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Cost/Benefit
Issues |
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Porous paving may cost
10% more than standard paving material, but since it absorbs rain
near where it falls, it can sometimes save money in expensive drainage
systems, making it 12 to 38% cheaper overall (Thompson and Sorvig,
2000). Even if the porous pavement does not negate the need for expensive
drainage systems, its many benefits may still outweigh the additional
costs. Porous pavement can serve to treat water by removing pollutants,
improve road safety because of better skid resistance, and improve
recharge to local aquifers (EPA, 1999). When using porous paving,
there is some chance that pollutants might not be filtered out and
could lead to groundwater contamination (see Construction and Siting
Issues). According to Thompson and Sorvig, porous pavement can reduce
both runoff and the concentration of overland flow, thus slowing downstream
erosion and siltation (2000). |
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Porous paving can sometimes
reduce maintenance costs, especially with snow removal. Snow that
falls on porous pavement often melts fast and drains into the pores.
But porous pavement requires maintenance itself; the EPA recommends
that it should be vacuum swept at least four times a year, followed
by high-pressure hosing to get rid of clogs. Estimated costs of this
maintenance for a porous pavement parking lot are $200 per acre per
year (EPA, 1999). |
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