AWWA INF53967

The City of Austin, Texas, needed to connect a newly annexed neighborhood calledDavenport Ranch to its drinking water system. The existing treatment plant atDavenport was unable to meet the required capacity of the region. It wasnecessary to quickly connect a 24-inch diameter pipeline to the City system toprovide the quantity and quality of water service needed. One of the significantobstacles to connecting the Davenport Ranch region was the 1,640-ft. widecrossing of Lake Austin. Also, the proposed alignment was adjacent to a majorhighway (Loop 360) and needed to cross beneath a 1,100-ft. wide highwayinterchange with severe space limitations. Both crossings were located in alimestone formation with some shot rock fill material. Horizontal directionaldrilling (HDD), a form of trenchless technology, was selected for both crossings.HDD would permit the crossing of both obstacles with minimal impact to thecommunity and environment while allowing continued access to both crossing areas. Includes figures.