I-5 bridge needs wider options

Earlier this week I posted about a forum scheduled for January 4th, 2007, concerning the Columbia River Crossing (CRC) task force, which is charged with making recommendations about a possible replacement for the I-5 bridge between Portland and Vancouver.

One of the co-sponsors of that forum is Friends of Clark County, a non-profit group that works on "smart growth" issues.

The CRC task force received staff recommendations (PDF file) in late November. According to the executive summary, staff proposes advancing three options to the DEIS (Draft Environmental Impact Statement) process.

The three options are the required "no build" option, build a new bridge with bus "rapid transit" or build a new bridge with light rail. So more creative ideas are in the process of being rejected, or so it would appear.

Lora Caine, the president of Friends of Clark County and someone I worked with during my days as a volunteer for Washington Conservation Voters, was kind enough to respond to some email questions I posed to her recently. Her response was so informative that I wanted to post it here, with her permission. By way of explanation, she's following up a series of emails where I had inquired about the "no-build" option, which as I understand it would be required to seek federal funds.

The only way "no build" would happen is if there were absolutely no money to build the project, and not for a very long time. The study still wouldn't end up with "no build" as its recommendation but would be shelved giving it a defacto "no build" ending.

The U.S. Coast Guard is a permitting authority - meaning they have a say whether this project gets built or not. Any new bridge placed in the river will need to have their approval of safety for marine traffic.

The marine channel right now is not deemed the safest as it is laid out in an "S" curve. The railroad bridge downstream has a swing span close to the Washington shore and the I-5 bridges have the lift span more in the center.

Any bridge built between would place pier supports in the river for marine traffic to navigate. If the bridge is closer to the I-5 bridges (assuming they would be left in place), then the piers could match the current pier supports. If the bridge is built near the railroad bridge then the bridge would have to match the channel there but be far enough away to avoid the swing of the bridge.

Likely, the U.S. Coast Guard would want to have a new bridge that incorporates the rail lines if the decision were to place the bridge addition that far downstream - thus avoiding more hazardous marine navigation. Adding railroad lines to the supplemental bridge builds a bigger bridge similar to the proposed replacement bridge. Adding light rail would also make it wider. All bridge options include bike and pedestrian lanes, too.

Three problems with a bridge further downstream that I see: 75% of the peak hour traffic in the 5 mile stretch of I-5 gets on and off within that area. A bridge further downstream would not necessarily alleviate the current traffic. Second, a bridge downstream near or even below the railroad bridge would connect to the Portland side - for what purpose? To make it even easier to work in Hillsboro/Beaverton and live in Clark County - the continued bedroom community of the future?

Third, freeway connections to return to the I-5 corridor from the new bridge will entail impacts to homes, businesses and industry - just the same as building a replacement bridge next to the current bridges. No easy solution, huh?

One area planning expert suggested adding lanes between the bridges. The bridges would need to be lifted, as he suggested, or the new lanes would need to be incorporated into a new span lift configuration. The bridges were not engineered to add the extra weight of more lanes (as staff pointed out from my question).

Lifting the bridges would also be costly in my estimation as anything done to the bridges like that will also require retrofitting them for seismic safety - more costs to be borne. And getting the traffic onto a new bridge before lifting the piers would also mean the need for at least the same capacity on the new bridge as is available now. Freight movement is a big piece in this complex puzzle necessitating the need for at least the current capacity. All this will take years, of course.

I can see advantages in every suggestion and problems, too. That's why I am not ready to decide how to vote. I DO want the low cost option in the final study even if it is to get the staff to try to be careful and frugal in their cost estimations for the final options.

As I've stated before, I don't envy the CRC folks their task. We don't want to viaduct this thing to death.

But if 75% of the traffic comes from the area near the bridge, it might be worth preserving for study the option of some kind of "local use" bridge, most likely the current spans. I'm certain there are problems with that idea as well (like what is to be done about Hayden Island impacts,) but hey, that's why we study things, isn't it?

Here's a link to a page about the forum from the Coalition for a Livable Future.