EVOLUTION OF INTEGRATING GREEN INFRASTRUCTURE IN SPOKANE, WA. Marcia Davis, PE and Mark Papich, PE City of Spokane, Washington

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1 EVOLUTION OF INTEGRATING GREEN INFRASTRUCTURE IN SPOKANE, WA INTRODUCTION Marcia Davis, PE and Mark Papich, PE City of Spokane, Washington The City of Spokane, which is the largest City in eastern Washington State and the second largest City in the state, has embarked on a unique, integrated approach to improve the health of the Spokane River that runs through the center of the City. This approach focuses on stormwater as the means to solve multiple problems at the same cost. This holistic view of projects integrates funding to build better streets, new water mains and improve parks. The basis of the integrated approach is aligning business and environment interest to protect our greatest assets, the Spokane River and the Aquifer. The City of Spokane is a regional water purveyor, sewer collector, treatment plant operator as well as responsible for street and stormwater within the City Limits. This gave the City the flexibility to operate integrate goals of projects as well as the funding. This paper explores how the stormwater projects have changed since 2010 as the City has changed from a silo department culture to integrated and cooperative thinking on projects. A brief over view of the history to stormwater and chronological highlight of the stormwater projects. HISTORY OF STORMWATER IN THE CITY Prior to construction of the City s wastewater treatment plant, stormwater runoff was initially identified as nuisance water, combined with the sanitary sewer, and discharged directly to the Spokane River and its tributary, Hangman Creek without treatment. In the late 1950's, the City built the first primary treatment plant and interceptor systems to provide treatment prior to discharge. Combined Sewer Overflow (CSO) regulators were installed at the same time as the treatment plant interceptor to allow stormwater to outfall to the river during precipitation events. During the 1980 s, a large portion of the combined system north of the Spokane River was separated by creating several Municipal Separated Storm Sewer Systems (MS4) to reduce the CSO. Water quality concerns have continued to influence decisions relating to stormwater. In 1978, the Spokane Valley Rathdrum Aquifer (Aquifer) was designated as a sole source for the 400,000 people in the region. To protect the Aquifer, treatment before infiltration became a requirement, but sending stormwater to the MS4s was still encouraged. Starting in 1998, the region began working to improve dissolved oxygen in the Spokane River resulting in a Total Maximum Daily Load (TMDL) to remove more than 90 percent of total phosphorus from point sources, including stormwater discharges. The EPA Phase II stormwater regulations went into effect in early 2003 and the Washington State Department of Ecology (Ecology) first issued the Eastern Washington Phase II permit in The current permit was reissued on August 1, 2012 and will expire July 31, In 2009, the Washington State Departments of Health and Ecology issued a revised Health Advisory for Spokane River Fish Consumption. In response to this advisory, Ecology published an assessment study and initiated a direct-to-implementation strategy that emphasizes identifying and reducing PCBs at their source(s) in the watershed. In 2013, the City of Spokane passed a Low Impact Development Ordinance pursuant to a Consent Decree with the Spokane Riverkeeper and in preparation of future NPDES Phase II permit requirements. Also in 2013, the City began the Integrated Clean Water Plan. This plan was developed without a consent decree or administrative order and includes work that meets regulatory requirements and other projects that simply make sense for the health of the Spokane River. As part of this plan, the City has

2 committed to managing stormwater on site whenever we rebuild a street or complete major construction in the right-of-way. This strategy has helped minimize flows to the treatment plant and MS4 discharges, gain greater value for dollars spent, and provide above-ground amenities for the public. CURRENT STORMWATER MANAGEMENT PRACTICES Today the City of Spokane's stormwater management system is a large, complex system that was designed according to the stormwater guidelines at the time of construction. The system includes: More than 400 miles of combined sewers that carry stormwater to the City's wastewater treatment plant; more than 300 miles of separate storm sewers that discharge to both bioinfiltration swales and rivers; approximately 130 MS4 discharge points to the Spokane River and Hangman Creek; About 1 billion gallons of untreated stormwater annual discharge; Thousands of public and private bioinfiltration swales; and About 20 green retrofit projects. Stormwater management practices by the City have changed to meet the increasingly more stringent water quality requirements. While new developments and public works projects are designed to meet current stormwater requirements, most public works projects become retrofits because the majority of the City s street network is built-out. PILOT PROJECTS AND EXPERIMENTS In 2009, the director of Wastewater Management recognized stormwater management practices would have to change to meet the requirements of both the Phase II Eastern Washington Municipal Stormwater Permit and water quality assessments for dissolved oxygen and PCBs. The first project the City embarked on was an experiment to see how a green infrastructure project could be implemented in Spokane. After this first project, more innovative stormwater were created as the City s approach to stormwater management was evolved. Twelve of these innovative projects are briefly described below. Broadway Spokane Urban Runoff Greenways Experiment (SURGE) Broadway Avenue is a part of the combined sewer system. The SURGE project separated stormwater from the combined sewer system, treated runoff by bioretention and infiltrated treated water. Broadway was the first project chosen for the Spokane Urban Runoff Greenway Experiment (SURGE). SURGE was a demonstration program to determine the suitable criteria for retrofitting existing curb and gutter systems with plant-based Low Impact Development (LID) stormwater treatment systems in Spokane s urban environment. Based on the SW 12th Avenue project of Green Streets program in Portland, Oregon, this SURGE project was intended to show how a similar system will function in Spokane s colder and drier climate. This was the first installation of pervious concrete sidewalk by the City of Spokane. The project results were planned to be used to develop design criteria for future LID design retrofits.

3 The BMPs selected for Broadway were bioretention, pervious concrete, and native landscaping. The bioretention are low-impact development (LID) stormwater facilities that are located close to the origin of where the precipitation falls, small-scale controls distributed along the street and integrated into the existing features of the site. The bioretention collect and treat the 6-month NRCS Type II, 24-hour design storm, the water quality treatment volume (first flush). Storm garden detention capacity exceeded the volume produced by the NRCS Type 1a 100-year, 24- hour event. Stormwater runoff that bypasses the bioretention is collected into the existing combined sewer system. The existing stormwater collection system and combined sewer system were not be altered by this project. The maintenance required within bioretention areas has been minimized through the use of adaptive native landscaping. American Recovery and Reinvestment Act of 2009 loan with forgivable principal funded this project. Ancillary benefits The streetscape from this project greatly improved the character of the street, has attracted new businesses, and better property maintenance. The interpretive sign installed for the project educated all users by explaining stormwater. Broadway SURGE achieved the BMPs design goal, but detention capacity exceeded what is necessary. The use of the concrete cast in place box was expensive. The pervious concrete sealed because of a wet mix and it was misted during installation and it did not infiltrate. Everyone needs to be committed (Designers, Inspectors and Contractors) Maintenance plant and tree needs to be clearly understood and consistent. The plants were not watered for two years because of miscommunication at the City. Lincoln Spokane Urban Runoff Greenways Experiment (SURGE) Lincoln Street was the second SURGE project and was constructed in conjunction with the City of Spokane s 10-Year Street Bond Program. During design it was determined that the 4-lanes of Lincoln Street could be reduced to 2-lanes to serve the current and projected future traffic volumes. With the removal of two travel lanes, space was available for stormwater management. Lincoln Street SURGE constructed bio-infiltration cells to collect and treat storm flows between 29th Avenue and 19th Avenue, and conveyed flow to Cannon Hill Park to fill the pond and percolate into the ground. The pond leaks and normally potable water is used to fill it; the stormwater provides an offset to the drinking water. The stormwater in Lincoln Street was collected into the combined sewer. The Lincoln Street SURGE project separated water quality treatment stormwater volumes from the combined sewer system for treatment and disposal to reduce the CSO Basin 24a overflow discharges to the Spokane River and reduce the volume of stormwater to be treated at the treatment plant. One

4 goal of the Lincoln Street SURGE project was to demonstrate the cost-effectiveness and environmental benefits of partial separation technology within the CSO basin system. A series of 7-foot wide bioretention curb extensions are provided along Lincoln Street to collect the 6-month NRCS Type II 24-hour design storm (first flush). A series of check dams are used to slow the flow down because the street grade is over 7%. A perforated drain beneath the bioretention areas collects and conveys stormwater in a separate storm drain system within Lincoln Street. The collected stormwater is conveyed to Cannon Hill Park pond. Overflow from the pond is infiltrated with two Type 2 drywells within Cannon Hill Park The SURGE part of the Lincoln project was funded by the City of Spokane Wastewater Management utility rates. Ancillary Benefits The project conserves water used to fill the Cannon Hill Park pond. The curb extensions provide traffic calming for the neighborhood. The neighborhood is aesthetically improved with the bioretention areas. Lincoln SURGE successfully removes stormwater from the combined sewer system. Approximately 300,000 gallons goes to the pond every year. Flow from the bioretention areas is less than expected because more runoff is retained in the soil column than was expected. The bioretention areas were planned to be maintained by residents, but results have been inconsistent. The Mahonia Repens (creeping Oregon grape) is growing well, but some of the other plants have not survived. Public perception of the planting palettes has been mixed. The City has decided to maintain all stormwater facilities. River Runoff Reduction The River Runoff Reduction project installed drywells on residential streets to reduce the amount of untreated stormwater being conveyed to the Spokane River through MS4s. The project was divided into two phases and was construction in conjunction with City of Spokane 10-Year Street Bond projects. The goal of this project was to remove stormwater from discharging to the river. Drywells were thought to be a simple and low cost per impervious acre solution. Catch basins with 4-foot sumps were connected to 37 drywells to manage stormwater runoff about 1 acres of impervious area from 2 stormwater basins. The project was funded by a Clean Water State Revolving Loan. Ancillary Benefits None

5 While drywell installation of this project met the Underground Injection Control (UIC) requirements, confusion developed concerning when it was appropriate to use drywells. A flow chart was developed to determine when it was appropriate to use drywells to manage stormwater as well as how we address stormwater separation projects in general. The flow chart has been largely underutilized throughout the City. The cost of drywells in the retrofit projects cost more than anticipated because of conflicts with curbs, underground utilities, and connecting to existing drywells. Olmstead Brothers Green Stormwater Facility The Olmstead Brothers Green Park is located within the Kendall Yards development and is owned and operated by Greenstone. The park also manages runoff from both City streets and the development. Greenstone and the City entered into an agreement to jointly manage stormwater in the park. The stormwater system has three distinct components: a storage tank and pumping station, a force main, and a treatment and infiltration facility. The completion of this project provides for improved water quality in the Spokane River and the Spokane Valley-Rathdrum Prairie Aquifer. Prior to this facility being constructed, stormwater from approximately 11 acres of Monroe Street discharged directly to the Spokane River. By separating this stormwater from the MS4 system, pollutant discharge to the Spokane River is reduced. The tributary area removed from the current separate storm sewer system within Monroe Street was approximately 6-acres. For a 10-year design storm the approximate design flow will be 18 cubic feet per second (CFS), which equates to approximately 300,000 gallons of water during the 10-year storm. The catch basins in North Monroe Street convey stormwater to a storage facility located on the Kendall Yards property. The storage facility releases stormwater to a wet well of a pumping station. From this wet well, the stormwater pumps using a 500 GPM pump through an 8-inch force main to the treatment and infiltration facility located in the proposed park. An overflow system was also constructed to handle flows in excess of the 10-year storm. This system consists of a series of drywells. The storage facility, pumps, and bio-infiltration area also serve part of the Kendall Yards development. The cost of the system was proportionately shared with Kendall Yards. The project consists of manifold and bubble-up structures which distribute stormwater over a level spreader leading to the bioretention treatment system. Additional components of the project include pervious concrete sidewalk and a pervious paver plaza. The bioretention area provides treatment for stormwater that previously discharged to the Spokane River thus reducing the discharge of pollutants to the river. This project was funded by a Clean Water State Revolving Loan for the pump and tank, and by a stormwater grant from Ecology for the infiltration facility. This funding covered only the

6 Union Basin portion of the project from City rights-of-way. The developer funded the force main and the infiltration facility for their development at the park. Ancillary Benefits The stormwater provides a water feature and the permeable pavement a plaza with the park. The turf grass area provides recreational space as well as disposal for stormwater overflow. An interruptive sign was installed at the park plaza for stormwater education. This project was a successful collaborative effort between the City of Spokane and Kendall Yards, a large residential and commercial development in the City. The dual use of the park as a stormwater facility provides a multiple benefit. Both the City and the developer shared mutual interest and commitment to the success of this project. This project constructed stormwater improvements to the Union Basin that prevents stormwater from discharging to the Spokane River. The basin collected runoff into a municipal separated storm sewer system (MS4), discharging directly to the Spokane River. Union Basin has been identified as a high contributor of PCBs and other industrial pollutants to the Spokane River. Industrial land use, a high impervious area percentage and lack of sediment control for unpaved areas have enabled the spread of these pollutants. Sampling has confirmed the presence of PCBs above water quality criteria and ubiquitous nonpoint PCB sources from historic industrial land uses. Because no significant point sources of PCBs have been identified, reducing PCB source contribution to the MS4 system to a level that meets the water quality standard is infeasible. The preferred method of reducing PCB discharge to the Spokane River is through treatment and infiltration of stormwater in the basin. The Union Basin includes approximately 29-impervious acres in an industrial developed area that discharges through an MS4. The stormwater is managed in three projects. The first project separated approximately 10 acres, using bioretention facilities and tree boxes at one intersection. A portion of the basin will be managed using bioretention facilities as part of the new Martin Luther King Jr. street project. The final project will manage 13 acres using a storage, pump, bioinfiltration, and drywell BMP. The existing piping system will drain to a storage tank which will pump stormwater up to the surface to the proposed bioinfiltration area. Due to high groundwater and soil contamination, stormwater cannot be infiltrated at this site. The bioinfiltration area will be equipped with an underdrain system and PVC liner. Stormwater will collect into the underdrain system and be conveyed to drywells east of the bioinfiltration area for discharge in native soils. This first part of this project was funded with a stormwater grant. This project has been listed on the draft funding offer list from Ecology to receive Stormwater Financial Assistance Program (SFAP) grant funding.

7 Ancillary Benefits The bioretention swale adjacent to river will be maintained as green space. The tank and pump system were necessary because all the stormwater could not be managed within the existing right-of-way as expected. The engineered soil used in the first portion of the project had too much organic matter and does not drain well. Cochran Basin Cochran Basin is the largest stormwater basin in the City s MS4. The basin is approximately 5,328 acres, of which 845 acres is impervious right-of-way. The Integrated Clean Water Plan identified the largest water quality benefit will be from removing 90% of the annual runoff from Cochran Basin. The proposed preliminary design will add two infiltration ponds and one biofiltration channel in City Park property near Downriver Golf Course. Due to the sheer size of the basin, three separate facilities will be needed to manage the runoff. The Disc Golf Course is the first suitable site where 7.4 acres of bioretention are proposed. The second site is about 0.3 acres of bioretention will be constructed in TJ Meenach Park. The third facility will be a bio-filtration channel with drain field located at TJ Meenach Bridge and Downriver Drive. is currently being provided by Ecology through a $2,000,000 proviso grant. In addition, the ponds at the Disc Golf course are on Ecology s draft offer list to receive $3,500,000 in grant funds through the Stormwater Financial Assistance Program (SFAP). Approximately $15,000,000 in additional funds will be needed to complete the project. Ancillary benefits The disc golf course will be enhanced with the project. Trails will be constructed with the TJ Meenach facility. River access will be improved at TJ Meenach Bridge. Sometimes, an end of pipe solution works best. Up basin solutions were investigated, but the cost of retrofitting in facilities was far greater than using City owned property at the end of pipe. The majority of the costs were due to repairing and rebuilding existing infrastructure with the construction of stormwater facilities. This project highlights the importance of careful coordination within various City Departments and user groups. Indiana Avenue Stormwater Stormwater was managed as part of the street reconstruction project for 10 blocks of Indiana Avenue. Stormwater from this area previously drained to an MS4 and was released to the

8 Spokane River. The street was narrowed to provide space for bioretention swales. These swales take up approximately half of the available street parking. Stormwater was managed on this project as part of the Integrated Clean Water Plan to manage stormwater on site whenever we rebuild a street. The drainage calculations reflect an impervious drainage area of 4.8 acres draining to bioretention areas for treatment and detention. Each bioretention area was equipped with drywells for emergency overflow and frozen ground conditions. These swales areas were planted with both turf grass and native plants to match the adjacent property. The project was funded by the City of Spokane Wastewater Management utility rates. Ancillary Benefits Construction of the stormwater facilities added landscaping to the street and created a pedestrian buffer. Engineered soil did not drain because the fines content too high. Matching landscaping to adjacent properties created public acceptance. Rowan Avenue Stormwater was managed as part of the street reconstruction project for 6 blocks along Rowan Avenue. Stormwater from this area previously drained through an MS4 to the Spokane River. Stormwater was managed on this project as part of the Integrated Clean Water Plan to manage stormwater on site whenever we rebuild a street. A bioretention swale was constructed in the green space on the east side of Driscoll Blvd between Crown Place and Sanson Avenue. A collection system was construction for approximately half of the Rowan Avenue project that could gravity drain to the Driscoll Blvd. green area. Diversion structures were installed to convey the prescribed flows to the swales with excess flows diverted back to the MS4 system. The project was funded by the City of Spokane Wastewater Management utility rates. Ancillary Benefits Landscaping and trees were added in the Driscoll Blvd. green space. Engineered soil did not drain. For the other 10 blocks of the Rowan Avenue project stormwater continues to the MS4. The original concept was to move the curb, but the design engineer felt the cost was too high and a partial management solution was chosen for this project. The remaining area will be analyzed to be managed with future projects at downstream locations.

9 Havana Street Permeable Pavement Bike Lanes Havana Street was reconstructed as part of a water main installation project. The project area previously drained to gravel ditches or swales and eventually to the Spokane Valley Rathdrum Prairie Aquifer. Porous asphalt bike lanes were added on both sides of the road and doubled as a stormwater facility. Bioretention areas were also be added as a secondary facility. The constructed alternative collects stormwater from 3.2 impervious acres within the porous asphalt bike lanes for treatment and infiltration through the pavement structure and base. A cation exchange test was not performed. In lieu of the cation exchange test, a 12-inch sand layer was placed under the porous asphalt structure to provide stormwater treatment. A secondary bioretention system was constructed adjacent to the roadway on both sides of the road. The bioretention system is equipped with an 18 engineered soil layer to provide treatment. The roadway has been constructed without curb so runoff that is not infiltrated in the pavement structure will be allowed to runoff to the bioretention area via dispersion. Both the pervious pavement and the bioretention areas are sized to detain the 10-year design storm and treat the 6-month design storm, per the SRSM. The porous asphalt is anticipated to provide more than sufficient treatment and detention volume. The supplemental bioretention areas are approximately 4 inches deep for both aesthetic purposes as well as taking advantage of available bottom area. It is not anticipated that the bioretention areas will be utilized often, unless the porous asphalt becomes plugged or does not infiltrate as anticipated. was provided through an Ecology Stormwater Financial Assistance Program (SFAP) grant with 25% matching funds from City of Spokane utility rate fees. Ancillary benefits The project provided a consistent street cross section. Prior to the project, the cross section varied in width as well as whether or not there was curb or sidewalk within particular sections of the road. The porous asphalt bike lines provide a dedicated pathway for cyclists within the roadway prism. The porous asphalt drains well. The drain rock layer below the porous asphalt pavement was not thick enough for both hydraulics (sufficient storage volume for the design storm event) and frost considerations. Frost considerations should include both the potential for frost heave and the potential for reduced permeability of subgrade soil as a result of extended periods of freezing weather. Monroe Street Stormwater Improvements Overview and Goal Monroe Street is an arterial street within the City of Spokane. The southern 8 blocks of the project has wider area behind the curb and the northern 8 blocks is steep and narrow.

10 Stormwater improvements along Monroe Street were constructed as part of a street improvement project. Two method of bioretention were chosen to match the topography and topology of the site. Runoff from Monroe Street previously drained to the CSO system. The goal of this project is to separate stormwater from the combined sewer. For the southern part of the project, bioretention areas with native adaptive plants were chosen to remove approximately 2.3 impervious acres. The constructed bioretention areas are located adjacent to the proposed curbs on both sides of the road and are sized to detain the 10-year design storm and treat the 6-month design storm. The depth is approximately 1-foot deep for both aesthetic purposes as well as taking advantage of available bottom area. Drywells were installed for emergency overflow purposes. The proposed swales include check dams to mitigate the grade through much of the alignment. The bioretention area widths vary from 5.5 feet to 10 feet. In order to fit the BMPs within the right-of-way, several design deviations (from City of Spokane standards) were required. These included reducing standard widths of swales, driving lanes, pedestrian buffers and swale side slopes. For the northern portion of the project, a separated stormwater system was construction to convey approximately 6.5 acres of impervious surface area runoff to a bioretention area located inside the Monroe Street eastbound on-ramp loop to Interstate-90. The bio-retention area will be equipped engineered bioretention soil media with an underdrain system, ultimately discharging downstream to a series of drywells located over a paleochannel that generally flows south to north in downtown Spokane. Extensive hydrogeologic and geotechnical investigations discovered a paleochannel that runs through downtown Spokane. The bioretention area is sized to detain the 10-year design storm and treat the 6-month design storm, but an overflow structure is also constructed convey large flows to the drywells. The project was funded by a stormwater grant from Ecology and through City utility rate fees. Ancillary benefits Traffic calming has been provided by narrowing the curb to curb width. The neighborhood is aesthetically improved with the addition of the bioretention facilities. The stormwater bioretention area is located within a WSDOT interchange area at the base of the Spokane s south hill. This interchange area was previously unmaintained grasses, shrubs and weeds and a gathering place for homeless people. The area is much more aesthetically pleasing now, with the planting and landscape to discourage loitering. We learned that it is possible to reduce traffic lanes and road widths on an arterial street while maintaining traffic flow and function as well as providing stormwater management facilities. With this project, we learned that there are opportunities (in this case a paleochannel) to provide treatment at one location and utilize a conveyance system to deliver the treated stormwater to a discharge location. The paleochannel started as a rumor until the investigation identified the location and infiltration capacity.

11 We also learned that communication and coordination with WSDOT at the inception of a project is critical to meeting project schedules. CSO Basin Stormwater Separation This project will provide stormwater management of CSO Basin 14 and CSO Basin 15 in the west central part of Spokane. The two basins have similar basin characteristics and are located within one of the oldest neighborhoods in Washington State. The basin areas are prominently residential with limited parking and mature trees. Stormwater entering the City s combined sewer system will be reduced by constructing underground soil cells to treat and infiltrate runoff. Approximately 21 impervious acres of stormwater generated from the right-of-way from CSO Basins 14 and 15 will be treated using soil cells. These soil cells will be equipped with trees and engineered soil for treatment. They will be located primarily under the sidewalks and will provide storage space as well as treatment. This project has been listed on the draft funding offer list from Ecology to receive Stormwater Financial Assistance Program (SFAP) grant funding. Ancillary benefits The trees planted as part of the soil cells will provide aesthetic improvements to the neighborhood. Select locations will receive curb bump outs to provide pedestrian and transit stop improvements. Bioretention swales takes a lot of room, remove parking, and require on-going maintenance. The cost of irrigation to plant swales at the intersections would be almost 10% of the project cost. In selecting soil cells, parking will not be removed and maintenance is minimized because the facility is underground. CSO Basin 25 Stormwater Separation Overview and goals CSO Basin 25 covers a small area located between the Peaceful Valley historic neighborhood and downtown. The majority of the basin is along Main Street and held in place by a historic retaining wall. Also in this basin area is a City park located in an area of significance to the Spokane Tribe of Indians. This project will install a separated storm pipe system that conveys to bioretention facilities in City Park property. The project will remove all of the street runoff from CSO Basin 25. CSO 25 Basin predominately consists of four blocks of arterial streets comprising approximately 3.5 acres of impervious street and sidewalk area. In addition, the existing buildings are plumbed into the system, adding approximately 1.5 acres of roof area. This project also proposes to incorporate 3.3 acres of the Maple Street Bridge, a major arterial, which currently discharges directly to the Spokane River via an MS4 pipe. Bioretention with approximately 30,000 square feet of bottom area will be constructed within City Park for treatment and infiltration of stormwater.

12 This project has been listed on the draft funding offer list from Ecology to receive Stormwater Financial Assistance Program (SFAP) grant funding. Ancillary benefits The project provides aesthetic improvements to Riverwalk Park and will also rebuild the community garden in the park. Pedestrian and vehicle safety will be improved in one intersection. Involving the neighborhood group early and often was important on this project. We found an opportunity to remove a MS4 with this project. Historic and cultural resources take time and creativity to move the project forward. Summary These 12 projects give a general overview of the changes in stormwater management for the City of Spokane from the lessons learned and the changes in funding strategies. The table below provides a summary of the project construction cost and area of stormwater managed. Project Construction Year Construction Cost Impervious Acres Integrated Cost Per Acre Broadway SURGE 2009 $ 572, No $ 818,286 Lincoln SURGE 2010 $ 880,000 6 No $ 160,000 River Runoff Reduction $ 400,000 6 No $ 66,667 Olmstead Brothers Green $ 640, No $ 58,182 Union Basin $ 3,000, No $ 103,448 Cochran Basin 2017-??? $ 30,000, No $ 35,503 Indiana Avenue $ 620,000 5 Yes $ 129,167 Rowan Avenue 2015 $ 640, Yes $ 58,182 Monroe $ 1,450,000 9 Yes $ 164,773 Havana 2016 $ 560,000 3 Yes $ 175,000 CSO Basins 14 and $ 3,100, No $ 147,619 CSO Basin $ 1,125,000 5 Yes $ 225,000 in early projects have guided the City to make better decisions and more cost effective choices. Although in many ways Spokane is unique, the innovations and lessons learned are applicable to other communities as they proceed with stormwater management. The City s take away list: State of the Art design takes time, creativity and effort, but it allowed us to manage stormwater in a highly developed urban environment. Cultural shifts are most effective when lead from the top. Management needs to be willing to make changes in structure. Stormwater is the integrating factor of projects and the driver for innovating financing and working together. Viewing projects as a shared cost and benefit allows innovation and new ways of thinking.

13 For instance reduction of pavement area reduces the costs of both road maintenance and stormwater management. Integrating projects results in overall lower costs for the same benefits. Stormwater facilities need to be maintained by the City for on-going success.