随着北卡罗来纳州奥兰治水和下水道管理局（OWASA）运营的系统不断扩大，以适应不断增长的用水需求，该机构也在努力更换老化的基础设施。本文描述了OWASA和设计顾问McKim&Creed如何在一个涉及更换现有原水管线的项目上进行合作，包括1942年安装的石棉水泥原水输送干管和1932年安装的铸铁干管。OWASA的意图是用一根新的直径更大的干管替换两条12英寸的原水干管。在本项目设计阶段的同时，OWASA还制定了一份全面的水和下水道总体规划。作为总体规划的一部分，决定确定新原水输送干管的尺寸，以提供2050年预计的36 MGD输送能力，并具有额外的能力，通过水处理厂拟建的未来泵站将原水从大学湖水库泵送至采石场水库。 这增加了整个原水系统的冗余度和可靠性。如果OWASA在从Cane Creek水库输送原水时遇到问题，新的大学湖原水干管将有足够的输送能力为OWASA社区服务。为了确定预计36 MGD输送能力所需的新干管的尺寸，OWASA开始对大学湖原水泵站进行评估。对各种管道直径和材料进行了彻底的水力分析，确定直径为42英寸的球墨铸铁管是满足OWASA需求的最具成本效益的选择。在设计阶段之前，OWASA意识到受本项目影响的社区的敏感性，并理解管道的路由将是至关重要的。 初步设计阶段侧重于评估新原水干管的几个备选路线，特别强调对社区和社区的影响、可行性和成本效益。潜在路线的数量被缩小到具有最大潜力的路线，然后对这些路线进行更详细的重新评估，以确定最终的管道路线。最终，最终的路线将需要通过树木繁茂的地区、既有社区、城镇街道和北卡罗来纳州交通部高速公路的混合物进行建设。这一彻底的评估和消除过程产生了一个路线选择，该路线选择将影响降至最低，同时为OWASA提供一条原水输送干管，在未来50年内为社区提供服务。

As the system operated by the Orange Water and Sewer Authority (OWASA), North Carolina, continually expands to accommodate increasing water demand, the agency is also working to replace aging infrastructure. This paper describes how OWASA and design consultant McKim & Creed collaborated on a project that involved the replacement of existing raw water lines, including an asbestos-cement raw water transmission main installed in 1942 and a cast iron main installed in 1932. OWASA's intent was to replace the two 12-inch raw water mains with a new larger diameter main. Concurrent with the design stage of this project, OWASA was also developing a Comprehensive Water and Sewer Master Plan. As part of the Master Plan, it was decided to size the new Raw Water Transmission Main to provide the 36 MGD conveyance capacity projected for the year 2050, and have additional capacity to pump raw water from University Lake Reservoir via the water treatment plant's proposed future pump station to the Stone Quarry Reservoir. This increases the overall raw water system redundancy and reliability. In the event that OWASA experiences problems with raw water conveyance from its Cane Creek Reservoir, the new University Lake Raw Water Main will have sufficient conveyance capacity to serve the OWASA community. To determine the size of the new main required for the projected 36 MGD conveyance capacity, an evaluation of the University Lake Raw Water Pumping Station was initiated by OWASA. A thorough hydraulic analysis of various pipe diameters and materials was performed, whereby it was determined that a 42-inch diameter ductile iron pipe was the most cost effective choice to meet OWASA's needs. Prior to the design stage, OWASA realized the sensitivity of the neighborhoods that would be impacted by this project and understood that routing of the pipeline would be critical. The preliminary design stage focused on the evaluation of several alternative routes for the new raw water main, with particular emphasis on impacts to the neighborhoods and communities, feasibility, and cost effectiveness. The number of potential routes were narrowed to those with the greatest potential, which were then reevaluated in greater detail to determine the final pipeline route. Ultimately, the final route would require construction through a mixture of wooded areas, established neighborhoods, town streets, and North Carolina Department of Transportation highways. This thorough process of evaluation and elimination resulted in a route selection that minimized impacts while providing OWASA with a raw water transmission main that would service the community for the next 50 years.