Here's a question that's soon to be important for urban planners and BMP designers: Do some stormwater BMPs provide ideal breeding habitats for mosquitoes that can transmit human disease? (The answer is yes, according to a recent national study carried out by the California Department of Health Services and reported on page 24 of this issue.) Even if the risk seems small now, what happens when these structures and devices become more prevalent in urban areas?

Fortunately, changes in BMP design and improved maintenance procedures can help eliminate the risks. Public health agencies are available to work with stormwater managers on such issues as design and siting of BMPs and monitoring of existing structures to see if improvements are needed. With some slight modifications and careful planning, the problem is surmountable. But the mosquitoes are carrying another threat, not to public health but to public perception.

Thee years ago, attention was focused on the West Nile virus. The mosquito-transmitted, sometimes-fatal, encephalitis-causing virus was found for the first time in the US in the summer of 1999. Dozens of people on the East Coast were infected, and the virus was responsible for at least seven human deaths in the New York City area. People panicked; the New York City Department of Health set up a 24-hour line to answer questions and quell fears.

In terms of the number of people so far affected in the US, the West Nile virus is a relatively small problem; by comparison, about 20,000 people die in the US each year as a result of the flu. As public health agencies and vector-control specialists point out, it's not the comparatively rare and exotic diseases that pose the greatest danger but, rather, the ubiquitous problems that, through years of effort, have been carefully controlled, such as malaria and St. Louis encephalitis. As a frightening and news-garnering issue, however, the West Nile virus has greater impact: We're afraid of–and inherently interested in–the new and the unknown.

Those who design and place BMPs, and the municipalities who rely on those BMPs to achieve water-quality standards, should be aware of–and should be seen to be taking steps to prevent–the "mosquito problem" for two reasons. First, of course, an outbreak of a mosquito-related disease could be costly in both dollars and detriment to human health. Second, if the outbreak can be linked, even tenuously, to a stormwater management practice, the costs in terms of public perception of stormwater treatment efforts–so vital in these days of NPDES Phase II compliance and achieved in many communities with such effort–would be extremely high as well. BMP designers and their clients might even face liability suits. We could all easily end up in the spotlight for exactly the wrong reasons.

Manufacturers of stormwater treatment systems that have been identified as potential standing-water breeding grounds for mosquitoes have actively participated in finding solutions–some surprisingly easy, such as sealing potential entry points to an underground unit–and we applaud their rapid efforts to fix the problem. All manufacturers should now be addressing the issue–ensuring their systems pose no risk and publicizing the fact that they do not–not only for the sake of public safety, but also for the sake of the stormwater industry and the progress made so far.

It can take a stormwater utility or public education program months of effort to work its way into the public consciousness by mounting ad campaigns and stuffing educational fliers into utility bills. A single headline ("Killer Insects Lurking in Stormwater Treatment Pond") will do more to fix stormwater efforts indelibly in the public mind than all the previous months of work and will place there an image much harder to erase.