Steve Johnson worked for the Minnesota-Wisconsin Boundary Area Commission from 1977 to 1987, including work on the St. Croix River. From 1987 until 2004, he directed the Minnesota DNR’s river programs. He gave a presentation at last week’s Asian carp forum in Stillwater about the potential economic impacts of Asian carp. This article is based on his presentation.

“You can’t eat scenery,” a politician once told me.  Sure, the river valley’s pretty, but the world runs on jobs and money, he explained.  If it doesn’t help drive the economy, it’s expendable.

Let’s ignore for the moment the argument that the world needs a few places where we can catch our breath and just relax, and let’s follow that money argument.  With silver carp knocking at our door and knowing they’ve essentially destroyed recreational boating in the Illinois River, what is it we might lose if boating and sportfishing were wiped out in the St. Croix Valley?

From 1977 to 2003, various agencies regularly counted boats in use on the St. Croix from Taylors Falls to Prescott.  We know from those reports that boating, which had increased rapidly through the 1960s and 70s, hasn’t grown much since about 1985 (the boats have gotten bigger, but their numbers haven’t changed much).

That data shows that around 1-2 p.m. on a nice-weather weekend or holiday there are about 2,700 boats out in active use on the river (not in the marinas, but out either moving, anchored out or on a beach somewhere).  Anglers are often out in the morning and would be missed by that count, and some boaters prefer to go out in the evening when things start to settle down and would also be missed.  So the day’s total is really quite a bit more than that.  But not every day is really nice, so let’s round down and say there were maybe 2,500 boats out on a typical weekend day.

Weekday use peaks at about 6 p.m. at about 800 boats if the weather’s nice.  Again, lots of people out on a weekday are off the water by 6 p.m., and not every day is nice, so let’s estimate total weekday use at 700 boats.

We know how many weekdays and weekends there are in a 12-week summer, so using those rough numbers suggests there are 107,400 boat use days on the Lower St. Croix in a typical summer.  Research has also shown that the average boat on the St. Croix has four people in it—that’s more than the average boat on the Mississippi River, since St. Croix boats tend to be larger and there are fewer one- or two-passenger fishing boats here than on the big river.  So, that rough math suggests the summer season on the St. Croix includes 429,600 boater use days.

In 1995 an economist working for the Corps of Engineers prepared a report on the economic value of boating recreation on the entire Upper Mississippi River System, which includes Lake St. Croix.  People who use the river spend money in two ways, he determined.  Most obvious, they spend money on the day they’re on the river—bait, gas, beer, food, restaurant meals, etc.  They also spend money on durable goods—the boat, the marina slip, fishing rods, tackle, whatever—and the value of those durable goods needs to be spread over the life of the product.  Not surprisingly, he found that marina-based boaters spend more than boaters who access the river from a ramp or private home.

Calculating in 1990 dollars, the economist found a typical boater spends $28.38 for a day on the river, while a marina-based boater spends $41.38.  Everything costs more today than it did in 1990, and using a Bureau of Labor Statistics inflation calculator, we can estimate boater spending today at $54.81 per day from launch ramps or homes, and $72.62 for a marina-based boater (in 2012 dollars).

We know from all those boater counts that about 30 percent of boats in active use at any time are from marinas, while the rest come from other sources.  Combining those dollar numbers with the boat totals we estimated for the summer season tells us recreational boating and sportfishing will pump $25,865,790 into the St. Croix Valley’s economy this summer.

That’s not counting shoulder season—and the season certainly started early this year—and that’s not considering how spending multiplies as it circulates through the community.  We’re working with some pretty old data here and we should acknowledge a true number might be different—but it would still be large.

Really large.

If leaping carp show up here in big numbers, we have a lot to lose–$25 million for starters, plus a lot of intangible enjoyment that you can’t put a dollar figure on.  And with that kind of economic impact, spending $10 million on research or $14 million on a barrier doesn’t sound like a bad investment.