Gossamer Grove – Shafter, CA

Project Details:

Lennar Communities wanted to construct a new, large housing development called Gossamer Grove in Shafter, California. This development has a master plan for hundreds of homes with access to all types of amenities, like parks, trails, schools, and commercial properties. This development will help bring new families to the City of Shafter while giving Lennar the opportunity to build and sell new homes in a fast developing area of California.

The City of Shafter has worked with Romtec Utilities on many lift station projects and recommended our services to Lennar and its engineer, Quad Knopf, to provide a wastewater lift station for the Gossamer Grove development. Due to the size of this development, the wastewater lift station required a variety of forward-thinking design features. These features would allow the capacity of the lift station to “scale up” with the growth of the neighborhood. To do this, Quad Knopf creating a construction schedule with phases that would coincide with lift station upgrades.

The total plan included 4 phases. The Romtec Utilities lift station would need to operate effectively and without interruption during every phase. The lift station needed to add on 1630 gpm of pumping capacity from phase 1 to the full build out. Additionally, the City wanted a control building for the electrical control panel and a future build site adjacent to the new lift station. The future build site will allow the City to one day replace the lift station with requiring demolition or bypass pumping. This is a great feature for lift station planning.


Romtec Utilities Scope of Work:

Romtec Utilities began the design process by working to understand the Quad Knopf plan to “scale up” the lift station. The plan included utilizing an existing gravity main with a temporary force main during the first phase of the lift station operation. Eventually, the gravity main would be phased out in favor of a new force main with larger capacity. Quod Knopf also favored an approach that would prevent any future digging requirements to upgrade the lift station for each new phase. Romtec Utilities began by establishing the end goal for the lift station and engineering backwards to a functional and reliable lift station.

Romtec Utilities engineers found the correct pumps to handle the eventual flow to the lift station. To prevent any need for retrofit work, Romtec Utilities then found a smaller pump capable of operating on the same discharge elbows. The phase 1 design include a triplex pump configuration of 7.5 hp Xylem pumps. Initially, just one pump is needed to handle the inflow of sewage, but in the end, this system can be upgraded to utilize a triplex configuration of 25 hp Xylem pumps. For the City, this means as the demand increases, more pumps can be cycled on to meet the duty point and 25 hp pumps can be added to increase the total pumping capacity.

In order to accommodate the temporary force main, Romtec Utilities designed this lift station with a force main junction vault. This includes the tie-ins to the temporary force main and the new force main –which was stubbed out and capped where it will be constructed. When the new force main is ready, the lift station operators simply need to close the valve and cap the temporary line. This process avoids any need for future construction or excavation.

Another interesting feature of this lift station from a design stand point is the inclusion of a 30,000 gallon emergency storage tank. The geographical size of this development will include a lot of houses, and to prevent ever having issues with capacity at the treatment facility downstream, this storage tank will provide substantial capacity to resolve any future maintenance issues.

Romtec Utilities also designed and supplied a control building through our sister company, Romtec. This lift station control building was the first for the City of Shafter, so Romtec Utilities and Romtec worked to establish the City standard. This included features like access, configuration, interior & exterior electrical outlets, exterior lighting, and even an exterior sink. It also included the complete control panel with all associated electrical connections and the complete odor control system. Romtec also worked with Lennar to achieve a specific aesthetic for the building that would match themes found in other aspects of the development.