Hailing Walter Mondale as one of the nation's champions of conservation, state officials Tuesday renamed several places along the St. Croix River for the former vice president as an acknowledgment of his role in protecting it.

The spots at four riverside state parks, along with a stretch of the river itself, now bear the name of the man who, as a Democratic U.S. senator, co-sponsored the Wild and Scenic Rivers Act in 1968 to shield select waterways such as the St. Croix from dams, runaway development and dumping.

"We got there just in time," Mondale said of the federal legislation and the many pressures on vulnerable waterways in the late 1960s.

Mondale spoke to about 150 supporters and friends Tuesday at William O'Brien State Park near Marine on St. Croix, at the ceremonial unveiling of a day-use area named for him.

He recalled his long association with the area. He and his late wife, Joan, used to have a cabin along the river just north of the state park among a collection of houses that pre-dated the river's designation as a federally protected waterway.

The river was the site of an early date for the young couple, he said.

"We canoed down the river and when it was over, I asked her to marry me," he said. She said yes, and only 61 days later they tied the knot.

An initial effort in March by House Majority Leader Ryan Wink­ler, D-Golden Valley, and state Sen. Karin Housley, R-St. Mary's Point, to rename Interstate State Park near Taylors Falls for Mondale met resistance for both its timing and location.

First, former state Rep. Phyllis Kahn pointed out that a law she sponsored in 2009 barred legislators from naming things after living persons. Winkler said that he preferred to act sooner rather than later.

Then the location drew objections. Winkler and Housley had turned to Interstate park as a place within the boundaries of the St. Croix National Scenic Riverway for a Mondale memorial. If the Minnesota portion of the park was named for Mondale, they reasoned, then Wisconsin could name its twin park across the river after the late Wisconsin Sen. Gaylord Nelson, who with Mondale sponsored the Wild and Scenic Rivers Act.

Locals objected to the name change for historical reasons, as did residents near St. Croix State Park when Winkler looked for another riverside state park to rename.

The solution, made official this week, names several features along the river after Mondale as well as a portion of the river.

They are the Walter F. Mondale Day-Use Area at O'Brien State Park; a scenic overlook and trail at Interstate State Park; the visitor center at St. Croix State Park; and a trail at Wild River State Park.

Also, the section of river from Sunrise River Landing to the William O'Brien landing will now be known as the "Walter F. Mondale Segment" of the St. Croix National Scenic Riverway.

The St. Croix River from Gordon Dam to Taylors Falls was protected by the original 1968 act, and an amendment four years later added the lower St. Croix to the list.

The legislation came at a time in the nation's history when rivers were being threatened by toxic waste, rampant development and unregulated dumping. It was an era that saw an oil slick set ablaze on the Cuyahoga River in Cleveland in 1969, galvanizing early environmental efforts.

From its original list of eight rivers, the National Wild and Scenic Rivers system grew to eventually include some 13,400 miles of waterways in 226 rivers across 41 states and Puerto Rico, according to the National Park Service.

The Wild and Scenic Rivers Act was considered landmark legislation when it passed.

"There was nothing like it before it," said Julie Galonska, superintendent of the St. Croix riverway.