| | Published January 30th, 2013
| Orinda Averts Sinkhole Calamity
Complete Tarabrook repair will take time and money
| | By Laurie Snyder | | |
The holiday season in Orinda became even more bustling than usual for residents when Mother Nature dumped heavy rains in early December, motivating an aging 24-inch corrugated metal pipe (CMP) to give up the ghost at the same time that a Contra Costa Sanitary District (CCCSD) sewer line failed on Tarabrook Drive near Evergreen Drive. The end result was an eye-popping sinkhole that prompted the Orinda City Council to declare a State of Emergency.
According to the series of related city staff reports, council members "directed staff to continue pumping storm water flows around the blocked pipe and to proceed with retaining a consulting engineer to design a permanent repair.... This option will protect public health and safety as well as public and private property by allowing storm water to drain safely and efficiently through temporary facilities in the short term while allowing the City the necessary time to design and construct an appropriate long-term solution."
Chuck Swanson, the city's director of public works, explained that Orinda's sinkhole is actually worse than its more famous cousin in Lafayette.
The use of $45,000 in Urgent Road Repair funds was approved by the council Dec. 7 to cover a temporary fix. Additional tweaks were needed to better manage storm flows and there are now several pumps to convey drainage around the blocked pipe. The city is responsible for operating the pumps, which are set to turn on automatically.
The permanent fix will require much more. A design engineer will be engaged "to evaluate the situation, develop a conceptual plan, prepare hydraulic analyses, make recommendations for replacement/repair, and prepare engineering designs and specifications for construction," according to the staff report. On Jan. 15, staff asked the council to approve an additional $100,000 to cover pumping expenses, including the related equipment rental until June 2013. Those supplementary funds will be drawn from Urgent Road Repair funds and General Fund unrestricted reserves. In addition, council was asked to approve two staff-recommended contracts with firms which will carry out the permanent repairs.
Harrison Engineering Inc. of Pleasant Hill was proposed as the designer of the Tarabrook Drive Stormwater Improvements Project after staff solicited proposals from 10 local engineering firms. Only one other firm - Nichols Consulting Engineers - opted to compete for the project. Harrison was chosen based on the firm's experience, planned approach to the problem, and ability to perform the services requested.
Lamphier-Gregory, the only firm to respond after another 10-engineering firm approach by staff for a separate contract, will manage environmental services.
City leaders project that Harrison's consulting fees will cost $99,000 plus $11,880 for oversight and administration by city staff - versus the rejected Nichols' estimate of $221,362.15. Lamphier-Gregory's fees are projected at $43,813 with a 10 percent contingency fee plus $4,381 for city oversight. All expenditures will be drawn from the General Fund balance.
Council praised city staff for its handling of the situation, thanking area residents for their kindness with deliveries of hot coffee and food to workers who were subject to miserably cold and wet conditions. Council members also expressed their desire to have repairs completed by fall 2013 before unanimously approving the contracts and funding outlays.
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Lamorinda Weekly, Moraga CA