Green infrastructure: A cost-effective alternative to traditional water management

Aerial view of water retention on a south Florida ranch. Source:

By Lauren Contorno

Did you know the EPA estimates the cost of upgrading sewage systems across the country at $390 billion over the next two decades? It’s common for municipal sewage systems to have combined pipe systems to handle sanitary waste and stormwater. As a result, combined sewer systems are being overloaded by stormwater runoff, which often times leads to flooding and combined sewer overflows (CSOs).

Faced with flooding problems, aging water infrastructure and these daunting repair costs, many cities have been considering cost-competitive green infrastructure alternatives to a complete infrastructure overhaul. But how can municipal planners determine if green infrastructure is a cost-effective option and how many and which parcels of land should be protected from development? Furthermore, how can government officials incentivize citizens to invest in green infrastructure? Resources for the Future (RFF), a nonprofit organization that conducts research primarily in the fields of environmental policy and economics, recently held a seminar discussing these issues.

Using a GIS-based model called Hazus and the East River watershed ofWisconsinas a case study, RFF researchers demonstrated how cities can conduct a cost-benefit analysis of preserving open space for flood mitigation. TheEast Riverfloodplain has an estimated 23,000 acres of open space, including farmland and natural areas such as wetlands and forests, that are projected to be developed by 2025. By comparing the estimated future flood damage costs that would result if these open areas were developed versus the relative benefits of protecting them, RFF was able to calculate the annual monetary value of permanently preserving the open space. Unlike impervious surfaces that result from development, open space allows rainwater to soak into the ground, helping to reduce flood damage and the costs associated with it. Moreover, given that this open land is located in a floodplain, the land is naturally wet and not suitable for development.

RFF noted that while it may not be cost-effective to purchase and preserve an expansive area of open space, strategically pinpointing high-benefit land parcels for green infrastructure projects is more economically viable. Two of the most common methods for land preservation include government purchase of land to be maintained as public open space, and conservation easements, which protects the land from development in perpetuity.

“But what’s in it for me?” landowners may ask. Even if green infrastructure is sustainable and cost-effective, it may be difficult to convince landowners to invest in green infrastructure, such as natural detention ponds, especially if it could impact existing productive uses like farming or ranching. RFF panelists discussed the possibility of incentive programs through a case study in the Florida Everglades.

In Florida, decades of human activity has dramatically altered the natural hydrology of the state. Namely, drainage of wetlands in the Northern Everglades for urban and agricultural development has led to increased stormwater flow into Lake Okeechobeeand the St Lucie and Caloosahatchee Estuaries, threatening vulnerable wildlife habitat and resulting in a massive loss of freshwater into the ocean. In an effort to restore this area’s natural hydrology, the Florida Ranchlands Environmental Services Project (FRESP) launched the Dispersed Water Management Northern Everglades—Payment for Environmental Services Program (NE-PES) in an attempt to capture and retain water on private lands in the Northern Everglades to prevent it from rushing too quickly into Lake Okeechobee and surrounding estuaries. In order to incentivize ranchers in the area to use parcels of their land for stormwater capture, FRESP partnered with South Florida Water Management District (SFWMD), a state agency, to enter into 10-year paid contracts with eight ranchers. In all, it was a $7 million investment that retained 4,800 acre feet of water per year! As this case study demonstrates, incentive programs and collaborative public and private partnerships can be an integral part of green infrastructure implementation.

Here in the Chicago metropolitan area, investment in green infrastructure will be vital in order to create a sustainable water management system that will be resilient to climate change and the extreme weather events it will bring. The Midwesthas experienced a 31% increase in very heavy precipitation events between 1958 and 2007 and these trends are expected to continue. Faced with the need to combat future flood threats, the lessons provided by the Resource for the Future seminar can serve as a great guide for city planners and policymakers in conducting cost-benefit analyses and in designing incentive programs.

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