1082 Sunrise Avenue, Suite 100, Roseville, CA 95661
(916) 783-4100
(916) 783-4110

Newcastle Wastewater Treatment Plant Decommissioning

2013 APWA Sacramento Chapter Project of the Year Award

Wastewater Treatment Plant Decommissioning Project includes Annexation and Proposition 218 Processes

In 2006, the Newcastle Sanitary District (NSD) faced Regional Water Quality Control Board (RWQCB) discharge violations resulting from inadequate capacity at their wastewater treatment plant (WWTP). The NSD’s two treatment ponds, two storage ponds, and spray field disposal system could not meet the needs of the District’s 285 connections in a 420-acre service area. Extended rain events forced the District to irrigate the spray fields to prevent overtopping or breaching pond levees when the storage ponds reached flood levels. In addition, the NSD faced significant inflow and infiltration, and increasingly higher water quality standards, which required major costly improvements to the aging collection system.

The NSD WWTP was not able to meet increasingly stringent treatment limitations. The capacity of the plant was simply too small to handle the existing flows of the collection system during large storms. The plant was at risk of contaminating the adjacent Red Ravine Creek. In addition, the majority of the residents neighboring the plant draw well water as their potable water source. Neighbors, municipalities, and the agencies involved agreed changes were needed to protect the sensitive environment and the underlying groundwater in the Newcastle community.

Placer Nevada Wastewater Authority (PNWA) studies recommended Placer County’s small wastewater treatment systems merge with a more effective and efficient regional wastewater treatment system. Analysis showed decommissioning the NSD plant and routing wastewater to one of two regional treatment centers would alleviate capacity and quality issues as well as reduce ratepayers’ long-term costs.

The plan to merge the Newcastle Sanitary District into the regional system clearly demonstrates this project’s commitment to sustainability. Having the wastewater treated at a regional level allows for a better ability to meet RWQCB requirements for discharge more economically. The much larger user base provides a more feasible economic base to support the necessary regulatory upgrades. After a competitive selection process, the NSD selected Bennett Engineering Services to manage the plant decommissioning process and new pipeline design. The firm helped the District overcome several challenges to complete the five-year project successfully.

Funding Acquisition and Management

The team assisted the NSD to acquire and manage three sources of project funds. Applications were prepared for grants from the U.S. Environmental Protection Agency (EPA), California State Revolving Fund (SRF), and a loan from the South Placer Municipal Utility District (SPMUD), which would eventually annex the NSD service area. In addition, the team facilitated Proposition 218 rate increase hearings for the service area, winning two increases from the NSD’s previously extremely low rates.
Alignment Analysis and Selection

The team analyzed several pipeline alignments to connect the NSD treatment plant to a regional plant in either Lincoln or Roseville. Each option required collaboration and careful coordination between several public agencies along with neighborhoods impacted by the alignments.

Because the NSD treatment plant was surrounded by private property, there were no options available that offered existing public easements. Analysis for the recommended alignment included elevation, varying distances, routing along paved versus unpaved roads, and creek crossings. The team ultimately recommended an 8,000-foot pipeline alignment connecting to the SPMUD and Roseville’s Dry Creek Wastewater Treatment Plant.

Easement Acquisition and Public Relations

The selected alignment required trenching along a private road as well as through private property. The team managed the easement acquisition, including preparation of easement plats and legal descriptions. The eminent domain process was required for an absentee land owner. The team processed permanent and construction easement record documents for each property affected by the pipeline. The team also successfully managed neighborhood relations during construction, including concerns about repaving roads, access during construction, and the inconvenience of construction that did not directly benefit the homeowners. This was an important aspect of the project for this small, tight-knit community.

Design, Plans, and Specifications

Challenges in the design process included managing fluctuating flow rates, system redundancy, coordinating switch over from the treatment plant to pump station, and sludge disposal. In addition to regular system flow rates, the aging system’s substantial inflow and infiltration rates had to be accounted for in flow calculations. Gravity flow was routed from the existing plant to dual pump stations. The forcemain design included dual, 4-inch force mains that provide redundancy and maintain wastewater velocities above cleansing velocity. Since the new pipeline would be feeding an existing SPMUD gravity pipeline, it was critical to design the new pipeline to manage flow for optimal scouring but not overwhelm the existing capacity of SPMUD’s system.

The team gained valuable experience with the process of removing almost a century of sludge deposits, which exceeded initial volume estimates. Significant testing for contaminants was required to determine the necessary disposal method. After pumping off the surface liquid, the contractor treated the sludge to further separate and remove liquid, then mixed the remains with dry content to achieve a mixture with acceptable water content for the disposal site. Plans for removal and disposal of site appurtenances such as structures and valves and a final grading plan were also provided.

Bidding Assistance, Construction Coordination, and Inspection

The team assisted with the bidding process, including collection, live opening, review, and a recommendation to the Board for award of the contract. Construction inspections were coordinated with SPMUD, since they would be acquiring the system at the end of construction.

Recognizing the potential for collection system backup, the team carefully coordinated with the contractor and treatment plant operators to perform the final switch from the treatment plant to the new pumping stations to prevent overfilling ponds or system backups.
The grading plans returned the site to a natural drainage pattern. As the contractor removed sludge and the actual underlying topography was determined, grading was adjusted to suit actual conditions. Record drawings were prepared to reflect as-built conditions.

Decommissioning and Regulatory Management

With numerous agencies involved, BEN|EN was a key contact in the release of the NSD from the PNWA, its transfer to the South Placer Wastewater Authority (SPWA), and its acquisition by SPMUD. During the process of funding, analysis, design, and construction, the team maintained a positive relationship with the RWQCB. Continuous communication, site visits, and monthly and quarterly progress reports contributed to the constructive relationship. The team also coordinated Environmental Protection Agency (EPA) reviews and inspections required for funding reimbursement.

The team submitted plans for plant decommissioning to the RWQCB for approval. Demonstrated requirements, such as site testing for contaminants had been met, and a final closure report was submitted. The RWQCB approved the closure in December 2012.

Economic Challenges

The largest economic challenge the community faced was the significant increase in sewer collection rates to help fund the project. Historically low rates had left the District without adequate capital for improvements required by new regulations. The team knew the increases would be difficult for the community to accept, but with limited public funding available, the increases were inevitable. In 2006, the rates were raised from $19 per month to $38 per month and in 2008 from $38 to $78 per month.

Understanding the impacts on ratepayers prompted the NSD and SPMUD boards to require an intensive alternatives analysis. Upgrading the plant to meet the RWQCB requirements would allow the NSD to stay in business and avoid any potential conflicts between agencies during the annexation process. This alternative, however, was more costly and would, therefore, require the District to raise rates even higher. The alternative to decommissioning the site and annex into SPMUD was chosen instead. The NSD and SPMUD boards made it clear that they were willing to expend the extra effort to go through with the annexation in an effort to keep rates reasonable. This level of effort became apparent to the Newcastle community during the second Proposition 218 hearing in 2008 and subsequent rate increase.

Impact to the Community and Its Residents During Construction

Because the WWTP was surrounded by residential homes and private roads, it was necessary to make a concerted effort to inform the community (especially the immediate neighbors) of the construction and how they would be affected. There were approximately 40 residents significantly affected by the construction on two small, private roads. The BEN|EN team went door to door to every neighbor that could potentially be affected by the construction and explained the project, answered any questions they had, and assured them everything was being done to minimize impact to their neighborhood. This effort was well received and created further community support for the project.


It may sound simple for SPMUD to annex the NSD, but it took enormous effort and the willpower of leaders at several agencies involved—NSD, SPMUD, PNWA, SPWA, City of Roseville, and Placer County—to recognize the project vision and move it forward. These public agencies came together with one goal in mind and successfully completed the decommissioning and annexation. After the presentation and questions from the audience, the Newcastle Sanitary District received a standing ovation from the community thanking them for their efforts to keep the community safe and provide an economically feasible solution to the problem.

The NSD Board is comprised of five volunteers from the Newcastle community. The NSD had one paid employee who operated the treatment plant. With these limited resources and marginal income, it was difficult to maintain the collection system and treatment plant. The NSD definitely did not have the funds or staffing to provide the resources of most agencies. SPMUD stepped in to make sure the project moved forward. They provided thousands of staff hours and equipment to ensure the project was successful:

  • Camera work for the entire collection system and treatment plant to identify problems to be fixed. The process took approximately two months for three full-time SPMUD employees to complete.
  • Design review
  • Assistance in coordinating with other agencies during the annexation process
  • Full-time inspection services during construction
  • A loan to the District to fund the project at a competitive rate

These services provided a substantial financial benefit to the community. Because SPMUD was able to provide these services at cost, the NSD saved an estimated $500,000. The NSD would not have been able to complete this project without SPMUD’s generosity and enthusiasm.

“We have a great team working on this that is technically excellent and easy to work with and that gets results!”
Ed Sander, Former General Manager, Newcastle Sanitary District