Newhope Placentia Interceptor Replacement
Design: 2014 – 2019
Construction: 2015 – present
Cost: $80 MM
This supplements our potable water supply and prevents seawater intrusion into Orange County’s local aquifers. To increase the amount of ultrapure water they can produce, they’ve asked OCSD to supply as much Secondary Effluent as possible. To facilitate this, OCSD has begun segregating high-strength / industrial waste from municipal wastewater, and sending as much municipal wastewater as it can to OCSD Plant No. 1 (located in Fountain Valley) so they can supply it to OCWD, and sending industrial / high strength waste to Plant No. 2 (Huntington Beach), where it will be treated and sent to OCSD’s ocean outfall.
This 7-mile alignment travels N-S and terminates at OCSD Plant No. 1. The existing and new alignment is contained within a busy arterial surface street (State College Blvd.) that traverses some of the most densely populated parts of North Orange County; the Cities of Brea and Fullerton (Package A) and the City of Anaheim (Package B). The sewer’s alignment crosses numerous railway lines; Cal State Fullerton; a CALTRANs offramp and its right of way; runs parallel to Metropolitan Water District’s 85” diameter “Lower OC Feeder” transmission main; a planned grade separation project; crosses Katella @ State College in Downtown Anaheim, near Disneyland; and terminates near the intersection of State College and Orangewood, in the shadow of Anaheim Stadium. Constructing this project will disrupt local traffic, businesses, places of worship; may risk damage to major pieces of critical infrastructure (MWD 85” pressure pipeline, railway lines, etc.); and place a heavy burden on the residents, commuters, and ratepayers near the construction zone. In addition to upsizing 7 miles of pipe, OCSD had identified ~3,500 LF of additional, existing 30” pipe to be replaced under this contract (Package C).
In a nutshell, this is a high-profile public construction project with huge stakes for all involved stakeholders. To accommodate their needs and because this project is on the critical path for OCSD’s broader CIP, OCSD accelerated the Package A design schedule to nail the timing, all without accepting any downgrades to design quality.
To trench or not to trench, that is the question
Several major roadway or railway crossings require the use of trenchless excavation methods to install our new pipe. These construction methods allow a Contractor to install a pipeline without digging a continuous open trench (known as “Open Cut”), which can snarl traffic or disrupt access. Crossings at busy intersections like Cerritos, Ball, and Katella Avenues or the CA-91 Freeway; or at existing railroad crossings required the use of multiple trenchless technologies like Microtunneling / Jack & Bore / HDD. It also required design coordination with stakeholders like BNSF, UP, CALTRANS, City of Anaheim and Fullerton.
Many perceive trenchless technology as a silver bullet—a convenient, if expensive way to avoid public disruptions to traffic or business activity. But the truth is that Trenchless methods still require major excavations for launching and receiving pits, and can make for slower progress, thereby extending stressful construction periods for local residents. As such, the L+R team identified the crossings and portions of the alignment where Trenchless was best suited to meet the specific needs of the project, and deployed “open cut” for other portions of the pipeline, allowing the contractor to quickly install in open-cut trenches to minimize the duration of the construction impact to local residents.
Upsizing a large sewer pipe in a crowded utility corridor
Underground construction projects have a principal challenge that cannot be eliminated: nobody knows what’s actually underground. We can study it, we can attempt to find it with radar, we can even partially dig something up—but until major excavation begins, it’s all speculation. During the course of the construction of this type of large diameter sewer project, a Contractor will run into numerous unmarked underground utilities like Cable TV or electrical ductbanks, water pipes, and similar utilities—on this job the Contractor unearthed an entire bridge that had been constructed decades prior and was buried and abandoned in place. Drawings or existing data did not identify the location or existence of this bridge, and the structure itself represented what could’ve been a major setback for the construction of NHP. The L+R team’s responsive and decisive plan of action quickly determined the best available re-route for the pipeline, transmitted that information to the Contractor and discovered a solution with minimal cost or schedule impact to the District.
NHP’s alignment runs parallel to MWD’s Lower OC Feeder, an 85” diameter water main that supplies major parts of Orange County with drinking water. To avoid cross-contamination of potable water, the CA Department of Public Health, Drinking Water Division (DDW) has set rules for the placement of sewer pipes adjacent to existing water transmission mains: All wastewater pipelines must maintain a lateral separation of 10’ minimum from, and be installed vertically below existing water mains—a requirement that would likely make the optimal alignment of this new pipeline unfeasible. To develop a solution, the L+R design team coordinated with and received official permission from DDW / Metropolitan to develop the necessary material selection and special design features (internally laminated and rubber gasketed FRP pipe and manhole joints) for NHP to make feasible the preferred pipeline alignment and avoid the use of an expensive large-diameter steel casing while making no sacrifices to public health and water security.
Success looks like a “Good Neighbor”
As a special district created to serve the greater good for the residents of Orange County, OCSD takes its mission very seriously. And while sewer upsizing projects serve that greater good, so does being a responsive, thoughtful neighbor for the average OC resident. This project required heavy public outreach and coordination with local governments, schools, places of worship, and businesses. Throughout the design phase, the L+R team proactively identified ways to minimize the construction impact on residents and local governments. Our thoughtfully crafted construction schedule seeks to minimize the impact of construction on Angels baseball, numerous civic events in the City of Anaheim (e.g. conventions) and in general seeks to minimize the disruption of installing 60” diameter pipe in fully built-out parts of Anaheim.
Creative solutions to create the best outcomes
As part of the original scope of Package C, OCSD planned on the replacement of 3,500 LF of 30” sewer pipe that has been damaged over the course of its service life. Even though this portion of the work presented fewer technical challenges than the large-diameter portions of this alignment, early on L+R developed design and construction alternatives to mitigate the cost and impact of this portion of the job — and eventually eliminated the need to dig up and replace the existing pipe, instead moving forward with a CIPP based rehabilitation of the existing pipe saving the District upwards of $4 million and virtually eliminating the construction impact on local residents.
NHP Package A construction was completed in Q3 of 2017. Package A’s 3-½ miles of pipe traverses Brea and Fullerton and its terminus at the 91 Freeway, at the border of Anaheim and the construction duration was just under 12 months. This portion of the construction was completed with an official change order rate of 2.5%, an extraordinary low change order rate, especially for this project type and location. NHP Package A was also awarded ASCE Orange County’s Wastewater Project of the Year, which recognized the quality of our design and OCSD’s effectiveness at executing construction. Package B is currently in construction and will present numerous high-stakes railroad and traffic crossings, even more stakeholders (e.g. Disneyland and the Angels). Our approach to designing and constructing NHP Package C resulted in a savings of approximately $4 MM and will begin construction at the end of 2020.