URBDP 466A/598G Assignment #1
Name: Simin Xu
Systems Analysis of Green Stormwater Infrastructure in Seattle 1 SYSTEM INTRODUCTION AND ITS CHARACTERISTICS 1.1
DEFINITION AND USES The concept of Green Infrastructure can be traced back to 140 years ago, when Frederick Law
Olmsted involved a large artificial landscape into the New York urban center, which could be deemed as the prototype of green infrastructure. The terminology of originating in the United States in the mid1990s highlights the importance of the natural environment in decisions about land-use planning.1 It is a term that describes the abundance and distribution of natural features in the landscape like forests, wetlands, and streams.2 According to United States Environmental Protection Agency (EPA), green infrastructure uses vegetation, soils, and natural processes to manage water and create healthier urban environments, and is a cost-effective and resilient approach to our water infrastructure needs that provides many community benefits.3 Also, EPA has extended the concept of Green Infrastructure to apply to the management of stormwater runoff at the local level through the use of natural systems, or engineered systems that mimic natural system, to treat polluted runoff.4 In contrast with Green Infrastructure which using environmentally friendly techniques to manage stormwater, Grey Infrastructure is conventional techniques which contains waste and hazardous substances from farms and gardens.5
Maryland Department of Natural Resources, Annapolis, MD, Maryland’s Green Infrastructure Assessment: A Comprehensive Strategy for Land Conservation and Restoration, May 2003. 2 Ted Weber, Anne Sloan, and John Wolf, “Maryland’s Green Infrastructure Assessment: Development of a Comprehensive Approach to Land Conservation,” Landscape and Urban Planning 77, no. 1–2 (June 15, 2006): 94–110. 3 United States Environmental Protection Agency, “What Is Green Infrastructure,” Data & Tools, last updated on June 13, 2014, http://water.epa.gov/infrastructure/greeninfrastructure/gi_what.cfm. 4 U.S. Environmental Protection Agency, Managing Wet Weather with Green Infrastructure: Action Strategy 2008, January 2008. 5 United States Environmental Protection Agency, “US EPA Green and Gray Infrastructure Research,” Overviews & Factsheets, last updated on July 2, 2014, http://www.epa.gov/nrmrl/wswrd/wq/stormwater/green.html#green. 1
Green Stormwater Infrastructure (GSI) is a part of Green Infrastructure, mainly used for water storage. It is a fresh terminology defined by Seattle Public Utilities (SPU) as a Low Impact Development (LID) - based stormwater management approach that strive to mimic pre-disturbance hydrologic processes of infiltration, filtration, storage, evaporation and transpiration by emphasizing conservation, use of on-site natural features, site planning and distributed stormwater management practices that are integrated into a project design.6 Seattle’s GSI suite includes trees, bioretention, permeable pavements, green roofs and rainwater harvesting.7 GSI always been used in public right-of-ways, called “Natural Drainage Systems” (NDS), and private parcel thresholds to storage water and improve the water quality.8
1.2
HISTORY OF GSI The history of GSI can be dating back to the spring of 2001, when the first GSI project
completed in Seattle's pilot Street.9 It is a 14-foot-wide, meandering road that closely mimics the natural landscape, rather than traditional piped systems to reduce impervious surfaces and provide surface detention in swales.10 It was very successful, collected approximately 2.3 acres stormwater and the reduction in run-off volume is as high as 99 percent.11 After that, many other projects followed the GSI model. Inventory of GSI projects in Seattle is in next section. In July 2013, City Council unanimously passed Resolution 31549, which defines GSI as a critical aspect of a sustainable drainage system and states it should be used to manage runoff whenever possible.12 It also sets a new implementation target to manage 700 million gallons of runoff annually with GSI by 2025 and directs departments to collaborate on an Implementation Strategy.13
Seattle Public Utilities, “Low Impact Development,” Drainage & Sewer, http://www.seattle.gov/util/MyServices/DrainageSewer/Projects/GreenStormwaterInfrastructure/LowImpactDevel opment/index.htm. 7 Ibid. 8 Seattle Public Utilities, Green Stormwater Infrastructure (GSI) - Program Overview and Annual Report 2013, 2013. 9 Seattle Public Utilities, “Street Edge Alternatives,” Drainage & Sewer, http://www.seattle.gov/util/MyServices/DrainageSewer/Projects/GreenStormwaterInfrastructure/CompletedGSIPr ojects/StreetEdgeAlternatives/index.htm. 10 Seattle Public Utilities, “Street Edge Alternatives,” Drainage & Sewer, http://www.seattle.gov/util/MyServices/DrainageSewer/Projects/GreenStormwaterInfrastructure/CompletedGSIPr ojects/StreetEdgeAlternatives/index.htm. 11 Ibid. 12 Seattle Public Utilities, Green Stormwater Infrastructure (GSI) - Program Overview and Annual Report 2013, 2013. 13 Ibid. 6
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1.3
SERVICE AREAS AND INVENTORY The GSI in Seattle involves municipality projects (mostly NDS) and private household programs.
After the first project in Sea Street, other part of the city including Carkeek Cascade, Broadview, High Point, and Pinehurst followed this LID model. Construction in these cities were completed before 2007. The current projects of GSI are including Ballard Natural Drainage System, Delridge Natural Drainage System, Swale on Yale, and Venema Natural Drainage System. (See Table 1) The private household programs are basically Rain Wise Program. Each household are voluntary to use sloping roof of their house, and porous pavers, driveway with grass center, compostamended soil, and rock-filled trench in their courtyard. They are also encouraged to plant trees in their parcel in order to reduce flooding and restore waters for people and wildlife, and protect property.14 Table 1 - Basic Characteristics of GSI Projects
Current
Completed
Projects
Complete Major Function Time Water Quality Flow Control
Street Edge Alternatives (SEA Street)
2001
110th Cascade Project
2002
Broadview Green Grid
2004
Pinehurst Green Grid
2006
Y
Y
Y Y
Y Y
High Point Natural Drainage System Ballard Natural Drainage System Delridge Natural Drainage System
2009
Y
Y
after 2013
Y
Y
after mid2015
Y
Swale on Yale
unknown
Y
Venema Natural Drainage System
after summer of 2015
Y
Y
Location On 2nd Ave NW, between NW 117th and 120th Streets Along four blocks of NW 110th St, between Greenwood Ave N and 3rd Ave NW N 107th St., from 4th Ave N. to Phinney Ave N From NE 117th St. to NE 113th St., 16th Ave. NE to 23rd Ave NE, and NE 113th St. at the intersection of 25th Ave. NE From 35th Ave SW to High Point Drive SW and SW Juneau St. to SW Myrtle St. A Between NW 85th St. to NW 65 St, 15th Ave.NW. to 32nd Ave. NW Along several blocks of 17th Ave SW in the South Delridge neighborhood On Yale Avenue North and Pontius Avenue North Along NW 120TH St., from 3rd Ave NW to 1st Ave. along NW 122TH St., from 3rd Ave NW to Palatine Ave.
Service Area
Covered Blocks
3.2 acres
1
21 acres
4
32 acres
15
49 acres
12
140 acres
34
about 665acres
20 projected blocks
unknown
unknown
unknown
4
about 15 acres
about 5
Data are summarized from projects’ brochure and plan from USP website. The service area and covered blocks of current projects are measured in Google Map.
As we can see, the first GSI project only covers 1 block, but it triggered GSI in other part of Seattle area. Among all the completed project, High Point Natural Drainage System is the largest one, which covers a service area of 140 acres, and it is both used for flow control and water quality
Seattle Public Utilities, “RainWise Program,” Drainage & Sewer, http://www.seattle.gov/util/MyServices/DrainageSewer/Projects/GreenStormwaterInfrastructure/RainWise/index. htm. 14
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improvement. In the future, the largest Ballard Natural Drainage System will cover a service area of approximately 665 acres. Location and vicinity of these projects are in Figure 1 and Figure 2.
Figure 1 - Location of GSI Projects
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Figure 2 - Vicinity of Completed GSI Projects Sources: collected from SPU & SDOT, “Location Map,” Construction Project Plan Set.
Generally, techniques used in GSI are including vegetated swales, narrower streets, porous sidewalks, cascading pools, curvilinear street design, rain gardens.15 The following table shows the techniques used in each completed projects. (See Table 2) Table 2 - Techniques Used in GSI Projects
GSI Components Projects Street Edge Alternatives 110th Cascade Project Broadview Green Grid Pinehurst Green Grid High Point Natural Drainage System
Vegeted Narrower Porous Cascading Curvilinear Rain Wetland Pavement Swales Streets Sidewalks Pools Street Design Gardens Ponds Reduction Y Y Y Y
Y Y Y
Y Y Y Y
Y
Y
Y
Y
Y
Y
Y
Y
Y Y Y
(Data summarized from SPU & SDOT, Construction Project Plan Set; and also Robert L. France, Handbook of Regenerative Landscape Design, p294-304,2008.)
Water Environment Research Foundation, “Incorporating Water Quality Features into the Right-of-way,” Case Studies, 2009, http://www.werf.org/liveablecommunities/studies_sea_wa.htm. 15
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Other than these municipality projects, private household RainWise programs are also important part of GSI. The city of Seattle and King County now offer rebate for RainWise program. The total number they offered is more than 40,000 eligible household in Seattle, and 135 new rain gardens and cisterns were installed via RainWise.16
1.4
COST AND REVENUE SOURCE For most projects, the cost are not limited to construction cost, but an extensive design and
communication cost of working closely with residents. According to SPU’s cost and benefit analysis, the cost of GSI project in SEA Street, 100th Cascade project and Broadview Green Grid respectively are $325,000, $285,000 and $280,000 per block, which means the total cost of these projects are $325,000, $1140,000 and $4200,000 by using the cost per block plus by the number of blocks.17 However, another statistic in SPU’s website shows that $850,000 were actually spent on SEA street GSI project.18 High Point Natural Drainage System project is a part of the High Point Redevelopment Project which covers a construction cost of over $70 million.19 The actually cost for other completed projects are difficult to find. Major revenue sources for these projects comes from Seattle Public Utilities Drainage and Wastewater Fund of SPU. For specific revenue of this Fund and the projected cost of CIP projects, see Section 8 – Budget and Financing. Despite no exactly cost for GSI projects in Seattle, the use of green infrastructure practices to reduce runoff volume is cost-competitive with conventional Stormwater systems. It has been estimated that green infrastructure is 5%-30% less costly to construct and about 25% less costly over its life cycle
16
Seattle Public Utilities, Green Stormwater Infrastructure (GSI) - Program Overview and Annual Report 2013, 2013. 17 SPU, Seattle Public Utilities – Natural Drainage System Program Costs and Benefits Document, http://www.seattle.gov/util/groups/public/@spu/@usm/documents/webcontent/spu02_019986.pdf. 18 Seattle Public Utilities, “Street Edge Alternatives,” Drainage & Sewer, http://www.seattle.gov/util/MyServices/DrainageSewer/Projects/GreenStormwaterInfrastructure/CompletedGSIPr ojects/StreetEdgeAlternatives/index.htm. 19 Seattle Housing Authority, High Point Development | Seattle, WA, http://www.svrdesign.com/high-pointredevelopment-seattle-wa/6xnkclbt6sgq89of2yg7eo51qxlebm. 6|
than traditional infrastructure.20 Data from Seattle Public Utilities indicates construction cost savings equivalent to $329 per square foot, or $100,000 per block.21
1.5
DATABASES AVAILABLE For data relating financial and budgeting, see:
City of Seattle Adopted Capital Improvement Program; (PDF file available at the website of City Budget Office of Seattle Government)
The City of Seattle Comprehensive Annual Financial Report; (PDF file available at Website of Financial Services of Seattle Government)
Cost-Benefit Analysis of Street Edge Alternatives, 110th Cascade Project, and Broadview Green Grid; (PDF file available at website of Seattle Public Utilities)
For data relating characteristics and outcomes of each projects, see:
Page narrative of each project’s link available at Services > Drainage & Sewer > Projects > Green Stormwater of SPU;
Multiple monitoring reports in Measuring Success part of GSI. (9 PDF files are available concerning water quality and volumne in website of SPU)
For data relating technique means of GSI, see:
Construction plan of completed projects; (PDF files are available at each projects’ link in website of SPU)
For data relating broad definition of GSI and NDS, see:
Green Stormwater Infrastructure page of SPU’s website; (PDF are available concerning the history and projects of GSI)
20
See for example, Christopher Kloss et al., Rooftops to Rivers: Green Strategies for Controlling Stormwater and Combined Sewer Overflows, 2006; and Natural Resources Defense Council, Rooftops to Rivers II: Green Strategies for Controlling Stormwater and Combined Sewer Overflows, 2011. 21 Members and Committees of Congress, Green Infrastructure and Issues in Managing Urban Stormwater, March 21, 2014, http://nationalaglawcenter.org/wp-content/uploads/assets/crs/R43131.pdf. 7|
2 CONDITION AND PERFORMANCE Existing GSI projects provide many benefits in water system concerning water quality and flow control, Table 3 is a summary of the performance of completed projects. (See Table 3) Table 3 - Summarized Performances of Completed GSI Projects
Existing GSI Projects
Water Flow
Water Quality
Street Edge Alternatives 99% reduction in runoff volume
No records Provides excellent water quality benefits. Post48-74 % reduction in runoff volume; Manages construction monitoring showed that water 110th Cascade Project high volumes of stormwater from many acres pollutants like lead, copper, and zinc were of watershed area (5 to 50 acres) reduced by up to 90 percent. Broadview Green Grid 70% reduction in runoff volume
Pinehurst Green Grid High Point Natural Drainage System
No records
82% reduction in runoff volume, managing 9.7 million gallons of stormwater annually.
Provides water quality treatment per City of Seattle and Washington Department of Ecology (DOE) standards for the total drainage area.
Prevented 99% of the wet season runoff from flowing directly into Pipers Creek
No records
Data summarized from SPU website
All GSI projects implemented have an excellent performance in reduction in runoff volume, managing large amount of stormwater annually. Evidences show that 110th Cascade Project and Pinehurst Green Grid play a role in improving water quality.22 For the private household program – the RainWise Pilot, the city of Seattle provides 99% rebates to property owners who construct a rain garden or stormwater cistern on their property. Eventually, it helps to reduce sewage overflows from the private part. Not only that, GSI also has many community benefits like it improves air quality, beautify neighborhoods, improve pedestrian safety, offers education opportunities, supports biodiversity improves habitat etc.23 In Broadview, Seattle Department of Transportation (SDOT) also teamed with UPU to incorporate traffic-calming elements and pedestrian improvements with modifications to enhance the drainage function.24 This is an example of how drainage projects can benefits transportation condition of a community.
22
Seattle Public Utilities, Green Stormwater Infrastructure (GSI) - Program Overview and Annual Report 2013, 2013. 23 Robert L. France, Handbook of Regenerative Landscape Design, P294-304, 2008. 24 Ibid. 8|
In fact, the SEA Street was the first GSI projects in US.25 It has established a prototype for many cites including Portland, Minnesota, Chicago, Milwaukee, Philadelphia, Washington, Kansas city etc.
3 ADMINISTRATIONS The GSI project and program is not only the responsibility of SPU, other agencies and private households are also encouraged to involve in the GSI. Major partnerships of GSI projects and programs are including Seattle Public Utilities (SPU), Seattle Department of Transportation (SDOT), Department of Planning Development (DPD), Office of Sustainability and Environment (OSE), Department of Parks and Recreation (Parks), Seattle City Light (SCL), Department of Finance and Administrative Service (FAS). These are how they cooperate from design and planning, to management, to maintenance.
3.1
GSI CONCEPT DESIGN AND MANUAL GUIDE A set of standard GSI concept designs and details are developed by a collaboration of SPU,
SDOT, DPD and King County planning, design, construction, and maintenance staff.26 For example, SPU and SDOT both strive to build GSI that enhance neighborhood greenways. SPU mainly focus on techniques that purify and control water. SDOT pay more attention to transportation elements like narrowing street, providing traffic slowing and enhancing streetscape aesthetics. SPU also collaborated with DPD to develop draft incentives for “beyond-code� GSI achievements in different new development and redevelopment contexts.27
3.2
GSI IMPLEMENTATION PLAN For this implementation plan, OSE, SPU, SDOT, DPD should establish a coordinated approach
for the integration of GSI in the public right-of-way including developing a package of standard designs, viable strategies for long-term public-private partnerships etc.28 OSE, SPU, SDOT, DPD, Parks, SCL, FAS should also develop a coordinated approach for integration of GSI citywide including examining and revising development-related codes, rules and
25
Seattle Public Utilities, Green Stormwater Infrastructure (GSI) - Program Overview and Annual Report 2013, 2013. 26 Ibid. 27 Ibid. 28 Micheal McGinn, Mayer, City of Seattle, Citywide Green Stormwater Infrastructure Goal & Strategy, Executive Order No. 2013-01, 2013, http://clerk.seattle.gov/~CFS/CF_312840.pdf. 9|
standards, demonstrating continued City leadership by ensuring capital projects implement GSI, conducting an economic valuation study.29
3.3
GSI RELATING PLAN DRAFT SPU produces Storm Water Management Plan to protect water quality and reduce the
discharge of pollutants. DOT produces Right of Way Improvements Manual to help design and construct the city’s right of ways. DPD proposes Seattle’s Comprehensive Plan and other Neighborhood plan. All of these plan or manuals guide the process of GSI projects.
3.4
GSI PROJECTS JOINT MANAGEMENT Seattle and King County entered into a joint program management contract to streamline
delivery of GSI projects in Seattle’s right-of-way.30 Also, Seattle and King County signed an agreement in 2013 to share delivery of the RainWise program.31
3.5
JOINT MAINTENANCE SPU are responsible for operation and maintenance of bioretention cells and other techniques
in GSI projects, and residents can also provide maintenance to improve curb aesthetics like planting trees.32 Among all the department mentioned including SPU, SDOT, DPD, and King County, SPU is the most important part of administration of GSI projects and programs because it is responsible for making criteria, project design and construction, revenue collection used for GSI, project management as well as maintenance of projects.
29
Micheal McGinn, Mayer, City of Seattle, Citywide Green Stormwater Infrastructure Goal & Strategy, Executive Order No. 2013-01, 2013, http://clerk.seattle.gov/~CFS/CF_312840.pdf. 30
Seattle Public Utilities, Green Stormwater Infrastructure (GSI) - Program Overview and Annual Report 2013, 2013. 31 Ibid. 32 Seattle Public Utilities, “Street Edge Alternatives,” Drainage & Sewer, http://www.seattle.gov/util/MyServices/DrainageSewer/Projects/GreenStormwaterInfrastructure/CompletedGSIPr ojects/StreetEdgeAlternatives/index.htm. 10 |
4 LAND USE DESIGNATIONS All GSI projects are located in single family residential land use. For High Point project, 1600 mixed homes including town homes and apartments are in the 34 covered blocks.33 The Table 4 is a summary of zoning designation of GSI service area. (See Table 4) Table 4 - Summary of Zoning Designation of GSI Service Area
Current
Completed
GSI Projects
Zoning Designation
Street Edge Alternatives (SEA Street)
SF 7200
110th Cascade Project
SF 7200
Broadview Green Grid
SF 7200
Pinehurst Green Grid
SF 7200
High Point Natural Drainage System
LR 3
Ballard Natural Drainage System
SF 7200
Delridge Natural Drainage System
Unknown
Swale on Yale
SM-75
Venema Natural Drainage System
SF 9600
(Data obtained by identifying the location of each projects from zoning map of City of Seattle, which is available in WAGDA. Because there are no record about the future service area of Delridge Natural Drainage System, its zoning designation is unknown.)
5 RELATIONS TO NATURAL ENVIRONMENT GSI can restore the function of natural environment. It is also a reflection on unsustainable development which uses more Grey Infrastructure. The most important purposes of this system is to control water flow and improve water condition, both of which can be done in a complete and healthy natural environment. However, in the process of urbanization, the original function of natural environment has been cut. More and more sewage and industrial effluent discharges in the natural environment which exceeds the capacity of the natural environment. The overwhelming built of infrastructures, like highways and roads, increasing the area of impervious surfaces which cannot absorb rainwater. These kind of problems are exacerbating as the increasing population and motor vehicle uses. Therefore, many cities now are facing challenges involving storm water runoff which pollutes natural environment and human health.
33
Robert L. France, Handbook of Regenerative Landscape Design, P294-304, 2008. 11 |
GSI is an artificial but natural way, serves as a supplementary of natural environment to deal with these two problems. It is artificial because it is made by human. However, the GSI mimic the natural, for example, water can purified through “biofiltration” - vegetated swales that use natural healthy plants and soils to capture and break down pollutants;34 water can also stormed by using porous pavement. Moreover, it encourages to use natural resources like local healthy plants and soils to realize bio-retention and bio-purification. The SPU Natural Drainage Systems Plant List summarized the plant types that can appropriately be used in GSI.35 Because it restore the natural function of environment, it is an effective way to protect the urban environment, ecology, and resources, thus a model of sustainable development. Besides the impacts on water systems, GSI has benefits on other various natural systems:
To Atmosphere
The healthy plants that GSI uses in swales and street-side landscaping can to some extent purify the atmosphere since some plants can adsorb harmful substances and reduce wind.
To land surface
GSI encourage to use soft interval like plants on the land surface rather than hard pavement, thus can cool the land surface temperature.
To biological
GSI can provide secure water to human and other biology, improving the health of life in the environment. It also provides livable environment for plants and animals, and creates green spaces for residents.
6 REGULATORY FRAMEWORK Major legally enforceable regulations affecting the system are as follows:
Seattle Public Utilities, Seattle’s Natural Drainage Systems - A Low-Impact Development Approach to Stormwater Management, 2007, http://www.seattle.gov/util/groups/public/@spu/@usm/documents/webcontent/spu02_019984.pdf. 35 Seattle Public Utilities, Seattle’s Natural Drainage Systems Plant Palette Draft 2000-2006, http://www.seattle.gov/util/groups/public/@spu/@usm/documents/webcontent/spu02_019985.pdf. 34
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6.1
FEDERAL LEVEL
Clean Water Act of 1972 (CWA)
The objective of this Act is to restore and maintain the chemical, physical, and biological integrity of the nation's waters by preventing pollution sources, provide assistance to publicly owned treatment works for the improvement of wastewater treatment, and maintain the integrity of wetlands.36 In the Clean Water Act, the Section 303 – Water Quality Standards and Implementation Plans sets criteria to measure attainment of different uses, and establishing policies to protect water quality from pollutants.37
National Pollutant Discharge Elimination System (NPDES) Regulations
As authorized by the Clean Water Act, the National Pollutant Discharge Elimination System (NPDES) permit program controls water pollution by regulating point sources that discharge pollutants into waters of the United States.38 In the National Pollutant Discharge Elimination System, the Stormwater Program regulates stormwater discharges from three potential sources including the one of municipal separate storm server systems that GSI monitored.
Safe Drinking Water Act of 1996 (SDWA)
The Safe Drinking Water Act (SDWA) is the main federal law that ensures the quality of drinking water. Under SDWA, EPA sets standards for drinking water quality and oversees the states, localities, and water suppliers who implement those standards.39
6.2
STATE LEVEL
Washington State Water Pollution Control Act – Chapter 90.48 RCW
This Act maintain the highest possible standards to insure the purity of all waters of the state consistent with public health and public enjoyment.40 In RCW 90.48.280 – Sewage drainage basins, the
36
Clean Water Act (CWA), 1972. United States Environmental Protection Agency, “Regulatory Information,” Last updated on Thursday, October 04, 2012, http://water.epa.gov/lawsregs/rulesregs/. 38 United States Environmental Protection Agency, “Regulatory Information,” Last updated on Thursday, October 04, 2012, http://water.epa.gov/lawsregs/rulesregs/. 39 Safe Drinking Water Act (SDWA), 1996. 40 Washington State Legislature, Chapter 90.48 RCW-Water Pollution Control. 37
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act states that “The department is authorized to prepare and/or adopt a comprehensive water pollution control and abatement plan.”41 Both of the Federal and State regulations are legally guidance document that control water quality from the macro level, rarely involve the requirement to use GSI to achieve the water control purposes. This requirement are specifically stated in local regulation frameworks.
LOCAL LEVEL
6.3 6.3.1
Local Legislation City of Seattle Stormwater Code The City of Seattle’s Stormwater Code contained in Seattle Municipal Code (SMC) 22.800-
22.808 requires projects to implement green stormwater infrastructure (GSI) to the maximum extent feasible (MEF).42 This projects are including Trail and Sidewalk projects, Parcel-Based Projects, Roadway Projects, Single-family residential projects and other projects with 7,000 square feet or more of land disturbing activity or 2,000 square feet or more of new plus replaces impervious surface.43 This means that green stormwater infrastructure BMPs must be fully implemented, constrained only by the physical limitations of the site, practical considerations of engineering design and reasonable considerations of financial costs and environmental impacts.44 This code also states that to prevent sediment from entering all storm drains, including ditches that receive drainage water from the project.45 All the above legislations are mandatory requirement of using GSI as a way to control water flow and mandatory requirement for water quality. Specific design guidelines and construction approach of GSI could be find in city manuals and guidelines.
6.3.2
City Manuals (Code Interpretation) relating GSI techniques City of Seattle Stormwater Flow Control and Water Quality Treatment Technical Requirements Manual
41
Washington State Legislature, Chapter 90.48 RCW-Water Pollution Control. City of Seattle Stormwater Code, 2009. 43 City of Seattle Stormwater Code, 2009. 44 Seattle Municipal Code, 22.801.140. 45 Ibid. 42
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In this manual, Chapter 4.3 is general requirements for all Infiltration facilities, including setbacks and site restrictions, and subsurface evaluation requirements. Chapter 4.4 outlines the design guidelines and criteria for use of GSI.46
Directors Rules on Green Stormwater Infrastructure to the Maximum Extent Feasible for SFR and Parcel Based Projects Clarification of Seattle’s code requirement is provided in Directors Rules of these documents.
Because the City Code legislated that all single-family residential and parcel-based projects should implement GSI to the maximum extent feasible, this is a guideline of GSI reporting and feasibility analysis to help applicant to meet the GSI to MEF requirement and documenting the specific opportunities and constraints that exist.47
Directors Rules on Green Stormwater Infrastructure to the Maximum Extent Feasible for Roadway, Trail, and Sidewalk Projects It guides roadway, trail and sidewalk projects to meet MET requirement.
Right-of-Way Improvement Manual It provides information on rules specific to the use of GSI Facilities within the Right-of-Way.48
7 BUDGET AND FINANCING The City of Seattle’s Capital Improvement Program (CIP) allocates existing funds and anticipated revenues to rehabilitate, restore, improve, and add to the City’s capital facilities.49 CIPs improve or maintain the utility infrastructure that serves Seattle residents.
SPU & DPD, “Stormwater Manual,” vol. 3 Stormwater Flow Control & Water Quality Treatment Technical Requirements Manual, 2009, http://www.seattle.gov/dpd/codes/dr/DR2009-17.pdf. 47 SPU & DPD, “Requirements for Green Stormwater Infrastructure to the Maximum Extent Feasible for SingleFamily Residential and Parcel-Based Projects,” 2013, http://www.seattle.gov/dpd/codes/dr/DR2012-15.pdf. 48 City of Seattle, “Seattle Right-of-way Improvements Manual,” Chapter 6 Streetscape Design Guidelines, http://www.seattle.gov/transportation/rowmanual/manual/6_4.asp. 49 Department of Finance, City of Seattle 2007-2012 Adopted Capital Improvement Program, http://www.seattle.gov/financedepartment/0712adoptedcip/2007-2012_ADOPTED_CIP_BOOK.pdf. 46
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From 2001-2006, the total allocation on City-Owned Utilities accounts $1,769,382 thousands, from which $328,503 thousands is used in drainage & wastewater system.50 (See Figure 3)
2001-2006 Adopted CIP by Department
2001-2006 Adopted CIP for City-Owned Utilities
Arts Commission
31%
23% 9%
20%
17%
Executive Services Parks and Recreation Seattle Center
City Light Drainage & Wastewater
27% 3% 1% 18%
51%
Solid Waste Technology Projects
Seattle Public Library
SPU – Water
Figure 3 - left: 2001-2006 Adopted CIP by Department; right: 2001-2006 Adopted CIP for City-Owned Utilities
From 2007-2012, the total allocation on City-owned Utilities accounts $2,412,433 thousands, from which $389,806 thousands is used in drainage & wastewater system that Seattle Public Utilities manages.51 (See Figure 4) GSI projects are actually in this drainage & wastewater system.
2007-2012 Adopted CIP by Department 1% 5% 4% 2% 26% 62%
2007-2012 Adopted CIP for CityOwned Utilities City Light
Fleets and Facilities Information Technology Parks and Recreation
Drainage & Wastewater
19% 3% 8%
54%
16%
Seattle Center
Solid Waste Technology Projects SPU – Water
Figure 4 – left: 2007-2012 Adopted CIP by Department; right: 2007-2012 Adopted CIP for City-Owned Utilities
Historically, the Drainage and Wastewater CIP has been funded primarily by revenue bonds.52 However, Drainage and Wastewater financial policies adopted in 2003 gradually increase cash 50
Department of Finance, City of Seattle 2001-2006 Adopted Capital Improvement Program, http://www.seattle.gov/financedepartment/0106adopted/Overview.pdf. 51 City of Seattle 2007-2012 Adopted Capital Improvement Program. 52 Ibid. 16 |
contributions from the Utility to the CIP to 25% of total CIP costs, by 2007.53 Overhead costs for the CIP are budgeted in the SPU operating fund and are reimbursed as CIP expenditures are incurred.54 The money allocated to drainage & wastewater primarily comes from Capital Projects Funds, accounting for resources set aside to acquire or construct major capital facilities, except those financed by proprietary funds.55 Within this Capital Projects Funds, the Drainage and Wastewater Fund from Utility Funds part is the mainly funding source of GSI projects. Table 5 is a summary of the SPU Drainage and Wastewater Fund from 2006-2012. (See Table 5) Table 5 - SPU Drainage and Wastewater Fund Summary (in thousands)
Fund Name SPU Drainage and Wastewater Fund
2006 43,665
2007 52,012
2008 70,731
2009 92,622
2010 74,416
2011 50,076
2012 49,948
Total 519,318
(Data comes from City of Seattle 2007-2012 Adopted Capital Improvement Program)
Here is how the Drainage and Wastewater Fund revenue comes from. The types of fund comes from fees, grants, and bond. This figure shows the revenue source of the Fund in 2012. (See Figure 5)
Drainage and Wastewater Fund Revenue (2012) Capital/Operating Grants Wastewater Service Rates
19%
1%
Drainage Service Rates Side Sewer Permit Fees
1% 0% 1% 0% 20%
Drainage Permit Fees
58%
SCL Call Center Service Interest Earnings Other Misc. Revenues Use of Bond Proceeds
Figure 5 - Drainage and Wastewater Fund Revenue (Data comes from City of Seattle, Seattle Public Utilities Drainage and Wastewater Fund 2013-2015 Rate Study, December 2012, http://www.seattle.gov/util/groups/public/@spu/@billing/documents/webcontent/spu01_004263.pdf.)
53
City of Seattle 2007-2012 Adopted Capital Improvement Program. Ibid. 55 Ibid. 54
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From this figure, Wastewater Service Rates, Drainage Service Rates, and Use of Bond Proceeds accounts large percent of the Fund Revenue. Among all revenue sources, Wastewater Service Rates accounted for 58% of the Fund in the year of 2012. Sometimes the Fund also include loan under other departments’ loan program. In 2005, the Fund entered into a loan agreement with the Washington State Department of Ecology under its Public Works Trust Loan program to borrow up to $2.7 million to support the construction of improvements of the High Point Natural Drainage Systems project.56 Other than the Capital Projects Funds, the Cumulative Reserve Subfund (CRF) is another source of ongoing local funding to support capital projects. This type of funding sources come from Real Estate Excise Tax, Internet Earnings and so on. Among them, the Real Estate Excise Tax can be used for Storm water.57 
Projected Costs for Completed GSI projects According to 2001-2006 adopted CIP, Street Edge Alternatives is scheduled a total cost for
$847 thousands, 110th Cascade (Pipers Creek Detention) for $883 thousands.58 According to 2002-2007 adopted CIP, Broadview Project (3rd Ave. NW & NW 107 St. Natural System) is designed to have an allocation of $4.41 million.59 The High Point drainage system is scheduled for completion in 2009 at a total projected cost of $5.3 million; $2.4 million had been spent at the close of FY 2005.60 Ongoing maintenance costs are projected at $65,000 a year.61 The projected total cost for Pinehurst Natural Drainage System was $4.7 million at completion in 2007.62 (See Table 6)
56
Department of Financial and Administrative Services, The City of Seattle Comprehensive Annual Financial Report for the Fiscal Year Ended December 31, 2012, http://www.seattle.gov/Documents/Departments/FAS/FinancialServices/2012CAFRComplete.pdf. 57 City of Seattle 2007-2012 Adopted Capital Improvement Program. 58 Department of Finance, City of Seattle 2001-2006 Adopted Capital Improvement Program, p396 and p407. 59 Department of Finance, City of Seattle 2004-2009 Adopted Capital Improvement Program, p346, http://www.seattle.gov/financedepartment/0409adoptedcip/DWF.pdf. 60 Department of Finance, City of Seattle 2007-2012 Adopted Capital Improvement Program, p624, http://www.seattle.gov/financedepartment/0409adoptedcip/DWF.pdf. 61 Ibid. 62 Department of Finance, City of Seattle 2007-2012 Adopted Capital Improvement Program, p649, http://www.seattle.gov/financedepartment/0409adoptedcip/DWF.pdf. 18 |
Table 6 - Summary of CIP Projected Cost for GSI Completed Projects (in thousands)
CIP Street Edge Alternatives (SEA Street) 110th Cascade Project Broadview Green Grid Pinehurst Green Grid High Point Natural Drainage System
CIP projected cost $847 $883 $4,411 $4,700 $5,300
Service Area 3.2 acres 21 acres 32 acres 49 acres 140 acres
8 MAJOR CURRENT ISSUES Major current issues to integrate GSI to control water flow and condition have been identified. Generally speaking, there are six types of issues relating to GSI including:
8.1
UNCERTAINTY Most decision makers and designers don’t know whether implementing GSI would contribute to
water quality, if it does, whether it is better than other technical approaches are uncertain. Even if they can hire experts in water quality to measure the water condition, lack of data always impede the measurement. Also, there is not enough understanding about what green infrastructure will cost to design, construct, and maintain in comparison with traditional wastewater and stormwater approaches and insufficient economic analysis of the environmental and social benefits of green infrastructure.63 These kind of uncertainty notoriously impede the acceptance of GSI, and most other Low Impact Development infrastructure.
8.2
REGULATION Because GSI is a fresh definition these years, the Federal, State, as well as Local ordinances
and manuals have been created for grey infrastructure for a long time, therefore, it lacks the specific guidance for the new GSI. Without design standards, local design professionals and engineers are less likely to deviate from the familiar measures of pipes, basins, and ditches.64 According to a research concerning the regulatory framework of Florida, most professionals, primarily engineers, suggests that the greatest obstacle to greater implementation to Low Impact Development is the existing status quo and apathy, and the second most important obstacle identified 63
Clean Water America Alliance, Barriers and Gateways to Green Infrastructure, http://www.uswateralliance.org/wp-content/uploads/2014/01/Barriers-and-Gateways-to-Green-Infrastructure.pdf. 64 Ibid. 19 |
was regulatory problems.65 However, the city of Seattle developed a series manuals and guidelines for GSI design and construction, which makes this issue less important.
8.3
LACK OF DATA Another issue of evaluating GSI is lack of data. Without reliable data, it is very hard to measure
its performances, cost, and other relating areas, which, is an important reason that whether there is a lot of uncertainty when implementing GSI. Local Jurisdictions do not accept manufactured solutions based on lack of acceptable data.66 They also expressed concern that manufacturers are advertising their products as LID compliant, which can be very misleading to the development community.67
8.4
COST In spite that the cost per block of traditional drainage systems are much higher than GSI
according to cost analysis for SEA Street, Cascade and Broadview of SPU, the real cost for installation and long-term operation and maintenance for some types of GSI is very high.68 According to the cost analysis of the storm sewer system in Orange County, CA. Extensive and intensive green roof systems are the most expensive to install, ranging from $7 to $325 per square foot and from $16 to $522 per gallon of runoff managed.69 Therefore, green roof is not recommended in Orange County. However, in Seattle, for household program of GSI system, green roof is encouraged to involve in house construction, which could not be cost efficient. Also, conventional systems are assumed to be operating properly as long as the stormwater basin is properly maintained through removal of sediments and trash, maintenance of proper vegetation, and mowing if it is a dry basin.70 However, LID is more complicate than conventional systems. Prior to do operation and maintenance, more preparation research work need to be down. For example, some techniques like green roofs have higher upfront costs although other techniques are
Thomas Ruppert, Esq., “Understanding and Overcoming Legal and Administrative Barriers to LID: A Florida Case Study,” 2008 International Low Impact Development Conference, http://ascelibrary.org.offcampus.lib.washington.edu/doi/pdf/10.1061/41009%28333%2950. 66 Southern California Stormwater Monitoring Coalition, Barriers to Low Impact Development, September 2012, http://www.lgc.org/wordpress/docs/resources/water/barriers-low-impact-development.pdf. 67 Ibid. 68 SPU, Seattle Public Utilities – Natural Drainage System Program Costs and Benefits Document, http://www.seattle.gov/util/groups/public/@spu/@usm/documents/webcontent/spu02_019986.pdf. 69 “The Costs of LID - Low-impact-development BMP installation and operation and maintenance costs in Orange County, CA,” February 13, 2013, http://www.stormh2o.com/SW/Articles/The_Costs_of_LID_20426.aspx. 70 Thomas Ruppert, Esq., “Understanding and Overcoming Legal and Administrative Barriers to LID: A Florida Case Study,” 2008 International Low Impact Development Conference, http://ascelibrary.org.offcampus.lib.washington.edu/doi/pdf/10.1061/41009%28333%2950. 65
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more cost effective.71 Since of that, most government are not only concerned with long-term operation and maintenance cost, but also concerned with former preparation works which requires human, material, and financial resources either.
8.5
FUNDING Because of the potential high cost of some types of GSI project, it is extremely difficult for local
government, communities and non-profits organization to train or hire staff to install or maintain, permits, planning and review, which, become more difficult when the cost are uncertain.72 For state, there is a lack of funding to develop state-level technique design and maintenance guidelines and plans that are integrated between programs.73
8.6
MAINTENANCE One unique maintenance challenge posed by green infrastructure is that it is often located on
private properties and thus difficult for public agencies to ensure that proper maintenance is occurring.74 That’s why many government involves public to do GSI maintenance. In Seattle, other than technique constructions are operated and maintenance by SPU, residents are encouraged to provide additional maintenance such as planting trees and improving aesthetics.
71
Clean Water America Alliance, Barriers and Gateways to Green Infrastructure, http://www.uswateralliance.org/wp-content/uploads/2014/01/Barriers-and-Gateways-to-Green-Infrastructure.pdf. 72 Ibid. 73 Ibid. 74 Clean Water America Alliance, Barriers and Gateways to Green Infrastructure, http://www.uswateralliance.org/wp-content/uploads/2014/01/Barriers-and-Gateways-to-Green-Infrastructure.pdf. 21 |
9 DIAGRAM
Feedbacks 22 |
APPENDIX - CIP PROJECTED COST
SEA Street
Source: City of Seattle 2001-2006 Adopted Capital Improvement Program
110th Cascade Project
Source: City of Seattle 2001-2006 Adopted Capital Improvement Program
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Broadview Green Grid
Source: City of Seattle 2004-2009 Adopted Capital Improvement Program
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
High Point Drainage System
Source: City of Seattle 2007-2012 Adopted Capital Improvement Program
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
Pinehurst Natural Drainage System
Source: City of Seattle 2007-2012 Adopted Capital Improvement Program
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