Kansas City Stormwater Overflow Control Plan

4 12 2009

Source: Kansas City, Missouri Overflow Control Plan Overview Document

This year Kansas City embarked on a massive $2.3 billion stormwater overflow control plan to address sewer overflows throughout the city. Its inclusion of a major $28 million green infrastructure pilot project has gained a lot of attention. The project has been recognized as the largest green infrastructure project in the United States. The Marlborough Neighborhood Pilot Project, as it is called, is located in the Middle Blue River Basin, one of the four major watersheds addressed by the plan. The entire pilot project encompasses nearly 100 acres of primarily residential neighborhoods. This program is anticipated to be expanded over a larger 744 acre area that will eventually include over 25 acres of mixed green infrastructure strategies (i.e. rain gardens, bioswales, permeable pavement, and green roofs) that have the capacity to sequester 3.5 million gallons of water. The green infrastructure strategies employed are designed to replace two underground tanks of similar capacity. In total the pilot project and its expansion are budgeted to cost $68 million.

Video of compiled images from Mark O’Hara’s Greenbuild Presentation about the Kansas City Plan. The video shows various Green Infrastructure Strategies recommended in the plan. Video compiled by Hawkins Partners Images provided by BNIM (Click here to see it if  video is not present)

In addition to the Marlborough Neighborhood Pilot Project, the plan also recommends the enhancement of the area’s highly acclaimed 10,000 Rain Garden Program. Over the past two years, the initiative is reported to have installed several hundred rain gardens, bioswales, and rain barrels. The purpose of the expansion it to develop an incentive program to accelerate the program’s progress and complement the public investments being made.

Wet retention basin projects have been identified as an appropriate strategy for treating stormwater downstream from six separated sewer system (SSS). The plan acknowledges that green infrastructure is beneficial and should be included where it is practical. The plan states:

“Every decision should be viewed as an opportunity to incorporate a green-solutions approach. The City has adopted an “every drop counts” philosophy, meaning it is important to reduce stormwater entering the system wherever practicable. This will be accomplished through changing the way the community develops and redevelops its sewer and stormwater infrastructure, educating citizens regarding steps they can take to reduce the amount of stormwater entering the sewer system, enabling citizens to take those steps, incorporating green infrastructure in the design of public infrastructure, and making targeted public investments in green infrastructure projects early in the Plan implementation.”

Areas identified that should be considered for green infrastructure projects include those meeting the following criteria:

  • Areas for which no or minimal conventional structural controls are proposed.
  • Areas in which widespread implementation of green solutions by the community at large offer the greatest opportunities for reducing the size and cost of conventional structural controls included in the Plan.
  • Areas for which it would be particularly desirable to further reduce the projected overflow
    activation frequency following completion of recommended controls.
  • Areas in which sewer separation is proposed but where no Water Services Department (WSD) investment in treating the separate stormwater runoff has been included in the Plan.
  • The plan’s ambitious Marlborough Neighborhood Pilot Project is very encouraging, particularly as a stand alone project. It is very significant and the City should be commended for their efforts. However based on the $2.3 billion budget established by the plan, it is evident that green infrastructure will play a supporting role. The plan was developed during the recent significant shift in the way we address stormwater management across the country over the last few years. It is not surprise to see this. What is encouraging is the magnitude of the pilot project and the extensive monitoring that will be conducted.

    The monitoring component will provide valuable data for the City and others across the country. In addition to understanding green infrastructure’s effectiveness to control Combined Sewer Overflows (CSOs) and improving water quality, monitoring it will provide insight into conflicts with local codes and ordinance, social-economic benefits, construction techniques, associated cost, and maintenance practices.

    The plan stresses that it is an evolutionary document, referring to it as an “adaptive management” approach. The approach involves evaluation of the strategy throughout the life of the project based on their experiences and data gathered through the monitoring efforts. While green infrastructure may not be the predominant tool of choice at this point, the longer-term nature of the plan provides the opportunity to adjust its course as confidence increases in green infrastructure. The City’s plan can become more green overtime as it builds upon its successes.

    Fairly or unfairly, like many pilot projects much rests on the success of the Marlborough Neighborhood Pilot Project. Many, both locally and nationally will be watching it with great interest. Failure of such a high profile project could significantly set back the growth of green infrastructure as the stormwater management tool of choice. Therefore, it is critical it is done to the highest standards possible. The project will serve as an example for those involved in stormwater planning and design to have full confidence and understanding of the complexities of utilizing natural systems. Natural processes are complex making them more difficult to quantify. A paper prepared in 2007 by the Center for Neighborhood Technology titled “Managing Urban Stormwater with Green Infrastructure: Case Studies of Five U.S. Local Governments”, identified the lack of performance data as a barrier to green infrastructure implementation. The more research we do and data we collect the better off we will all be.

    I anticipate this will be a successful demonstration of green infrastructure. It is exciting to see another city embrace green infrastructure on such a large scale. We will all eagerly await the results and follow its realization. Construction is expected to start soon.

    -Brian Phelps





    Portland’s Green Streets

    25 11 2009

    Streetsblog San Francisco had a great post last week that reported on a recent tour of Portland’s Green Streets taken during the Congress for the New Urbanism’s Project for Transportation Reform Conference. The post includes a number of wonderful green street examples. The quality of the installations are impressive. A representative of Portland’s Bureau of Environmental Services (BES) was quoted as saying the green streets were necessitated as a result of the City’s need to comply with a Clean Water Act lawsuit. The cost of conventional stormwater infrastructure topped nearly $150 million. This cost encouraged the city to explore alternatives like green streets for reducing water volumes. David Elkin,the BES representative quoted in the post, estimates the solution saved the City $60 million dollars in stormwater pipe replacement. The post is worth checking out.

    -Brian Phelps





    Triple Bottom Line of Green Infrastructure

    18 11 2009

    Before and After of Green Infrastructure Improvements
    (Source:“Green Cities Clean Waters” Plan)

    In an earlier post titled “Making Green Infrastructure Common Place” we discussed the recent release of Philadelphia’s $1.6 billion dollar “Green Cities Clean Waters” Plan. Its thrust is to transform over 4,000 acres of impervious areas within the City’s Combined Sewer System to green space over the next 20 years through the use of green infrastructure strategies. This would involve converting over 34% of all existing impervious areas. Of this, the conversion will primarily be made on public property and right-of-ways. Green streets, the most widely used management tool, will comprise nearly 38% of these improvements (see graphic). The report claims this is “the largest green stormwater infrastructure program ever envisioned in this country”. While green infrastructure has been utilized and proven in many parts of the country, the sheer magnitude and commitment of the city is a radical departure from the conventional approach to stormwater management practices.

    Map of Green Street Locations
    (Source:“Green Cities Clean Waters” Plan)

    So why did Philadelphia decide to rely so heavily on green infrastructure as a means of reducing overflows in their CSO system? Quite simply it was cheaper, significantly cheaper. The plan estimates over the next 20 years the plan is to be implemented, the “triple bottom line” benefits (social, environments, economic) of the plan alone will add up to a present value of $2.2 billion dollars. The following is a breakdown of the benefits that comprise this figure.

    • Heat Stress Mortality Reduction (35%)
    • Recreation (22%)
    • Property Value Added (18%)
    • Water Quality and Habitat (14.5%)
    • Air Quality (4.6%)
    • Avoided Social Costs from Green Jobs (3.7%)
    • Energy Savings (1.0%)
    • Carbon Footprint Reduction (0.6%)
    • Reduction in Construction- Related Disruptions (0.2%)

    So instead of employing conventional underground infrastructure that is one-dimensional, and is estimated to cost $16 billion, the city has decided that implementing a multi-dimensional strategy with multiple benefits made more sense. But not only is it more desirable, it is politically easier to implement because it makes the city a more beautiful and healthy place. So if you are going to have to spend the money anyway, why not make it count.

    The shortcomings of the conventional “tanks and tunnels” approach were not only that it exceeded the EPA’s affordability standard for stormwater management (2% of median household income), but it also did not address water quality issues and could require green infrastructure tools anyway to meet these requirements. In addition, the report points out that the conventional solution isn’t aligned with the EPA’s broader goals of sustainability, reduces streams baseflow thereby damaging the resources that is designed to protect, and doesn’t offer any secondary triple bottom line benefits. Furthermore, since the conventional solution is not delivered incrementally it is not flexible and does not offer any benefits immediately.

    Green infrastructure on the other hand offered the city the opportunity to revitalize and restore the city’s streams and rivers, enhance the quality of the built environment throughout the city, improve air quality, reduce the heat island effect, and sequester carbon. While accumulating these benefits, the approach was more flexible, offered immediate benefits, and, most importantly, the cost of implementation was offset by the dollar value of the benefits. (see Volume 2: Triple Bottom Line Analysis of the plan for specifics)

    While conventional infrastructure has its place, the combination of the two can play a significant role in addressing many of the issues facing our cities. It is critical that we continue to move toward making these strategies common place. By doing so we can make our cities healthier and more beautiful for all of us to enjoy, while at the same time responsibly managing our stormwater.

    -Brian Phelps





    Opportunities

    9 11 2009

    Are words necessary?

    curb and gutter

    green street





    Deaderick Street’s Transformation

    28 10 2009

    The Tennessee Urban Forestry conference was in town recently and asked Hawkins Partners to give a guided tour of the Nashville Public Square and Deaderick Street. This marked our first “official” tour of Deaderick Street to discuss all of the exciting new aspects of the green street.

    Deaderick_Street_3

    The recent transformation of Deaderick Street recalls the historic importance of the street and enhance the corridor’s prominence as an important civic axis. Prior to the renovations, the street had become most widely known as the central transfer point for the Metro bus system. In the Fall of 2008 the bus system’s hub was relocated one block over to the ambitious Music City Central, presenting an opportunity to re-envision the street itself

    Deaderick_Street_4

    The renovations to the street primarily focused on addressing stormwater issues and urban trees. The existing streetscape was home to an assortment of unhealthy trees ranging in sizes from 2” caliper up to 24”+. Each and every one of them were shoehorned into a 4’x4’ planting zone and struggling to adapt to urban conditions. The renovations included removing those trees and providing larger and deeper planting areas that would not only give a larger volume of soil for the tree roots, but also provide many areas in which the stormwater could travel to, thus reducing the loads into the storm system. Bioretention zones were implemented in pedestrian bulbs at the intersections and in relation to the existing catch basins. These planting areas were also excavated to a depth that would accept enough engineered soils to allow infiltration and planted with plants that can adapt to the extremes of wet and dry conditions. Pervious area within the corridor was increased by over 700%.

    Deaderick_Street_1

    Many other elements of sustainability were included, such as:

    • Crushed and recycled concrete used for the pavement subbase,
    • Fly ash utilized in the concrete mix,
    • Porous concrete,
    • LED light fixtures,
    • Native and drought tolerant plant materials,
    • Solar powered parking meters,
    • Water efficient irrigation system,
    • Many local vendors and fabricators,
    • The addition of bike racks to help encourage a healthier way to travel, and
    • The addition of recycling receptacles along the street.

    We’re hoping that in the near future, permanent retail kiosks that were proposed in the master plan will be added to the street, further enlivening the corridor. Those kiosks are proposed to have an extensive greenroof on each. In addition, the master plan identified areas for future free standing retail buildings and liner buildings that could be added on the blank facades.

    – Laura Schroeder





    St. Louis Roadtrip: Citygarden’s Green Street

    23 10 2009

    citygarden_green_street_1

    citygarden_green_street_3

    citygarden_green_street_2

    A couple of us at the office decided to make a roadtrip to St. Louis to see the new Citygarden, a three-acre sculpture park designed by Nelson Byrd Woltz that opened mid-summer. It was a pleasant surprise to see that the street cutting through the two blocks comprising the garden is a green street. The pedestrian bulbs on the south end have openings in the stone curbs to allow water to enter. Small strips of asphalt were also added at each opening along the curb to help divert additional water. The rain gardens are further expanded by incorporating small steel boardwalks along the sidewalk that allow water to move from the pedestrian bulbs to a larger landscape area on the opposite side of the walkway. The boardwalks draw attention to the rain garden as you pass over it. This green street was just one of the many exciting elements found in Citygarden. The park is an impressive addition to the city.





    Nashville’s First Green Street Opens

    21 10 2009

    deaderick_street_opening_3

    Jim Snyder, Metro Public Works and Kim Hawkins, Hawkins Partners
    present graphic panel to Mayor Karl Dean.

    deaderick_street_opening_1

    View of Streetscape During Event

    deaderick_street_opening_4

    View from Public Square to Legislative Plaza

    On October 8th, Nashville’s first green street opened with great fanfare. Mayor Karl Dean, Kathleen O’Brien (President and CEO of the Tennessee Peforming Arts Center), and Billy Lynch, the Director of Nashville Public Works Department, spoke at the street’s eastern terminus in Public Square. The celebration also included music by Decca Records and SONY/ATV artists One Flew South, featuring Grammy Award-winning composer Marcus Hummon, and Transit, a band formed by Nashville MTA employees. A recording of the event has been posted on Metro Nashville’s website. (Link)