Gov. Mark Dayton has already vowed to veto education funding legislation, citing early education as a top priority. A governor who has also championed water quality should swiftly veto another budget bill — the agriculture and environment spending legislation.

Signing it would put the gubernatorial stamp of approval on multiple measures that would weaken protections for Minnesota’s treasured waterways. Dayton, serving his final term and looking to burnish his legacy, would tarnish it if he let this shortsighted legislation sail through. It needs a do-over in the looming special session.

Some might object to a veto, because this legislation also contains needed avian flu aid. But lawmakers can find ways to send that provision to the governor while they rework water-quality provisions that will prove deeply unpopular as Minnesotans fully understand the impact.

That these measures even reached the governor’s desk is frustrating when Minnesota was poised this year to make serious progress on water cleanup. In January, Dayton boldly called for strengthening the state’s “buffer” law, which requires vegetative strips along many waterways. The strips help filter out agricultural runoff, a key source of river and stream pollution, especially in the southwestern part of the state.

Dayton’s buffers advocacy earned praise from conservation groups, but put him crosswise with the state’s formidable agricultural lobby. Farming has enjoyed for decades special exemption from the federal Clean Water Act. The buffers initiative would have been an important step in stemming runoff that can include sediment, fertilizer and harmful bacteria.

The legislation now before Dayton includes a watered-down version of his buffers initiative. It’s an improvement, but it essentially amounts to better enforcement of current laws rather than the expanded protection in Dayton’s original vision. That’s still a positive step.

But there’s little positive to say about other water-related measures in the bill. Among other things, the legislation calls for dissolving the Minnesota Pollution Control Agency’s long-standing Citizens’ Board. The move smacks of retaliation on behalf of special interests. In 2014, the board voted to require an environmental-impact statement for a proposed 9,000-head dairy operation.

The bill also undermines a promising biofuels compromise between agricultural and environmental groups that could have helped attract biofuels investment in the state while creating incentives for growing perennials and cover crops. These fight water pollution naturally.

Other backward water-quality measures in the bill are almost too numerous to list. Wastewater facilities in the Red River watershed shouldn’t get a pass on meeting new standards. Diverting money dedicated to landfill cleanup is lousy policy. So is a move that could harm wild rice by exempting some mining waste from water protection rules.

A governor who takes his natural-resource stewardship responsibilities seriously will send this bill back.