An aerial photo of two Minnesota rivers is often hauled out to illustrate the state's regional gaps in water quality. Viewed from above, there's a jolting contrast between the pristine St. Croix River and the muddy waters of the Mississippi where the two join near Prescott, Wis.

But there's another aerial river photo that more accurately illustrates why making all of the state's waterways swimmable and fishable is such a monumental challenge, mostly for political reasons. That photo is taken a few miles upstream near Fort Snelling, where the Mississippi's role is reversed. Even after flowing through Minneapolis and St. Paul, its waters look clean until they're sullied by another river flowing into it — the Minnesota, which picks up agricultural pollutants as its winds a course through the state's heavily farmed southern prairies.

With legislators weighing the fate of Gov. Mark Dayton's "buffer strip" water-quality initiative, this lesser-known photo is worth considering, especially the critical truth it conveys about a key source of state water pollution — the agricultural industry. If Minnesota is to truly carry out the mission given to it by voters in 2008 — when the clean-water-focused Legacy Amendment passed with overwhelming support — efforts to fight water pollution must include serious steps by farmers. That's an uncomfortable reality when this politically influential industry has enjoyed a decades-long exemption from the federal Clean Water Act, which targets so-called "point sources" such as wastewater treatment plants or other industry.

Laudable progress has been made in Minnesota and elsewhere in reducing sewage and chemical discharge. But without widespread efforts from agriculture, the state's water cleanup will fall far short of Minnesotans' expectations. That's why Dayton's initiative, which will require vegetation strips between farm fields and many state waterways, merits strong support, not watering down, as some Republican legislators recently proposed. Unlike years of voluntary programs and other pollution-control incentives aimed at farmers, this initiative would actually move the needle by imposing deadlines and accountability. It's not a cure-all, but it's action where action is desperately needed.

The fact that meaningful action is needed to combat agricultural runoff, which can include sediment, fertilizer and harmful bacteria, is undeniable. Some rural communities have drinking water made unsafe by nitrate pollution, an alarming situation detailed in an April 2 Star Tribune story. The most recent evidence was a report released last week by the Minnesota Pollution Control Agency (MPCA), which detailed a stunning division in water quality between the state's north and south.

The MPCA report was well-researched and well-written. Dayton and MPCA officials, however, were too diplomatic as they presented its findings last week. Yes, both urban and rural Minnesotans need to do their part to clean up water pollution, as Dayton emphasized. But significant efforts already have been made with cities' wastewater discharge, and progress is also underway to better manage stormwater.

Saying that agriculture needs to make a concrete contribution is a hard but necessary truth. Policymakers shouldn't be soft-pedaling this. Nor should legislators be backpedaling on buffers or other water-quality protections. Unfortunately, there are a raft of bills this session aimed at undermining clean water. One would give lawmakers veto power over new water-quality standards. Minnesota waters are in crisis. Forward thinking, not more kowtowing to special interests, is needed to save them.