Groundwater barriers are used to maintain separation between contaminated and non-contaminated groundwater regimes. They are often used as part of site reclamation works. In this paper, case studies of actual constructed barriers will be used to illustrate some innovative technologies that include slurry cut-off walls, biopolymer drainage trenches, soil-mixed barriers, and passive reactive barriers. In each case, a specific site will be used to illustrate the application of the technology to a project where the contaminated site will be returned to productive use. Examples of design mix considerations and results will be provided and significant details of construction will be described. Quality control data from the actual projects will be used to show how the final products conformed to the standards set for the works and to the design mixes established for the projects. The principal technical and economic advantages for each method are described. Example applications include a large size slurry wall project recently performed in Australia as well as other examples from the US where there is fully mature market for these technologies.