Published on March 15th, 2016 |3
DWM Commissioner’s Peachtree Creek Tunnel cost rated ‘Pants On Fire’
The Commissioner of the Department of Watershed Management stated during the March 9 City Utilities Committee workshop that a Relief Tunnel for Peachtree Creek to eliminate sewage overflows in Memorial Park/Bobby Jones Golf Course would 1) not be effective, 2) cost between $500 million to $2 billion, and that 3) lining the 100-year-old Peachtree Creek trunk sewer would provide structural integrity.
decided to analyze DWM Commissioner Jo Ann Macrina’s statements in response to questions by Council Member Yolanda Adrian and in response to a proposal by Council Member Mary Norwood that the DWM consider a Peachtree Creek Relief Tunnel similar to one at Nancy Creek.
As BuckheadView readers may recall, Norwood championed a relief tunnel for the Nancy Creek trunk sewer in the early 2000’s to relieve chronic sewage overflows caused by development in Buckhead and Sandy Springs. The project was completed in early 2006.
As for Peachtree Creek, BuckheadView recently included commentary about potential solutions for sewage overflows, much of that discussion focused on a Peachtree Creek Tunnel as a solution similar to Nancy Creek.
In response to Council Members Adrian and Norwood asking why DWM was not considering replacing the 100- year-old overflowing trunk sewer and replacing it with a tunnel similar to Nancy Creek Macrina stated:
“Because it is a very different situation than Nancy Creek, very different. So you can’t use the same solution if the situation is different….The same solution that you put into Nancy Creek is not going to work here. It is not going be effective because it is a different situation…There are different issues different technical issues that we know will not be effective and so we don’t want to spend between $500 million and $2 billion on one storage facility in Peachtree Creek when it will not be effective.”
Instead of a capacity relief project, Macrina advocates rehabilitation of the existing pipe stating:
Is it true a Peachtree Creek tunnel alternative would “not be effective” as stated by Macrina?
In 2008, the DWM completed a report titled Draft Peachtree Creek Basin SSO Remedial Measures Plan. The Report included a number of tunneling alternatives that would either connect directly to the RM Clayton wastewater treatment facility or to the Nancy Creek Tunnel at a shaft location upstream of RM Clayton.
The Report clearly states that a tunneling alternative is the preferred alternative. “Therefore, implementation of one of the C alternatives (tunneling options) is more attractive….For an approximately 25-year level of service alternative C1 (deep tunnel design) becomes the recommended alternative with an associated cost of $222 million.”
Would a Peachtree Creek tunnel cost between $500 million and $2 billion as stated by Macrina?
Macrina stated that a Peachtree Tunnel alternative would cost between $500 million and $2 Billion. Norwood asked for the backup data on the estimate, which BuckheadView looks forward to reviewing.
The 2008 DWM Report included estimates of between $180 million to $260 million, which probably included significant contingency for unknowns.
While BuckheadView understands that costs today will be higher than in 2008, inflation has been benign for many years, so the difference between Macrina’s statements and DWM reports cannot be justified.
Would sewer rehabilitation be an effective method for eliminating sewer overflows in Memorial Park/Bobby Jones Golf Course, as implied by Macrina?
Macrina states that an unspecified technology will provide structural integrity to the existing pipeline.
While presumably an investment of $30 million to recondition a 100-year-old sewer pipe would in fact enhance the structural integrity of the sewer, the answer was in response to a different set of questions. The questions were focused on resolution of sewage overflows in Memorial Park and Bobby Jones, not the structural integrity of the pipe.
The 2008 DWM Report also discusses results of hydraulic modeling of projects involving only rehabilitation:
“Eliminating capacity limitations in the Peachtree Creek Basin trunk and outfall system solely through sewer rehabilitation was investigated using the hydraulic model…. The model results show that using an achievable level of I/I reduction does not eliminate all capacity limitations in the Peachtree Creek Basin. As such, this alternative is eliminated from future consideration.”
This would indicate that lining the sewer to eliminate infiltration and inflow (I/I) to provide structural integrity will not resolve the chronic sewage overflows in Memorial Park and Bobby Jones Golf Course. The issues appear to be unrelated.
Generally, we believe Macrina’s statements lack factual support. A Peachtree Creek Relief Tunnel was the preferred alternative in a DWM Report completed in 2008. The cost estimate provided by Macrina in the City Utilities Committee meeting was two- to four-times higher than the most cost estimates provided by DWM Consultants to DWM.
Macrina’s implication that sewer rehabilitation will solve sewage overflows (in addition to raising manholes) also lacks factual support (if in fact Macrina was addressing the Council members’ questions of how to solve sewer overflows rather than making an engineering observation about an unrelated question).
We judge Commissioner Macrina’s statements to be UNTRUE and UNRELATED to questions posed by City Council members as to how to solve chronic sewage overflows in Memorial Park and Bobby Jones Golf Course.
As for her cost estimates for a Peachtree Creek Relief Tunnel, we rate her statements PANTS ON FIRE.