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Dallas, TX, United States

Barnhurst J.E.,MWH Americas Inc.
Pipelines 2013: Pipelines and Trenchless Construction and Renewals - A Global Perspective - Proceedings of the Pipelines 2013 Conference

The wastewater system backbone of the New Orleans Sewerage & Water Board (the Board) is comprised of large-diameter, steel force mains in diameters from 54- to 72-inch size. During Hurricanes Katrina and Rita, the town and associated infrastructure experienced damages associated with the flooding resulting from these storms. In 2005, two back-to-back major storms inflicted great damage on the City and the surrounding area. On August 29, 2005, Hurricane Katrina hit the Louisiana coastline as a Category 4 storm. The water level in Lake Pontchartrain peaked at 8.6 feet (7.6 feet above the normal sea level). Breaches in the levees built to protect the City occurred at the 17th Street Canal, the London Avenue Canal, and the Industrial Canal. The breaches led to flooding in nearly 80 percent of the City with water depths reaching 25 feet in some areas and adding very large external loads to the existing forcemains. Less than a month later, Hurricane Rita made landfall on September 24, 2005, as a Category 3 storm. Levees were again overtopped in at least three locations along the Industrial Canal, re-flooding the City's Lower Ninth Ward, a few neighborhoods surrounding Lake Pontchartrain, and neighboring St. Bernard Parish. © 2013 American Society of Civil Engineers. Source

Triana E.,MWH Americas Inc. | Labadie J.W.,Colorado State University
Journal of Irrigation and Drainage Engineering

The long-term sustainability of irrigated agriculture is contingent on application of cost-effective water conservation measures and improved management in the face of intense competition for limited freshwater resources from municipal, industrial, and environmental/ ecological interests. A geographic information system (GIS)-based decision support system (GeoDSS) is presented for maximizing water savings from efficiency improvements and conservation measures through integrated management of large-scale irrigation systems. The GeoDSS incorporates the GeoMODSIM network flow optimization model as implemented within ArcGIS Desktop (ESRI, Inc.) and is applied to the large-scale, complex Imperial Irrigation District (IID) water delivery system in California in support of the IID/San Diego County Water Authority (SDCWA) Water Transfer Agreement. IID GeoDSS automatically constructs a GeoMODSIM flow network within an ESRI geodatabase composed of feature classes for IID canals, drains, reservoirs, farm gates, interceptors, and pumpback locations. Following calibration of the baseline network, GeoMODSIM simulations predict substantial water savings from mixtures of strategies of varying cost for improved water management and increased delivery system efficiency and on-farm water conservation, without the need for fallowing or retirement of IID irrigated lands. © 2012 American Society of Civil Engineers. Source

Turker U.,Eastern Mediterranean University | Alsalabi B.S.,MWH Americas Inc. | Rizza T.,Lefkosa
Environmental Earth Sciences

The groundwater of the deep Yeşilköy aquifer is the only water resource for agricultural and domestic consumption at the Karpaz Peninsula of Cyprus, which stretches approximately 100 km from the northeast of capital Nicosia to the northern tip of Cyprus. During the last decade, over-pumping and following dry periods have depleted the groundwater resources and the water surface elevation of the aquifer has dropped. The aim of this study is to understand the behavior of the Yeşilköy aquifer in the last decade for the proper management of groundwater resources. This has been achieved based on well survey and field survey studies, monitoring programs followed by pumping tests, and safe yield analysis. Most of the research effort has been focused on field and well survey studies to quantify agricultural water consumption and abstraction rates from the aquifer. A long-term groundwater level monitoring program, short-term continuous groundwater monitoring and pumping tests provided information for the regression analyses while deriving a sixth order polynomial relationship between the period parameter and the head parameter. The equation was helpful to predict the short-term behavior of the water level when the present hydrogeological conditions prevail. The pumping test results satisfied the hydraulic properties of calcarenite formation yielding T = 1,782 m2/day and S = 0. 0012. The results of safe yield analysis show that the annual deficit of the aquifer is 0. 496 million cubic meters (MCM), which is equivalent to a 0. 6 m drop in groundwater levels per year. Finally, the resultant annual safe yield of the aquifer is estimated as 0. 84 MCM. © 2012 Springer-Verlag. Source

Heidari T.,MWH Americas Inc. | Heidari T.,Clemson University | Andrus R.D.,Clemson University
Journal of Geotechnical and Geoenvironmental Engineering

Liquefaction potential of four Pleistocene beach sand deposits in the Greater Charleston area, South Carolina, is assessed. The assessment is based on a review of 51 sites of conspicuous craterlets and horizontal ground displacement that occurred in beach sand deposits during the 1886 Charleston earthquake and an analysis of 82 seismic cone penetration tests with pore-pressure measurements. Of the 51 ground failure sites, 23 are associated with the Ten Mile Hill beds; 13 with the Wando Formation; 13 with the Silver Bluff terrace and younger deposits that lie adjacent to the harbor, rivers, and creeks; and two with the Ladson Formation. Liquefaction potential is analyzed using the seismic cone data with and without correction for age-related processes (diagenesis) and then expressed in terms of the liquefaction potential index (LPI). Probability curves are developed from the LPI calculations for different earthquake ground-shaking parameters. The probability curves for the Wando Formation overpredict liquefaction potential when no corrections for diagenesis are made. When corrections for diagenesis are made, the probability curves for all four sands generally agree with the observed field behavior. © 2012 American Society of Civil Engineers. Source

Morley M.C.,MWH Americas Inc. | Fatemi M.,University of Nebraska - Lincoln
Practice Periodical of Hazardous, Toxic, and Radioactive Waste Management

Groundwater contaminated with the high explosive Demolition eXplosive, or hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) may also contain the nitroso-RDX metabolites hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX), and hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX). Although adsorption to activated carbon effectively removes RDX from contaminated water, the treatability of the nitroso-RDX compounds by adsorption has not been previously reported. Single-component isotherms were completed and the Freundlich parameters (K and 1/n) were calculated for adsorption of these compounds to Calgon F400 from unbuffered high purity water under aerobic and anoxic (<1 mg/L dissolved oxygen) conditions. Under both conditions, MNX was the most adsorbable, followed by RDX, DNX, and TNX. The presence of dissolved oxygen slightly increased the Freundlich parameters for all compounds except TNX. Under aerobic conditions, Freundlich capacity parameters (K) ranged from 46.4 (mg/g)(L/mg)1/n for TNX to 164.2 (mg/g)(L/mg)1/n for MNX, while under anoxic conditions, K ranged from 47.1 (mg/g)(L/mg)1/n for TNX to 133.6 (mg/g)(L/mg)1/n for MNX. Additional testing showed that 7 days were sufficient for adsorption equilibration in most cases. Simplified granular activated carbon (GAC) column modeling demonstrated that the presence of these compounds in groundwater can reduce GAC service life. © 2010 ASCE. Source

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