AWWA ACE63095

The 37th Street Water Treatment Plant is one of two water treatment plants owned andoperated by the City of Norfolk, Virginia. It was constructed originally in 1920, andserves the citizens in the western half of the city, as well as U.S. Naval StationNorfolk. The treatment plant is served by two 36-inch raw water mains, eachapproximately 16 to 20 miles long. These mains originate from the City of Norfolk'sWestern Branch Pumping Station, located in Suffolk, Virginia, and traverse throughthe cities of Chesapeake, Portsmouth, and into Norfolk. One main, installedoriginally in the 1920s, includes some of the original reinforced concrete bar-cylinderpipe with lead joints. The other main was installed originally in 1943, and containslarge portions of 1940s vintage reinforced concrete (steel) cylinder pipe. Both ofthese mains have undergone varying degrees of upgrades and repairs during the past30 to 40 years, including several emergency repairs in recent years. Based on theage(s) of these mains, fear of other future catastrophic failures, and because the twomains are the only sources of water supply to the 37th Street plant, the City of Norfolkdetermined it was necessary to conduct a condition assessment of the two pipelines.Since these water mains are located in several cities, and lie within limited right-of-way/easement corridors, it was more prudent and cost effective to conduct a conditionassessment of the mains up front, rather than opt for wholesale replacement. Thecondition assessment helped determine the structural integrity, pressure capacities,and overall condition of the existing water mains, as well as the capability torehabilitate and/or need to replace these pipelines. It included analysis of the existingconditions of the raw water mains, evaluation of the frequencies of repairs and causesof failure, as well as thorough investigation and inspection of representative segmentsof each pipeline.This paper presents the components involved in the condition assessmentprogram, including: records research and compilation of data; site selection for fieldinvestigations; coordination with neighboring jurisdictions; evaluation andprioritization of pipeline deficiencies; public outreach; and, recommendations forrehabilitation or replacement of the water mains, plus a few of the repair projectscurrently under design. It summarizes the existing conditions of pipe joints,associated appurtenances, aerial crossings, special structures and other facilities alongeach pipeline, along with environmental conditions and other factors that will impactthe usefulness of these water mains. In addition, the paper describes thedevelopment of a data/document management file system utilizing digital aerialphotography, which was used to organize existing as-built record drawings, propertyand deed information, and other important documents, into a single environment. Includes table, figures.

Product Details

Edition:

Vol. - No.

Published:

06/01/2006

Number of Pages:

15

File Size:

1 file , 280 KB