Keep the Water Moving

Detention and retention ponds can be found everywhere, on commercial settings, municipal and residential areas, on golf courses and construction sites. They serve a variety of purposes, are cost-efficient, convenient, and for the most part, maintenance free. In addition, they collect runoff and harmful pollutants such as parking lot excesses, fertilizers, minerals and sediments, animal waste and other superfluous nutrients.

Both types of ponds are used as storm water control devices. They withhold the accumulated water for a short period of time, allowing minerals and sediment to settle on the bottom, where plant life begins to consume nutrients. However, once water is accumulated and unloaded of excesses, detention ponds will pass the additional water to another waterway while retention/water hazard ponds will rid this water by transferring it back into the environment via evaporation, seepage into the ground or through irrigation.

Property managers, superintendents and facility managers have the responsibility of maintaining these ponds. Their concern about the relationship between the West Nile Virus and detention/retention ponds stems from the fact that mosquitoes thrive and breed in stagnant water and many of these ponds have little or no circulation.

Since the outbreak of the West Nile Virus in 1999, the Center for Disease Control andPrevention (CDC) has reported more than 4,100 human cases in the United States, including nearly 300 fatalities. The chance of being bitten by a mosquito peaks from late summer to early fall. Property managers and superintendents are concerned that having a water feature on their property poses a threat to their patrons, tenants, and employees.

Reports by the CDC are both cautionary and assuring, indicating that there is no real reason to worry, especially when prevention practices are applied.

Charlie Barebo, CEO of Otterbine Barebo, Inc. explained, "Standing water supports the breeding grounds of mosquitoes. Therefore, the first step to eliminating the West Nile Virus is to break the sequence by eliminating the source." The CDC concurs that the primary role people play in contributing to the continuing cycle of the West Nile Virus is by maintaining environments, specifically standing water, in which mosquitoes can lay eggs.

Barebo suggests installing aerating fountains into all stagnant waterways, and says, "Aerators and aerating fountains are an effective and efficient solution. They break the surface of water and create circulation. These effects restrict eggs or larvae from completing the lifecycle, and also hinder females from laying eggs."

Over the past three years, the Chicago Park District in Illinois has installed aerators
and fountains to prevent lagoon water from stagnating. For the past two years, property managers for Musikfest, a 10-day music festival in Bethlehem, Pennsylvania, have installed aerators in surrounding canals. Musikfest annually attracts more than one million people from around the country. "Aerators keep the canal water moving, which keeps the mosquitoes away," says Musikfest spokeswoman Sharon McCarthy. "The fountains create a lovely backdrop to our main stage concert venue, and are a wonderful addition to the ambiance and excitement of an outdoor summer event."

Besides circulating stagnant water, aerating fountains characteristically offer added benefits of aesthetics and oxygenation, which is particularly beneficial to lessening the amount of algae and odors. Because of the tremendous amount of nutrients constantly entering retention and detention ponds, it is not uncommon to have excessive algae problems which discolor the water, cause odors, kill fish and create anoxic conditions. This not only accelerates the aging process of the pond, but lessens its ability to properly filter water.

Aerating fountains infuse the water with oxygen, which helps good bacteria break down excess nutrients, prevents sludge from settling at the bottom and keeps water clear, clean, and odor free. "The benefits to the property manager of aerating fountains for water quality are tremendous. They are very cost effective to operate, and add to the overall beauty of a landscape. This effect can even be expanded into the night with the addition of lights," Barebo adds.

Source: Irrigation and Green Magazine, September 2003, www.igin.com