The Mill Creek Development plan has been in process for nearly four years. The initiative includes plans for water channel improvements and has been a recurring topic of discussion at Walla Walla City Council meetings. Two groups have taken charge of this issue: the Mill Creek Coalition and a group led by the Washington Department of Ecology.
The group led by the Department of Ecology is focused more on the ecological effects of the Mill Creek channel like erosion and flooding, whereas the Mill Creek Coalition takes a more hands-on approach through initiatives like building or repairing channels in collaboration with a Corps of Engineers.
The state’s principal concern is flooding and property damage that Mill Creek can cause to surrounding buildings and infrastructure. Flooding can also pose dangers to motorists and community members.
According to the Army Corps of Engineers, Bennington Lake was created as a place to which rainfall could be diverted in order to avoid catastrophic flooding in the downtown area. When the amount of rainwater flowing through Mill Creek reaches a certain threshold, it is diverted to the lake where it is gradually released after the storm.
The Corps credits the project with helping to reduce damage to buildings in flood events in 1996 and 2020.
Walla Walla faces a significant challenge with its aging concrete channel. The water system has been investigated by engineers upon request of the Walla Walla County Mill Creek Flood Control Zone District.
Walla Walla Mayor Tom Scribner mentioned the importance of collaboration to address issues like flooding, citing consistent meetings with the Corps of Engineers.
“We have been meeting/working for years with the Corps of Engineers to decide what could/should be done to minimize flooding. A plan has been agreed upon, I think, and a total cost determined, and then, for reasons unknown to me, things seem to have stalled,” Scribner said.
According to Scribner, the Army Corps of Engineers and the City Council have agreed to patch up the old channel, but plans have been stalled for months now with concerns related to federal funding.
Concerns about the environmental repercussions of the repairs are also prevalent. Improving water quality and the livability of the water as an environment for the native and local species is just as important as fixing flooding.
Associate Professor of Anthropology and Environmental Studies Dr. Eunice Blavascunas believes Walla Walla’s connectivity with the floodplains can also be greatly improved.
“Walla Walla absolutely needs more floodplain connectivity and improved habitat for fish passage. The history of regulating water for agriculture over the last 170 years has left us with incised river channels that have lost their connectivity with the floodplain,” Blavascunas said.
Improving the water system will not only affect the bodies of water in question, but will also have spillover effects to wildlife and the ecosystem writ large.
According to the Environmental Protection Agency (EPA), water system improvements are multifaceted.
“[Improvements include] nutrient cycling, carbon storage, erosion/sedimentation control, increased biodiversity, soil formation, wildlife movement corridors, water storage, water filtration, flood control, food, timber and recreation, as well as reduced vulnerability to invasive species,” said the EPA in educational materials on healthy watersheds.
Due to the current financial stall, the Mill Creek Development Plan has come to a halt.
According to Walla Walla County, construction was intended to run from Nov. 30, 2020 to January 2021 but plans remain delayed.
Alongside the Mill Creek Development plan is the Floodplains by Design project. This project is mainly focused on floodplain connectivity as its main priority. This project will improve floodplain connectivity through moving floodplains to areas where they have historically existed and away from infrastructure.
All three projects, the Mill Creek Development plan, the Mill Creek Watershed plan and Floodplains by Design, are interconnected and each stress the importance of water maintenance.
