Tarrant Regional Water District
Tarrant Regional Water District
News Article | August 15, 2017
A University of Texas at Arlington civil engineer will model the behavior of large-diameter water transmission pipes' behavior in different types of soils to establish modeling standards that can be used by the industry in future infrastructure projects. Ali Abolmaali, the chair of the UTA Department of Civil Engineering, and co-investigators Arash Emami and Himan Jalali will use a one-year, $200,000 Tarrant Regional Water District and Water Research Foundation tailored-collaboration grant to gain an understanding of the best method of modeling large water pressure pipes reaction when laid in various backfill materials with differing depths of soil above them. TRWD has funded several research projects with UTA on large pipe design. Previous work by TRWD and UTA has resulted in development of a comprehensive, robust, nonlinear finite element model. This model was verified by soil box testing and experimental field tests conducted at the Rolling Hills Booster Pump Station in Fort Worth and by measurements of actual installations. "What our data will show will serve as a template for future construction standards when using these kinds of large-diameter pressure pipes," said Abolmaali, who also is the Tseng Huang Endowed Professor in civil engineering. "Modeling the behavior of pipes with different backfill is integral to making the infrastructure last and work to the best of its ability." Future work, if the modeling proves successful, may lead to developing informed design equations to improve the reliability and economics of large diameter pipelines. These pressure pipes are between 60 to 108 inches in diameter. Once the water provider places them in soil or backfill material, it is difficult to move or repair them. "We have to get it right the first time," Abolmaali said. "This research will help us to be right. We have to be right because this is where people get their drinking water from." Abolmaali will use 3-D computer modeling techniques to simulate the pipes behavior observed in various types of soil. In addition, Abolmaali's research will use tested material properties and methods of soil compaction from field installations to simulate pipe strain due to loading coupled with the pipe trench wall, and bedding and backfilling characteristics. The Integrated Pipeline Project, a joint project developed by Dallas and TRWD, initiated this research. The IPL is a 149-mile pipeline of mostly l08-inch diameter pipes, which is now under phased construction by Dallas and TRWD from East Texas' Lake Palestine to Tarrant County's Benbrook Lake. The soils in the IPL project area include shrink-swell soils which complicate pipeline design and construction. The IPL is being built in phases, allowing some parts of the IPL to be used for testing the model development of this project, creating an ideal situation for large pipe research. A professional advisory group of leading academics, industry, design and owner engineers will review the data the research produces. This group will collaborate to determine the best method modeling, allowing designers to be confident that the mathematical simulations will represent the actual behavior of the pipe. Peter Crouch, dean of the College of Engineering, said Abolmaali's project will have a tremendous impact on the North Texas region and could impact other water providers in the future. "This research allows water providers and their contractors to build in the right way, a long-lasting, more sustainable way," Crouch said. "More importantly, it ensures the flow of drinking water for millions of people." David Marshall, TRWD engineering and operations support director, said Abolmaali's project could confirm that the designs will ensure reliability while minimizing the cost for construction for the district and its users. "Having reliable water transmissions pipelines is essential to Tarrant Regional Water District's s business," Marshall said. "Having a way to confidently simulate the pipe's behavior will ensure all parts of the design are correct before installation begins. Water transmission is a necessity for a growing North Texas and we need to make sure it's as reliable as possible." The project directly relates to a main tenet of building sustainable urban communities, part of UTA's Strategic Plan 2020 Bold Solutions | Global Impact.
News Article | June 5, 2017
A UTA civil engineer and hydrologist has expanded his weather-watching audience to iPhone users. D.J. Seo, the Robert S. Gooch Endowed Professor of Water Resources Engineering and a civil engineering professor at The University of Texas at Arlington, designed a cell phone app called iSeeFlood. The app, developed in 2016, was initially available only for Android cell phones. It is now available for iPhones. iSeeFlood encourages the public to file timely reports when they see flooding of varying severity on the streets, in and around their homes, and in streams and creeks. Such flash floods can be dangerous to pedestrians and motorists alike. Any advantage in knowing where, when and how fast flash-flooding is occurring can save lives and property. Visit this link for the iOS download. Visit this link for the Android download. Visit https:/ for an interactive display. For iSeeFlood, Seo is collaborating with DeepStratus, a technology company based in northern Virginia to improve the app and data display. "We are hopeful that the collaboration with DeepStratus will help UTA take this cell phone application worldwide," Seo said. "This crowdsourcing tool can not only inform the citizens for real-time decision making but also help build the data we need to understand and cope with flash flooding worldwide in a more intelligent and data-driven way." Seo said DeepStratus is also harvesting weather-related tweets and social media posts to help collect and build the data needed to make informed decisions on flash flooding and to advance flood science. "Urban flood management has become an integral part of planning and services in metropolitan areas like North Texas," Seo said. "We need big data and crowdsourcing approaches to assemble needed information is especially needed in urban areas where so much development is taking place." Since last year, Seo's team has also been installing about two dozen innovative wireless sensors around creeks, streams and flash-flooding zones in Fort Worth, Dallas, Grand Prairie and Arlington to improve high-resolution modeling of urban water systems. The sensors recorded and transmitted information about how much water was flowing, providing additional data to help the cities and National Weather Service make quicker and more accurate forecasts and alerts. "But it's too expensive to put up sensors wherever flash flooding data are needed," Seo said. "That's why we need to rely on crowdsourcing and this phone app is a great way to gather the data we need." Ali Abolmaali, UTA Department of Civil Engineering chair and Dr. Tseng Huang Endowed Professor, said Seo's work will help design changes in how North Texas is built. "Once the data are collected, it's invaluable to the cities where they came from," Abolmaali said. "I could see this kind of phone app and data collection spreading across the globe." Seo's iSeeFlood app and sensor work is but one of the many projects he and his UTA team are working on. UTA also is hosting a Water Management Workshop Tuesday, June 6, in the Rady Room of Nedderman Hall on campus. The National Weather Service, Dallas Water Utilities, the Tarrant Regional Water District, the Brazos River Authority and many city water departments will be attending to discuss water supply and flood forecasting initiatives and needs. The iSeeFlood app and the wireless sensors are research outcomes of Integrative Sensing and Prediction of Urban Water for Sustainable Cities, a joint project among The University of Texas at Arlington, University of Michigan and University of Massachusetts Amherst. The project is supported by a $1.2 million National Science Foundation grant Seo received in 2014 to improve sustainability of large urban areas affected by extreme weather, urbanization and climate change through the NSF's Cyber-Innovation for Sustainability Science and Engineering, or CyberSEES, program. Seo joined UTA in 2010 following professional appointments to the National Weather Service's Hydrologic Research Laboratory in Maryland and as a senior researcher in the Environmental Remote Sensing Research Laboratory at the Korea Institute of Science and Technology in Taejon, Korea. Seo earned his master's degree from the Massachusetts Institute of Technology and his doctoral degree from Utah State University.
News Article | June 12, 2017
DENVER--(BUSINESS WIRE)--The Water Research Foundation (WRF) announced today that it has awarded the 2017 Dr. Pankaj Parekh Research Innovation Award to Mr. Stuart Krasner from Metropolitan Water District of Southern California and two Outstanding Subscriber Awards for Applied Research to the City of Calgary and Tarrant Regional Water District (TRWD). Mr. Krasner and both Outstanding Subscriber Award recipients were honored during WRF’s Annual Subscriber breakfast at the American Water Works Association’s annual conference, ACE17. The Dr. Pankaj Parekh Research Innovation Award honors researchers and research teams who have made significant contributions to advancing the science of water through WRF-sponsored projects. The award is named after Dr. Pankaj Parekh, a tireless advocate of water research who dedicated over 40 years of his life to ensuring safe drinking water and protecting public health. WRF’s Outstanding Subscriber Award for Applied Research honors subscribing utilities that have successfully applied WRF research to make notable improvements to their water treatment, delivery, and/or management processes. “A large part of the Water Research Foundation’s success depends on partnerships with remarkable leaders in the water community, like those we honored today,” said Rob Renner, Chief Executive Officer of the Water Research Foundation. “Mr. Krasner and the professionals at the City of Calgary and TRWD have contributed so much to WRF’s research efforts over many years. We are proud of their work and grateful for their achievements.” For 40 years, Mr. Krasner’s research has focused on disinfection by-product (DBP) research, both in terms of the chemistry of formation as well as developing a better understanding of the impacts of DBPs on public health. His current research into the occurrence, formation, and control of emerging DBPs will undoubtedly play a role in the shaping of future regulatory development in the United States and abroad. Over the past four decades, Mr. Krasner has been actively involved with WRF, serving as the Principal Investigator (PI) or Co-PI on more than 22 different research projects. “Winning this award is a great honor. I worked with Pankaj so I hope to do justice to his name,” said Krasner. “I appreciate the Water Research Foundation for the support they've given me, which has allowed me to do this kind of research.” The City of Calgary provides drinking water, wastewater, and stormwater services to over one million people. A Founding Member of WRF, since 1987 Calgary has developed and participated in a series of WRF research projects that look at risk governance and enterprise risk management. Calgary is a global leader in the water sector and has worked with WRF to bring international utilities together to sponsor research. “It is absolutely fantastic to win this award. This is recognition that we've been doing the right thing over the last 30 years,” said Rob Pritchard, General Manager at the City of Calgary. “We've always felt that we were up there amongst our peers in terms of our approach and I think to be recognized in this way is incredible.” TRWD owns and operates four reservoirs and has constructed more than 150 miles of pipelines, 27 miles of floodway levees, more than 72 miles of Trinity River Trails, and a 2,000-acre wetland water reuse project designed to increase water supplies for the Dallas-Fort Worth area. In the last few years, they have invested $3 million in research focused on improved design of large-diameter buried steel pipelines, prompted by their desire to improve the reliability of a new pipeline they are building. Tarrant has already saved about $20 million compared with the estimated cost of construction, and much of these savings can be traced to the large-diameter pipe design research they have championed. “TRWD has always been an organization looking for a better path. Being recognized for the fact that we take great advantage of working with WRF on our system and operations shows that we're really supporting our customers by being progressive in what we do,” said David Marshall, Engineering Services Director at Tarrant Regional Water District. Award nominations are accepted from WRF’s Board of Directors, staff, subscribers, researchers, and other water community partners. The Board of Directors’ Awards Committee selects each year’s winners. For additional information about WRF’s annual awards and past award winners, please visit www.WaterRF.org/awards Water Research Foundation (WRF) is a non-profit research cooperative that advances the science of water to protect public health and the environment. Governed by utilities, WRF delivers scientifically sound research solutions and knowledge to serve our subscribers and stakeholders in all areas of drinking water, wastewater, stormwater, and reuse. WRF has funded and managed more than 1,500 research studies from asset management to treatment, utility finance to resource management, conveyance systems to water quality.
News Article | November 4, 2016
A UTA civil engineering professor and hydrologic researcher expects to improve the accuracy of rainfall maps produced by the National Weather Service by 10 to 20 percent for heavy-to-extreme rainfall events through a National Oceanic and Atmospheric Administration grant. D.J. Seo, the Robert S. Gooch Professor of Water Resources Engineering in the Civil Engineering Department, is collaborating with Lin Tang, a research scientist at the University of Oklahoma; Jian Zhang of the NOAA's National Severe Weather Storms Laboratory; and David Kitzmiller and Greg Fall of the NOAA's National Water Center. Seo said that more accurate rainfall maps such as those available from http://water. , will positively impact decisions made by emergency managers, water managers, municipalities, the agricultural sector, the insurance industry and others. In addition, the more accurate precipitation information affects everyday people. Under the grant, UTA will receive $188,442 and OU will receive $197,546. That $385,988 is part of $6 million in total funding from the NOAA's National Weather Service as part of its Joint Technology Transfer Initiative. The total funding was dispersed to more than 100 academic institutions. The initiative's aim is to get new tools and technologies more rapidly into the hands of weather forecasters. "NOAA has sharpened its focus on speeding up this important transition of technology to National Weather Service day-to-day operations," said John Cortinas, director of NOAA Research's Office of Weather and Air Quality, which manages the Joint Technology Transfer Initiative in close coordination with NWS, in a news release. "This funding represents another important step to get new tools and technologies more rapidly into the hands of our weather forecasters who serve communities around the nation." Seo said the project will take into account the weather radar networks, tens of thousands of rain gauges and satellite sensors that the National Weather Service employs. "We'll be using that information, running it through a new suite of algorithms to determine heavy-to-extreme precipitation amounts more accurately," Seo said. "Our goal is to improve the accuracy by 10 to 20 percent. Being able to estimate precipitation better has a chain reaction of sorts on the entire water prediction and management enterprise. If we're more accurate in precipitation, then we can be more accurate in our streams, creeks and rivers. That leads to being more accurate in flood warnings and in the operation and management of our reservoirs." Greg Waller, service coordination hydrologist for the National Weather Service's West Gulf River Forecast Center, said Seo's work will enhance the agency's ability to better serve the public. "Dr. Seo is a great teammate," Waller said. "His work will help us forecast flooding more accurately. That helps meteorologists and invariably helps the public. We are looking forward to another collaborative effort with UTA." College of Engineering Dean Peter Crouch said the research Seo and his team are carrying out in this project is another example of UTA-led research that cuts across data-driven discovery, sustainable urban communities and global environmental impact, three tenants under UTA's Strategic Plan 2020: Bold Solutions | Global Impact. "Creating a better tool in determining precipitation amounts is especially beneficial in severe weather episodes," Crouch said. "Improving forecasts could save lives and property." Seo joined the University in 2010 following professional appointments to the National Weather Service's Hydrologic Research Laboratory in Maryland and as a senior researcher in the Environmental Remote Sensing Research Laboratory at the Korea Institute of Science and Technology in Taejon, Korea. Seo earned his master's degree from the Massachusetts Institute of Technology and his doctoral degree from Utah State University. In the spring of 2016, he launched a new Android cell phone app called iSeeFlood to encourage the public to file timely reports when they see flooding of varying severity on the streets, in and around their houses, and in streams and creeks. At that same time, Seo's team also installed innovative wireless sensors to improve high-resolution modeling of urban water systems. Researchers about a dozen of the high-tech sensors in Fort Worth, Grand Prairie, Dallas, Arlington and Kennedale. Seo was awarded in 2014 a four-year, $1.2 million National Science Foundation grant to improve sustainability of large urban areas from extreme weather, urbanization and climate change. That project built on Seo's previous work to help establish the Collaborative Adaptive Sensing of the Atmosphere, or CASA, radar system in North Texas. UT Arlington installed the first radar station in North Texas atop of Carlyle Hall in 2012 as part of Seo's research. The CASA system provides weather data every minute compared to every five to six minutes with previous weather radar systems. CASA can adapt to focus on smaller areas, giving the users more detailed information to better monitor and track storms and precipitation. Seo was also awarded a two-year $283,000 grant in 2015 from the National Oceanic and Atmospheric Administration Climate Program Office to forecast inflows into water supply reservoirs and to generate optimal solutions for operation of water supply systems for major water providers in the region. He and his team collaborate on the project with the Tarrant Regional Water District, the National Weather Service, the Trinity River Authority and the North Central Texas Council of Governments. About The University of Texas at Arlington The University of Texas at Arlington is a Carnegie "highest research activity" institution of more than 50,000 students in campus-based and online degree programs and is the second-largest institution in The University of Texas System. The Chronicle of Higher Education ranked UTA as one of the 20 fastest-growing public research universities in the nation in 2014. U.S. News & World Report ranks UTA fifth in the nation for undergraduate diversity. The University is a Hispanic-Serving Institution and is ranked as the top four-year college in Texas for veterans on Military Times' 2016 Best for Vets list. Visit http://www. to learn more, and find UTA rankings and recognition at http://www. .
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.
Snead II J.W.,CH2M HILL |
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 Integrated Pipeline (IPL) system is a raw water supply program that integrates Tarrant Regional Water District (TRWD) - and City of Dallas-owned water supplies from Lake Palestine, Cedar Creek Reservoir, and Richland Chambers Reservoir. As one of the largest water supply projects in the nation and one of the largest ever undertaken in Texas, the IPL will consist of a 350 MGD raw water transmission pipeline from Lake Palestine to Lake Benbrook, with connections to a new 250 MGD Pump station at Richland Chambers Reservoir, a new 277 MGD Pump Station at Cedar Creek Reservoir, and a new 150 MGD Pump Station at Lake Palestine. The pipeline will be approximately 150 miles in length and will contain 3 booster pump stations. As part of the IPL, TRWD retained a team led by CH2M HILL to study invasive species that might threaten the major components of the IPL system. © 2013 American Society of Civil Engineers.
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.
News Article | November 23, 2016
When you prepare the Thanksgiving meal, do you ask each person to make a dish of their choosing, with no coordination for an overall cohesive meal? Probably not. Most likely, you plan, because you want everything to fit together. Now imagine a water utility with different departments like water quality, finance, and administration. Most water utilities have high energy costs, so each department needs to manage and reduce its energy use – but typically there’s no plan to synchronize these efforts. With such a piecemeal approach, the utility may get overall energy savings, but it’s not maximizing the potential to meet ambitious efficiency goals or reduce power costs. Enter the Energy Management Plan (EMP), a tool that sets up an organization-wide strategy for energy use. By creating a coordinated vision, an EMP establishes clear efficiency goals and gives departments the flexibility and direction for meeting them. That’s what this summer’s EDF Climate Corps fellow focused on at Tarrant Regional Water District (TRWD), which supplies water to 2 million users in the Fort Worth area. The TRWD fellow found opportunities where an EMP could improve the utility’s energy efficiency and management, leading to potential savings and less wasted water. Energy is a high cost for water utilities. It takes a lot of electricity to treat and distribute water, on top of fueling the offices and facilities. In many cities, water-related energy costs can be 30 to 40 percent of their total energy bill. With energy efficiency alone, those costs could be lowered by 15 to 30 percent – representing thousands of dollars. Installing low-water clean energy like solar or wind at a water utility could further bring down electricity costs. But these initiatives aren’t going to start themselves. That’s where an EMP comes in. Basically serving as a road map, an EMP gets all departments working toward the same goal: reducing energy use and costs. It also helps prioritize the most cost-effective projects, such as targeting a high-energy pumping station for equipment upgrades or establishing leak-detection programs to reduce wasted water (and associated wasted energy). Further, when water utilities identify high-energy-use pain points in their systems, it could potentially lead to partnerships with electric utilities, which might even help pay for major energy efficiency projects. As opposed to most water utilities, many electric utilities already have energy efficiency programs and funds dedicated to meeting those goals. But if an electric utility has been offering efficiency programs for years, it may have exhausted the low-hanging fruit and need to explore new options, such as efficiency through water conservation. By pairing up, both the water and electric utilities could maximize available efficiency and water conservation funds, helping each side reduce its energy use. California is a pioneer in this type of partnership. Improving energy efficiency can not only lower costs and save energy, but save water too. That’s because many of the resources we currently use to make energy – like coal and natural gas – require a significant amount of water. The U.S., for instance, gets nearly 90 percent of its power from fossil fuel-fired and nuclear power, which accounts for nearly half of the country’s total water withdrawals. Therefore, cutting energy use indirectly cuts water use. With a changing climate, many cities and areas will face increased water stress that could put additional pressure on electric systems. Plus, as the population grows, demand for water and electricity increases. Finding opportunities to protect water supplies – like through energy and water efficiency – will be critical. TRWD operates more than 150 water facilities, and most of the energy it uses is for moving water from East Texas. The utility is committed to lowering energy costs – currently there are about a dozen different programs aimed at doing so. Our EDF Climate Corps fellow’s main mission this summer was to develop a plan to streamline operations and consolidate TRWD’s energy achievements and goals into a cohesive energy management plan. These recommendations can help TRWD improve overall operational and energy efficiency, and they exemplify what EDF Climate Corps does best: find ambitious yet achievable goals to reduce energy use and expand clean energy deployment. Future iterations of an EMP could include increased use of self-generation clean energy (e.g. solar panels) to further reduce TRWD’s energy demand. In fact, this summer, another EDF Climate Corps’ fellow for San Antonio Water System (SAWS) – San Antonio’s municipally-owned water utility – not only identified energy-efficiency savings for the utility, but also evaluated the feasibility of onsite solar generation, of which SAWS is already a national leader. No one wants a Thanksgiving meal of only side dishes. But that imbalance is what many water utilities currently are working with: They may have some sort of process to reduce energy use, but lack a comprehensive utility-wide energy agenda. Rolling small or piecemeal programs into a larger EMP could increase operational efficiency, lowering costs while saving water and energy. Texas is a great example of a state with water utilities ready to embrace the rewards of cohesive energy plans, and we look forward to seeing progress over the coming years.
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.
Hotchkiss T.R.,Kimley Horn |
Weaver E.,Tarrant Regional Water District
Pipelines 2016: Out of Sight, Out of Mind, Not Out of Risk - Proceedings of the Pipelines 2016 Conference | Year: 2016
It is well understood in the civil engineering industry that the economy of flexible pipe systems relies almost entirely on the pipe-soil structural interaction. As correctly noted by one of our generation's preeminent steel pipe design researchers, Dr. Reynold Watkins, the design of flexible pipes is largely dependent on the surrounding soils. The selection of flexible pipe materials and the design of the flexible pipeline system begins with and depends almost entirely on the ground conditions through which the pipeline will be constructed. The Tarrant Regional Water District (TRWD) and Dallas Water Utilities (DWU) began design of the Integrated Pipeline Project (IPL) in 2008 and have been advancing the art and science of large diameter pipeline project delivery ever since. The $2.3 billion IPL is a joint project between DWU and TRWD and will, when completed, include 150 miles of pipeline from Lake Palestine to Lake Benbrook. The pipeline crosses a number of challenging obstacles and passes through a number of highly variable ground conditions, from rippable (soft) rock to running, saturated sands and everything in between. The 13-mile long alignment of IPL Section 15-2 crosses the Waxahachie Creek valley west of IH-45 before following a long, gentle ridgeline roughly between Ennis and Waxahachie, Texas. The pipeline crosses some very design-challenging soils, including the notorious, heave-susceptible Blackland Prairie. The geotechnical/geophysical program prepared by the Program Team noted a number of "Areas of Geologic Concern" in Section 15-2, most notably in the "Waxahachie Creek Bottoms," an alluvial valley with a broad floodplain and shallow, water-bearing sands within and just beneath the "typical" trench profile. The design team worked collaboratively with the pipeline owners and their program management team to develop best-value design and construction procurement approaches to deliver the project in a way that fairly attributed and mitigated the ground condition risks while assuring the best life-cycle value for the owners. This paper describes the project constraints faced and approaches taken to mitigate both design and construction risks. These approaches included clearly defining the design intent that was predicated on assumed ground/trench conditions and the following construction inspection and management practices: Clear delineation of areas of geotechnical concern in the bidding documents; Clear definition of the ground conditions assumptions made in pipe and trench envelope design in the bidding documents; Definitive pre-construction validation of ground conditions ahead of material procurement; Validation of in-situ trench conditions during pipeline installation; Provisions for alternative trench and backfill envelopes in both the bid schedule and plan and specifications that equitably mitigate bidding and construction cost risks related to ground conditions. © 2016 ASCE.