Head-to-Head Comparison of Open-Cut vs. HDD: City of Yuma, AZ Water Line Replacement Project

摘要

In 2016, the City of Yuma, Arizona undertook the replacement of approximately 5,800 L.F. of existing aging and undersized asbestos cement water lines in the vicinity of the downtown core to reduce maintenance and repairs and improve water service levels. The original water lines were installed between 1938 and 1940. Six line segments of existing 2-inch to 6-inch asbestos cement water lines were replaced by 6-inch diameter PVC pipe. To gain a better understanding of the pros and cons of traditional open-cut construction compared to Horizontal Directional Drilling (HDD), the City separated the project into approximately 2,000 L.F. of HDD and 3,800 L.F. of open-cut. Being the same project, it provided an excellent opportunity to study a true head-to-head comparison of the two methods. PVC C900 DR18 was installed using open-cut, while Fusible PVC (FPVC) DR18 was installed by HDD. Data was collected in the field over a two-month period with factors analyzed including comparison of environmental impacts, traffic impacts, and productivity. The results found HDD to have inherent advantages in all three areas when compared to traditional open-cut. The eCalcTM program was used to determine airborne emissions generated during the project by each of the two methods.