Thursday, March 01, 2012

Wet and wonderful

What every lake homeowner needs to know to help keep Smith Mountain Lake clean and healthy

SML residents and visitors take great pleasure from being in or near the water because it is, in the words of Smith Mountain Lake Association’s Stan Smith, “excellent quality.” Yet enough human missteps can change the health of the lake and the pleasure we take in it, including, as all homeowners should know, property values. Simply put, a clean lake contributes to increased property values while one that is polluted can mean relatively decreased ones.

“You’re not going to buy a house on a lake where you can’t use the water for recreational purposes,” said Smith, chairman of SMLA’s water quality monitoring committee.

While that may seem intuitive, it is important for homeowners to understand the science that affects lake livability and waterfront property values so they can help maintain the health of Smith Mountain Lake.

For the past five years, Delia Heck, assistant professor of environmental science at Ferrum College, has led undergraduate science students in the Smith Mountain Lake Water Quality Program. The program, a joint effort between Ferrum and SMLA, has thrived for a quarter of a century. At the end of the summer, their labor results in the production of a 100-page scientific report that Heck processes into a four-page newsletter called The Lake Monitor. The publication summarizes Smith Mountain Lake’s trophic state index in plain language and is available to the public.

Trophic state index (TSI) measures the quantities of a biologically limiting factor, phosphorous, present in water. This is one of those cases where less is more:  lower numbers can be evidence of cleaner water. The higher the number, the more phosphorus is present and the more likely algae will bloom beyond control. Algae, though seemingly unassuming to the untrained eye, can cause serious health problems. The blooms can take a disproportionate amount of oxygen from the lake when they die off and decompose, causing fish and other animals to leave the lake or die and, in rare instances, induce skin and respiratory problems in humans.

Smith Mountain Lake, however, is far from toxic. There are three classes of trophic indices: oligotrophic, mesotrophic and eutrophic (from best to worst). SML’s trophic index tends to rate in the mesotrophic category.

According to the September 2011 issue of The Lake Monitor, “...the water closest to the dam can be classified predominantly as oligotrophic while waters up the channels are mainly eutrophic. This is typical of the differences between the more river-like characteristics of the upper channels of Smith Mountain Lake and the lake-like characteristics of the main basin, which is closer to the dam.” The cleanest water lies in the deepest part of the lake because, Heck explained, sediments settle to the bottom, taking the phosphorous with it.

The report also indicated that the TSI improved from 2010 to 2011 as did water clarity measures, bacteria populations and phosphorous levels, indicating the lake is getting healthier.

Teresa Criner of Wainwright & Co. Realtors said she tries to give her clients a sense of these water quality concepts when showing waterfront property.

“Events like storms, floods and droughts can change how water looks now from when they first visited the property,” Criner said. “I also tell them that less-developed areas upstream tend to have more sediment.”

Criner shows clients how water depth, for instance, is dependent on Mother Nature’s mood swings.

“I have a method that’s rather primitive,” she said, “I take a rock tied to a string that has a knot at every foot and drop it into the lake,” she said, explaining that clients can visualize the water depth and see how it varies from property to property or from visit to visit. Another technique involves taking a clear glass to the lake and filling it with water for clients to inspect. Despite the difference in quality from place to place, Criner said Smith Mountain Lake’s water ranges from “good to very good to excellent. We’re blessed.”

Smith added: “Smith Mountain Lake’s water quality is excellent. It’s not deteriorating. People ought to enjoy it. Smith Mountain Lake Association will keep monitoring the water quality and will be the first to blow the whistle [should it show signs of decline].”

Keeping SML beautiful and healthy

Clear leaves away from the lake. Raking or blowing leaves into the lake depletes the water of oxygen and adds nutrients that help algae grow. With too little oxygen and too much algae, lake water quality declines. Consider composting your autumn leaves instead.

Fertilize smart. Always choose low-phosphorous fertilizer and never fertilize your property in the spring when rains are more likely to wash residue into the lake.

Create a buffer garden. A buffer garden is waterfront landscaping that utilizes trees, shrubs, perennials, non-turf grasses, and/or grass-like plants to act  as a filter for runoff, catching sediment, debris and pollutants before they reach the water. Buffer gardens protect the shoreline from erosion and provide a place for wildlife to live and play.

For more information, contact the Smith Mountain Lake Association at 540-719-0690 or log on to www.smlassociation.org.