Nisqually Delta

The Nisqually River Delta runs beneath I-5 south of Lakewood. The delta faces two significant environmental problems: salmon health and flooding.

I-5 over the Nisqually River Delta is a liability to the environment and to regional transport.

The interstate’s current design may be compromised by flood or the wandering riverbend at Wah-He-Lut within 20 years. Salmon populations are also suffering, as the areas where salmon typically acclimate to seawater are shrinking and desalinating.

The Nisqually Indian Tribe and the City of Lakewood, among other agencies, hired the U.S. Geological Survey to examine the highway through the delta. Within 20 years under normal conditions, concluded USGS, I-5 may be compromised. In an avulsion event from a flood or sudden acceleration of erosion, that timeline may be even shorter.

r/Tacoma - Nisqually River Delta & I-5: Environmental and Structural Issue Brief

The riverbend at Wah-He-Lut has crept closer to the highway since 1997

David Troutt is the Natural Resources Director for the Nisqually Indian Tribe. Since 1997, he’s been advocating for a redesign of I-5 over the Nisqually River Delta. He’s watched as salmon populations have diminished and as the river adjusts its path around man-made barriers.

“To give you a sense of the urgency here, when I started back in 1987, we were fishing for 105 days a year from July through February… By 2015, the number of days had reduced from 105 to 8.”
David Troutt, Natural Resources Director, Nisqually Indian Tribe

To reconstruct I-5 through the delta may cost roughly $4 billion, which would be among the most expensive infrastructure projects in state history.

When I-5 closes, it chokes the region. We all remember the effects of the 57-hour closure after the Amtrak derailment in 2017.

We’re also watching the effects of climate change unfold before our eyes. Historic flooding has overwhelmed Bellingham. What were once 100-year flood events might now be 50-year flood events. As recently as 1996, flooding devastated the delta.

One day soon, as a result of natural erosion in 20 years or as a result of a flood even sooner, I-5 will be a big problem.

The City of Lakewood, the Nisqually Indian Tribe, and the South Sound Military & Communities Partnership (SSMCP) all support legislative action to prepare for the redesign and reconstruction of this section to respond to environmental and structural issues looming ahead.

More Information Coming Soon…


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