In hopes of reversing the buildup of salt in Bowdoin National Wildlife Refuge's wetlands, the U.S. Fish and Wildlife Service is considering several options to slow the environmental damage.
"It's a very, very complicated issue and very detailed," said Carmen Luna, the refuge's manager. "There are a lot of things contributing to the salinity. It didn't happen overnight. It's a long-term issue."
Refuge officials will hold a public meeting at 6 p.m. Thursday in Malta's Great Northern Hotel to discuss the four alternatives it devised with the help of Montana state officials. Once a decision is made, it will be included in the refuge's 15-year comprehensive conservation plan, which should be completed next year. It would then be up to Congress to fund any remediation project.
The 15,551-acre Bowdoin refuge is just east of Malta in north-central Montana.
Bowdoin's many ponds and surrounding vegetation are home to water birds and shore birds, as well as deer. The refuge's waterfowl and upland game birds are big draws for hunters, who comprise the largest number of visitors to the site.
Luna said the area is also seeing more eco-tourists, with visitation climbing steadily by about 200 to 300 visitors every few years.
"Over the years, as this area is being discovered, our numbers have increased," Luna said.
The rise in visitor numbers has pumped money into the Malta economy for everything from purchases of gas and food to hotel rooms, she added.
So. keeping the refuge vital is important to more than just wildlife; it's also about the region's economy.
Salt is a naturally occurring mineral in the Malta area's soil. The area was once part of a vast glacial lake, said Mike Hansen, assistant state soil scientist with the U.S. Department of Agriculture's Natural Resources Conservation Service in Bozeman.
"Those lake bed sediments are saline to begin with," he said. "Evaporation to the surface occurs naturally. Periods of drought can exacerbate the problem."
Too much water, such as from excess irrigation, can also move the salt through the soils, he said.
If the excessive salt buildup is not removed from the refuge, Luna said, it would eventually die.
"When it gets to higher elevation levels, you get a decline in vegetation and wildlife," Luna said. "It just keeps collecting over time. It could be 50 to 100 years from now, but eventually, if we can't do something the system, will crash."
The agency has considered four alternatives to remedy the problem:
• Construct evaporation ponds and remove the saline residue by rail car. The estimated cost is $48 million to $58 million, which Luna said is too expensive.
• Promote flushing of the lakes when Beaver Creek, which flows south and east of Bowdoin Lake, overflows its banks.
• Inject saline lake water underground and promote flushing of Lake Bowdoin when Beaver Creek naturally floods. The projected cost of this alternative is $6 million to $12 million.
• Pump water from Lake Bowdoin to the Milk River through a pipeline. This option would require easements across private lands. The estimated cost is $4 million to $6 million.
Luna said the buildup of salt hasn't been readily visible in the short term, but, in looking back at earlier records from the refuge, it's clear that there has been a decline in the number of breeding birds on the refuge.
"It's still a productive system for right now," she said. "It's still a valuable resource for the public."
Contact Brett French at email@example.com or at 657-1387.