Ahead of President Joe Biden’s visit to Canada this week, Montana’s U.S Sen. Jon Tester, Democrat, wrote to the president in order to voice several concerns the senator has about northwest Montana.

Two of Tester’s top concerns had to do with water management on the border. Tester asked Biden to work with Canada on the selenium pollution in the Kootenai River and Lake Koocanusa. He asked the president to aid in the renegotiation of the 1964 Columbia River Treaty.

“I write to you ahead of your upcoming trip to Ottawa, Canada. In preparation for your trip, I respectfully request that you address issues critical to Montana, United States-Canada trade relations and the American economy,” the letter said.

In the brief letter the senator raised several issues for the president to consider during his visit with Canadian Prime Minister Justin Trudeau.

Among Tester's top concerns is a vaccine requirement for truck drivers crossing the U.S-Canada border – the mandate is affecting supply chains and trade, according to the senator. Tester then asked Biden to negotiate a new softwood lumber agreement with Canada in order to create jobs in the American timber industry.

“I also strongly encourage the administration to work with the Canadian Government to resolve the ongoing selenium contamination issue in the Kootenai watershed in Montana,” wrote Tester.

For years, the contamination from upstream metallurgical coal mining along the Elk river has seeped across the border, according to Tester. Selenium in small amounts is necessary for life, but in high concentrations it can cause environmental issues especially for fish reproduction.

Tester said levels of selenium coming from the Elk River have been increasing and that selenium concentrations have led to the degradation of water quality and aquatic life in Lake Koocanusa.

“Selenium contamination stands to cause significant harm to fish populations in Lake Koocanusa and the Kootenai River, threatening both Montana’s outdoor recreation economy and the Confederated Salish and Kootenai Tribes’ treaty-guaranteed water and fishing rights,” wrote Tester.

Tester urged the president to request a referral to the International Joint Commission in order to resolve the transboundary water issue.

According to State Sen. Mike Cuffe R-Libby, one way selenium concentrations could become problematic would be if the Canadian government exercised its treaty rights to pull water from the Kootenai River. Canada has the right to divert up to 1.85 million acre feet from the Kootenai river to the Columbia, Cuffe said.

Cuffe said he has been encouraging Sen. Tester to work to prevent this from happening. Currently in the Montana Legislature Cuffe has a bill that has been progressing through the legislature seeking elimination of Canada's right to divert water from the treaty.

“Should they ever exercise that right, number one it's going to decrease production at Libby Dam. Number two it's going to increase the percentage of selenium in Lake Koocanusa. Number three it's going to be detrimental to the aquatic health of the Kootenai and the Columbia and Lake Koocanusa,” Cuffe said.

The modernization of the 1964 Columbia River Treaty regime was mentioned by Tester’s letter, but his letter did not draw the same connection to selenium pollution. The treaty was a stand alone issue in the senator's letter, and he did not mention specific concerns he had about the treaty.

“The Columbia River Treaty has direct impacts on the economy, environment and flood control of Montana communities, any changes could have major impacts far into the future,” Tester wrote. “The United States now has less than one year to finalize negotiations with Canada before reaching a point at which either party can initiate significant changes to the treaty including termination, with 10 years notice to the other country.”

The treaty was originally brokered between the U.S and Canada to increase flood control on the Columbia River, but now Sen. Steve Daines, Montana Gov. Greg Gianforte and Tester have indicated that they are ready to negotiate the treaty differently, according to Cuffe. Tester is calling on Biden to negotiate an agreement that “will serve all the communities that rely on the Columbia River.”

“They have never made an attempt to divert that water, however it remains a threat to Montana as long as it's in the treaty,” Cuffe said.