Like roads, Minnesota’s waters became a hot issue this legislative session (though unlike roads, lawmakers actually passed a bill). In the same spirit as my previous maps of all of Minnesota’s roads, here’s a few maps highlighting the water in the Land of 10,000 Lakes — starting, of course, with all those lakes:
In fact, there are 28,176 distinct lakes, ponds and wetlands on that map.
Here’s the state’s rivers:
Some of these are so small they don’t have any names. More specifically, there’s 3,768 “unnamed streams,” 2,032 “unnamed creeks” and at least 6,572 unnamed lakes and ponds.
There are actually a lot more recognized bodies of water than are on this map, but I excluded things like artificial ponds, drainage ditches, intermittent streams and lakes, underground aquifers and sewage ponds. A map with every single aquatic feature in the state is so dense as to be almost unreadable.
Unfortunately, I don’t have data about width or flow rate, so the Mississippi and Minnesota rivers are the same width on this map as those unnamed streams.
(This post was originally published on June 9, 2015. It has been updated with new, more accurate maps. See below for more information.)
Here’s the above two maps combined into a single map of every lake and river in Minnesota:
This is a lot of water. Just in this subset of permanent, natural rivers and streams, there’s 34,167 miles of water. (Counting all those ditches multiplies the length up to 117,432 miles.) That includes 13,944 miles classified as one of 970 “rivers” and 20,173 miles classified as one of 19,659 “streams,” an average length of about 14.4 miles per river, and just 1.03 miles per stream. Among the lakes, we’re looking at 5,752 square miles of water — bigger than the state of Connecticut. And this DOESN’T include Minnesota’s portion of Lake Superior, or the parts of the Lake of the Woods in Canada. The combined perimeter of all that lake shoreline is a whopping 55,035 miles.
Another facially obvious fact that’s underscored by this sort of map is is how the state’s borders are defined by bodies of water. Two-thirds of the state’s western border consists of lakes and the Red River; almost all of the state’s eastern border is the St. Croix and Mississippi Rivers and Lake Superior, while most of the north is the Boundary Waters network. Only the southern border is entirely an artificial line on the map. (And in fact Minnesota’s southwestern border was almost a river, too.)
Excluding the artificial and intermittent streams made the biggest difference in the agricultural south and west of the state, which are criss-crossed with a dense network of drainage ditches.
If you’re curious, here’s what the map looks like with all the intermittent or artificial bodies of water:
Compare the two versions side-by-side here:
But we can do more than just visualize these rivers and lakes. Let’s analyze.
Here’s a pair of maps looking with more detail into how Minnesota’s rivers and streams are distributed around the state. For each, I looked at the prevalence of lakes and rivers in each county. The lake map colors each county by the percent of its land mass covered by lakes; the river and stream map is colored by the number of miles of flowing water in each county, divided by each county’s area.
(Adjusting by area makes a difference. For example, Beltrami County has the eighth-most river miles in the state with 749.1. But it’s also the state’s third-biggest county by area. So controlling for size, Beltrami actually only has the 66th-densest river network out of Minnesota’s 87 counties.)
As you can see, the Arrowhead region of the state has lots of lakes, but the most water is found following a rough line from Mille Lacs up to the Lake of the Woods, as well as an arc running from Hennepin County up to Becker County. The Red River Valley and the southern portion of the state have very few lakes.
Here’s the rivers. Though northeast Minnesota is also dense here, the rest of the state follows different density patterns:
The most striking facet to me is the difference between the south and north banks of the Minnesota River. To the south, there’s plenty of natural streams and rivers, while to the north, there are relatively few. The southeastern corner of the state is also a lush riparian region. The northwest part of the state doesn’t have much, but remember that part of that (the part with a lot of really short rivers) has a ton of lakes, which explains part of the “blank” area on the map.
Here’s another way to look at the concentration of rivers and lakes: heatmaps.
Look back up at any of the maps of Minnesota’s waters. Can you follow the Laurentian continental divide as it winds through northern Minnesota? Rivers north of that line flow north to Hudson Bay; rivers south of it flow either south to the Gulf of Mexico through the Mississippi-Missouri system, or east to the Atlantic Ocean through the Great Lakes.
Probably not. Part of it seems apparent — the mountains of the Iron Range, where river on one side flows toward Lake Superior and on the other side does not. But that’s misleading — part of the area west of those mountains is still in the Lake Superior watershed. Similarly, it’s hard to tell in the western and central part of the state where the divide runs just by looking at the water.
This is where the waters split in the Land of 10,000 Lakes:
After the jump, I discuss a little bit about the mistake I made when I first published this post last week. You can probably ignore it if you don’t care deeply about map-making; I’m posting it primarily in the interests of transparency.
This post was originally published on June 9, but within an hour after clicking “post,” I began to have concerns. A quip on Twitter about whether there were 10,000 lakes on the map led me to check — and to my horror there were only about 4,000. Though my map showed more than 20,000 miles of river and thousands of lakes, it was clearly not “every lake & river in Minnesota” as I had branded it.
I found a new, more extensive dataset and confirmed that there were a lot more rivers and lakes that I hadn’t mapped the first time. That fuller dataset is what produced the maps you now find above.
The dataset that had made the maps below was actually just a map of bodies of water being monitored for pollution by the Minnesota Department of Natural Resources. Streams and ponds not being monitored weren’t included. It’s still a very useful map and a good display of the state’s major rivers and lakes, but not for the purposes I was using it for.
On the left here is what I originally posted as “every lake and river”; on the right is the version I posted above:
By far the biggest difference is the Arrowhead region of northeast Minnesota, which has gone from mostly empty to a thick network of streams.
As you’ll notice along the Minnesota River, there are actually some rivers that are on the older, sparser map but not on the new one. Most of those are actually ditches, canals and intermittent streams — they show up on the map above with every single body of water but got filtered out of my map with only the permanent bodies of water.
More than just an aesthetic difference, though, this made a difference in the analysis — particularly in the distribution of rivers around the state. Here’s a before and after:
And, if you’re curious, here’s the lake comparison: