Maine Stormwater Conference

Green Infrastructure / LID

Monday, November 16

Presentations from the 2015 Conference are available here.

10:00 – 11:30
Session I – Hittin’ the Streets with GI

10:00 – 10:30
Green Streets Lessons Learned from Philadelphia and New York
Fernando Pasquel & Mark Van AukenARCADIS

The Philadelphia Water Department (PWD) and the New York City Department of Environmental Protection (NYCDEP) have adopted ambitious green infrastructure programs to support their Long Term Control Plans to reduce Combined Sewer Overflows. Green infrastructure can reduce reliance on storage tanks and other large-scale infrastructure projects by providing localized, disconnected storage facilities and promoting infiltration and evapotranspiration of stormwater. As city streets represent a large portion of City owned impervious area, Philadelphia and New York City have targeted implementation of green infrastructure within the public right-of-way. The NYCDEP is building thousands of Right-of-Way Bioswales (ROWBs) in the sidewalks of city streets as part of its Green Infrastructure Plan for reducing combined sewer overflows, published in 2010. Similarly, PWD has targeted Green Streets during the initial years of their Green City, Clean Waters Plan for Combined Sewer Overflow Control, signed into agreement in 2011. This presentation will highlight lessons learned from the first few years of Philadelphia’s Green Streets program and New York City’s Right-Of-Way Bioswales program. NYC and PWD have structured their green infrastructure programs using an adaptive management approach, where lessons learned from implementation are used to influence the future direction of the programs. Lessons will be drawn from the planning, design, construction, and monitoring phases of each program. The creation of design standards and workflows will be highlighted along with modifications to standards based on experiences encountered during design and construction.

10:30 -11:00
Greening the Black – Porous Asphalt Alley Demonstration Project, Boston MA
Bethany Eisenberg, VHB

While permeable pavements are seeing increased use as a key technology for reducing stormwater runoff and combined sewer overflows, increasing groundwater recharge, and valuable green infrastructure practice, there is often still a hesitancy for its use in the North East. Hurdles include; fear of potential clogging, pavement failure or increased maintenance and construction costs. Additionally, there has been a noticeable lack of available standard specifications for construction leaving a gap between the concept and actual construction phases. VHB proposed the idea for a permeable pavement demonstration project in the City of Boston and teamed with Charles River Watershed Association, the Project Manager, and the City of Boston Public Works Department and Boston Groundwater Trust to complete a Porous Asphalt Alley Demonstration Project. This presentation will share the process of choosing the project site, selecting the materials, developing new details and specifications and completing construction. Lessons learned and tips for future projects in the northeast will be shared.

11:00 – 11:30
The Big Green Apple
Ginny Roach, CDM Smith

For the past four years, CDM Smith has been working with the New York City Department of Environmental Protection Office of Green Infrastructure and partnering agencies to plan, site, design and construct green infrastructure improvements in Queens, the Bronx and Brooklyn. Green infrastructure improvements include right-of-way bioswales stormwater greenstreets and various types of green infrastructure practices (porous pavements, vegetated bioretention areas, and redirection of roof runoff to green infrastructure) on public properties. This presentation will review the collaborative engineering behind the recommended improvements, construction challenges and lessons learned, as well as project costs.

1:00 – 2:30
Session II – GI: The Next Generation 

1:00 – 1:30
Volume Reduction in Systems Not Designed for Volume Reduction
Tom Ballestero, University of New Hampshire Stormwater Center

Many green infrastructure systems (bioretention, tree filters, permeable pavements) are built upon low permeability soils that are expected to provide very little infiltration.  However, monitoring of systems in coastal New Hampshire is demonstrating remarkable volume reduction.  Two such systems are reported here:  a tree filter and an underground storage system.  At each location, precipitation, inflow and outflow were recorded since 2012 and 2014, respectively, and continues today.  The undersized tree filter collects runoff from a parking lot and demonstrates a median volume reduction of 67% and more remarkably, during snowmelt only events, demonstrates a median volume reduction of 98%.  Median peak flow reduction is 83%.  The subsurface storage system collecting water from a commuter parking lot demonstrates a cumulative volume reduction for the 9-month monitoring period of 86%.  The tree filter was designed for the water quality flow and the underground storage system was statically designed for the water quality volume.  All systems are situated in glacial till soils with infiltration capacities less than 0.3 inches per hour although invariably there is urban fill below the parking surfaces.

The remarkable volume reduction on the low permeability soils imply that there is significant stormwater movement laterally into the soils:  a flux typically not considered in design.  The performance of the underground storage systems demonstrates the conservativeness of static design versus the actual dynamic performance of systems.

This presentation will review the designs, the site specific conditions, example hydrographs, and full storm datasets.

1:30 – 2:00
Engineered Biofilter for Advanced Green Infrastructure
Daniel Bourdeau, Geosyntec

An innovative stormwater treatment biofilter was engineered and constructed to treat low level contamination in stormwater runoff from impervious areas on a portion of a former federal government energy research facility in the Simi Hills of Ventura County, California (Site). Runoff from this Site is characterized with contamination of nutrients, metals, dioxin and sediment. This innovative green infrastructure biofilter design incorporated collaboration with an Expert Panel comprised of industry leaders from around the county, including Dr. Pitt of the University of Alabama. The biofilter design incorporates an advanced media mix that was developed during a comprehensive bench scale media filtration study conducted by Dr. Pitt. This bench scale study was used to optimize pollutant removal, media costs and availability, infiltration rate and media contact time. A plant suitability pilot test was also conducted to determine how vegetation performs in advanced media and how the root structure can aid in the performance of a media filtration system. The biofilter design also incorporated an advanced outlet control configuration to accurately control the biofilter hydraulics, thus creating the required media contact time necessary to achieve stormwater treatment goals. The biofilter has been performing for the past two years and has had two seasons of performance monitoring data including nutrients and bacteria removal. The project was the recipient of the 2013 California Stormwater Quality Association’s Award for Outstanding BMP Implementation Project. The presentation will focus on the following: (1) a summary of the bench scale study used in the selection of the media; (2) the design components of the biofilter system; (3) construction lessons learned for implementing an advanced filtration system; (4) a summary of performance data and lessons learned over the two year monitoring period.

2:00 – 2:30
Real-time Control: The Next Generation of “Smart” Green Infrastructure
Andrea Braga, Geosyntec

State, local governments and private enterprises have made significant investments in stormwater BMPs for flood attenuation and water quality treatment. As regulations become more stringent, investment in enhancing stormwater BMPs will be needed to meet future pollutant reduction requirements. The presentation will focus on the engineering aspects and outcomes of recent research, modeling, and case studies performed by the authors where dynamic real time controls of stormwater BMPs have been implemented for optimized BMP performance.

3:00 – 4:30
Session III – Panel Discussion: Are There Holes in Porous Pavement?

Experts from the region share their experience with designing, installing, or analyzing porous pavement. Invited panelists include the following:

To view speaker bios click here.