New Guide Helps Municipalities Monetize the Value of Green Infrastructure
By CostBenefit on Jan 27, 2011 | In General, Water, Energy, Land + Water, U.S., Natural Hazards, Green Roofs, Research Institute NGO NonProfit, Costs and Benefits, Press Release (May be biased), Wastewater, Free Report at Time of Entry
Download the guide at http://www.cnt.org/repository/gi-values-guide.pdf.
The guide fills an information gap that has hampered widespread deployment of green infrastructure—the practice of managing stormwater with natural systems. “The Value of Green Infrastructure” brings together current research on green infrastructure performance and presents methods for calculating related benefits in water management, energy, air quality, climate, and community livability.
“When you can assign economic value to the wide array of green infrastructure benefits, planners, builders, and city officials can accurately evaluate the advantages of these approaches for managing stormwater in their communities,” said Danielle Gallet, infrastructure strategist at CNT and one of the principal authors of the guide. “Establishing a framework for calculating the benefits of green infrastructure is a first, key step to making it a mainstream practice.”
Green infrastructure is a network of decentralized stormwater management practices—such as green roofs, trees, rain gardens and permeable pavement—that can capture and infiltrate rain where it falls, reducing stormwater runoff and improving the health of surrounding waterways. The practices provide multiple environmental, economic and social benefits, including, but not limited to:
* Less polluted stormwater runoff
* Improved air quality
* Energy savings
* Increased property values, and
* Reduced greenhouse gas emissions.
“This guide helps quantify the multiple energy, economic and environmental dividends we’re seeing in Portland with our own sustainable stormwater efforts,” said Mike Rosen, Watershed Division Manager of Portland’s Bureau of Environmental Services. ”Every planner, stormwater manager or developer who’s deciding how to invest their water infrastructure dollars for the next 20 years should read this informative, thought-provoking handbook.”
Municipalities have often struggled to quantify green infrastructure’s monetary benefits. However, any cost-benefit analysis comparing grey infrastructure with green infrastructure is incomplete if it fails to factor in the multiple benefits that only green infrastructure uniquely delivers. These benefits are above and beyond the basic stormwater control benefits, which are assumed to be equal to a similar investment in grey infrastructure.
The values presented in this guide are not the final word. More research is needed to put more accurate dollar figures on the full range of green infrastructure’s benefits. Based on existing research data, many of the estimates in this guide likely undervalue the true worth of green infrastructure benefits, but it is an important first step in the right direction.
“Living green infrastructure has just taken a giant leap forward with the publication of this practical, user-friendly guide that will help policy makers, designers, manufacturers and installers evaluate the many benefits of these important and too often undervalued technologies,” said Steven W. Peck, the founder and president of Green Roofs for Healthy Cities.
Aurora, Illinois is an example of a municipality that understands the many benefits conferred by green infrastructure. In 2009, the city installed permeable pavers, bioswales and infiltration trenches at its new police headquarters, managing the runoff from the property and from adjacent uphill land. The features minimize the discharge of water and pollutants to nearby Indian Creek and eliminate the persistent basement flooding in nearby homes. The guide’s aim is to make Aurora’s efforts standard practice across the nation. “When you do the math, the benefits of green infrastructure really add up,” said Betsy Otto, Vice President for Conservation and Strategic Partnerships at American Rivers, a funder of the project. “This guide will help communities decide where, when, and to what extent green infrastructure practices should be incorporated into their planning, development and redevelopment activities.”
Center for Neighborhood Technology www.cnt.org
Press Release dated January 21st, 2011
Reduced Water Treatment Needs
For cities with combined sewer systems (CSS), stormwater runoff entering the system combines with wastewater and flows to a facility for treatment. One approach to value the reduction in stormwater runoff for these cities is an avoided cost approach. Runoff reduction is at least as valuable as the amount that would be spent by the local stormwater utility to treat that runoff. In this case, the valuation equation is simply:
runoff reduced (gal) * avoided cost per gallon ($/gal)
= avoided stormwater treatment costs ($)
The Metropolitan Water Reclamation District of Greater Chicago has a marginal cost of treating its wastewater and stormwater of $0.0000919 per gallon (CNT 2009). Using Example 1.1, in which the 5,000 SF green roof provided a runoff reduction of 71,100 gallons, the annual avoided cost for water treatment associated with this site becomes:
71,100 gallons * $0.0000919/gallon = $6.53 in annual avoided treatment costs
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