Challenge

The Sacramento County Department of Waste Management & Recycling operates a landfill in Sloughhouse, CA, that has expanded and required new design features across the site’s various modules to meet regulatory requirements.

Solutions

GLA has provided engineering and construction support services for several projects at the Kiefer Landfill since 2015, including construction quality assurance (CQA), design specifications and plans for various projects, closure assistance, construction management, and master planning. We have provided construction design and CQA for phases 1 and 2 at the landfill, including designs for expansion of the Module 4 in both phases, an ongoing design for phase 1 of Module 5, and a liner infill design at Module M1L-M3. In particular, the liner infill design at M1L-M3 presented a problem due to existing stormwater infrastructure that prevented completion of the liner. We remedied this issue by reconfiguring the stormwater collections features to complete the tie-in of Module 3 to Module 1.

GLA also designed and provided CQA services for phases 1 and 2 at Module 4. We provided design and construction support for the expansion under phase 1, which involved interim slope stability analysis, leachate collection and removal system design, and stormwater design. GLA also assisted with critical issues and assisted in selecting a construction contractor, in particular providing critical support for the excavation, segregation, and stockpiling of 3.5 million cubic yards of material. GLA’s support services for this phase also included providing full-time CQA services for the entirety of the one-year and three-month construction project and preparing a final CQA Report.

GLA also provided design services for the phase 2 liner expansion at Module 4, which was combined with the phase 4&5 partial finale closure of Module 1. This combined project included a 26-acre cell expansion and 46-acre partial final closure and involved excavating and stockpiling of soils, waste excavation, ripping and recompacting of the existing intermediate cover, geosynthetics installation, construction of the leachate collection and removal system gravel and piping, stormwater components, and landfill gas system management. A unique feature of this project involved using the 500,000 cubic yards of soil excavated and segregated during the Module 4 as final cover for Module 1, thereby eliminating double handling of the soil. GLA also provided CQA for the construction of this project.

Results

GLA’s engineering design, construction support, and CQA actions have helped to keep the Kiefer landfill operating through multiple phases of expansion. Our designs have ensured the landfill meets all regulatory requirements, with a focus on protecting the environment and human health.

We are proud of the long-term, wide-ranging scope of services provided for this project because it shows the breadth and depth of talents of our staff.

Project Manager