Keeping Clean Storm-water Runoff

The Energy Independence and Security Act of 2007, also known as EISA, requires federal agencies to maintain or restore a site’s pre-development hydrology when projects impact more than 5,000 square feet of a site. (Section 438 of EISA)

[PHOTO BY TYMCO]

In more Lehman’s terms this means the EPA is looking to ensure that new construction and major renovation sites do their part to ensure that storm water runoff is clean when passing through these projects.  The EPA offers a list of practices to keep clean water running, here, but these are not the end all, be all for solutions.  Maintaining a clean site is very important when keeping these practices and sweeping is one way to make certain that any water coming through the site is as clean as possible. The idea that the water will be 100% filtered and clean is an impossible one when you consider all of your construction equipment and traffic, however once your initial lift and sewer are in place, adding a sweeping service will lower the contaminants (measured in PPMs) in the runoff. A suggested method is to reduce or eliminate the presence of curbs. The idea there is that absence of curbs allows the water to run through the property quicker and without restraints, but that’s inevitable when the projects calls for sidewalks and parking dividers/islands.  Another example for best management practices (BMPs) is to install pervious asphalt, concrete and walkways that allow the water to seep through and into the ground versus through the site and into sewers; this to a good idea, until the dirt accumulation is so tight the water runs past it.

How does sweeping help? Glad you asked! Only sweeping litter might help your quality test numbers but will still leave unacceptable levels of contamination. Sweeping with the right equipment and having operators that know what they are sweeping for is the key to improving the cleanliness of the runoff water.

  • Not all sweeping units will make the cut; to really eliminate the fine particles you need the following;
    • A regenerative air unit. A sweeper that use forced induction AND vacuum
    • A sweeping unit the is regularly cleaned and maintained with new suction hoses, access point seals and sweeping curtains
  • A company with a diverse fleet is ideal; having only one type of sweeping unit will limit performance. Although you will need a regenerative air sweeper to eliminate the finer particles, sometimes, especially in new developments, the amount of dirt, gravel and mud becomes too much for even the bigger air sweepers.  In this case you need a fleet that can provide a larger scale brush sweeper which would then be followed by an air sweeper. Having only one or the other will leave some jobs only half complete. It is more convenient to have the all in one instead of having to hire two types of sweeping companies.
  •  You need sweeper operator that is aware, experienced and knowledgeable in the BMP field. You may think all driver’s are the same, FALSE. A driver with little to no experience will simply drive around until it “looks clean” then leave and with his premature departure he leaves behind the fine particulates that will elevate contamination results. Implementing suggestions such as sewer inlet filtration and pervious grounds are great when combined with an experienced sweeper who will make sure those areas are closely monitored and frequently cleaned. Having a driver that can identify these areas, alone, is a plus. These areas require additional equipment; gutter brooms for the curb-lines and sewer inlets, shovels and good old elbow grease.
  • Talk is great but you also need a company that has verifiable references, documentation and experience. The reality is that anyone can provide a reference number to call, but a trustworthy company  will be able to provide more than just the contact number, examples;
    • Valid business license. Anyone can buy a sweeper, however that does not make them a legitimate and experienced sweeping company
    • High rated (verifiable) insurance. Most major projects will require a minimum one million+ in coverage
    • Longevity. You don’t want to trust the results of your State mandated audits for quality to a start-up company
    • Experience in the field. References to verifiable names in the contractor markets. ‘Joe Builders’ normally don’t meet the qualities of a reputable reference. Your choice should have experience with reputable companies that have used their services and attest that their ‘numbers’ have improved and/or not faltered

These are only some of the things you should consider when tasked with providing a clean working environment and ensuring that the runoff coming through your property is not contaminating your surrounding grounds and local sewer systems. To speak with someone regarding this type of service and/or if you know what you need and the above description fits the mold , we’re the company for you! Contact us Today!

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