**2.1. Specimens**

Three samples of geonets were used. The first geonet is a 5.6mm thick high density polyethylene (HDPE) traditional bi-planar geonet. A photograph of this sample is shown in **Figure 1**. Analysis of Porous Behaviors by Water Flow Property of Geonets by Theoretical Simulation 61 http://dx.doi.org/10.5772/intechopen.85951

**Figure 1.** Photograph of various geonets samples: (a) bi-planar, (b) tri-planar, and (c) cylindrical type.

The second and third geonet are also HDPE, and have 8.6 mm tri-planar, 8.2 mm cylindrical type bi-planar structure, respectively. All these material are used for landfill cover and lining system drainage. Typical specifications for samples are provided in **Table 1**.
