March 2012, Vol. 24, No.3

Waterline

Debunking misconceptions about porous pavement in cold climates

The use of porous pavements in northern areas is increasing. And contrary to common beliefs, porous pavement often performs better than standard pavement in cold climates, according to an article by Tom Ballestero and Rob Roseen of the University of New Hampshire (Durham) Stormwater Center.

Standard pavements are designed to prevent moisture in the subsurface. This becomes difficult as pavements age, particularly with pavements that experience frost heaves. When surface cracks allow infiltration into the subbase, standard pavements deteriorate.

Porous pavements, on the other hand, are designed to drain, and the stone at the base of these systems breaks any capillary connection to groundwater. These design elements make porous pavement more resistant to freezing and frost heave. The pavement is not negatively affected by freezing, because it remains porous and does not become an impermeable ice block.

Not all permeable pavements perform the same in winter conditions. Concrete porous pavement systems perform poorly, with weakening and spalling of the surface from winter salt application. And darker surfaces with greater solar exposure tend to require less winter maintenance than lighter surfaces, the article says.

Read the full article in the Jan. 5 issue of The Stormwater Report at bit.ly/xPg4MZ.

College football stadium receives LEED certification

Apogee Stadium, the centerpiece of the recently developed Mean Green Village, received Leadership in Energy and Environmental Design (LEED) Platinum Certification from the U.S. Green Building Council (Washington, D.C.). The University of North Texas (UNT; Denton) stadium is the first newly constructed collegiate football stadium in the United States to receive this level of LEED certification, according to a UNT news release.

The 31,000-seat stadium features low-flow plumbing estimated to reduce water consumption by more than 52%, the news release says. The stadium also features onsite renewable wind energy generated by three wind turbines; preserved or restored native landscaping; construction materials containing recycled content and local manufacturing; permeable pavers; indoor natural lighting; and energy-efficient heating, ventilation, and air conditioning and lighting equipment estimated to reduce energy consumption by 25%.

Stadium construction was led by the UNT System (Dallas), and it was designed by HKS Sports and Entertainment Group (Dallas) and built by Manhattan Construction Co. (Tulsa, Okla.).

Fewer trees for more water

Thinning forests in the Sierra Nevada mountains to boost water runoff could increase the amount of water available in California, according to a report by scientists at the University of California–Merced (UC–Merced), University of California–Berkeley, and Environmental Defense Fund (New York).

The team of scientists proposes to test the hypothesis that forest management strategies that use thinning to reduce fire risk and maintain the historical mix of trees also can increase water yield and extend the snowpack in the Sierra Nevada, according to a UC–Merced news release.

With recent climate change, warmer temperatures have reduced the amount of water available as runoff, and selectively reducing the number of trees, which use large amounts of water received through precipitation, could help counter these effects, the news release says. Forests are much denser now than in past centuries, and the scientists believe thinning can be done in ways that enhance the forests’ overall ecological health, the release says.

The team plans to reduce forest density in test areas and examine the effects on water runoff, forest health, and other ecosystem services to provide a template for broader forest management as part of the Sierra Nevada Watershed Ecosystem Enhancement Project, the release says.

Access the report, Forests and Water in the Sierra Nevada: Sierra Nevada Watershed Ecosystem Enhancement Project, at bit.ly/SNWeep

The triple threat: treating wastewater, generating energy, and producing drinking water

A portable wastewater treatment system that also generates energy and produces drinking water is being developed through the “solar-bio-nano” project being led by Wei Liao, Michigan State University (MSU; East Lansing) assistant professor of biosystems and agricultural engineering. The project is funded by a $1.92 million U.S. Department of Defense grant, according to an MSU news release.

Shipping water from ports to bases during military operations can drive the cost of water up to nearly $16/L ($60/gal). A portable, self-sustaining system would enable military bases to move more easily and be more cost-effective, Liao said in the news release.

The system will include three components: a solar unit that is as much as 80% lighter than traditional solar units, a biological conversion process that breaks down wastewater and food scraps to produce methane that can be used as fuel, and a nanofiltration system that takes the discharge from the biological processes to provide drinking water, the release says.

The system, which could be transported by a tractor–trailer, is able to serve about 600 people and is designed to reduce the costs and demands for water and fuel, Liao said in the news release. The system also has potential to be used in other situations, ranging from agricultural operations to municipal wastewater treatment plants.

Ilsoon Lee, MSU associate professor of chemical engineering, and Abraham Engeda, MSU professor of mechanical engineering, also are working on the project.

 

© 2012 Water Environment Federation. All rights reserved.