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Monday, October 29, 2018

Exploring the Green Infrastructure Workforce

Image via the Stormwater Guidance Retrofit Manual courtesy of Philadelphia Water

Urbanization has altered the natural landscape and affected the hydrologic cycle. Where the natural hydrologic cycle maintains a balance of water circulation through evaporation, precipitation and groundwater recharge, and absorption and transpiration by plants, urbanization has resulted in an altered hydrologic cycle through construction of impervious surfaces such as buildings, roads, and parking lots.

The water has nowhere to go except into a city's seemingly endless configuration sewer pipes, systems which are becoming increasingly overburdened and thus prone to overflows and outfalls of polluted runoff into watersheds, such as rivers, lakes and creeks during heavy rains.

In urban areas with combined sewer systems, such as Philadelphia, Chicago and New York, the impact is can be particularly troublesome because the discharges, known as CSOs or combined sewer overflows, often contain untreated sewage.

Green stormwater infrastructure is an incremental, ecologically centered, low impact development approach to mitigate these outfalls by reducing the amount of runoff that goes to the sewer system and by utilizing the water as a resource, via rain gardens, tree trenches, permeable paving, rain barrels, green roofs and more.

Because of its incremental approach, the implementation cost for cities is often much less than heavily engineered concrete gray infrastructure efforts. It may not be the sole solution, but it offers a plethora of benefits measured in more ways than just pollution prevention. Benefits such as awakening the urban ecosystem through tree planting and stream restoration, bringing together local communities over health and environment issues, and spawning a thriving new "green collar" workforce that offers opportunity to urban areas left buried in the ruins of the industrial age.

The NatureWORKS report by Jobs For the Future, jff.org, for example, contends that "in urban green infrastructure, there is an opportunity for entry-level jobs with the possibility for advancement. It is a win-win for cities to invest in sustainability and achieve both a healthier, greener community and a job development program."

Other efforts, such as with the Great Urban Parks Campaign, the National Recreation and Parks Association and the American Planning Association are also working to demonstrate the benefits of green infrastructure in urban communities. Their video below states that "using parks for green infrastructure is a creative and cost-effective alternative to gray infrastructure that allows nature to filter pollutants from rain water, reduce storm water issues and give communities access to more green space."

The NatureWORKS report is available for download in PDF at the following link: https://jfforg-prod-prime.s3.amazonaws.com/media/documents/NatureWORKS-Issue-Brief-032317_v3.pdf

Monday, February 8, 2016

Rain barrels, green roofs, permeable pavement: better ways to help manage urban stormwater runoff and reduce waste

As meteorologists monitor the El Nino condition currently gaining strength in the Pacific Ocean, Californians look with hope to the much-needed rain and snow it could yield. But if we're going to make the most of the precipitation, we need to put a LID on it.

Large bioswayle integrates stormwater runoff treatment with planting feature for neighborhood. (Photo credit: Wikipedia)

LIDs, or low-impact development technologies, mimic pre-urban stream functions. Examples are green roofs that absorb and evapotranspire rainfall; rainwater tanks attached to homes and other buildings; and permeable pavement for roads, driveways and parking lots. Rainwater could even be used in the home for toilet flushing and laundry.

These are just some of the strategies suggested by an international group of experts who recently collaborated on a review article in the American Chemical Society journal Environmental Science & Technology.

Stanley Grant, senior author of the paper and professor of civil & environmental engineering at the University of California, Irvine, brought together academics from three UC campuses (UCI, UCLA and UC San Diego) and Australia's University of Melbourne; water managers from Orange County Public Works; and engineers from consulting firm Michael Baker International to examine how urban population centers could better meet water supply needs while protecting natural stream ecosystems.

"This team offers a key example of the significant role that University of California scientists can play in finding innovative solutions for major state problems," said co-author Lisa Levin, a Distinguished Professor at Scripps Institution of Oceanography. "With drought so pervasive, California cannot afford to waste its precious stormwater; nor can it afford to send contaminants into the ocean. The options addressed in this article tackle both of these issues."

Managing stormwater runoff in urban environments is a challenge for engineers and water officials. During pre-industrial times, rainwater gradually seeped into the ground and, from there, into rivers, lakes and oceans. Humans, however, have replaced forests and grasslands with a lot of impermeable surfaces that send runoff in a torrent directly to the closest waterways. "The massive volumes and pollutants associated with stormwater runoff are a deadly one-two punch for streams and lead to a condition known as 'urban stream syndrome,'" said Asal Askarizadeh, lead author and UCI graduate student in civil & environmental engineering.

Symptoms include erosion, flooding and rising stream temperatures; an imbalance in nutrients, carbon and oxygen in the water; and an increase in unwanted sediments, chemical pollutants and human pathogens.

The antidote, Askarizadeh said, is to harvest and reuse as much of the stormwater runoff as possible and allow a portion to infiltrate into the ground to support streams and groundwater.

"Using LIDs to create this kind of localized, widely distributed approach to stormwater management will require individuals and public agencies to be open to significant change," said co-author David Feldman, professor and chair of UCI's Department of Planning, Policy & Design. "We expect the government to manage our water supply completely, and in some places, it's even illegal to harvest rainwater locally. Laws and habits are going to have to change if we are to adapt to new climate and urban realities."

One of the significant changes the authors argue for is a movement toward distributed infrastructure (rainwater tanks and green roofs) as a complement to the centralized infrastructure (aqueducts, water treatment plants and, more recently, desalination plants) cities have long relied on. "The reason is that in order to protect receiving waters and streams, we need to capture the runoff as close to where it's generated -- for example, your home -- as possible," said co-author Brett Sanders, professor and chair of the Department of Civil & Environmental Engineering at UCI.

"The question then becomes: What do you do with the stormwater once you've captured it?" said co-author Megan Rippy, a UCI postdoctoral researcher in civil & environmental engineering. "Our work provides a blueprint for estimating how much of the captured water should be infiltrated into the ground and how much should be harvested for any purpose that keeps it out of the stream, such as for nonpotable purposes in the home. The ratio of those two volumes depends on local climate and what the landscape looked like in pre-industrial times."

"The bottom line is that these solutions are good for the environment and good for people too; they just require changing habits," Grant said. "For example, over 2 million people in Australia use rainwater from their roofs to flush toilets -- and that makes good sense. Using drinking water to flush toilets is literally washing our future down the drain."

With funding from a National Science Foundation PIRE grant, he and his colleagues were able to spend time in southeastern Australia studying how people there have dealt with their historic drought. "They have had a positive experience implementing LID technologies to manage scarce water resources, and in doing so, they've provided a good example of how universities can work with governments and private-sector entities to come up with solutions to water challenges," Grant said. "And the best part is that after emerging from one of the longest droughts in Australia's history, Melbourne has been voted year after year as the most livable city in the world. We could definitely use some of their magic."

Source: University of Californa - Irvine.

Saturday, June 14, 2014

Green Roofs: Cost-Effective Means of Preventing Sewer System Overflows

Image Credit: Columbia University

Green roofs are a cost-effective means of preventing sewage system overflows, according to new research from Columbia University.

The ability to stop overflows of course stems from the fact that green roofs retain water and thus prevent said water from simply flowing into the sewers.

As an example, the green roof on top of the Con Edison building in Long Island City, Queens (investigated by the researchers) — home to around 21,000 plants — retains roughly 30% of the rainwater (on a quarter acre) that falls on it. That’s a pretty significant amount of water.

The press release from Columbia University provides more:

If New York City’s 1 billion square feet of roofs were transformed into green roofs, it would be possible to keep more than 10 billion gallons of water a year out of the city sewer system, according to the study led by Stuart Gaffin, research scientist at Columbia’s Center for Climate Systems Research.

New York City, like other older urban centers, has a combined sewer system that carries storm water and wastewater. The system often reaches capacity during rains and must discharge a mix of storm water and sewage into New York Harbor, the Hudson River, the East River and other waterways.

The Con Edison Green Roof was built (and research on it began) back in 2008. An adjoining “white roof” was also constructed.

Previous to these new findings, the researchers had already determined that the green and white roofs were quite effective at reducing energy costs and, also, urban air temperatures.

“The information we are collecting from Con Edison’s roofs is invaluable in helping us determine the costs and benefits of green infrastructure projects,” Gaffin stated. “Without solid data from experiments like this, it is impossible for us to know which projects are the best options for protecting the environment.”

When you take into account the cost of building and maintaining a green roof, the cost of capturing rainwater works out to about 2 cents a year to capture each gallon of water.

We’ve also reported previously that green roofs and solar panels are a great fit. Green roofs help to keep the solar panels cooler, which boosts their efficiency. For more on that, see one or all of these three stories:

Green Roofs Pave the Way to Cheap Solar Power

Green Roofs & Solar Panels: The Future of Renewable Energy?

Green Roofs Boost Solar Panel Performance

In related news, a similar “simple” solution to the management of high urban temperatures was recently put forward as a solution in Australia — white roads. While the concept of using white roads to reflect light and thereby reduce temperatures is certainly nothing new, it hasn’t yet been applied on a truly large scale, something that the Cool Change Cities Project is setting out to do.

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This article was written by James Ayre via Clean Technica.