More highlights from the 2015 Cities Alive speaker program.
New York City funding GI on private property. Margot Walker, Green Infrastructure Division, New York City Department of Environmental Protection (DEP), said the city is in year 3 of installing green infrastructure to handle stormwater.
The city is funding larger green infrastructure on private property (minimum $35,000 grant) to manage a 1” storm. DEP has funded high profile project like Brooklyn Grange. Other high profile projects include rain gardens and permeable pavers at Queens College, a green roof at the New School and multiple community gardens. 2014
If you’re really interested in New York City’s movement to rain gardens and bioswales for handling stormwater and you love numbers, take a look at “Report for Post Construction Monitoring Green Infrastructure Neighborhood Demonstration Areas.”
GI spurs more GI, problems when people are not considered. Suzanna Randall, Green Program Manager, NY State Environmental Facilities Corporation, reviewed a portfolio of green streets and parking lot stormwater management projects that provided multiple lessons. Successful demonstration projects, like porous pavement at Lake George, can blossom additional green infrastructure in a town. There have also been failures. Lack of construction controls in North Tonawanda of a parking lot bioswale retrofit led to total replacement of media and plants, because the original specified media was not delivered and installed. In Buffalo, neglecting to include the community that is expected to care for sidewalk bioswales before a green street project was planned, created ground level trash pits filled with dead plants. Including plant expertise is critical as was discovered in downtown Canandaigua for a bioswale/porous pavement combination on a roadway. Most results, however, are positive. Onondaga County is one of New York’s leaders in stormwater management where the County’s Savetherain.us documents plans and specifications for stormwater management programs. The county estimates that between the 79 projects completed they are capturing 36.7 million gallons of stormwater runoff a year.
Green roofs are a constantly changing ecology. Brad Garder,Furbish, http://furbishco.com calls it stewardship, not maintenance when speaking about ongoing green roof operations. Green roofs are a changing ecology he says. His presentation focused on roofs that are 5- to 10-years old. Balancing expectations with the client is critical, especially when it comes to the plant community. Does the owner want to maintain the exact plant specifications in the original design, or is plant stability and/or diversity the goal? Will they be happy when Sedum kamtschaticum takes over at 90%? If the client wants a consistent green carpet, that’s not a bad thing. One client, Dansko, wanted diversity, then Allium sp. started to take over. To fix it, the crew removed some of allium, but now will not let the allium set seed. If the roof features geometric patterns, must the client have those several years out? One herringbone pattern on a D.C. roof with Sedum spurium John Creech and Sedum fulgida has lasted, he said. Most patterns don’t. “If we are going to make happy green roofs, we have to learn from the ones that are not happy.”
New York City green roofs bring 10-15% rental premiums. Amy Norquist, Greensulate http://greensulate.com, said that New York City green roofs yield a lot of “unexpected value.” Value is fluid, she said. One person’s value is not necessarily another’s. One client, a multi-residence building has a green roof deck for residents to use. That building’s value held steady in the economic downturn, she said, and now there’s a 10-15% premium compared to adjacent properties because of the roof amenity.
Toronto’s green roof mandate responsible for 2 million+ sq. ft. Jane Welsh, City of Toronto, said that green roofs cover 2 million sq. ft. of the city’s rooftops and it’s climbing due to the city’s mandatory green roof policy. She explained that Toronto’s 2009 green roof requirement was the outcome of working with stakeholders to implement policy.
Buildings with up to 54,000 sq. ft. must have 20% green roof; 215,000 sq. ft. and above, 60%. Exemptions cover renewable energy, private terraces, and amenity areas. Developers can pay cash in lieu of the green roof at $18.70/sq. ft. Those monies are used to fund eco-roof incentives on existing buildings. From January 2010 to 2015 the city installed 2.6 million sq. ft. of green roofs she said. About 300 building permits were written; 30 cash in lieu payments were made. Cool roofs with stormwater management are an alternative, so far 132 have been constructed. Ensuring enforcement is a challenge, she said. The city is exploring using satellite imagery for monitoring. She said the mandate has promoted new businesses. Before the requirement, Toronto had 77 green roofers, now there are 153. Toronto Green Roofs: http://www1.toronto.ca/wps/portal/contentonly?vgnextoid=3a7a036318061410VgnVCM10000071d60f89RCRD
Washington, D.C.’s stormwater standard drives GI on the ground. Dr. Hamid Karimi, Department of the Environment, Government of Washington, D.C. says it’s vital to make sure the people who will implement green infrastructure policies and regulations are on board with it. While Washington, D.C. has provided incentives for green roofs for 10 years, Hamid realized that it would take 200 years to retrofit the city’s 69 sq. mi. of roofs using incentives alone at the rate they were going. “It’s clear, incentives alone do not work.”
Washington now has an aggressive stormwater standard: You must retain 1.2” (90th percentile storm) on new construction and 0.8” of redevelopment/renovation, which is the majority of construction. The city is flexible in meeting the standard: 50% of the work may be done offsite; payment may be made in lieu of implementation; or the builder could find another property to retrofit with stormwater control. He said the flexibility has enabled stormwater control projects in disadvantaged areas of the city where the land is less expensive. The city has a strong inspection and enforcement program, he said. The city also set up a stormwater credit-trading program so that private property owners can sell their credits to others who need them. Washington, D.C. also has green ratio requirements for large tract development. “If they [the project] use Federal or D.C. cost-share funds, the building has to be LEED.” The city also charges a fee for stormwater service so that all building owners pay a rain fee, even federal buildings and embassies, which cover more than one third of the city. D.C.’s stormwater credit trading program: http://doee.dc.gov/src
Three-tiered Low Impact Development for stormwater. Ingrid Merete Ødegard, Norwegian University of Life Sciences, and Daniel Roehr, University of British Columbia, spoke about a 3-step LID stormwater strategy from Norway popularized by a stormwater researcher, Lindholm. The idea is to retain small amounts of rainfall (less than ¾”) on private property using green roofs, green walls, trees, bioswales/rain gardens and permeable pavement surfaces. Medium rainfalls (3/4” to 1 ½”) should be delayed on site with bioretention, bioswales, and retention ponds. Larger rainfalls (more than 1 ½”) should be safely dispersed into open creeks, rivers and “planned” flooding of roads, ball fields, swales and other spaces, Ingrid explained. Public support of LID is important, landowners should understand the environmental benefits.
“The public needs to believe LID is a positive change to their garden and a valuable investment to the community.” Daniel said. The strategy is to divide up LID on public and private lands. “LID always needs a backup system to conventional sewer or emergency overflows into flood secure areas.”
Green roofs need to be commodity, not oddity. Dr. Richard Sutton, University of Nebraska, said we know a lot about the benefits of green roofs, but little about the costs. Most landscape architects throw out $25/sq. ft. as a cost, “but it shouldn’t cost that much.” Richard believes $10-$12 is more appropriate. “Green roofs need to become more of a commodity and less of an oddity,” he believes. For cost savings he says forget about trays and “other fancy gizmos,” use seed rather than plants, and local recycled inorganics instead of expanded shale or clay media.
The Living Architecture Performance Tool. Steven Peck, Green Roofs for Healthy Cities, said that a living architecture benchmark matrix is under development, which will assign high, medium or low values to the multitude of costs and benefits associated with green infrastructure installation and maintenance. The Living Architecture Performance Tool is currently under development by Green Roofs for Healthy Cities. The tool is intended to provide performance-based criteria for major living architecture such as green roofs and green walls, he said. Living Architecture Tool: http://www.greeninfrastructurefoundation.org/programs/performance-tool-program
Back-of-the-envelope calculations for financial benefits of GI. Paul Mankiewicz, Gaia Institute, said “you must feed green infrastructure water.” It’s physics, you give plants water and they transpire. When that water is in the form of rain water that would normally go into a combined sewer system, it’s relatively easy to calculate benefits in the form of avoided water treatment ($3/100 cu. ft.) and energy savings, he said. Using an example of 60,000 trees, which would intercept from 600,000 to 6 million gallons of stormwater, avoiding $2,400 to $24,000 per day in water treatment costs and saving about $500,000 in air conditioning per day.
Green infrastructure analogous to nature. Mark Morrison, Mark Morrison Landscape Architecture, said layered landscapes are better for stormwater. Canopies can intercept 40% of the rain that falls, he explained. “We cannot recreate nature, but we can create an analogous environment.”
Plan to attend Cities Alive 2016 in Washington D.C. from October 30-November 5. For information visit Green Roof for Healthy Cities. http://greenroofs.org