One More Problem in the Age of Short-Term Thinking

The good news is there are people doing research that matters. The bad news is that their findings sometimes expose an almost insoluble problem, and the solutions cost money no one will want to spend.

Yesterday's Star Tribune carried a story headlined Urban river's big polluter? Lawns, dogs. It detailed the research of U of M ecology professor Sarah Hobbie, which found:

• 76 percent of the phosphorus that turns our local lakes scummy and green comes from pet waste. Leaves and grass clippings washing down the storm drains supply most of the rest.
• Most of the nitrogen that flows out of urbanized areas comes from overuse of lawn fertilizers by a small segment of home owners.
• Roofs and our acres of pavement send all of this into the river through our storm sewers.

And remember, urbanized areas are not the major contributors to the total N and K loads in the Mississippi; that honor (60 percent) belongs to farmers. Waste-water treatment plants and industrial sources produce the next-largest percent. Nitrogen is what forms the dead zone at the mouth of the Mississippi we've all heard about.

But the amounts we generate in cities affect our own water quality more directly. The phosphorus effect is most obvious, because of the green lakes, but the nitrogen gets into ground water to become nitrate, which can kill humans, especially infants.

A couple of key facts:

• The amount of nitrogen from home-owners over-fertilizing their lawns is more than the amount from golf courses, cemeteries, parks, and campuses combined. About 20 percent of home-owners generate 70 percent of the fertilizer output. They're wasting money and wrecking the joint, but I'm sure they don't care as long as their lawn is green.
• Dog poop is part of the problem that could be addressed, but there's nothing you can do about their urine. It's going to wash down the drain.

Cities generally sweep their streets once in fall. Timing that sweeping, city-wide, is tricky because the leaves fall on different dates depending on the weather, and different species of trees lose their leaves at different times. According to the U's Hobbie, adding three more sweeps would decrease the phosphorus runoff by 23 percent.

But even though the cost of adding more sweeping is less than that of building storm water retention ponds to allow for phosphorus removal, I can imagine that St. Paul's street maintenance budgets — already under pressure from cuts to Local Government Aid and challenges to the assessment system — are not going to be expanded to sweep more often. Even if it's cheaper in the long run.

Because that's not the way things work, especially in this age of short-term thinking.