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WorldSweeper.com's 'Sweeping as a BMP' Seminars Provided Info Not Generally Available to Pollution Managers

The WorldSweeper.com seminars showcased how sweeping can best be used by stormwater pollution runoff programs.

by Ranger Kidwell-Ross

In May of 2006, the first seminars in recent times that were exclusively dedicated to discussing the effectiveness of sweeping as a Best Management Practice (BMP) for stormwater pollution runoff were held in the L.A. and San Francisco areas of California.

Sponsored by WorldSweeper.com, and co-sponsored by Allianz/Madvac, the seminars were designed to assist decision-making by state and local administrators charged with reducing the amount of pollution in the state's storm water runoff. As seems so often the case, California has taken the lead in taking action designed to reduce runoff pollutants.

The interest in changing the focus of California sweeping programs to water quality improvement is near its peak due primarily to existing NPDES stormwater regulations and upcoming Total Maximum Daily Loads (TMDLs). TMDLs will specify the amount of various stormwater pollutant loadings allowable throughout most California waterways. As a result, they will also specify the stormwater pollutant reductions needed to achieve instream water quality standards. It is logical then for California communities to look at sweeping as a BMP needed to provide these reductions.

Seminar information was provided by myself, as editor of WorldSweeper.com, along with noted sweeper researcher, Roger Sutherland, who is president of the Oregon-based engineering consulting firm, Pacific Water Resources. About 75 people signed up for the L.A. seminar, and 45 for the one held in San Jose. Attendees tended to be those in charge of developing storm water pollution BMPs for their various communities, although the audience ranged from municipal sweeper operators to members of the regional state water quality boards.

Information was presented that showed sweeping is likely a much better BMP for reducing runoff pollution than is widely understood. A recent CalTrans study concluded that the cost of structural BMPs, e.g., grassy swales, settling ponds, retro-fit of storm drains, costs between $10 and $70 per pound of pollutant removed before including the cost of the necessary land purchases. Sutherland's sweeping industry studies show that today's crop of mechanical broom sweepers can do the same job for between $5 and $10 per pound, with regenerative air and vacuum sweepers in the range of $2 to $5 per pound. That's a huge difference.

Attendees also learned how to get a rough estimate of the loading on their streets, what percentage of street 'dirt' is likely to be made up of targeted pollutants, and how they can assess the impact of sweeping via computer modeling. Because of the computer model Sutherland has been refining since the '70s, municipalities can get a high-confidence loading assessment without the costs associated with doing a protracted and expensive stormwater pollutant loading study.

Clearly one of the items wanted by the attendees was a way to assess the pickup ability of various sweeper makes and models. Unfortunately, there is currently no such testing that has taken place. My guess is that if the sweeping industry doesn't come up with one of its own, the California sweeping community/storm water managers will devise one in the not-too-distant future so they can make better machine purchasing decisions.

In general, at least according to the information we received in our seminar surveys, it would appear that sweeping is not being done as often as it should. For many communities, it appears they might be better off, in terms of lower costs for runoff pollution removal, to sweep as much as four times more often than they currently provide.

Surprisingly, about half of the cities responding to our seminar survey are not even requiring cars to be moved during sweeping. Although sometimes a political 'hot potato,' this is an action that can provide immediate pollution reduction benefits. In the seminar, it was clear that many managers had not thought through the fact that each car parked on the street during sweeping actually represents about three car lengths that go unswept. That's because it takes the sweeper about a car length to swing around a car, with another required to get back to the curb.

If reducing non-point pollution runoff is, indeed, a serious factor to an agency, it is vitally important that parking restrictions are put into place. Many cities doing so have discovered that fines will more than pay for their sweeping programs.

Roger Sutherland's PowerPoint presentation from the seminars is now online on our website. For more information, you may reach Ranger via email at ranger@worldsweeper.com, or by calling 360-724-7355. Sutherland's contact info is roger.sutherland@pacificwr.com; phone 503-671-9709, ext. 24.

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