Sea Level Rise Will Make Oregon’s Existing Flooding Problems Worse

January 31, 2018 | 9:23 am
Kristy Dahl
Principal Climate Scientist

In 2013 Annie Pollard opened her pub, the 7 Devils Brewing Co., in Coos Bay, Oregon. Less than two years later, the pub flooded during a heavy rain that coincided with a high tide, and Pollard found herself stacking sandbags and mopping up floodwaters. While high tide flooding is relatively infrequent in Coos Bay, when it does occur, businesses like Pollard’s are at risk, and inundated roads cause traffic in town to snarl. Pollard and other business owners are acutely aware that such floods could become a much bigger problem for Coos Bay in the future.

Sea level rise in Oregon

The hot spots of sea level rise in the US tend to be located on the East and Gulf Coasts, where sinking land and changes in ocean circulation are amplifying the global sea level rise rate. But when we take a deeper dive into our interactive maps of chronic flooding due to sea level rise, it’s clear that small but significant areas within many of Oregon’s idyllic coastal towns–Coos Bay and Tillamook, for example–are also at risk of chronic inundation in the coming decades. And residents of coastal Oregon like Annie Pollard are considering what that means for their homes, businesses, and communities.

Life in coastal Oregon

The Oregon coast is dotted with small towns that contribute to the state’s economy. “A lot of port facilities are right at sea level,” notes Bill Bradbury, the former Secretary of State of Oregon, and they are “definitely part of the economic infrastructure along the coast.” In Tillamook County, in northern Oregon, fertile lands for agriculture sustain, among other businesses, the Tillamook Cheese Factory.

These industries are intimately connected to the water. Regular flooding of Tillamook, for example, helped to make the land as fertile as it is today. And a network of seawalls and other structures have held back the sea since the 1800s in order to maintain the land for agriculture.

Residents of Oregon have noted, though, that the state’s traditional coastal industries have changed in recent decades. Bradbury speaks of how his hometown of Bandon, with about 3,000 residents, used to have a sizeable fishing industry, but it has since declined. Similarly, Pollard has noted that declining fisheries and the reduction of old growth forests caused an economic downturn that transformed Coos Bay from a working community to one that caters more to retirees. And the region’s oyster industry has had to adapt to the fact that ocean acidification is making it harder for oysters to grow. Sea level rise is poised to bring additional changes to Oregon’s coast.

Flooding in coastal Oregon today

Annie Pollard’s experience with flooding in Coos Bay a few years ago is mirrored by that of other residents and business owners in the state. When coastal Oregon floods today, it tends to result from heavy rainfall (typically in the winter months) exacerbated by high tides that prevent the water from draining into the ocean.

Floodwaters made railroad tracks in Coos Bay unusable in January of 2015.

In the town of Tillamook, such flooding, which occurs every 2-3 years, affects Marcus Hinz’s kayaking business, Kayak Tillamook. Hinz notes that his customer base declines in the wake of a flooding event. Most of his customers come from the I-5 corridor (southern Washington, central Oregon, Idaho). A single flooding event can scare customers away for the season, even if Hinz’s company is operating normally within a couple of weeks of the flood. “Our small company doesn’t have marketing to compensate for the news,” Hinz says.

In the wake of a flooding event Hinz and his staff have to re-scout the waterways, because each flood changes the flow of water and the dynamic of Tillamook Bay. And in 2015, he lost all three of his company’s vans due to flooding. The company is just now regaining its footing.

A similar dynamic with high tides that prevent heavy rains from draining takes place in the Coquille Valley, located inland of Bill Bradbury’s hometown of Bandon. This broad, low-lying region is connected to the Pacific by the Coquille River, which drains out from the Coast Range. The Valley is primarily agricultural land–cattle and sheep graze there, and hay is grown for livestock.

“The Coquille Valley floods almost every winter,” says Bradbury, but that flooding could become much more frequent within the next 15-20 years.

When will Oregon face chronic flooding?

UCS’s 2017 When Rising Seas Hit Home analysis shows that by 2035, with a moderate rate of sea level rise, parts of the Coquille Valley that do not see any flooding today could be flooding, on average, every other week simply due to higher sea levels. By 2060, the flooding would be even more extensive.

In Coos Bay, again with a moderate sea level rise scenario, an increasing number of streets could see flooding during high tides by 2035, and significant portions of the town could see flooding by 2060.

These results suggest that sea level rise could have a significant impact on Oregon’s coastal towns. More frequent flooding could, for example, affect the ability of business owners like Annie Pollard and Marcus Hinz to reliably operate and draw customers. And more frequent, widespread flooding of the Coquille Valley could challenge agricultural production in the area and exacerbate existing tensions between those who would like to maintain the land for farming, and those who want to restore low-lying areas to wetlands.

“We’re all going to have to get creative”

Marcus Hinz has witnessed some of the challenges associated with building resilience to sea level rise in Tillamook. In 2011 the community approved the Southern Flow Corridor project, which aims to create a corridor for water flow between Highway 101 and Tillamook Bay. While the ecological and flood mitigation benefits are clear, it has also meant buying land from farmers that will be restored to salt marshes, something that Hinz says has been difficult for landowners. And as the area adjusts to a new flow regime, the slough systems will change, as will the routes available for Hinz’s customers. “We’re all going to have to get creative,” he says.

Farther south in Coos Bay, Annie Pollard notes that local business owners are looking toward a future in which flooding is going to worsen, and that reduces their willingness to make financial investments. Many of the older building in Coos Bay are “beautiful and serviceable,” Pollard says, but are unlikely to be in the future. And while businesses currently have flood insurance, in order to maintain that insurance every renovation has to be carried out according to new standards, at high cost. So, Pollard reports, business owners are choosing not to upgrade their existing properties.

From ensuring that upgrades to existing infrastructure are affordable, to developing scientifically sound plans to improve water drainage that also respect existing communities and landowners, Oregonians are already grappling with the multifaceted challenges that resilience-building presents. And in cases like the Coquille Valley, solutions that accommodate floodwaters will become critical because, as Bradbury puts it, “You can’t build a wall to keep the water out of a place like the Coquille Valley.”

Getting ahead of climate change

The results of our When Rising Seas Hit Home analysis show that taking swift action to reduce carbon emissions could spare hundreds of communities from experiencing chronic flooding. Oregon is one of the nation’s leaders when it comes to addressing climate change. More than a decade ago, the state pledged to reduce its carbon emissions by 30% by 2020. And the state has undertaken important steps such as developing a complete inventory of local flood control structures, many of which were built in the 1800s.

After nearly a decade of decreases, emissions in Oregon (blue) ticked slightly upward in 2014. Projections (red) show state emissions to be off track to meet reductions goals (yellow).

But a report released last year by the Oregon Global Warming Commission notes that statewide emissions have been rising in recent years and that without additional actions, the state will not meet its 2020 emissions reductions goals. And it will take time and careful research into which flood control structures are helpful and which potentially exacerbate existing flood issues before local flood resilience measures can be implemented.

Oregon may not be a hotspot of sea level rise. And because it will take decades for the benefits of emissions reductions to be felt, today’s business owners like Annie Pollard and Marcus Hinz may not benefit from such reductions themselves. But for the towns of coastal Oregon to continue to be dynamic, thriving places for the next generation of entrepreneurs and residents, the case for building resilience to flooding and reducing carbon emissions is clear.