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Keyes J.,Wright Water Engineers Inc.
41st International Erosion Control Association Annual Conference 2010 | Year: 2010

This presentation is a nuts-and-bolts account of the benefits and requirements of a successful auditing program for stormwater from construction sites. Covered topics include: what deficiencies in Stormwater Management Plans and BMP implementation are commonly cited by regulators; samples of fines levied; the key components and considerations of an audit program; and regulatory requirements for a construction site stormwater auditing program. Case studies from various industries are described. Copyright © (2010) by the International Erosion Control Association. Source


Guo J.C.Y.,University of Colorado at Denver | Blackler G.E.,University of Colorado at Denver | Earles T.A.,Wright Water Engineers Inc. | MacKenzie K.,Master Planning and Criteria Development
Journal of Environmental Engineering | Year: 2010

In practice, the challenge of storm-water low-impact-development (LID) design is often related to how to quantify the effectiveness of a LID layout. In this study, the watershed imperviousness was chosen as a basis to evaluate the performances of various LID designs. Often, LID designs apply cascading planes to drain the runoff flow from the upstream impervious area to the downstream pervious area. In this study, the conventional area-weighting method is revised with a pavement-area-reduction factor (PARF) to produce the effective imperviousness. PARF is employed as an incentive index to quantify the on-site runoff volume reduction and cost savings from downsized sewers. Two sets of PARF are derived: conveyance-based and storage-based LID designs. The conveyance-based LID approach is to drain runoff flows on various porous surfaces while the storage-based LID approach is to temporarily store runoff flows in an on-site basin. For a specified LID layout, the PARF provides a consistent basis to translate the infiltration and storage effects into the reduction on the area-weighted imperviousness. The nondimensional governing equation derived in this paper indicates that the PARF depends on the ratio of the soil infiltration rate to rainfall intensity, the ratio of receiving pervious area to upstream impervious area, and the on-site storm-water storage capacity. The PARF serves as a basis for the engineers, planners, and/or developers to select a LID design and also for regulatory agencies to assess meritorious credits for cost savings. © 2010 ASCE. Source


Guo J.C.Y.,University of Colorado at Denver | Jones J.E.,Wright Water Engineers Inc. | Earles A.,University of Colorado at Denver
Journal of Irrigation and Drainage Engineering | Year: 2010

As recommended, culvert entrances in urban areas should be protected with a rack or a grate because urban flood flows are quick, concentrated, and fast. Safety around storm-water facilities is an increasing concern for the public. Many forensic cases indicate that a trash rack at the entrance can prevent a human body from being washed into the culvert pipe, but on the other hand, a trash rack increases the flow velocity and results in a pinning force on the human body landed on the rack. While having a trash rack at a culvert entrance has the potential to result in a pinning force and to accumulate trash/debris, the public safety benefit of a trash rack in preventing a person from being drawn into an underground conduit outweigh the risks of the potential pinning force and/or trash/debris blockage. The conventional approach can only provide the total external force acting on a culvert-rack system, including the reaction forces from the wing walls and the rack with or without blockage. This study presents a new method of superimposition that can solve the external forces one by one progressively. Results from the case study indicate that the hydrostatic force due to the high headwater in front of the culvert entrance is mostly balanced by the reaction force from the wing walls. The pinning force on the submerged trash rack is mainly the response to the change in the flow momentum force. In comparison, the pinning force is much smaller than the total external force. A pinning force is a normal force on the rack surface. The effort to escape from being pinned on the trash rack is to overcome the friction along the rack surface. © 2010 ASCE. Source


Keyes J.,Wright Water Engineers Inc.
43rd International Erosion Control Association Annual Conference 2012 | Year: 2012

This presentation will cover the main changes in the proposed EPA CGP and strategies for achieving and maintaining compliance with the permit. Main topics that will be discussed include buffer protection, stabilization, water quality and required BMPs. Source


Wolfram P.J.,Los Alamos National Laboratory | Lorenz W.F.,Los Alamos National Laboratory | Lorenz W.F.,Wright Water Engineers Inc.
International Journal for the History of Engineering and Technology | Year: 2016

Ancient Roman engineers are famous for their use of arcades, or arched bridges, to elevate roads and aqueducts across valleys. The Romans first designed and built arches using stone blocks and then later changed to special concrete construction. In this paper, we illustrate how early unmortared arches could have been built using geometric design principles. This simplified analysis is sufficient to demonstrate, via retrospective analysis, the need for reconstruction efforts for arches violating these design criteria. Well-preserved remnants at the Simian Bridge and Vallon des Arcs arcades, located in southern France near Arles, are excellent examples of Roman arch engineering and are used as case studies to understand geometric arch design in practice. These arcades are vital parts of a larger aqueduct system used to provide the waterpowered industrial Barbegal Mill and city of Arles with water in the first century A.D. Analysis of currently standing arches implies that Roman engineers may have relied extensively upon geometrical rules of thumb for design of these structures. In particular, modern stability analysis demonstrates the effectiveness of geometrical rules of thumb in determining structural failure requiring reconstruction at the Simian Bridge. The reconstruction that exists at the Simian bridge shows a shift from stone blocks to concrete. This shift may have occurred as a result of the Roman engineers' increased awareness of geometrical criteria for arch design. © 2016 The Newcomen Society for the Study of the History of Engineering & Technology. Source

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