Recommended methodology for determination of design groundwater levels

This paper describes a new methodology for the determination of Design Groundwater Levels (DGWL) or “reasonable maximum” groundwater levels required for design of road structures, such as pavements and bath structures. Existing methodologies, are not tailored for road design purposes, nor rigorously defined and suffer from gaps that may potentially result in either unacceptable risks or over-conservatism in road construction. The proposed methodology is based on hydrogeology concepts and incorporates various types of data that are collected through all the stages of a construction project. Application of the methodology is illustrated by determination of DGWL for the Gateway WA project which is a significant freight access road project around the Kewdale and Perth Airport precinct in Western Australia.