Last week Hamilton residents got a chance to weigh in on a large revegetation project planned for installation along the river in Skalkaho Bend Park. Although the project only recently came before the City of Hamilton for review by the Committee of the Whole it has been in the development stage for quite some time, according to City Public Works Director Donnie Ramer.
After an initial meeting on October 13 that was disrupted by a power failure, Ramer told the council members at the last COW meeting on November 5 that his staff and the Bitterroot Water Forum have been working on the project for some time, sifting through the options and preparing a plan to address the migration of the river which threatens to cut its way through the park.
Ramer told the COW members that the river has been eating away at the bank in the area of the park at the rate of about 4 to 8 feet a year and threatened to cut the park in half when it reaches the C&C ditch, which runs through the park. He outlined three basic options that could be pursued in the face of this erosion process.
Number one was do nothing. In that case, he said, scientists predict that the river may erode as far as the ditch in 40 years, cutting the park in half.
Number two was to do a light treatment in the area where vegetation would be planted to develop a root system that would slow the erosion and migration.
Option number three was to do some hard rip-rapping in the area stabilizing the bank in one spot.
He said the staff and scientists and consultants agreed that option 2 was the best option. That plan involves planting a thick line of willows and some cottonwood trees about 30 feet back from the current river bank, giving the vegetation time to mature and develop good root systems before the river reaches the area.
Heather Barber, Director of the Bitter Root Water Forum, said that once they noticed the lack of any good vegetation in the grassy park area and the rate at which the bank was eroding, they enlisted the help of many experts including hydrologists, geomorphologists, wildlife biologists, fisheries experts, cartographers and others to analyze the area and come up a plan of action.
Barber said with the help of Geum Environmental Consulting they analyzed maps from 1954, 1995 and 2017 to chart the historical paths of the river and decided that something needed to be done to save the park.
Barber said that rivers want to wander naturally and they are not interested at all in trying to stop that migration in its tracks with some hard revetments or rip-rap. But something must be done, she said, so they are looking at the lighter option of slowing it with vegetation.
The plan calls for digging a swale about 30 feet back from the river and filling it with 10,000 willows and some larger trees for about 1,500 yards in length. An eight-foot-tall fence is also planned to be placed around the plantings to protect the young plants from browsing animals. The fence may be removed after five years or so. She said paths will be maintained by the river so people can enjoy the view of the mountains across the way.
Barber said that doing some mitigation now is better than waiting until it has to be an extreme emergency and something drastic done at the last minute such as rip-rap if the park is to be saved. She also said that extensive public involvement was always a part of the plan but the COVID-19 pandemic and other external factors slowed that down. She said the Water Forum was hesitant to bring the project forward for a while because they did not want to interfere with the Bitterroot Land Trust’s efforts to place a conservation easement on the land and transfer it to the City.
“We didn’t want people to get confused,” said Barber, adding, “I wish we could have done this outreach like we planned.” She said there was never any attempt to hide anything. She said some people were concerned about the fact that plans to get the willows needed were already under way, suggesting that the decision had already tacitly been made. Barber responded to that, saying that the willows being collected could be used on any other project if this one is not approved.
“We can do other things with those willows,” she said. She went on to say, “We don’t want to stop river processes, but we love this park and we want to keep it. We can’t guarantee the success of the plan, but we think it’s the right approach.”
Chris Clancy, a former fisheries biologist on the Bitterroot River for FWP and a member of the Water Forum’s board of directors, supported the plan. He said the river was going to migrate and it would be nice to mitigate that as it moves through the park. He said the plan is not foolproof and it could fail but it is worth the try and that the plan was logically and ecologically sound.
Retired wildlife biologist and fisheries manager Rob Harris felt differently about the project. He had concerns about the efficacy of the planting and the unintended consequences to the viewshed. He defended grassland habitat as a viable habitat with plenty of adjacent areas of the river covered with willows and cottonwoods. He also said he believed the original owner who transferred the land to the Bitterroot Land Trust and then the City believed that it would be left in its current condition. He also said that he was shown a report about the potential plantings in the floodplain but told not to show it to anyone. He said the report shows that there is not any real need for erosion control in the area.
The issue was kept in committee for further discussion and more public participation.