Solving Odor and Corrosion Problems with New Technology - City of Sebastopol Laguna Force Main Rehabilitation 
Green Valley recently completed a project for the City of Sebastopol that included its share of challenges and new technology. The challenges included avoiding seasonal wetlands, crossing State Highway 12, and working under the jurisdiction of at least six different municipalities and regulatory agencies.

Green Valley met these challenges by incorporating trenchless pipeline construction methods with horizontal directional drilling under the wetlands and jacking and boring under State Highway 12 as well as utilizing a Vortex Flow Insert (VFI) to reduce hydrogen sulfide corrosion.

The City of Sebastopol had been exploring methods to reduce hydrogen sulfide (H2S) off-gassing in its wastewater prior to discharging. Hydrogen sulfide is an odorous gas that impacts air quality and corrodes concrete and steel components in the sewer system. A Vortex Flow Insert (VFI), a specialty product manufactured by IPEX, was installed. VFI's have no moving parts and require no maintenance and have delivered significant cost savings in installations across North America. The City is delighted that this more environmentally solution eliminates the need for costly chemicals and also offers its community improved air quality. Click here to learn more about the VFI (PDF).

The project required the replacement and/or rehabilitation of over 6,000 lineal feet of 14-inch diameter sewer force main. Green Valley chose to design the project in two segments to allow for the force main to remain in service while new sections were constructed and/or rehabilitated. As a fast-track design project, additional aspects of the project included tie-in points on an existing pump station, casing information, and pressure transducer and valving. Utilities investigation and coordination was a critical component to this project as the alignment crosses over a fiber optic line and a 48" County Water Agency aqueduct as well as several 42" and 48" reclaimed water mains that run to the Geysers.

Green Valley's construction management and inspection team worked closely with North Bay Construction and City staff during the construction of the Force Main. It was a complicated project that necessitated intricate scheduling and organization in order to meet production and project deadlines. Change orders were less than 2% of the total project cost.

"The assistance provided, and positive working relationship throughout this project made for a very pleasant working experience. Thank you all for your great work." Brendan Smith, Project Superintendent North Bay Construction

Pierson Reach Pedestrian Bike Path, Santa Rosa   
Winner of 2005 CELSOC Engineering Excellence Award
This half-mile-long path connects Santa Rosa's "historic" Railroad Square with the City's downtown area. Pierson Reach is an urban design and restoration project that stretches along Santa Rosa Creek and allows the community to enjoy the lush creek and riparian ecosystem within the natural environment. The overall Santa Rosa Creek Master Plan envisions that adjacent property owners will reorient their buildings towards the creek where public gatherings, art exhibits, and pedestrians will utilize the pathways and enjoy the natural habitat of the area. Green Valley Consulting Engineers provided complete structural and civil engineering services for this recently constructed project. As a part of design, extensive permitting was required from six separate agencies.

Sonoma County Regional Parks-West County Bridge 
The West County Trail Bridge Phase 2b project is a bridge over the Santa Rosa Creek that links the Prince Memorial Greenway with the Joe Rodota Trail. Green Valley was the Project Engineer/Manager and provided hydrology/hydraulic calculations to set the chord elevation of the prefabricated truss bridge as well as designing the bridge abutments and connections. Green Valley also designed the civil site improvements for the circular connecting focal point on the north bank, in conjunction with a landscape architect Don McNair. In addition, Green Valley provided construction staking services for this project and was responsible for extensive permitting with the Sonoma County Water Agency, City of Santa Rosa, Dept. of Fish and Game, US Army Corps of Engineers. Extensive soil remediation was required due to contamination.

R4 Effluent Storage Reservoir, Sonoma  
The project scope included a 300 acre-feet earthen reservoir designed to California Division of Safety and Dams regulations, a 2,700-gpm pump station with associated electrical controls and telemetry, piping, valves, flow meters and a cathodic protection system. The design of the storage reservoir required earthen embankments 18 feet in height, an impermeable flexible membrane liner, and a separate groundwater pump station used to alleviate high ground water problems. The additional storage provided by the reservoir will allow our client to decrease discharges to surface waters during critically wet years and provide additional reclaimed wastewater to area vineyard owners for irrigation purposes.

Mendocino Avenue Water and Sewer Main Rehabilitation 
The Mendocino Avenue Water and Sewer Main Replacement was an extensive reconstruction project which included the replacement of 100-year old water and sewer mains, including the upgrade to 12" water mains with new fire services on a 4-lane major thoroughfare through 4 signalized intersections.

Construction staging was critical as Mendocino runs thru the heart of the downtown commercial and retail center of Santa Rosa, as well as serving multiple high rise residential complexes. Over 19,000 thousand motorists use the thoroughfare on a daily basis. To facilitate construction, a detour plan was made to convert the Avenue to one-way traffic. Extensive staging and traffic control plans were created by Green Valley for the turnover.

The street reconstruction included stamped and colored asphalt concrete at key intersections and ADA upgrades of pedestrian ramps at all intersections.