Maura Dougherty is joining SCS’s Southwest Business Unit as a Senior Project Manager in the solid waste engineering practice. Dougherty will execute engineering design, operations support, and construction quality assurance projects. She is responsible for project management, client service, business development, technical leadership, and overseeing professional staff teams. Dougherty reports to Vice President and Southwest Business Unit Director of Engineering, Vidhya Viswanathan, P.E., from SCS’s Pleasanton office.
“Maura is a senior professional with proven extensive success in solid waste engineering, construction, and construction quality assurance solutions,” said Viswanathan. “Her experience managing landfill and landfill gas collection and control system engineering and construction projects strengthen our efforts to support our solid waste and recycling clients.”
Dougherty is a registered Professional Engineer in California, Oregon, Washington, and Hawaii. She brings over 20 years of experience overseeing landfill engineering and construction projects, coordinating with regulatory staff, conducting design and technical reviews, and supporting construction work. Dougherty earned her B.S.E. in civil engineering at the University of Princeton and her M.S. in environmental engineering from U.C. Berkeley.
Marion County has awarded SCS the planning, designing, permitting, bid phase services, construction quality assurance (CQA) services, and construction contract management for the approximately 50-acre baseline landfill cell No. 3 closure. The County sought a firm specializing in solid waste, with landfill closure experience in Florida to provide the required design and permitting services, and with the in-house capability to conduct the construction quality assurance (CQA) services required during construction. The entire project is estimated to take three years to complete, with construction spanning multiple rainy seasons.
Weather-related issues during closure construction are one of the critical factors to address. An overly aggressive contractor could strip too large of an existing vegetative area, try to place too much protective cover material over the barrier layer system; either can potentially cause significant erosion during rain events.
The County’s concern about CQA is to prevent placing the protective cover material over the newly installed barrier layer system. Should an unqualified contractor replace the protective cover material on the barrier layer, it will increase construction time and increase the potential for damage to the system. This damage is often not found until the contractor has demobilized from the site, and the facility begins to conduct the required surface emissions monitoring. The resulting repairs to the barrier layer are often a cost the owner incurs, not the contractor.
Based on decades of experience designing, building, and operating landfills, the SCS CQA professionals prevent these types of construction mistakes. Working closely with contractors to ensure construction events are thought through to the operations phases while providing recommendations if the construction plan may encounter potential issues.
“Our entire team is excited to have the opportunity to continue serving Marion County, especially with a project of this magnitude and importance to Marion County,” said Shane Fischer, a vice president with the SCS team. “Our professionals are committed to delivering the highest quality engineering and construction services possible for the long-term success of the project.”
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Sometimes geosynthetic material specifications for a specific project, i.e., lining system or final cover system, is a performance-based specification which does not specify the type of product for use in construction. What does the engineer need to do when the selected contractor submits a product for approval in accordance with a performance-based specification? What should the engineer do when the owner purchases the material and identifies a product for use based on the performance-based specification?
Specifications that SCS has prepared are performance-based and include a qualifying procedure whether the product is introduced by a contractor or owner. This qualifying procedure is specifically left to the engineer to carry out by laboratory testing of typical samples of the specific product for use in construction. Typical reported values by the manufacturer or test results submitted by the contractor or owner are not acceptable under these procedures. Since the engineer is taking the liability of accepting a specific type of product for his or her project, the engineer should have the right to perform laboratory testing before the product is approved for use in the project, that only makes sense in the world of taking liabilities!
The testing performed by the engineer for qualifying a product do not count toward conformance testing of materials delivered to the site. The qualifying procedures are solely for accepting a certain type of product to be used in the project, but the specific rolls of pre-qualified product manufactured for use in engineer’s project must go through the required conformance testing specified in the specifications before use in the project.
The process of qualifying a product, ordering the qualified product, and performing conformance testing on the pre-qualified materials takes time. Engineers need to consider the amount of time necessary for the involved stages of approval into the construction schedule. If using material purchased by the owner, the owner needs to keep the timeline in mind to allow the engineer to carry out all necessary testing for the approvals to be in place before construction begins.
Repeating the qualifying procedure for a product from one project to the next depends on how the performance-based specification is written. Sometimes, the engineer accepts a product that was qualified for use in a prior project as long as the product has not changed since last used in accordance with statements by the manufacturer. If the performance-based specification includes such options, SCS highly recommends identifying the period between a prior project and the next project in the specification. In some cases, this means the product must go through a qualifying process even if it has not changed for many years but the previous set of qualifying data is older than a certain number of years. The period is based on the engineer’s judgment, but most professionals normally use five years in their specifications. During a five-year period, if the product changes or there are indications that the product might have changed due to recorded changes in certain reported values by the manufacturer, the qualifying process must be followed irrespective of the number of years passed since a recent past project to maintain quality and minimize risk.
Questions? Contact the author, Ali Khatami.
Discovering unexpected pockets of soft soils at the time of construction can delay your project and drive up costs for landfills, support features, and many other types of construction. If you don’t find them, building over them can result in unexpected settlement affecting a structure or building, or cause a slope stability problem for a berm or stockpile. You can avoid both of these scenarios with early investigation and appropriate construction planning.
While landfill development investigations typically require numerous soil borings within the proposed waste limits of the landfill, it’s common to overlook perimeter areas. Pockets of soft soil deposits can be associated with nearby existing wetlands, lakes, or rivers; with wind-blown silt or ancient lake deposits from periods of glaciation; or with fill placed during previous site uses.
The landfill perimeter areas may contain tanks for leachate or fuel, buildings, perimeter berms for screening or landscaping, stockpiles, and other features. A tank or building constructed over soft soils could experience unexpected settlement affecting the performance and value of the structure. The potential for a slope stability problem can increase for a large berm or stockpile built on soft soils.
The first step to avoid these problems and identify problem soils is to include perimeter areas in your subsurface investigation. Perform soil borings or test pit excavations at the locations of the proposed perimeter features such as tanks or berms. If you encounter soft soils, address them like this:
Contact SCS’s geotechnical engineers for more information on how to find and test soft soil areas early in a landfill’s project schedule, so you can effectively address associated construction issues in a way that considers cost and minimizes unexpected project delays.
Have you ever found in the sleeve or the pocket of a new shirt the “Inspected By…” piece of paper? You probably don’t think twice about it. You simply look at it and throw it away. However, if you were to think about it, what might the process be to inspect the garment? To be sure the sleeves are the same length, or the collar is sewn on correctly, or that it has all the buttons. That tag is intended to signify that the product was reviewed and has met its required standards to be placed in service.
Ever wonder if anybody reviews the bottom of a landfill? When is it ready to be placed in service?
When I was a kid, a landfill was, for the most part, a hole in the ground filled with trash. Well, we still dig a hole, but since the early 1990’s, municipal solid waste landfills (MSWLF) require a containment system on the bottom and sides of the landfill beneath the waste. These containment systems, i.e. liner systems, are designed to protect human health and the environment by serving as a barrier between the waste and liquid in the landfill from the soil and groundwater outside the landfill. These liner systems are typically constructed of compacted clay liners and geosynthetic materials which are documented and inspected to ensure the liner system was built in accordance with the permit requirements and its overall purpose of protecting the environment.
The landfill liner inspection process is usually called Construction Quality Assurance (CQA) and is an important and integral component of protecting the environment. CQA is generally performed by a third party firm to provide an unbiased evaluation of the liner construction independent of the owner or the contractor.
SCS provides Landfill CQA services across the country. We have proven, experienced field staff that observe, document and test specific physical properties of the soil liner and geosynthetics. Our engineers are experienced and licensed to certify that the liner was built in accordance with the permit requirements.
Landfill CQA is not limited to the liner system. SCS provided CQA for final cover systems, leachate forcemain systems, and methane extraction systems.
If you are wondering more about landfill CQA or have a need for your facility, give us a call. We’d be happy to discuss in more detail and assist with your project. SCS is ready to serve, and help to bring your project in service.
Contact Jeff Reed