Bellingham's Iowa Street has a flooding problem that city engineers have known about for years, and starting Monday, construction crews will finally begin addressing it at the source. The City of Bellingham is launching Phase 1 of its Iowa Street Stormwater Repair project on July 13, a $470,000 infrastructure investment targeting the chronic flooding that hits the I-5 interchange area during heavy rains.
For anyone who has navigated standing water near the Iowa Street off-ramps during a winter storm, or watched the intersection at Lincoln and Ohio Streets disappear under a gray sheet of rainwater, this project represents progress that has been a long time coming.
Contractor Dawson Construction will perform the work at night to limit disruption to daytime traffic, but drivers who use the corridor in the late evening and early morning hours should expect temporary closures and detour routes through mid-to-late July.
Why Iowa Street Keeps Flooding
The flooding near Iowa Street is not the result of one simple failure. It is the predictable outcome of three forces converging on the same point in Bellingham's street grid.
Geography is the first factor. Two large upstream drainage basins, one on Sunset Hill to the north and another covering Alabama Hill to the southwest, funnel enormous volumes of stormwater downhill toward the Iowa Street area during heavy rain. Those basins are among the largest in Bellingham's stormwater system, and the volume they generate during a major storm exceeds what aging pipes can efficiently move.
Infrastructure failure is the second factor. The stormwater pipes running beneath the Iowa Street corridor near I-5 have deteriorated significantly over time. Tree roots have infiltrated the pipes, narrowing their interior diameter and slowing flow. Some sections have partially collapsed, reducing capacity further. A system that was already undersized for the drainage area it serves has been made worse by decades of root intrusion and structural decay.
Whatcom Creek is the third factor. During prolonged or intense rainfall, Whatcom Creek rises and backs up into the storm drain system, a phenomenon called surcharging. When the creek is high and the pipes are already compromised, stormwater has nowhere to drain. It rises through catch basins and spreads across the road surface instead.
The 2021 atmospheric river events illustrated the problem vividly, flooding intersections in the corridor and affecting nearby properties. Bellingham's 2020 Surface and Stormwater Comprehensive Plan identified Iowa Street as a priority repair zone, and this project is one of the first major physical outcomes of that planning work.
What the $470,000 Will Fix
Phase 1 concentrates on two specific areas: the stretch around the southbound I-5 off-ramp at Ohio Street, and Lincoln Street between Kentucky Street and Ohio Street. Dawson Construction will replace deteriorated pipe sections, remove root intrusions, and increase the overall capacity of the stormwater system on the west side of I-5.
The $470,000 is funded entirely through Bellingham's Stormwater Maintenance fund, which is supported by stormwater utility fees collected from property owners. No new tax or bond measure is required.
Because the work zone crosses both city right-of-way and state highway property, Bellingham is coordinating with the Washington State Department of Transportation. WSDOT will assist with ramp access management on nights when work is active near the Ohio Street off-ramp. The city maintains a dedicated project page at cob.org/project/iowa-street-stormwater-repair with updates and contact information.
What Drivers Should Expect Starting July 13
All Phase 1 work is scheduled for nighttime hours. Most drivers who use Iowa Street during the day will notice no impact. The disruption will be concentrated on the overnight shift, when construction crews are active and sections of Lincoln Street and the Ohio Street off-ramp vicinity will be temporarily closed.
Detour signs will be posted throughout the work zone. Bellingham Public Works asks that drivers follow posted signage, allow extra travel time on affected nights, and watch for construction workers near freeway infrastructure.
The Phase 1 construction window is approximately two weeks, but timelines for underground work can shift based on what crews find when they open the ground. Unexpected pipe conditions, groundwater levels, or utility conflicts can add days. The city will update the project page as the schedule evolves.
A Day Shelter Connection Worth Noting
The Iowa Street stormwater project has a secondary implication that extends beyond traffic and drainage: the proposed day shelter site at 2020 Pacific Street sits in an area with documented flooding history. Advocates for the shelter have flagged water damage vulnerability as a concern, and Bellingham officials have indicated that the Iowa Street project improvements could help reduce flood risk at that location, making it more viable for long-term use as a human services facility.
It illustrates how infrastructure decisions ripple through a city in unexpected ways. Fixing a stormwater pipe under Lincoln Street has consequences not just for commuters navigating an icy wet intersection in January, but for the city's capacity to site critical services for people experiencing homelessness.
Phase 2: The East Side of I-5 Still Waits
Phase 1 addresses only the west side of I-5. The east side of the Iowa Street interchange has similar infrastructure problems, with aging pipes that contribute to flooding on that side of the freeway as well. Phase 2 will address those issues, but it remains in early planning with no firm start date announced. City engineers estimate Phase 2 is one to two years away.
That timeline reflects both the complexity of engineering work adjacent to an active freeway and the funding cycle for capital stormwater projects. Residents on the east side of I-5 near the Iowa Street interchange should expect existing flooding patterns to persist through at least one more major storm season.
For the west side, however, Phase 1 represents the most significant stormwater investment in the Iowa Street corridor in years. When the pipes are replaced and the capacity is restored, the next storm rolling off Alabama Hill will find infrastructure ready to handle it.
Residents with questions about the project, specific traffic impacts, or the detour schedule can contact Bellingham Public Works through the city's main website or the Iowa Street project page.
