San Jose Outfall

The scope of this project entails a replacement of flow meters, weirs, and electrical upgrades to the San Jose Wastewater Treatment Plants outfall channel. Due to the location of this project (an artesian slough that drains to the bay) understandably there were strict environmental requirements to adhere to. For example, we had biologists performing bird nest monitoring, there were tide work windows, and open trench restrictions to name a few. The bulk of the work for this project can be broken down into 3 main scopes. First is the flow meter replacement. This involved excavating and shoring a pit between 2 live existing RCP outfall pipes. 3 CIDH piles were then drilled and installed between the 2 RCP pipes. A pile cap was then installed and a precast flow meter vault placed on the pile cap. The second main project scope was the weir upgrades. This involved installing a geogrid fabric inside the slough with the help of divers. New riprap was then placed on top of the fabric with a long reach excavator. Additionally, the old wooden weir boards were replaced with new aluminum weirs. This weir was not shut down for our construction so this work had to be done during a high tide work window with the help of divers. The third main scope of the project was to install a new transformer and 3,500 LF of concrete encased duct bank from the outfall station back to the main treatment plant.

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