AMEC Environment and Infrastructure

Boulder City, CO, United States

AMEC Environment and Infrastructure

Boulder City, CO, United States

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Shepley M.G.,UK Environment Agency | Shepley M.G.,Environment Canada | Soley R.W.N.,AMEC Environment and Infrastructure
Geological Society Special Publication | Year: 2012

The predictions from a numerical time-variant distributed groundwater model are used to assess the spatial and temporal impacts of groundwater abstraction for an unconfined and layered, moderate diffusivity aquifer; the West Midlands-Worfe Permo-Triassic Sandstone in the UK. These impacts have been determined by comparing a recent actual baseline predictive simulation with simulations where groundwater abstractions are switched off, including a 'naturalized' simulation. By reference to the historic simulation, the predictive model results are compared against observed groundwater levels. The predictive simulations demonstrate that observed groundwater levels could be an indicator of groundwater abstraction impacts on surface water flows where widespread stream disconnection has occurred due to high rates of abstraction. This relationship also depends on the aquifer hydraulic characteristics, the interaction between groundwater levels and the surface drainage network and other artificial flow influences. Abstraction impacts on groundwater levels are large for the West Midlands-Worfe aquifer, but can be obscured by the climatic recharge signal in observed groundwater level records. This is a consequence of the moderate diffusivity and the main groundwater abstraction development preceding systematic monitoring. The groundwater model can be used to identify which observation boreholes have negligible abstraction impacts; this may be valuable for identifying groundwater level records that are useful for climate change analysis.


Lippai I.,Water Resources Consultant | Wright L.,AMEC Environment and Infrastructure
Procedia Engineering | Year: 2014

Forcing the assigned demands on a system that lost a major portion of its supply may produce erroneous results such as unrealistically low negative pressures. A more realistic model would allow for the partial reduction of delivered water when the catastrophically-impaired network can no longer deliver the assigned demands. A number of auxiliary programs were developed to replace conventional system demands with various alternative demand constructs. These alternative demand constructs were then used to investigate the impact of catastrophic failure on model performance. Five different demand constructs are presented, applied to a water system model and subjected to catastrophic failure. © 2014 Published by Elsevier Ltd.


Shu X.,University of Tennessee at Knoxville | Huang B.,University of Tennessee at Knoxville | Shrum E.D.,AMEC Environment and Infrastructure | Jia X.,Tongji University
Construction and Building Materials | Year: 2012

A laboratory study was conducted to evaluate the moisture susceptibility of plant-produced foamed warm mix asphalt (WMA) containing high percentages of recycled asphalt pavement (RAP) in Tennessee. WMA loose mixtures were collected and compacted at asphalt plant and were compared to hot-mix asphalt (HMA) samples through laboratory performance tests. In addition to widely-used AASHTO T283 freeze and thaw (F-T) and tensile strength ratio (TSR) tests, Superpave indirect tension (IDT) tests, dynamic modulus test, and Asphalt Pavement Analyzer (APA) Hamburg wheel tracking test were also utilized to evaluate asphalt mixtures subjected to freeze-thaw (F-T) and moisture-induced stress tester (MIST) moisture conditioning. The results indicated that the Superpave IDT tests and the dynamic modulus test had potential to accurately characterize moisture susceptibility. With incorporation of RAP, foamed WMA is expected to perform as well as HMA in terms of moisture susceptibility. © 2012 Elsevier Ltd. All rights reserved.


Ravichandran N.,202 Lowry Hall | Huggins L.,AMEC Environment and Infrastructure
Geotechnical Special Publication | Year: 2014

Using shredded tires as an alternative backfill material for retaining walls is an effective method for recycling a common and abundant waste material. In this paper, the engineering properties of the shredded tire from various sources were compiled. Retaining walls were designed for static and seismic conditions using the average properties following LRFD method and compared with that of conventional granular material. The performance of retaining wall backfilled with shredded tires was then investigated by applying design earthquake acceleration-time histories using advanced finite element software and compared with that of sand backfill. Results show that the shredded tire backfill significantly reduces the wall tip deflection and maximum shear force and bending moment along the wall. © 2014 American Society of Civil Engineers.


Wright L.,AMEC Environment and Infrastructure
Procedia Engineering | Year: 2014

Forcing the assigned demands on a system that lost a major portion of its supply may produce erroneous results such as unrealistically low negative pressures. A more realistic model would allow for the partial reduction of delivered water when the catastrophically-impaired network can no longer deliver the assigned demands. A number of auxiliary programs were developed to replace conventional system demands with various alternative demand constructs. These alternative demand constructs were then used to investigate the impact of catastrophic failure on model performance. Five different demand constructs are presented, applied to a water system model and subjected to catastrophic failure. © 2014 Published by Elsevier Ltd.


Lopez A.,AMEC Environment and Infrastructure
Proceedings of the International Conference on Radioactive Waste Management and Environmental Remediation, ICEM | Year: 2013

As the worldwide hydraulic fracturing 'fracking' market continued to grow to an estimated $37 Billion in 2012, the need to understand and manage radiological issues associated with fracking is becoming imperative. Fracking is a technique that injects pressurized fluid into rock layer to propagate fractures that allows natural gas and other petroleum products to be more easily extracted. Radioactivity is associated with fracking in two ways. Radioactive tracers are frequently a component of the injection fluid used to determine the injection profile and locations of fractures. Second, because there are naturally-occurring radioactive materials (NORM) in the media surrounding and containing oil and gas deposits, the process of fracking can dislodge radioactive materials and transport them to the surface in the wastewater and gases. Treatment of the wastewater to remove heavy metals and other contaminates can concentrate the NORM into technologically-enhanced NORM (TENORM). Regulations to classify, transport, and dispose of the TENORM and other radioactive waste can be complicated and cumbersome and vary widely in the international community and even between states/provinces. In many cases, regulations on NORM and TENORM do not even exist. Public scrutiny and regulator pressure will only continue to increase as the world demands on oil and gas continue to rise and greater quantities of TENORM materials are produced. Industry experts, health physicists, regulators, and public communities must work together to understand and manage radiological issues to ensure reasonable and effective regulations protective of the public, environment, and worker safety and health are implemented. Copyright © 2013 by ASME.


Lew M.,AMEC Environment and Infrastructure
Structural Design of Tall and Special Buildings | Year: 2011

L. LeRoy Crandall, President and Chief Executive Officer of his own company of LeRoy Crandall and Associates (LC&A) and a Director of the Board of Law Engineering, was active in the Civil Engineering profession serving proactively in leadership roles in professional societies. LeRoy Crandall and his firm of LC&A was involved in the more complex projects of the times, and this required innovative solutions and new technologies to be introduced to make the projects more feasible, constructible and economical. LeRoy Crandall was involved in the foundations of most of the tall buildings in Southern California and pioneering work in implementing tie-back shoring made large and tall buildings more constructible and allowed for deeper excavations. LC&A acquired equipment and software to allow for determining the dynamic soil properties of a site to allow for site characterization and permit the estimation of site-specific ground motions for design.


Norton M.,AMEC Environment and Infrastructure | Lane A.,Halcrow Pacific Pty Ltd
Proceedings of Institution of Civil Engineers: Management, Procurement and Law | Year: 2012

An integrated framework for the management of water in England and Wales is proposed that optimises the organisation of service infrastructure, customers and stakeholders to derive optimal social, economic and environmental health. 'New Water Architecture' recognises the intrinsic links between water stakeholders, and between water and other essential resources, particularly food, energy and biodiversity. A systems-based approach strengthens integration of physical infrastructure, controlling institutions, and the overarching society consensus. Consideration is also given to future pressures with resilience to climate change strengthened by initiatives that slow water passage across the landscape. Implementation of the framework requires coordinated water policy across traditionally discrete resource sectors. This need is investigated alongside specific initiatives related to system management, abstraction licensing and pricing. Capital investment should be targeted towards 'low-regret' infrastructure argued to be high flow storage, aquifer storage and recovery, sustainable drainage systems and water transfers. These examples deliver multiple benefits and can be further optimised if existing networks, particularly inland waterways, are revitalised to enable regional integration of water sources.


Rima S.D.,AMEC Environment and Infrastructure
ICSI 2014: Creating Infrastructure for a Sustainable World - Proceedings of the 2014 International Conference on Sustainable Infrastructure | Year: 2014

Billions of dollars are spent worldwide every year on nuclear remediation projects. Most of this work is done now as it was done decades ago and is very labor and resource intensive. AMEC has developed technology that has been deployed on projects across the United States and in Canada, Japan, and the United Kingdom that makes such projects shorter in duration and more sustainable through reductions in waste volume requiring permanent disposal and through minimization of resources to complete such projects. Benefits to local communities and taxpayers have included return of land to beneficial public use quicker and at lower cost than traditional methods; reduction of impacts from large workforces and heavy equipment; reduction in greenhouse gas emissions from shorter duration projects using less fossil fuels; and reduction in the volumes of materials that are otherwise needlessly diverted to landfills for disposal as radioactive waste. Information is presented on development of sustainable approaches and solutions to such projects, as well as a case study of where it has been successfully used. © 2014 American Society of Civil Engineers.


Harding B.L.,AMEC Environment and Infrastructure | Wood A.W.,National Oceanic and Atmospheric Administration | Prairie J.R.,Bureau of Reclamation
Hydrology and Earth System Sciences | Year: 2012

The impact of projected 21st century climate conditions on streamflow in the Upper Colorado River Basin was estimated using a multi-model ensemble approach wherein the downscaled outputs of 112 future climate projections from 16 global climate models (GCMs) were used to drive a macroscale hydrology model. By the middle of the century, the impacts on streamflow range, over the entire ensemble, from a decrease of approximately 30% to an increase of approximately the same magnitude. Although prior studies and associated media coverage have focused heavily on the likelihood of a drier future for the Colorado River Basin, approximately 25 to 35% of the ensemble of runs, by 2099 and 2039, respectively, result in no change or increases in streamflow. The broad range of projected impacts is primarily the result of uncertainty in projections of future precipitation, and a relatively small part of the variability of precipitation across the projections can be attributed to the effect of emissions pathways. The simulated evolution of future temperature is strongly influenced by emissions, but temperature has a smaller influence than precipitation on flow. Period change statistics (i.e., the change in flow from one 30-yr period to another) vary as much within a model ensemble as between models and emissions pathways. Even by the end of the current century, the variability across the projections is much greater than changes in the ensemble mean. The relatively large ensemble analysis described herein provides perspective on earlier studies that have used fewer scenarios, and suggests that impact analyses relying on one or a few climate scenarios are unacceptably influenced by the choice of projections. © 2012 Author(s).

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