If you love lakes, read this book

To paraphrase an old saying, there are lies, damned lies, and book jacket blurbs. So when the publisher says on the back of Darby Nelson's paperback, For Love of Lakes, that the book is "in the tradition of Aldo Leopold's A Sand County Almanac," you are temped to say, "Yeah, yeah..."  Well, I have read Sand County multiple times and I have read For Love of Lakes, and in my humble opinion the two book titles do belong in the same sentence. Nelson's book is that good.

As one who has loved lakes all my life -- first Lake Michigan on whose shore I grew up and then multiple lakes in Wisconsin's Northwoods -- I found this book enriched me on several levels. Nelson, like Leopold, combines the sensitivity of an artist with the insight of a scientist (he is an aquatic ecologist and college professor by background). From this book I learned a great deal about what makes a lake tick -- explained in ways that I am sure his students at Minnesota's Anoka-Ramsey Community college much appreciated. Consider phosphorus and its effect on algae in lakes. Nelson first describes all the ingredients in his wife Geri's blueberry muffins and explains how, if she happens to have only two teaspoons of baking powder, she can only make one batch of muffins -- no matter how much flour and sugar and how many eggs she may have on hand. Then:

"...(I)n lakes, except in unique circumstances, the 'tin' of phosphorus usually empties first. Compared to demand, it is phosphorus that is available in least supply, the bottleneck to alchemy. Little phosphorus in lake water begets few cyanobacteria, algae and aquatic plants. Lots of phosphorus begets lots of blue-green (algae) or aquatic plants or both."

If there's a better description of the effect of phosphorus on lakes, you've got to show me. If our Wisconsin legislators -- and their constituents -- could read those simple words, they might understand this phenomenon better and we might have less squabbling over whether we really need to spend so much money to keep phosphorus out of the water.

I also learned about the geological history of the lakes of the Upper Midwest and the glaciers that formed them. Through Nelson's descriptions, I could almost see in my mind's eye a time-lapse movie of the glaciers advancing and receding across the landscape, and hear the crunching of rock and the flowing of glacial melt water.

Perhaps even better than all that was Nelson's sheer joy and awe at seemingly ordinary events like observing the tiny water fleas and other creatures in a jar of lake water, or snorkeling thought weed beds on his favorite lakes and seeing sunfish stare right at him through his mask. And one can't help but notice Nelson's passion for protecting our lakes -- a passion he lived out by serving three terms in the Minnesota state legislature and advocating all sorts of conservation-oriented legislation.

Nelson's 250-page journey takes us on visits to dozens of lakes he has known and loved, from Henry David Thoreau's Walden Pond to the "ghost" Lake Agassiz, which once extended north from the Minnesota-South Dakota border area for hundreds of miles into Saskatchewan and Ontario. It is a fascinating journey that, if you take it, will deepen by many fathoms your appreciation for lakes in general and for the special lakes you love. It will also will inspire and motivate you to do your share to protect them -- and fight for their protection in the public arena. It is hard to consider an ecological education complete without having read this book.

Canoe Reconnaissance

This is our first spring as regular visitors to Birch Lake. This weekend I kept a promise to myself and canoed the entire perimeter, splitting the trip into two days, two hours at a time. Luckily the weekend was calm, so it was easy to paddle at a relaxed pace along the shoreline.

Have you canoed your lake in spring? It’s a good time for a couple of reasons: There are no motorboat wakes to contend with, and the water is clearer before the sun and warmer temperatures have a chance to feed the algae. I would have liked to take a Secchi disc reading; I am sure it would have shown better light penetration than in summer.

Having no water-testing equipment, I just cruised along shore, a gentle paddle stroke at a time, eyes down on the water on the shoreward side – I’m a fisherman and so always want to see what’s active. What I saw bodes well for opening day two weeks from now. Numerous smallmouth bass were in the rocky shallows and under logs. Walleyes (identified by the white tail spot) haunted the woodpiles – in one case at least a dozen of them, in an assortment of sizes, some clearly in the keeper range.

In a back bay I found a substantial school of perch that, while still small, had made it past the fry stage and so have boosted their odds of survival to adulthood. One reed bed held a cluster of crappies. Here and there a northern pike or small musky hung suspended over gravel and sand bottom. One large musky cruised under the canoe. The lake’s many painted turtles were in evidence, some swimming underwater, others sunning on logs (until my quiet approach sent the plopping to safety). It was disappointing, though not surprising, to see a few rusty crayfish skittering tail-first across the bottom.

You learn things every time you look closely at a lake. I believe I found a few new fishing spots – that walleye-populated woodpile being one – and discovered why certain other places that look good in summer in fact are not (too shallow, bottom too mucky). It was a pleasant way to get to know “our” lake better and to get ready for fishing season. I also met a few lake neighbors, putting in their piers or sprucing up their waterfronts. Piers are back in place at most of the cottages and pontoon boats are in the water.

I would definitely recommend a slow canoe or rowboat ride around your lake before the weather warms up and the water gets busy. What you see will open your eyes to a world that’s bigger and more interesting than you realize.

Putting In the Pier

I am not a lover of chores, but there's one I truly enjoy, and that's installing the pier at our Birch Lake cabin. That's partly because of all that the job portends: a seemingly endless spring, summer and autumn, filled with fishing, swimming, sunset watching, visits from friends and family. Perhaps that makes the sheer mechanics of it, enjoyable in themselves, all the more so.

The first time we put the pier in, three years ago, it was a bit of a project. The whole thing was new, and my son and I had to figure out how to assemble the various components, notably the main supports. That meant screwing baseplates onto the posts, sliding the crosspieces on, and setting them in position. Then there was the matter of bolting on the rails that would hold the cedar boards, and getting everything meticulously square and level. Now that we have the main supports assembled, it's just a question each spring of moving them into position and bolting the rails on. Because I put the supports back in the same order each year, only a modest amount of leveling is required.

I put the pier in this year the Saturday before Easter, which was April 7. It took all of an hour and 15 minutes, start to finish. Square, level, crescent wrench, 5/16-inch socket wrench -- that's it. Eighteen nuts to thread onto bolts and tighten down. Carrying the cedar boards from under the screen porch down the steep slope to our waterfront was a bit tiring, but the pier is only 40 feet long, so at two 2-foot sections per trip, that's 10 times up and down. I spread that out over two days, and so it wasn't taxing.

Now the pier is in place. I bring my boat to the lake on opening day of fishing season, Saturday, May 5. A pleasant chore is done and done well. A long open-water season lies ahead.

Waiting for ice-out

Friends Steve and Mary Jo visited our Birch Lake retreat last week. Steve and I went ice fishing – he showed me the routine of setting tipups for walleyes. It was single-digits cold with wind gusts to 25 mph and more, blowing new snow in miniature tornadoes across the lake. Boring holes with the gasoline-power auger, we found the ice 18 inches thick.

Now February is winding down, and I’m waiting for ice-out. I’ll be waiting for a while, I realize, but I look forward to observing, for the first time ever, the thawing of a lake. I never had that opportunity until we bought our land and had year-round access to the lake. I do know that lake-dwellers keep track of ice-in and ice-out dates as major milestones of each year.

While I wasn’t there to see it, I know that the ice went out early on Birch in 2010. I waded in the lake, not at all uncomfortably, in mid-April of that year. 2011 was a different story. When our family held a ceremonial groundbreaking for the cabin on April 16, the lake was still frozen stiff, it was cold, windy and snowing, and we drank our champagne huddled inside our RV trailer.

This year all signs point to early ice-out, but of course that can change – March can still be brutal and April chilly, and the ice can linger even into May. Now that the cabin is complete, we can be there as the days finally get warm and the ice recedes. I can’t wait to watch it happen.

This wonder we call water

Early this week my wife and I took the springer spaniel, Freckles, for a walk from our Birch Lake cabin. We hiked down our private road, along a short section of snowmobile trail, and then onto the lake. Here Noelle hesitated; she had never skated or walked on a frozen lake before. Freckles had no such trepidation and tugged hard at the leash. We followed, taking an arcing path across the ice to where our pier would be in summer.

Isn’t it wondrous that we can walk on the lakes in winter, and that the water below teems with life forms, active and dormant? We owe it all to a singular property of water. Most liquids contract as they cool and keep on contracting until they solidify. Water, on the other hand, contracts until it reaches 4 degrees Celsius (39 degrees Fahrenheit), at which point it begins to expand, and continues to expand until it becomes ice. So as a lake cools down toward the freezing point (zero Celsius, 32 Fahrenheit), the densest water at 4 degrees Celsius is at the bottom. Ice forms at the surface and, because it is less dense than the water, it floats. Soon a skin of ice covers the lake, and it gets thicker with cold days and nights as winter deepens. This ice then insulates against the subzero temperatures and keeps the water below in the liquid state, in which life thrives.

Why water behaves this way is a matter of chemistry and physics – of molecular vibration, positive and negative charges, molecular shapes, hydrogen bonds and such. I don’t claim to understand it all. I do marvel at how earth’s most abundant substance – the one life depends on, the one life is made of – shows this benevolent anomaly of expanding, not shrinking, as it cools toward freezing. What if this were not so? Ice crystals forming on the surface would sink. As more and more water froze, would it begin collecting on the bottom? And would our lakes continue to freeze all winter, until they froze solid?

When walking on a frozen lake, or drilling through the ice and lowering golden shiner minnows from tip-ups to catch winter walleyes, it is wondrous to contemplate the special properties of water.

Rusty crayfish: An invasive menace

While walking on frozen Birch Lake recently I saw something I had never seen before. An ice angler ran to a tip-up displaying a flag and pulled up not a walleye but a crayfish. It was a rusty crayfish, a species native to the Ohio River valley that anglers brought to Wisconsin as bait and that has taken over a goodly number of lakes.

I thought crayfish just lay dormant all winter, but apparently not. At any rate, the rusties overran Birch Lake about 15 years ago, wiping out its rich cabbage weed beds and changing the whole structure of the fish population. Panfish and perch are all but gone, although walleyes are abundant and smallmouth bass reach genuine trophy size.

A trapping program run by the Friends of Birch Lake group has helped bring the crayfish population under control. So has increasing predation by fish and, at least according to rumor, so has a viral disease. Still, it’s upsetting to see such profound change brought on by a species that does not belong in the lake.

Invasive species – fish, plant, invertebrate – threaten many inland lakes, maybe including yours. If you want to learn about just how rusty crayfish can affect a lake, you can read my 2008 story from Wisconsin Natural Resources magazine at http://dnr.wi.gov/wnrmag/html/stories/2008/oct08/crayfish.htm.

What type is your lake?

Your lake is different from every other, of course – no two are alike, even in a place of many lakes like Wisconsin, where I live, or Minnesota. Still, it’s possible to place lakes into categories, and there are various ways to do it – by the way they were formed, by their level of nutrients, and by how they get their water, to name a few. Let’s start with this last classification.

The number of lake types based on source of water depends partly on who is doing the defining. The Wisconsin Department of Natural Resources lists four types, but there is a fifth that many geologists mention. Here are five basic lake types commonly found in Northern Wisconsin and Upper Michigan:

Drainage lakes. On these lakes, a stream brings water in, and a stream takes water out. That is, the lake has an inlet and an outlet – and in some cases more than one of each. The water level in these lakes tends to stay fairly constant – think of a bowl into which you run a slow flow of water from the tap. (Lakes created by a dams fit the descrption of drainage lakes, although they are usually classified as impoundments). 

Spring lakes. These lakes have no inlet on the surface, but they do have an outlet. They get their water mainly from groundwater flowing in. Many streams originate in spring lakes, which are quite common in northern Wisconsin.

Drained lakes. These lakes are like spring lakes in that they have an outlet but no surface inlet. They differ in that they are not fed by groundwater – they get their water almost solely from precipitation and runoff. For that reason, their levels can fluctuate: high in rainy times, low during droughts. During long dry spells, the streams flowing out of these lakes may dry up. Drained lakes are the least common type in northern Wisconsin.

Seepage lakes. These lakes have no stream flowing in or out. Their water comes mainly from rainfall and runoff, sometimes supplemented by groundwater. Their water levels are therefore cyclical.

Perched lakes. These lakes are truly landlocked. They have no inlet, no outlet, and no contribution from groundwater. In fact they sit on relatively high ground, above the water table, with a dense bottom sediments that hold the water in. Water levels in perched lakes can drop dramatically during long dry spells.

Which type is your favorite lake? If you don’t already know, consider doing some investigating to find out.