The city of Bend has nearly completed a plan that includes 58 new projects and could cost an estimated $25.2 million to decrease flooding due to storm runoff around the city over the next 20 years.
Bend Engineering and Infrastructure Planning Director Tom Hickmann said on Monday that most of the projects are small.
“The majority of them, each one seems like not that big of a deal,” Hickmann said of the projects, which include structures to capture stormwater and well holes to allow water to drain into the ground. “But if you go talk to homeowners in any of those areas that currently get impacted by storms, they would say it’s a big deal.”
The plan would result in the monthly residential stormwater fee, which is currently $4, increasing to as much as $6.80 over the next 20 years, depending upon how quickly the city implements the rate hike. Non-residential utility customers pay $4 per 3,800 square feet of impervious surface area, such as a parking lot, Interim Finance Director Sharon Wojda wrote in an email Monday. The City Council is scheduled to vote on the plan at a 7 p.m. Wednesday meeting.
City design standards now require all new development projects to be built in such a way that runoff from major storms will be contained onsite, such as through small landscaped areas where water can filter into the ground.
One large project included in the plan would address flooding problems at the NW Franklin Avenue underpass, below the railroad tracks. However, Hickmann said frequent maintenance has brought those problems under control, and the city will continue to monitor whether it is necessary to proceed with major improvements at the site.
The list of projects does not include any new treatment or filtration for storm runoff that still empties untreated into the Deschutes River from some points in the city’s stormwater system. Instead, the plan calls for the city to continue monitoring water quality to determine the impact of storm runoff. This water transports sediment into the river, and it also contains nutrients that can encourage the growth of algae.
“This can result in algae-filled channels, odors from decomposing algae, and reduced dissolved oxygen and pH levels,” consultants wrote in the stormwater plan. “Oxygen is taken up in the decomposition process, reducing its availability for fish, insects, and other aquatic life.”
The Oregon Department of Environmental Quality is currently developing water quality rules that could affect the city’s ability to continue discharging untreated storm runoff into the Deschutes River. DEQ staff involved in the effort were unavailable for comment on Monday.
The city never had a plan to manage the stormwater network that included a small system of pipelines that drain into the Deschutes River and roughly 5,600 well holes where storm runoff drains into the ground across the city. Approximately a decade ago, new Environmental Protection Agency rules forced city employees to better understand their stormwater system and plan for its future, Hickmann said.
At first, it appeared the city faced expensive investments, as much as $172 million to $214 million, according to a city staff report. However, Hickmann said Bend officials eventually decided to place the planning effort on hold, because the regulations continued to change so rapidly that drafts of the plan kept becoming outdated before the city could complete it.
“We finally said, ‘Look, let’s see what the final rules are,’” Hickmann said. The city restarted the planning effort approximately a year ago.
Meanwhile, the city formed a stormwater utility in 2007 and began to charge a stormwater fee to utility customers, “which essentially then gave us the resources to start complying with these new rules,” Hickmann said.
The fee revenue allowed the city to improve its maintenance of the well holes into which storm runoff drains. Previously, the wells often became clogged, and that caused flooding. The majority of stormwater fee revenue still pays for maintenance of the wells, Hickmann said.
So far, the largest stormwater capital project was the $3 million in work in 2013 at the Third Street underpass, which used to frequently flood. Hickmann said the city also began to filter some — but not all — of the storm runoff that flows from pipes into the Deschutes River since adopting the stormwater utility fee in 2007. Pipes dump stormwater into the river at 28 separate locations.
The pace of work has been slow because city officials do not want to issue any debt to pay for stormwater projects, something they regularly do for other major work . “We only collect a little less than $500,000 a year that we can apply to these capital improvement projects,” so it took years to save enough to pay for the Third Street project, Hickmann said.
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