwater runoff can be infiltrated, soils need to be capped, environmental and utility 3 constraints exist, or natural area remnants can be protected or restored. The investigations are 4 also useful to map the best locations for LID pract ices and how they can be connected as an 5 effective system. 6


### 4.4 Codes and Ordinance Review 7 Review Codes and Ordinances

. Change or supplement codes and ordinances as necess ary to 8 allow the use of certain redevelopment practices (e .g., rainwater harvesting/plumbing codes, 9 green roofs/building codes; green streets/road code s). See EPA’s Water Quality Scorecard 10 ( http://cfpub.epa.gov/npdes/greeninfrastructure/muni chandbook.cfm ) (USEPA 2009d), ), Better 11 Site Design: A Handbook for Changing Development Ru les in Your Community (CWP 1998) and 12 NRDC’s Out of the Gutter: Reducing Polluted Runoff in the District of Columbia 13 ( www.nrdc.org/water/pollution/gutter/gutter.pdf ). 14



### 4.5 Implement Demonstration Projects 15

: Implement demonstration projects to promote and dem onstrate green infrastructure techniques. 16 That approach is proven to promote progress in impl ementing innovative practices. 17


### 4.6 Incentives for Incentivize Early Adopters 18

. Offer the private sector incentives to install more expensive or (locally) experimental practices. 19 For example, New York City (Jones 2009 ) and ), the District of Columbia (Anacostia Watershed 20 Society and DC Department of the Environment 2010) and Baltimore ( Green Building Template: 21 A Guide to Sustainable Design Renovating for Baltim ore Rowhouses

. Prepared by TerraLogos: 22 ECO Architecture f or the Maryland Department of Natural Resources. De cember 2001 ) offer 23 direct subsidies to partially defray the cost of in stalling blue roofs and green roofs, and several 24 west coast communities offer stormwater utility fee discounts for redevelopment projects that use 25 green streets or green parking lots. 26 EPA provides examples of program types and municipa l case studies in the Managing Wet 27 Weather with Green Infrastructure Municipal Handboo k Incentive Mechanisms (USEPA 2009a). 28 The following are the primary types of green infras tructure incentives: 29
Stormwater Fee Discount: Base the stormwater fee on impervious surface area. If property 30 owners reduce need for service by reducing impervio us area and the volume of runoff discharged 31 from the property, the municipality reduces the fee

. 32 Development Incentives: Offered to developers durin g the process of applying for development 33 permits. Examples include: zoning upgrades, expedit ed permitting, reduced stormwater 34 requirements and increases in floor area ratios. 35 Grants: Provide direct funding to property owners a nd/or community groups for implementing a 36 range of green infrastructure projects and practice s. 373/15/20 2

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Chapter 3. Controlling Urban Runoff 3-124 Rebates & Installation Financing: Provide funding, tax credits or reimbursements to property 1 owners who install specific practices. Often focuse d on practices needed in certain areas or 2 neighborhoods 3 Awards & Recognition Programs: Provide marketing op portunities and public outreach for 4 exemplary projects. 5



### 4.7 Maximize Urban Forest Canopy 6

. Maximize vegetation and forest canopy across the si te to gain incremental stormwater treatment 7 using expanded tree pits, green roofs, foundation p lanters, and urban bioretention. Information 8 on urban forestry practices is in section 2, and in the fact sheet on reforestation/urban forestry in 9 section 6. 10 

### 4.8 Amend Compacted Amend compacted urban soils

. Urban Soils 11 Urban soils are often compacted resulting in poor infiltr ation rates. Amending the soil with 12 compost or another soil mixture can significantly i ncrease the infiltration rate for the soils. 13 Information on soil amendment practices are in sect ion 5 on turf management, and in the fact 14 sheet on soil amendment in section 6. 15
Exercise Caution with Urban Soil Contamination . Exercise caution in i nfiltration of 16 stormwater runoff in redevelopment projects with contaminated soils . Infiltration should 17 general ly be avoided when site history indicates that the site was a stormwater hotspot or 18 a brownfield. In such situations , EPA recommends using lined stormwater filtering 19 practices such as sand filters and bioretention to prevent groundwater contamination (see 20 Schueler 2007 or USEPA 2008). 21



### 4. 9 7 References 22 ASLA (American Society of Landscape Architects). 20 09. Guidelines and performance 23 benchmarks . Sustainable Sites Initiative Project. American So ciety of Landscape 24 Architects , Washington, DC

. 25 Brookings Institute. 2004. Toward a new metropolis: the opportunity to rebuild America . Arthur 26 Nelson. Virginia Polytechnic Institute and State Un iversity. Discussion Paper. Brookings 27 Institution Metropolitan Policy Project, Washington , DC. 28 Campbell DeLong Resources, Inc. 2008. Citizen Response to Sustainable Stormwater 29 Management in Inner Southeast Portland . Focus Group Research Conducted for City of 30 Portland Environmental Services , Portland, OR.

. 31 Cappiella, K., T. Schueler, and T. Wright. 2005. Urban Watershed Forestry Manual . Part I: 32 Methods for Increasing Forest Cover in a Watershed. U.S. Department of Agriculture 33 Forest Service, Newtown Square, PA 343/15/20 2

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Chapter 3. Controlling Urban Runoff 3-125 Cappiella, K., T. Schueler, and T. Wright. 2006. Urban Watershed Forestry Manual. Part 2: 1 Conserving and planting trees at development sites. U.S. Department of Agriculture, Forest 2 Service, Newtown Square, PA. 3 City of Philadelphia. 2009. Green City, Clean Waters

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