The "living river": Can you dig it?

NOTE: Thursday morning, former Tulsa street commissioner Jim Hewgley and I will be on Studio Tulsa on KWGS 89.5. The show will air at 11:30 a.m. and 7:30 p.m., and a podcast will be available, which I will link here.

Did you know that next week's Tulsa County sales tax vote includes money to excavate bedrock beneath a four mile stretch of the Arkansas River? That's according to a statement made by Jean Letcher, campaign manager for the pro-tax campaign.

It was on a Studio Tulsa program that aired on October 24, 2006, an interview with Canadian architect Bing Thom, that we heard the first inklings of the plan that we will be voting on next week. Thom was talking about his work for the George Kaiser Family Foundation and mentioned pedestrian bridges at 41st and 61st and "theming" the river, ideas that aren't in the Arkansas River Corridor Master Plan, but will require most of the $282 million in the proposed Tulsa County sales tax.

When the "living river" notion was mentioned at the end of June, when the Kaiser / Thom plan was unveiled, and lobbying began to get the plan funded through county sales tax, I assumed that the $90 million "living river" -- narrowing the flow of water south of 31st Street to create a more constant stream -- would be implemented using wing dams. Steve Smith, who used to run airboat tours on the river, introduced me to the idea last September:

The river's flow can be directed and improved to create recreational opportunities--wing dams, for instance, which extend only part of the way into the river, can be used to direct the flow of the river to scour out a central channel, which is also less prone to sediment build-up because of the faster current.

Sand would build up behind the wing dams, which would create areas that could be used like many of our stormwater detention areas--a recreation space during normal conditions, but open to carry flood waters when needed.

This kind of dam, used to create a very narrow waterway near the PSO plant at 31st St. on the west bank of the river, for instance, is responsible for the existence of the Tulsa Wave, considered to be the best kayaking spot between the Rockies and the Appalachians. A wider gap between wing dams in other parts of the river would provide a tamer current for the rest of us to enjoy.

Smith's idea was to use wing dams all up and down the river, to allow navigation along its full length through Tulsa County, rather than the low-water dams that are being proposed.

At Tuesday night's Council District 2 forum on the sales tax, someone asked about the "living river" and I began to explain and describe wing dams (although I couldn't remember the term). But Jean Letcher stopped me and said I was incorrect: Wing dams would not be used for the living river.

Letcher said that a channel would be excavated into the bedrock, beneath the sand, with the idea that the water would flow into this deeper channel.

That would explain why this "living river" is the most expensive item on the ballot. I asked Letcher if core samples had been done to check the underlying geology. She said no.

I have been told that the bedrock under the river is checkerboard limestone. It's visible near the surface at the 11th Street bridge and about 1/2 mile south near the spring on the McBirney grounds. These outcrops served as natural fords for cattle and horses and, at low water, people on foot. It's buried under sand elsewhere along the river.

I've also been told, by Bill O'Brien, who has researched the history of the Arkansas River in this area, that in 1907, a chasm opened up beneath the riverbed near 61st Street. There was a noticeable drop in the river's level at Muskogee, and it was eventually discovered that some of the river was draining into this subterranean void. I assume the void eventually filled to capacity, or perhaps collapsed in on itself, and the river returned to normal.

I know that limestone is susceptible to cave formation; I don't know if this particular kind is more or less vulnerable.

Digging into bedrock opens up questions of trapped contaminants (oil seepage from decades past), breaching or modifying the water table, and changing the local ecosystem drastically. I'd have thought wing dams would have been a much less intrusive, more gradual way to accomplish the same goals.

(A 1999 study on groundwater vulnerability by the Oklahoma Water Resources Board ranked the Arkansas River river bed as an area of "very high" vulnerability to groundwater pollution.)

That I'm just hearing about this a week before the election again points to how this plan has been rushed forward. If the same process was being used that was used last year for evaluating The Channels, there would have been time to make the public aware of these details and for committees of experts to evaluate the details for environmental and hydrological impact.