By Tim Leeds
The water level in Fresno Reservoir, which was recently full for the first time in five years, has been dropping, but federal Bureau of Reclamation officials said it will rise again once repairs on the St. Mary Diversion are completed.
"There was some minor damage, I guess. Just enough to shut the canal down," bureau hydrologist Tim Felchle said. "We're about done and about ready to start watering it back up again."
The diversion was shut down to allow workers to remove dirt left in the canals by heavy rain and snow in June. Workers also did some repair work on concrete chutes in the canals. That work was expected to be completed today.
After that, the bureau should be able to divert enough water to the Milk River to supply irrigation needs and have a carryover supply for next year, Felchle said.
The St. Mary Diversion, one of the first projects the bureau was authorized to work on after it was created in 1902, diverts water from Lake Sherburne, in Glacier National Park and the Blackfeet Indian Reservation, to the Milk River for irrigation. In dry years, the diversion provides almost all of the water in the river.
The Milk River is used by some communities, including Havre, Chinook, Harlem and Malta, for their water supply.
Havre water treatment plant superintendent Jeff Jensen said last week he hopes new water coming into Fresno once the diversion is open again will reduce sediment in the water. The water has such high turbidity that it's taking more work than usual to treat it, he said.
New water coming in will help reduce the sediment, Felchle said, although there will always be some mud in the river.
"The Milk has got its name for one reason, I think, because it's a milky, muddy river," he said.
Felchle said the repair work was needed both because of mud left over from the storm and normal wear and tear on the structures.
The bureau also took advantage of Fresno's being full to do the repair work.
"It worked out well for that. Normally this time of year we're bringing a lot of water over from St. Mary," Felchle said. "It gave us an opportunity without jeopardizing the water supply for the Milk River project."
Three or four concrete chutes that drop water to lower levels in the canals needed some work, he said.
"We didn't want to see chunks of concrete erode away and tear away other parts of the chute," Felchle said.
The work is being finalized and the diversion should be ready to reopen Wednesday or Thursday, he said.
The Milk River Irrigation Authority, composed of the irrigation boards in the Milk River valley, is trying to urge Congress to pay for major repairs on the diversion. Some components of the system are more than 80 years old.
The bureau hasn't received large orders for irrigation water yet, probably because of the large amounts of rain the area has received, Felchle said. Now that the weather has turned hotter, orders will probably start going up, he added.
The water supply is large enough that the system should provide enough water to satisfy irrigation orders, Felchle said. Lake Sherburne is only about 2 feet below full, and Fresno is about 5 feet below full.
Fresno's level is much higher than normal even with the diversion shut off, he added.
"Right now Fresno's sitting at what we'd call 140 percent of normal," Felchle said.
Nelson Reservoir, east of Malta, is about 75 percent of normal for this time of year, he said, but once the irrigation season is over the bureau will probably be able to fill it too.
"We're going to try to bring over and divert water to Nelson as we can," he said. "Normally when the irrigation season is over we will try to divert into Nelson."
The high water level will let the Bureau of Reclamation store enough water in the reservoirs to carry over into next year, Felchle said.
"I think that'll be better than we've had in the past few years," he said.
While sufficient snowfall over the winter is needed to keep the reservoirs full, having carryover makes the system less dependent on snowpack, he said.
Other factors cause complications in running the entire Milk River project, Felchle said. For example, piping plovers nest at Nelson in the spring, and releasing water to the reservoir after they build their nests can flood their nests.
The U.S. Fish and Wildlife Service has designated Nelson Reservoir as a critical habitat for the plover, listed as a threatened species.