What could possibly be wrong with such a win-win situation?
And their couldn't possibly be a downside to the 5000 square foot house
that is replacing a run-down little ranch on an acre lot; a house that will
automatically increase property values in the neighborhood; or any problem with
the construction of a 200,000 square foot high-tech manufacturing plant destined
to provide 2,500 new jobs.
Well, yes there is. The downside is the way that we traditionally build houses,
shopping centers, and office buildings. Traditional building methods and materials
bring with them a tremendous cost to the environment.
We start our occasional series of articles on building green and living green
by looking at what happens to the land and both the immediate and the remote
environment when a building is erected using modern building methods,
and what new initiatives, products, and techniques are now available to mitigate
that impact without diminishing the attractiveness or comfort of the home or
appreciably increasing the cost of construction.
While we are speaking mainly about residential construction, the only real difference
between an average house and a manufacturing facility or a shopping center is
the scope of the impact on the environment.
When a building is constructed several things inexorably happen that are harmful, destructive, or devastating to the environment:
- Existing landscaping is removed
- Habitat is damaged or destroyed
- Softscape or permeable ground cover is replaced with hardscape or non-permeable material.
Removing existing landscaping:
Cutting down a tree immediately removes a piece of nature's cleaning and cooling system. Trees help to remove pollutants from the air and replace carbon dioxide with oxygen and they provide shade that helps to keep underlying ground and buildings cool in summer, thus cutting back energy costs. Dead leaves provide nutrients to the soil and mulch that prevents (along with the tree canopy) the growth of vegetation that can feed brush fires in dry weather cycles.
It goes beyond trees. Indigenous plant species are scrapped in favor of nursery plants which may be prettier and meet the landscape architect's grand design, but require more work, more water, more fertilizer and pesticides than native varieties. Perhaps no single plant is less suited to grow in many areas than the all-American suburban lawn.
Destruction of habitat:
Clearing a building site with an eye only to make building quick and affordable (the scorched earth method) has unintended consequences for wildlife.
Granted, one might not want a bull moose wandering through the rose garden or bears at the bird feeder, but tearing down trees and uprooting native grasses or wildflowers impact the lives of animals large and small. The humus from rotting leaves provide cover and food for countless insects and amphibians which in turn are eaten by birds and reptiles, skunks and, yes, bears. Trees, meadow grass, and brush provide cover and nesting places for all kinds of animals and birds which, in turn, control harmful insects such as mosquitoes or pollinate flowers and crops. You know, the whole circle of life thing.
And, if you think destroying their habitat will make the larger examples of nature go away, ask any homeowner who is now supporting a herd of deer with a costly diet of hosta and yews. Animals have to go someplace and deer, bear, coyote, possums, and raccoons have shown an amazing ability to adapt to our habitats when their own is destroyed. The problem is that they tend to also adapt from eco-friendly creatures who contribute to that circle of life to destructive, even dangerous neighborhood residents.
The biggest assault on the environment, however, comes through replacing softscape with hardscape:
According to Environmental Health Perspectives, as reported by the National Institutes of Health, "paved surfaces are quite possibly the most ubiquitous structures created by humans." In the United States alone, impervious surfaces including paving, roofs, parking lots and so forth, cover an area of 43,000 square miles, an area nearly the size of Ohio. As much as 65 percent of this is what the nonprofit Center for Watershed Protection calls "habitat for cars:" i.e., streets, parking lots, and driveways.
Man has never designed a beautiful parking lot. The borders that surround the lot, the islands that punctuate it, can be spectacular, but there is nothing pretty about acres of asphalt or concrete. But that is not even the beginning of the problem. Impervious surfaces do not absorb water. Rain that is not readily welcomed back into the earth runs off, carrying along with it any waste or toxins it encounters along the way. And these "habitats for cars" harbor a multitude of such substances. A partial list would include particulate matter from the atmosphere (airborne pollution brought to earth by the rain), nitrogen oxides from car exhaust, rubber particles from tires, debris from brakes, phosphates from residential and agricultural fertilizers, antifreeze, and bacterial contamination. The asphalt itself contains coal tar pitch a recognized human carcinogen; and polycyclic aromatic hydrocarbons (PAH.) Telephone poles, landscaping timbers, and other treated woods leach creosote and chromated copper arsenate onto roadways; polyester, tile, and flat gravel roofs release varying levels of metals, PAH, and organic halogens in addition to the airborne particulates that land there.
If the toxic materials listed above land on a permeable surface - a gravel driveway or a grassy meadow for example, they percolate down into the subsurface where a vast array of microorganisms are capable of breaking down and destroying these potentially hazardous materials before they travel much farther into the earth.
If, however, 40 percent of the rainwater falling on a suburban lot (the average amount of impermeable coverage on a 1/4 acre residential plot,) is washing off of the roof, down the driveway, into the street and from there into a storm drain or stream, this cleansing does not have a chance to take place and the toxins ultimately end up polluting ocean and inland water. (As an aside, the average impermeable coverage of a shopping center is over 95 percent.) In addition, such rapid runoff contributes to flash flooding, and coming off of superheated asphalt on a hot summer day, can literally raise the water temperature of nearby streams, immediately killing fish and other aquatic creatures.
Perhaps the most dangerous long term ramification is that rapid runoff deprives
the earth of the ability to recharge its aquifers with the purified water that
would normally work its way through hundreds of feet of earth and rock to provide
pure drinking water years in the future.
Pretty depressing picture, but it doesn't need to be this way. There are new
and old materials and building techniques that can reduce the impact that a
new building of any size has on the land around it.
