Where Does The Water Go?

What are some of the common myths or misunderstandings you’ve heard about Devil’s Lake State Park? There are quite a few! One that came up recently is the idea that Devil’s Lake has some form of NATURAL underwater drainage. So, let’s talk about it. To date, we know of no underwater tunnels or caves that allow the water to drain away. (Or that travel between universes or dimensions!)

Devil’s Lake has NO natural outlet above or below the surface. As we talked about on our Facebook page not long ago, lakes do a good job of building up a bed that holds the water and won’t let go. In addition, of the surrounding watershed, 2.65 square miles (including the surrounding bluffs) drain directly into the lake. This is why Devil’s Lake can be prone to flooding and other problems such as the buildup of phosphorus.

Back around 2002, a 5,500-foot-long pipeline was sunk to the bottom of Devil’s Lake to draw out pollution caused by years of sewage running into the water from cottages and resorts that used to cover the shoreline. What’s worse, in the 1970s, the park’s sewer main was broken and not repaired for nearly 10 years! When you consider that, a good clean-out sounds like a great idea! By 2009, the local newspaper reported that over 6,000 lbs of phosphorus had been removed from the lake. Today, the drain remains in use to regulate the lake levels and control flooding. More recently, the lake has been extremely low.

Where Does All The Water Go?

So if there is no natural drain, where does all the water go? Well, as we said, today the DNR will drain the lake as they see fit. But before the pipe was installed, evaporation was the main culprit. Now, I won’t drag you through such things as the Penman formula, the Penman-Monteith equation, or the Priestley-Taylor model… But by overgeneralizing and doing a lot of math, we could estimate (If you’re a hydrologist, please correct me if I’m out of the ballpark here!) that Devil’s Lake can drop anywhere from 3 inches to 10 inches or so in a month simply from evaporation! Or, and again estimating seasons and other variables, Devil’s Lake could see something like 5 feet of annual average evaporation. People who visit the lake regularly would notice the lake going down each year, which is probably why the rumor of a natural drain persists.

“But I Read…”

So, I did my best to dig around and see if there was any published evidence of underground drainage in the lake. Wouldn’t you know, the only “hit” came when I asked Google… Its Ai came up with a 1917 supposition by Arthur C. Trowbridge in the History of Devil’s Lake, Wisconsin that the lake “possibly drains by underground channels into the Baraboo River”. Suffice to say, we’ve learned a lot since 1917.

So there you have it. More than you ever wanted to know about how the water gets out of Devil’s Lake.