City Councilor and Arkansas River Infrastructure Task Force Chairman G.T. Bynum speaks during this morning's meeting. KEVIN CANFIELD/The Frontier

City Councilor and Arkansas River Infrastructure Task Force Chairman G.T. Bynum speaks during a recent task force meeting.

The 49th Street low-water dam included in City Councilor G.T. Bynum’s latest Arkansas River infrastructure proposal needs six months to a year of vetting before it can be determined whether the dam is feasible and how much it would cost, officials familiar with the project have told The Frontier.

The officials spoke on the condition of anonymity.

The fate of the dam is important because city councilors and the mayor have indicated they plan to include low-water dams in the Vision 2025 renewal package that is expected to go to voters in April 2016.

Without hard numbers on the dam — or any certainty as to whether it can be built — placing it on the ballot could be problematic.

The latest dam proposal has not formally been vetted by the task force’s engineering working group.

Bynum is chairman of the Arkansas River Infrastructure Task Force, which has been working for more than 18 months to come up with a plan to build low-water dams in the Arkansas River.

He said Monday that it is “not true at all” that it would take a year to nail down the details on the 49th Street dam, noting that it took the task force six months to determine the cost of the Sand Springs, south/Tulsa Jenks and Bixby dams.

He also noted that the dams under consideration have been included in previous river-development proposals.

“The difference this time is we’re not doing things half-baked as opposed to how people have done them in the past,” Bynum said.

The task force’s initial proposal, presented at town hall meetings earlier this summer, called for building dams in Sand Springs, south Tulsa/Jenks and Bixby and overhauling Zink Dam in Tulsa. The proposal also included a maintenance endowment and matching funds for levee improvements. The estimated cost was $298 million.

Soon after the last town hall meeting, Bynum sent an email to area leaders scrapping the original proposal. Instead, he suggested a phased approach that calls for first building dams at approximately 104th Street and Riverside Drive (the south Tulsa/Jenks dam) and 49th Street and Riverside Drive, overhauling Zink Dam and improving the levee system.

The Sand Springs and Bixby dams would be included in Phase 2.

Bynum said at the time that he was responding to the public’s concern that Tulsa was being asked to pick up most of the cost of the dams while not having a true sense of the project’s return on investment.

The phased approach would give Tulsans a chance to show that dams could be built properly and in a cost-efficient manner before asking other communities to invest millions in the project, Bynm said.

The 49th Street bridge would address another concern of residents, Bynum told The Frontier last month, about water levels between Zink Dam and the south/Tulsa Jenks dam.

“When people think of ‘water in the river,’ they think of continuous water, not two lakes five miles apart,” Bynum said at the time.

Bynum made the same point Monday, saying his suggestion was just one for getting more usable water within the city of Tulsa.

A low-water dam upstream of the Interstate 44 bridge – at approximately 49th Street – was one of eight potential dam sites identified in the 2005 Arkansas River Corridor Master Plan. Five of the dams, including the one near the I-44 bridge, were designated as feasible based on hydraulics and their potential effect on water quality.

However, no detailed studies of the 49th Street dam exists.

Proposed Phase 1 low-water dams. Click on image to enlarge.

Proposed Phase 1 low-water dams. Click on image to enlarge.

Construction of a low-water dam at 49th Street could be complicated by the fact that it would be built just upstream from the Southside Wastewater Treatment plant, whose effluent enters the river at about 51st Street, directly south of the Interstate 44 bridge, officials familiar with the project say.

The location of the wastewater plant makes it impossible to move the dam further south because the plant’s effluent must discharge downstream from the dam “to minimize water-quality impacts to the pool” of what it would create, according to the Master Plan.

Odor from the wastewater plant is also a concern. The odors have been reduced since the Master Plan was approved but have not been eliminated.

As currently envisioned, the 49th Street dam would create a shallow, 1.2 mile-long lake going back to about 37th Street. The fear, according to officials, is that if the water backs up too far upstream, it would negatively impact the wildlife habitat there. That would prompt the need for extensive and costly mitigation.

Another complicating factor is that mitigation work is already planned in the river at approximately 31st to 36th streets as part of the construction of A Gathering Place For Tulsa. How mitigation related to the 49th Street dam would affect that project is unknown.

Bynum said those issues and any others task force members may have will be discussed at Thursday’s meeting.

As opposed to a few people making decisions behind closed doors, as has happened previously, the task force’s entire process has been a transparent one, Bynum said.

“The trade-off is this messy, lengthy, deliberative process to finally put something together,” he said. “It looks chaotic, I’m sure. But that is the nature of the vetting process.”