The Canadian and U.S. governments will update the Great Lakes Water Quality Agreement to "preserve the needs of our shared ecosystem," U.S. Secretary of State Hillary Clinton announced Saturday during a visit to Niagara Falls.

Clinton made the announcement during a ceremony in which she joined Foreign Affairs Minister Lawrence Cannon at the Rainbow Bridge to mark the 100th anniversary of the Canada-U.S. Boundary Waters Treaty.

Activists have long pushed for changes to the Great Lakes agreement to account for new environmental challenges such as invasive species, climate change, and new chemicals and contamination.

"We have to update it to reflect new knowledge, new technologies and, unfortunately, new threats," Clinton said.

"The agreement was last amended in 1987, and since then, new invasive species have appeared in our lakes; new worrisome chemicals have emerged from our industrial processes; our knowledge of the ecology of the region and how to protect it has grown considerably. In its current form, the Great Lakes agreement does not sufficiently address the needs of our shared ecosystem."

Speaking after Clinton, Cannon called the Great Lakes "fundamental to our mutual health and wellbeing," and said the two countries would work together to ensure that citizens, "have access to clean, safe and healthy water."

Clinton marked her first visit to Canada as secretary of state to celebrate the Boundary Waters Treaty, which created the independent International Joint Commission to "prevent and resolve boundary waters disputes between Canada and the United States," according to a U.S. State Department news release.

p>The IJC handles applications for, and then oversees, projects slated for boundary waters, such as dams. The commission also helps set policies to preserve the waters' chemical, physical and biological integrity.

"The Boundary Water Treaty of 1909 made official something that people on both sides of the border had known for generations," Clinton said. "That the rivers, the lakes, the streams, the watersheds along our boundary do not belong to one nation or the other, but to both of us, and we are therefore called to be good stewards in the care of these precious resources."

After the ceremony, Clinton and Cannon met on the Canadian side of the bridge for about an hour to discuss a number of bilateral and international issues.

The meeting covered a wide range of issues, both said afterward, including the two countries' missions in Afghanistan, security issues in Pakistan, the ongoing global economic crisis, peace in the Middle East, and improving relations within the Americas.

"Our country's prosperity and security are inseparable from those of the United States," Cannon said. "Americans, as you know, are our closest neighbours, allies and trading partners."

Cannon said he spoke with Clinton about concerns the Canadian government has regarding the Buy American provisions that are part of Barack Obama's economic stimulus bill.

The provision requires the use of American-made steel and other goods in infrastructure projects that receive stimulus funding.

Clinton repeated statements made by Obama and other U.S. officials in recent months, saying the provision includes exemptions to coincide with international trade obligations.

"As President Obama said, nothing in our legislation will interfere with our international trade obligations, including with Canada," Clinton said. "But we want to take a hard look as to what more we can do to ensure that the free flow of trade continues. We consider it to be in the interest of both our countries and our people."