Definition of the China Lake Syndrome: “Nuisance algae blooms as the result of too much development too fast, leading to the leaching of nutrients into the lake.”

This definition is found in the report of the Maine Department of Environmental Protection titled “China Lake, East and West Basins of 2001,” on page 5.

Algae blooms are not just a nuisance. They kill fish, and they can kill humans.

China Lake in Maine was not the first lake in the U.S. to undergo this syndrome, but unfortunately the name “China Lake Syndrome” is very catchy and it stuck to our near neighbor to the north.

China Lake is very similar to Lake Auburn. Please examine the table that accompanies this column. (Sebago Lake, the drinking water source for Portland, is included for comparison, since it is much closer to “ideal.”)

Lake Auburn was granted a filtration waiver in 1991 due to the exceptional purity of its water. Sebago Lake was granted a waiver at about the same time. (Only 37 lakes in the entire country have such a waiver.)

China Lake never obtained a waiver because of frequent algal blooms that started in the 1980s. The Kennebec Water District had to build a filtration plant that opened in 1993 to meet the standards set by the national Safe Drinking Water Act amendment of 1986.

Lake Auburn and China Lake have eerily similar vital statistics. However, the two lakes differ significantly in one statistic: Watershed Percentage Covered in Forest —  74% for Lake Auburn and only 56% for China Lake.

Actually, that is a huge difference, because most authorities agree that a drinking water supply lake should have at least 74% of its watershed covered in forest. Lake Auburn passes that criterion, but barely. China Lake falls 18% short.

 

Watershed Covered in Forest represents the best defense against the likelihood that water entering a lake will be polluted by human activity. Forest is the best ground cover for a watershed, since there is nothing that humans can do that will improve clean water.

Compared to trees, development is always bad. Houses, roads, driveways, fertilized lawns and septic systems can only increase pollution. Farms can send fertilizers, pesticides and soil into water bodies. Businesses, especially mines and dumps, result in many different types of pollution, as you can imagine.

All these damages can be reduced, but not eliminated. Forest is best.

The primary pollutant of drinking water supplies is phosphorus, since it is an essential element for the growth of algae. Not only does forest decrease the possibility of development causing the runoff of phosphorus, trees actually absorb phosphorus. Roofs, driveways and roads do not. That is why forests are so important.

The Kennebec Water District has tried mightily to reduce the amount of phosphorus going into China Lake, and the frequency of algae blooms has diminished, but they do still occur. When one occurs, the filtration plant must work extra hard to remove contaminants from the water.

That is why it is important for a water district to continue trying to keep the phosphorus “load” down even after a filtration plant has been built. It might not be possible for a filtration plant to remove all the contaminants generated by a severe algae bloom.

Due to the wisdom and foresight of our predecessors, Lake Auburn is still clean enough to qualify for a filtration waiver, saving the citizens of Lewiston, Auburn and Poland millions of dollars per year, but that waiver is tenuous.

Lake Auburn suffered an algae bloom in 2012. Nobody ever really understood why. The lake was treated with alum a few years later to prevent another bloom.

Unfortunately, alum treatment cannot be repeated frequently. In fact, alum can be dangerous. It precipitates with harmful phosphorus and carries phosphorus to the bottom of the lake, as intended.  But it can be stirred up by turbulence and raised to the surface, causing a new bloom and a feedback loop, especially in shallow waters.

Once a lake starts having algae blooms, it rarely recovers enough to regain a filtration waiver. Conditions are slowly worsening. Climate change and warming waters help algae grow.

We were lucky in 2012. We might not be so lucky again.

We should be restoring Lake Auburn watershed to forest, not building housing in its watershed.

Ben Lounsbury of Auburn majored in college in physical sciences, including water quality measurement, and is an MD.