Project GREEN, city discuss fate of Pittman Wash

Eleven people -- four city officials and seven members of Project GREEN -- sat around a square table Aug. 17 at the Silver Springs Recreation Center looking at schematics, reading memorandums, conversing over recommendations and discussing once more the fate of Pittman Wash.

The two entities have had several meetings over the past couple of months to discuss a potential project to put a concrete channel at the bottom of the wash . Project GREEN has collected more than 700 signatures from residents opposed to the project.

The project would address safety concerns, including an erosion problem at the bottom of the wash.

To receive funding from the Regional Flood Control District, the $4.5 million project must meet certain requirements, including being able to handle a 100-year flood .

Project GREEN gave the city two options for consideration: sheet pile protection and an articulated concrete block, which is a mat installed at the bottom of the channel that would work with vegetation to slow water velocity and prevent erosion.

A consultant firm, VTN, analyzed the alternatives and gave feed back.

For the concrete block, VTN said it had reservations about using this method because it wasn't confident in the ability to install the ACB system to create a stable surface. VTN also questioned the long-term reliability of the system and whether the design would protect against a 100-year flood.

In addition, the estimate for the ACB was $5.8 million. It also would result in higher yearly maintenance costs because of block repair.

VTN also determined that using steel sheet piles and large boulders to create drop structures would be difficult and does not recommend the design because of the high flow rates, narrow wash and the difficulty in protecting an existing sewer while driving sheet piles across the wash.

Robert Herr, the city's assistant director of public works, also presented a potential solution, which he said was a recent development and needed to be looked at more.

This option would relocate an existing manhole at the bottom of the wash to push the potential concrete channel design that the city proposed slightly to the side, making the project less intrusive on the wash.

There might be an extra cost to relocating the manhole.

"But if it is fairly minimal, it would be money well spent," Herr said.

Dennis Fritz, technical services manager with the city's utility services department, talked about the integrity of the sewer line, which has been exposed due to erosion.

Surprising many people in the room, Fritz took out a cardboard toilet paper roll to represent the sewer pipe, which was placed in the wash before the development that now surrounds it. The cardboard roll demonstrated how the pipe might look.

Fritz said the pipe is made up of pieces of plastic that were curled, mechanically snapped closed and welded shut, creating a seam.

"The material isn't bad," Fritz said, referring to the sewer pipe. "It is just susceptible to failure."

The riprap lining, the current solution that places large rocks at the bottom of the wash, is shielding the sewer pipe, but it doesn't solve the need for a permanent solution in the wash.

"The sewer was there before the houses," Fritz said.

Members of Project GREEN said neighbors in the area have asked about moving the sewer to keep the spring natural.

Fritz said if the sewer line was moved, it couldn't effectively meet the needs of the residents.

Project GREEN is slated to meet again before the next council meeting to discuss the new analysis.

"The ideal solution would be something the city, public works and utility services would agree on, as well as Project GREEN and the residents," Herr said.

Curt Chandler, president of Project GREEN, said the organization planned to discuss the city's proposals Aug. 24.

"I feel confident that we will be able to reach some sort of agreement," Chandler said. "The city has come a long way toward meeting our objectives, and we are quite pleased."

Chandler said that after the members of Project GREEN deliberate, they plan to discuss it with the city.

"We plan to get together and iron out the differences," Chandler said. "After that, I think it will go before City Council for a final resolution."

The issue is slated to go before the City Council at the Sept. 20 meeting.

Contact Henderson/Anthem View reporter Michael Lyle at mlyle@viewnews.com or 387-5201.