White Lake is navigating choppy waters

October is a glorious month at White Lake. The lake is more serene after a summer of activities on the water, and the Cypress trees are starting their fall display of color.

Three years ago, it was the lake itself that was displaying color — a deep green — that was best captured in a drone photo. The color was due to a cyanobacterial (blue-green algae) bloom, which was a new occurrence for the lake.

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The nutrient levels in the lake water were also higher than they had ever been. The low-dose alum treatment that was done in early May of 2018 was designed to “strip” nutrients from the water column and had the added benefit of eliminating the bad cyanobacteria with almost surgical precision. Once those bad actors were out of the picture, algae that were normal for the lake had their time in the sun, but by November the lake was clearer than it had been in years.

There has been a great deal of work done since the bloom to assess all of the possible nutrient sources to the lake — you can’t make assumptions if you haven’t looked at everything — and to determine the relative importance of the different water sources, to include rainfall, runoff groundwater/springs.

A lake monitoring program has also been established to collect high-quality data on lake chemistry, lake levels, rainfall, aquatic vegetation, algae and wintertime bird populations. The scientists doing this work are engaging other lake scientists for data review.

There has also been a great deal of work done to establish a web site that serves as a repository for information and data that is being collected: www.whitelakewatch.com.

What do we now understand about White Lake and its changes? With respect to nutrients, we can see a substantial increase in one nutrient — nitrogen — compared to the past. Atmospheric inputs of nitrogen have increased in this part of North Carolina, and rainfall is now the largest source of nitrogen to the lake, with much of it in a form that can be readily used by algae.

There is evidence that White Lake algae are oftentimes responding to the pulse of nutrients coming from “big rains” in particular, and this was first observed in the summer of 2013. There is now more runoff and less infiltration, which recharges the groundwater, than there was in the past. Stormwater runoff also contains sediment and debris, which mostly remains in the lake. Also, we are now experiencing more intense rainfall events, creating more stormwater volume.

With respect to changes in the acidity of the lake, rainfall, the primary source water for the lake, is now less acidic than it had been. However, the same types of algae and aquatic vegetation — things which prefer acidic conditions — are still found in the lake. Their abundance depends on nutrients, light and water temperature.

The idea of making the lake water acidic again has been raised in the past and has recently resurfaced, but even if it were possible (and it is not), it would not reduce nutrient levels, which are what fuels algal growth. Case in point: Nearby Bay Tree Lake is still acidic because of the acids that make the lake tea-colored, but it has algae levels very similar to what is found in White Lake.

White Lake is a very valuable natural resource — it is worthy of the best science has to offer to guide decision-making and management. I hope we can all agree on that. We need to move beyond the belief that there is a pie-in-the sky “fix” for the lake. Such notions become a distraction from the necessary actions, such as mitigating stormwater inputs to the lake, that need to be a priority.

White Lake is in much better shape than it was three years ago, and the town of White Lake is now updating its Comprehensive Plan, which is being coordinated by the Lumber River Council of Governments. This plan should be one of the “navigation maps” for the town to realize its mission to preserve and protect the lake. It is the time to address infrastructure needs, wastewater and stormwater in particular, and land uses that we know are harmful to the lake.

Can we continue to make progress at White Lake, or are we going to again get bogged down with negativity and personal attacks? This time needs to be different, for the sake of the lake.

Dr. Diane Lauritsen is with Limnosciences, which provides water quality monitoring for White Lake. She received her Ph.D. from N.C. State University, where her interest in Bay Lakes research was kindled.