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.

How We Met: Birch Lake

My memories of summer vacations on Duck Lake in the Upper Peninsula stayed with me and ran deep. And so I wanted to create a similar tradition with my own family, wife Noelle and kids Sonya and Todd. We tried week-long vacations at cabin resorts on Moon Lake (Duck’s neighbor in the UP) and Presque Isle Lake in far northern Vilas County, Wis. But I was looking for a place we could return to year after year, and for various reasons neither of those two quite fit.

The next year, in 1987, when Sonya was five and Todd two, we wrote to the Oneida County Chamber of Commerce for information on housekeeping cabins. Dozens of brochures came by mail; the one that appealed most was for Jung’s Birch Lake Cottages, near a place called Harshaw that we had never heard of, about a dozen miles southeast of Minocqua. We bought a week in a cabin called Bayside, sight unseen, for $400 (enough money back then to ensure, pretty well, a quality experience).

It was love at first sight. Noelle fell for the cozy two-bedroom cabin, with new furnishings, knotty pine walls and, as bonuses, a fireplace, microwave oven, and deck – in her words, “all the comforts we don’t have at home.” For me it was about the lake, 180 acres with expansive beds of cabbage weeds on the edges of which I could catch walleyes, bluegills, perch, and the occasional largemouth bass. The romance was sealed when, on our first night, I caught a 38-inch muskie right off our pier. There was a nice swimming area for the kids, and all the Northwoods icons were there -- loons, ospreys, eagles, deer, raccoons.

We visited Birch Lake for a week almost every summer thereafter, usually staying in the Lakeside cabin, right next to Bayview. Then in 2009, a wooded lot came on the market, straight across the lake from the cottages. We closed on the lot in December of that year, parked an RV trailer there, and by fall 2011 had our own cottage. The way we came to buy the land is a story in itself, for another time. Suffice it to say our relationship with Birch Lake has bloomed into something deeper and longer-lasting.

How about you? How did the romance with your favorite lake begin? How did you two meet?

How We Met: Dinner Lake

Dinner Lake, my second love, lies in Michigan’s Upper Peninsula about three miles over the treetops from Duck Lake. I discovered it on a side trip from the Duck Lake cottage, just a random exploration for more places to fish. I was about 24 then and feeling a little constrained just fishing one lake. I had no boat, but at the time that didn’t matter.

I just headed north on Highway 45 from Land O’Lakes, saw a plain wooden “Dinner Lake” sign at the first side road, took a right in the direction of the arrow, and followed the signs from there. The roads twisted back into the trees, first nice smooth asphalt, then much rougher asphalt, and then a skinny, bumpy gravel road for the last quarter-mile or so. The road dipped sharply down and bent around to the right, revealing the lake, a small blue jewel in a wooded hollow. Logs lay in the water on both sides of the boat ramp, and among them small bass hung motionless. I broke a piece off a twig and tossed it onto the water; a fish darted up, took it, and spat it out.

The boat ramp was on an almost circular bay, a narrow outlet giving way to the lake proper. I couldn’t see much of the lake itself, but several bare logs jutted out from the bay’s shore – great-looking cover. I hung around for a few minutes teasing the baby bass with bits of twig, then drove away, filing the spot in memory.

The next summer I bought a used blue fiberglass canoe. On a June weekend my friend Ed and I strapped it atop my 1964 Plymouth Valiant and drove north. We tented at the National Forest campground on Lac Vieux Desert and in the morning drove over to Dinner and slid the canoe in. We immediately found smallmouth bass among the logs, more than willing to smack a floating plug. As it turned out, loggy cover nearly surrounded the lake. We caught dozens of bass, about half of them above what was then the legal size of 12 inches.

I’ve returned almost every year since, with friends or alone. In time I discovered a rocky hump just off the east shore that is productive even when fish have deserted the shoreline cover. It’s a quiet lake, about 150 acres, ringed by small, well-kept cottages, most occupied just sporadically. I’ve never been able to spend an evening or weekend on the lake. In the early years there was a private campground on the east shore, but that soon closed. So it’s a lake I simply fish, once a year (with rare exceptions), almost as a matter of principle. After all, I discovered it. I don’t tell many people about it. My stock comment about it is: I’ll take you there, but I won’t just tell you where it is.

How about you? Where did your romance with your favorite lake begin? How did you two meet?

The Otter in Winter

Before the snow got too deep for easy walking, I took Freckles (our springer spaniel) for a daily winter hike on the ice of Birch Lake, near Harshaw, Wis., where we built a cottage last summer. One day we came upon the track of an otter following the very edge of the ice. The clawed paw prints and the belly imprint (or was it a tail drag?) in the snow made clear whose track we were following. Freckles did not seem to find a scent, so the trail must have been cold. We followed the trail along the shoreline, then across a bay, to where it led into the trees. Backtracking a long distance, we found a 6-inch hole in the ice near the marshy spot where a creek exits the lake. The snow on the shore near the hole was littered with scat.

I had seen otters (technically river otters) in the wild before, but never on Birch Lake, and I had never felt quite so close to one, although the animal was not present. Otters remain active in winter. Where they can find openings in the ice, they will enter the water to hunt for fish, clams and other prey. This otter clearly had made its own hole (the ice next to shore was thin). Otters can remain submerged for long spells and can breathe in the space (if it exists) between the ice and the water. I'll be keeping my eyes open for otters on the lake this winter, and maybe I'll be lucky enough to spot one while taking a snowshoe walk toward evening or on a moonlit night. I’m glad to know they live here on the lake we now call home.