FOREST LAKE, Minn. – The week after Labor Day can be one of the quietest times of the year for Minnesota’s 10,000-plus lakes. Coming off a surge in activity over the last holiday of summer, the fishing gear, floaties and personal watercraft get packed or hauled away, and the state’s lakes begin their gradual transition to the long off-season.
That’s when Steve McComas, Minnesota’s “Lake Detective,” does some of his best sleuthing.
On a September morning last year, the 59-year-old founder and principal of St. Paul-based Blue Water Science sat aboard his floating laboratory – an 18-foot jon boat – aiming a point-and-shoot digital camera at the shoreline of Forest Lake, one of the hundreds of developed lakes within an hour’s drive of the Twin Cities.
With his son Connor, 26, at the controls and moving at no-wake speed through the lake’s shallows, McComas leaned toward the viewfinder and began speaking a mostly mono-syllabic language, the beats of which were carefully transcribed by colleague Jo Stuckert, who rode in the bow with pen and paper in hand.
“Okay, Jo. Starting with the white townhouses. Let’s call it a ‘no-no-no-no,’” McComas says. “Next up, two parcels. It’s going to be a ‘no-no-no-no’ and a ‘no-no-no-yes.’”
“Next up, that’s what you’d call an urban cabin,” McComas continues. “It’s going to be a ‘no-no-no-no,’ with rock rip-rap. And the next one, that’s ‘yes, yes, no, no.’ Oh man, they had to aim that mower right down the bank there.”
The sequence of “yes’s” and “no’s” continues for more than an hour as McComas performs a lot-by-lot analysis of Forest Lake’s mostly developed shoreline.
An environmentally healthy shoreline lot – one that generally gets a series of four “yes’s” – is characterized by an abundance of natural vegetation from upland to shoreline and by a shore that remains cloaked in native grasses that give way to emergent aquatic plants like bulrushes and cattails. That littoral zone between the dry bank and the high-water line is likely to resist erosion, hold back runoff pollution and sustain life.
The poor performers – “no-no-no-no” – tend to come in one of three varieties: manicured green lawn, sandy beach or armored wall, often built of rock fill called “rip-rap.”
McComas, conducting the shoreline survey for the Comfort Lake-Forest Lake Watershed District, was careful not to pass judgment on the owners of the lakeside properties, where homes range from modest cabins to million-dollar retreats. “It’s private property, and people can have different ideas about what a shoreline should look like,” the Lake Detective says.
But the environmental implications loom large for the many thousands of miles of shoreline throughout Minnesota that have been converted into yards, beaches, boat launches and other altered landscapes. McComas pulls no punches about what happens to lakes whose edges have been substantially re-engineered by humans.
“We like to see at least 50 percent of shoreline lots kept in a natural state,” he says. “Much more than that, you’re going to start seeing problems.”
For example, stormwater runoff from house lots – carrying fertilizers, herbicides and pesticides, petroleum residues and even sewage – can choke lakes with pollution that diminishes water quality, damages fish and wildlife habitat and in some cases endangers public health through the spread of waterborne pathogens like E. coli, giardia and cryptosporidia.
Algae blooms, one of the primary symptoms of a lake overloaded with nitrogen, phosphorus and other nutrients, can spoil recreational pursuits like swimming and boating. And the rotting of such blooms can generate putrid smells and rob lakes of dissolved oxygen needed to sustain fish and other aquatic life.
Where motor boats and personal watercraft make near-shore passes, rotor blades chop submerged aquatic vegetation and wakes erode sections of shoreline where bare soils are exposed along high banks. The same vessels can also be carriers of invasive species like Eurasian milfoil, zebra mussels and curly-leaf pondweed, which move from lake to lake in boat hulls, fish wells and ballast compartments.
McComas, who holds advanced degrees in both civil engineering and aquatic ecology, has authored two books about the environmental risks associated with shoreline development, the first of which is titled “Lake Smarts,” and his ideas are buttressed by more than 600 surveys across 100-plus Minnesota lakes.
Asked for a prognosis on Forest Lake – which first saw development in the 1860s with the building of the St. Paul and Duluth Railroad before evolving into a resort lake and then Twin Cities ex-urb in the 1970s – McComas describes the 2,270-acre lake as “moderately fertile” with “a pretty good diversity of plant and fish species.”
“It’s in more of a protection mode than a restoration mode,” he adds.
Yet according to the Minnesota Department of Natural Resources (DNR), Forest Lake is one of more than 700 “impaired lakes and reservoirs” across the state. That means the lakes either fail to meet federal water quality standards or are unable to support one or more beneficial uses, such as recreation, fish consumption, or fish and wildlife habitat.
In Forest Lake’s case, the impairment is due to mercury and PCBs found in fish caught from the lake during 2006, a legacy pollution problem that is strongly associated with industrial air pollution and wastewater emissions. But for many other lakes in the state, and especially in the Twin Cities region, the primary water quality impairment is nutrient loading and eutrification, a condition strongly associated with runoff pollution from both urban and rural landscapes.
In total, state officials estimate that roughly 40 percent of Minnesota’s waters – including lakes, streams and wetlands – are impaired, with the highest concentrations of stressed lakes in the Minneapolis-St. Paul metro area, Central Minnesota’s “Chain of Lakes” region near Brainerd and Pequot Lakes, and areas surrounding the Paul Bunyan State Forest near Park Rapids.
Paul Radomski, a DNR research scientist and project manager for the state’s Sensitive Lakeshore Identification program, has spent much of his 30-year agency career tracking development pressure on Minnesota’s lakes.
From a field office in Brainerd, where second-home development has boomed over the last three decades, Radomski has observed a distinct shift in what people expect when they travel “up to the lake.”
Fast fading, and in some areas completely gone, are the small cabins, fish camps and roadside gas-and-bait shops that once gave northern Minnesota its identity as a place apart. In fact, most modern lake homes come with all the trappings of everyday life back home. Electricity, running water, satellite television and mobile phones are as much a part of contemporary lake life as floating docks and fishing boats.
“For people with long memories, they see the seasonal homes being converted into very large homes,” Radomski says. “And the average size of a new home has probably more than doubled over the years. Their ecological footprint is much larger as well, judging by the size of the houses, the docks, even the boats on the water. And it’s no longer one or two boats per dock. It’s multiple docks, multiple boats, multiple boat lifts. Frankly, it’s the kind of thing one used to see much closer to the cities.”
Using Division of Forestry aerial images dating back to the 1940s, Radomski has observed linear growth in lakeshore development across many of northern Minnesota’s large and mid-sized lakes. Lakes where pressure has been less acute are often too small or too shallow for recreational pursuits, he says.
And while state and private efforts at lake protection and restoration have focused heavily on containing invasive aquatic species like mussels and milfoil, Radomski said relatively little attention has been paid to Minnesota lake country’s most prevalent exotic species: Kentucky bluegrass.
“Our preference for having grass lawns from doorstep to dockside is changing the rainwater dynamics of the nearshore areas and greatly increasing runoff pollution from lake lots,” he says. “In some places, you’re seeing seven to nine times more phosphorus loading from a lawned lakeside compared to one with more natural conditions.”
Back on Forest Lake, it’s not hard to find such green monsters. And to the urbanized eye, they can be among the most attractive lots on the lake. But McComas says the definition of what makes the shoreline attractive has begun shifting as environmental consciousness weaves its way into landscape design and personal taste.
“I think a lot of our lakes are actually getting better than they were in the 1960s and 1970s,” he says. “Things can get better still, but the trend of developing right up to the lake edge is not as common as it used to be. To me, the best way to figure out how to manage these shorelines is to look at what mother nature is doing. That’s what works.”