THE LAST thing anyone associated with Lake Anna wants to hear is: “Stay out of the water.”

Whether you count on the lake as a swimming hole on a hot day, have a business that is somehow lake-dependent, or if you’re a real estate agent pitching waterfront properties, word of “toxic” conditions in the water is not going to make your day.

But with reports of toxic algal blooms at Lake Anna increasing and worsening in recent years, the threat of ongoing environmental damage raises greater concerns that take precedence over periodic inconveniences and marketing frustrations. Restoring the lake’s health will quickly alleviate the other problems.

Thanks to the scientific research and data that give direction to Chesapeake Bay restoration efforts, we know plenty about the pollution and other conditions that cause such blooms.

Like the Bay, Lake Anna is at-risk from tributary pollution and a watershed beset with similar issues. Unlike the Bay, the lake is a more closed system with a dam that slows the current and the flushing process. And while heavy rain exacerbates runoff issues in the Bay, it can have a positive cooling and diluting effect on the lake water.

Small bodies of water such as lakes are more susceptible to certain conditions than a large estuary such as the Bay. For example, persistent heat this summer and last more easily warms the lake’s water, creating hospitable conditions for algal blooms.

An interactive, online map of the lake provided by the Virginia Department of Health indicates that the areas of the lake hardest hit by swimming advisories are to the north and west, along the North Anna and Pamunkey rivers, and Terry Run. These waterways flow through agricultural areas that contribute fertilizers, pesticides and manures, but they don’t play host to wastewater treatment plant discharges like some rivers that feed the Chesapeake Bay.

In any event, tributaries such as those that feed the lake are relatively narrow and shallow, an environment in which it is easier for algae-causing bacteria to thrive.

Most recent reports extended advisories to “the splits,” or confluence of the North Anna and Pamunkey, and waters to the north and west around the Lake Anna State Park shoreline. New lake water samples are expected to be drawn and evaluated this week, with results announced next week. Officials say swimming advisories may remain in effect at least through September.

Because warm water contributes to algal bloom outbreaks, some have wondered whether water that is heated as it cools the North Anna Nuclear Generating Station—the man-made lake’s reason for being—is somehow responsible. But the plant is downstream from the hard-hit areas and the waters around it have been largely advisory-free. Moreover, the discharge of power plant water near the dam helps circulate the water and discourage algae growth.

Farmers around the Bay are using best management practices that might also help mitigate pollution and algal blooms in Lake Anna. Such practices include preventing manures from contaminating waterways, whether it’s runoff from chicken manure piles or cattle that make direct deposits in pasture streams. Farmers have also created buffers that filter out fertilizers and pesticides before the runoff reaches the water.

Residential development is another likely factor, with construction site soil that sneaks through any barriers designed to stop it, or fertilizer that runs off from residential lawns.

Like the Bay, Lake Anna is an economic engine and job producer for its surrounding areas—rural portions of Spotsylvania, Louisa and Orange counties. Residential development, tourism and associated businesses around it have increased steadily since the 13,000-acre lake was filled in 1974.

Recent descriptions of the algal blooms in the lake as “disgusting,” as a “thick, blue-green goop on the water’s surface,” and as a “visible scum” that poses “moderate to high risk to humans, pets and fish” aren’t going to turn up in tourism or real estate brochures.

But they should serve as a wake-up call to all those who value the lake, understand how its fragile ecosystem works and don’t want these blooms to become an annual occurrence.

Twitter: @FLS_Opinion

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