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Fort Worth, TX, United States

Gaughan M.,AECOM Technology Corporation | Hattan S.,Tarrant Regional Water District
Pipelines 2013: Pipelines and Trenchless Construction and Renewals - A Global Perspective - Proceedings of the Pipelines 2013 Conference | Year: 2013

The Tarrant Regional Water District (TRWD) with the City of Dallas Water Utilities (DWU), are currently engaged in the planning, design, and implementation of a 350 MGD raw water transmission system, which will run across north central Texas from Lake Palestine to Lake Benbrook, with connections to Cedar Creek Reservoir, Richland Chambers Reservoir and a Dallas delivery point. Collectively, the system consists of: approximately 145 miles of 84-inch to 108-inch pipeline; a 5-mile, 120-inch diameter tunnel; six 100-350 MGD pump stations; one 300 MG balancing reservoir; and ancillary facilities. The program developed by TRWD to accomplish these improvements is called the Integrated Pipeline Project (IPL). As a means to deliver this important infrastructure project in a sustainable manner, the IPL has conducted several specialty studies into the re-use of native soil as pipeline embedment. Specialty studies include: a. Route Characterization - Geophysical and geotechnical investigation to categorize soils by re-use potential and to identify marginal soils, b. Chemical Stabilization - Laboratory treatment of marginal soils to increase engineering properties such as strength and durability, c. Native Soil Flowable Fill - Laboratory and field trials to make flowable fill using native soils found along alignment including sands, clayey sands, limestone and lean-to-fat clay, d. Soil Box Testing - Laboratory investigation of large-diameter steel pipe determining pipe wall stresses and pipe deflection under various embedment configurations. e. Finite Element Analysis - 3-dimensional FEA study to test conventional and alternative embedment options for steel and prestressed concrete pipe, f. Flowable Fill Full Scale Pilot study - 2-mile installation of 108-inch pipe embedded in native soil flowable fill, and g. Cost and Sustainability - Analysis of various embedment options with a focus on the sustainable triple bottom line of people, planet and profit. This paper describes the various studies (with a particular focus on the cost and sustainability aspects), presents initial results, and describes a path forward for an innovative and sustainable approach to soil re-use on a water transmission pipeline project. © 2013 American Society of Civil Engineers. Source


Wilkerson M.,Fugro | Hattan S.,Tarrant Regional Water District | Marshall D.,Tarrant Regional Water District | Gaughan M.,AECOM Technology Corporation
Pipelines 2012: Innovations in Design, Construction, Operations, and Maintenance - Doing More with Less - Proceedings of the Pipelines 2012 Conference | Year: 2012

The Tarrant Regional Water District (TRWD) with the City of Dallas Water Utilities (DWU), are currently engaged in the planning, design and implementation of a 350 MGD raw water transmission system, which will run across north central Texas from Lake Palestine to Lake Benbrook, with connections to Cedar Creek Reservoir, Richland Chambers Reservoir and a Dallas delivery point. Collectively, the system constitutes approximately 150 miles of 84-inch to 108-inch pipeline and six pump station sites. The program developed by TRWD to accomplish these improvements is called the Integrated Pipeline (IPL) Project. The IPL crosses five (5) distinct physiographic regions and 20 geologic formations that outcrop along the alignment. The lithologies are all sedimentary in origin and range from loose sands and soft clays to soft shales, hard sandstone, and limestone beds, with several moderately hard limestone formations. Shallow groundwater can occur in any of the formations within the pipe depth zone. Desiring to provide a continuous characterization of the subsurface conditions to assist in the site specific design and construction of the pipeline, a two-step approach was undertaken with the IPL geotechnical program. Phase 1 includes a geophysical survey of the pipeline route with periodic geotechnical borings for ground truthing and calibration. Goals of the geophysical survey include: • Provide a continuous interpretation of the soil/rock conditions present • Identification of potential reuse materials; • Identification of possible geologic and man-made features present along the IPL route that may have gone undetected during a traditional boring program. • Provide an estimate of the depth to the groundwater surface • Provide baseline soil resistivity data to assist cathodic protection design; and • Provide refined locations for further geotechnical borings. Phase 2 includes hundreds of geotechnical borings selected for needs of pipeline design. This paper describes and compares the project conditions, geophysical data collection, geophysical analytic techniques, and geotechnical ground truthing for this innovative program. © 2012 American Society of Civil Engineering. Source


Wilkerson M.,Fugro | Larson J.,BioGeo LLC | Gaughan M.,AECOM Technology Corporation | Marshall D.,Tarrant Regional Water District
Pipelines 2013: Pipelines and Trenchless Construction and Renewals - A Global Perspective - Proceedings of the Pipelines 2013 Conference | Year: 2013

The Tarrant Regional Water District (TRWD) and the City of Dallas Water Utilities (DWU) are currently engaged in the planning, design and implementation of a 350 MGD raw water transmission system which will run across north central Texas from Lake Palestine to Lake Benbrook. Collectively, the system constitutes approximately 150 miles of 84-inch to 108-inch pipeline and six pump station sites. A geotechnical investigation was conducted along the pipeline alignment and included about 400 geotechnical borings, 150 miles of Electrical Resistivity Tomography (ERT), 100 Cone Penetration Tests (CPT), and geologic mapping. The vast amount of data collected was archived electronically in a geospatial database. Successful pipe design requires communication between IPL program management, the engineering geologist, geotechnical engineer and civil engineer. A unique planprofile was developed to illustrate the vast amount of geologic and geotechnical information collected for the IPL project. The plan-profiles were developed initially from correlation of strata using standard geologic techniques. The profiles were then modified using color codes to illustrate subsurface conditions and areas of geologic concern that are important to the civil engineer for design of the pipeline. © 2013 American Society of Civil Engineers. Source


Narasimhan B.,Indian Institute of Technology Madras | Srinivasan R.,Texas A&M University | Bednarz S.T.,U.S. Department of Agriculture | Ernst M.R.,Tarrant Regional Water District | Allen P.M.,Baylor University
Transactions of the ASABE | Year: 2010

A comprehensive modeling approach has been developed for use in formulating a watershed management plan to improve the water quality of Cedar Creek reservoir, one of five large water supply reservoirs in north central Texas operated by Tarrant Regional Water District. Eutrophication, or specifically the increase in concentrations of chlorophyll-a (chl'a') over the last 18 years, is a major concern for the water managers. To develop a watershed management plan, the watershed model SWAT was linked with the lake eutrophication model WASP. Several intensive field campaigns and surveys were conducted to collect extensive water quality and land management data for model setup and calibration. In addition to the streamflow, the SWAT model was well calibrated for sediment (including channel erosion) and nutrients. Further, a simple modification to the SWAT in-stream routine allowed simulation of the nutrient load due to channel erosion. The in-stream water quality parameters for SWAT were based on an independent QUAL-2E model calibration. The calibrated SWAT model showed that more than 85% of the total N and total P loading to the lake are from watershed nonpoint sources. Although cropland occupies only 6% of the watershed area, it contributed more than 43% of the sediment, 23% of total N, and 42% of total P loading from the watershed. The channel erosion contributed about 35% of the total sediment load. The watershed model identified subbasins that contribute considerable amounts of sediment and nutrients. Based on these loads, the calibrated WASP model showed that the watershed nonpoint-source nutrient load (total N and total P) should be reduced by at least 35% to see a significant reduction in chl'a' concentrations when compared to the WASP calibration levels. © 2010 American Society of Agricultural and Biological Engineers. Source


Pope P.G.,Carollo Engineers | Cullwell R.,Carollo Engineers | Gehrig J.,Tarrant Regional Water District
Pipelines 2015: Recent Advances in Underground Pipeline Engineering and Construction - Proceedings of the Pipelines 2015 Conference | Year: 2015

Monochloramine loss was studied in two, approximately 70-mile pipelines within the Tarrant Regional Water District (TRWD) raw water supply and transmission main system. Both bench-scale studies and full-scale sampling were used to determine the impact of several factors that may affect monochloramine loss in the pipelines. The conditions of bench-scale study were representative of the range of water quality conditions encountered at the pump stations. Bench-scale results were compared to full-scale samples taken along the pipeline. Samples collected along the 70-mile pipeline were measured for chloramine concentration, pH, dissolved oxygen, as well as parameters known to indicate nitrification such as nitrite and free ammonia. Samples collected along the pipeline were also filtered with a 0.2 μm filter. Filtering the samples removed any nitrifying bacteria potentially present. Comparing the chloramine decay between the filtered and unfiltered samples allowed the affect of nitrification in the pipeline to be observed. © 2015 ASCE. Source

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