Says district’s water-quality "A" is "grade inflation." District’s reply: "Is the mayor a water-quality expert?"
Mayor R.T Rybak pulled off his shoes and socks to step onto a weedy welcome mat at the shore of Lake Harriet in late June. Rybak wasn’t cooling off on a hot day — he was lured into the lake by the stench of decaying plants and dead fish.
"I just have one question," Rybak said, scooping a reeking bouquet of algae and lake-water milfoil. "Is this an A-quality lake?"
The "A" Rybak referred to was the grade that the Minnehaha Creeks Watershed District (MCWD) gave Lake Harriet in their recent 2002 report card. The MCWD evaluates water quality based on levels of chlorophyll, phosphorous and a secchi disc reading for clarity. The tests determine phosphorous levels in a lake.
Phosphorous is the ingredient that turns your lawn — and your lake — green. The more phosphorous in a lake, the greener it is. The amount of chlorophyll, the chemical used for photosynthesis, causes algae to grow. Algae and other weeds such as milfoil release nutrients or phosphorous that spawn even more plant growth. It can also cause the lake to smell.
"This year’s weeds are the worst I’ve seen them. I had trouble rowing my kayak out," said John Patten, who was docking his sailboat on a June Saturday. He’s been sailing on Lake Harriet every week during the summer for two years.
But John Mundahl, a schoolteacher from Whittier who was strolling around the lake Saturday, hasn’t noticed an odor or any more weeds than usual. "To me, this is just a typical southern Minnesota lake," Mundahl said.
Although the MCWD’s evaluation is scientific and limited, Rybak criticizes its Lake Harriet "A" as "grade inflation." He feels the grades — publicized this spring – provide a false impression that all is well.
"We have to think of the lake as citizens. I believe this is the first generation that’s losing its right to swim in our lakes," said Rybak, who lives a few blocks away, in the East Harriet neighborhood.
Rebecca Kluckhohn from the MCWD said the grade is a fair part of a standardized test. "I mean no disrespect, but is the mayor a water-quality expert?" she asked.
The district’s evaluation, based on something called Carlson’s Trophic Status, doesn’t necessarily determine the lake’s overall health. It does pay attention to phosphorus levels and clarity — which can have unpleasant side effects. "When water quality increases, so does the clarity of the lake. The sun can penetrate the surface and more plants grow. You can’t have it both ways."
Kluckhohn explained that the lake needs plants. Milfoil and algae are two plants that normally compete with each other. Milfoil spreads from lake to lake. At the bottom of the lake, decomposing plants consume oxygen. They choke out other life with too many nutrients. Bacteria breaks it down. The process smells.
So do dead fish. A walk around the lake’s perimeter shows dead fish stranded belly-up in the weeds. Lifeguards spend most of their mornings retrieving the aquatic casualties, one bystander said. Fish kills, however, are pretty typical in the summer, said Kluckhohn.
"You can’t compare a lake in Minneapolis to a lake in the Boundary Waters," she said.
Bottom line, Rybak says, "This isn’t the lake I swam in as a child."
MCWD Administrator Eric Evenson agreed. According to data compiled by the Pollution Control Agency, the lake had 60 total milligrams of phosphorous per liter in 1970, when a teenaged Rybak was splashing around. The most recent reading in 2002 was a much more healthy 19 milligrams of phosphorous per liter.
In Rybak’s defense, Evenson explains that the MCWD measurement is limited. "We just measure phosphorous. There are other contaminants, too. Everything from heavy metals, chloride, silt, dog waste and leaf litter. The key isn’t to say we’re getting better from an ecological standpoint. That’s OK, but who wants to swim in a lake with litter?"
Rybak is training for a triathlon and walks near the lake every day. Last fall, he ran a campaign called "Get in the Gutter With the Mayor," to keep leaves from being swept onto the streets and into the gutters. Leaves in the lake heighten levels of phosphorous. He’s currently working to "Make Our Lakes Fun Again."
"You have to think about everything that’s in your yard and in the gutter as something that’ll end up in the lake. It’s part of your yard, too. Do you want to swim with the stuff in the gutter?" he said.
There are lots of green lawns near Lake Harriet. Rybak encourages citizens to be especially vigilant. They should mulch clippings and stop using fertilizers that contain phosphorous. If possible, people should also wash their cars on their lawns or in the alley, not on the driveway where it washes into the street.
Ironically, the very water quality Rybak has worked to improve can lead to more plant growth, which leads to the stinky-plants-and-dead-fish-phenomenon he’s concerned with.
"Now seriously, do I smell like algae?" Rybak asked, climbing into his car barefoot and carrying his socks and shoes.