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Parking lot is big... big and eco-friendly

WILLIAMSBURG

There was much excitement Wednesday over a very large parking lot.

Dozens of local engineers, architects, developers and public officials - some taking photos, others furiously making notes - gathered outside a still-vacant shopping center to observe the phenomenon.

"People across the United States are watching this project very closely," said Keith Beazley, with the Virginia Ready-Mixed Concrete Association.

"I don't think there's anything else like it, really, in the country," said Stephen Romeo, vice president of Landmark Design Group, a local engineering company that planned the big lot.

Why the fuss?

The parking lot, which will serve an expansion of the Prime Outlets shopping mall in Williamsburg, is

advertised as "the largest pervious concrete project in the United States," one that covers 7 acres of Earth with this environment-friendly building material.

The lot is larger and more complex than others in Pennsylvania, Arizona and California, as well as an eco-friendly commuter parking lot at North Carolina State University in Raleigh, officials said.

Resembling a giant batch of gray Rice Krispies Treats, porous concrete allows rainwater to pass through to the ground below - while still providing a flat, stable place to park the family car.

This way, any rainwater - which often becomes polluted with drips of oil, gas, dirt, chemicals and heat - can harmlessly filter back into groundwater supplies instead of washing off and damaging nearby creeks or streams.

Storm water runoff is the biggest new source of pollution afflicting the Chesapeake Bay and other waterways today, and often is linked to increasing amounts of traditional concrete and asphalt, or "impervious surfaces."

At Prime Outlets mall, the filtered rainwater also will be "harvested," as Romeo described, to irrigate trees, shrubs and flowers that dot the parking-lot landscape.

To curb localized flooding, heavy rains will be piped to an underground field of plastic crates - hundreds of them, lashed together with plastic zip-ties - that will store and then slowly release excess water over time.

This storm-management system also will be covered with pervious concrete, and can be used, too, as an auxiliary parking lot.

Two local politicians spoke at an unveiling ceremony Wednesday and praised the project for seeking a balance between two forces frequently at odds with each other: economic development and environmental protection.

Finding and investing in such a green compromise, said state Sen. Thomas K. Norment, R-Williamsburg, "is not always a characteristic you see in the development community."

Pervious concrete has been around for more than 20 years but is only now finding an audience in Virginia. Higher upfront costs, fear of the unknown and concerns about ice have kept the technology from taking off, said Isao Ishibashi, a civil engineering professor at Old Dominion University.

"But industry people are starting to realize the material really works here," Ishibashi said.

The Virginia Ready-Mixed Concrete Association, a trade group, now promotes pervious concrete. Its officials ticked off a list of "green" concrete projects under way or completed - an apartment parking lot in Norfolk, sidewalks in Richmond, car washes in Northern Virginia, driveways at homes in Chesapeake and Virginia Beach.

Given the size, scope and newness of the Prime Outlets project, local and state regulators were skeptical at first. But the plans eventually were approved amid an increasing political climate that favors "smart" growth and environmental sensitivity, officials said.

Henderson Construction, the general contractor for the mall expansion, had never worked with pervious concrete before. But specialists were brought in, and paving has been ongoing since January. Older, failing lots also were replaced with pervious material.

On Wednesday, crews were still pouring concrete in some patches. But the project is expected to be completed in time for the grand opening of the mall expansion, in mid-April.

Scott Harper, (757) 446-2340, scott.harper@pilotonline.com

Posted to: Environment News

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Eco friendly? Eco stupid...

This way, any rainwater - which often becomes polluted with drips of oil, gas, dirt, chemicals and heat - can harmlessly filter back into groundwater supplies instead of washing off and damaging nearby creeks or streams.

What about those drips of oil, gas and other chemicals, won't they just pass through the pervious concrete to the ground causing the same problem? Anything rigid yet pervious will eventually become clogged with the aforementioned materials defeating the purpose. And as the article mentioned, wait till they get a good freeze. Solid concrete cannot hold up against ice, so how is this stuff supposed to be any better

Like many "eco-friendly" ideas, they look great on paper, but don't hold up practically, and end up costing 100 times as much in the long run (usually due to unscheduled and constant maintenance).

Astounding statement

"This way, any rainwater - which often becomes polluted with drips of oil, gas, dirt, chemicals and heat - can harmlessly filter back into groundwater supplies "

A positive step, but do they really believe the statement above?

Answers

The pervious concrete is layed on top of stone and said which help catch the oils and grease left from vehicles. Two, pervious will ALWAYS withstand ice. In conventional concrete there is a chemical called Air Entrainment that is put in the concrete to create small bubbles, these bubbles are used for the water to go in and freeze during a free-thaw cycle. If the water has some where to go to freeze and expand like these bubbles it keeps the concrete from cracking due to the expansion. With pervious there are many voids hence the ability for the water to flow through. It is designed for water to flow completely through and not stay in the concrete, if for any reason water is present and we hit freeze there are plenty of voids for the water to go in and expand thus keeping the concrete from crakcing. There is small maintenance to this product about once a year or once every couple of years you should send a sweeper/vacuum truck over and that will keep the voids from becoming clogged. However, if this is too much maintenance for you then a completely leaving the pervious alone will clog it but it will never become inpervious.

It's All Relative

Oil, gas, chemicals (including road salt) washing straight into a creek, will have a stronger, more immediate impact than if absorbed in the soil. Plus, the pervious pavement helps even out the flow of runoff. Cutting down on the storm surge, will cut down on the downstream erosion that also hurts the water quality.
But oil soaked earth, or chemicals in the groundwater, are still a problem. But there are bacteria in the soil that can help remediate the pollution somewhat. And at least dirt should be okay being filtered by the earth.
Altogether, it's a good thing to use pervious pavement. But it is a choice for the lesser of two evils.

Very cool

This is a big technological improvement. Rain runoff and lack of absorption into the groundwater has been a constant problem of development all through history. This will help prevent both droughts and flash floods. I wonder if we can get Rosemont redone with this material?

Wow! I really hope there's a

Wow! I really hope there's a picture in the article. I would love to see the parking lot especially that the article is very intriguing. Does it have openers for garage doors?

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