Simulations of vadose zone moisture flow and contaminant transport typically use closedform soil hydraulic properties (i.e., unsaturated hydraulic conductivity and soil water retention characteristics). Understanding large-scale vadose zone hydrological processes requires a solid approach to characterizing the large degree of heterogeneity of hydraulic properties in the field (e.g., Dagan & Bresler, 1983; Bresler & Dagan, 1983; Vereecken et al., 2007). As a result, the impact of soil heterogeneity on vadose zone flow and transport has been the focus of considerable research in recent decades (e.g., Hopmans & Stricker, 1989; Butters & Jury, 1989; Ellsworth & Jury, 1991; Destouni, 1992; Russo, 1993, 1998; Mallants et al., 1996; Hendrayanto et al., 2000; Avanidou & Paleologos, 2002; Hristopulos, 2003; Jhorar et al., 2004; Das & Hassanizadeh, 2005; Kozak & Ahuja. 2005; Kozak et al., 2005; Neuweiler & Cirpka 2005; Ward et al., 2006; Lu et al., 2007; Coppola, et al., 2009). Local scale soil hydraulic properties have been studied extensively (e.g., Gardner, 1958; Brooks & Corey, 1964; Laliberte, 1969; Farrell & Larson, 1972; Campbell, 1974; Mualem, 1976; Clapp & Hornberger, 1978; van Genuchten, 1980; Libardi et al., 1980; van Genuchten & Nielson, 1985; Hutson & Cass, 1987; Russo, 1988; Bumb et al., 1992; Setiawan & Nakano, 1993; Rossi & Nimmo, 1994; Kosugi, 1994; Zhang & van Genuchten, 1994; Leij et al., 1997). However, connecting heterogeneous properties and processes at different scales remains a major scientific challenge in hydrology (Dagan, 1989; Gelhar, 1993; Renard & de Marsily, 1996; Sposito, 1998; Grayson & Bloschl, 2000; Kasteel et al., 2000; Cushman et al., 2002; Farmer, 2002; Zhang, 2002; Williams & Ahuja, 2003; Pachepsky et al., 2003; Zhang et al., 2004; Vereecken et al., 2007). One way to connect soil hydrologic processes at different scales is to employ hydraulic property upscaling. The upscaling algorithms seek to aggregate a mesh of hydraulic properties defined at the small (support) scale into a coarser mesh with “effective” hydraulic properties that can be used in large-scale (e.g., landscape-scale, watershed-scale, basin-scale) hydro-climate models. The main goal of using effective hydraulic properties is to capture particular flow and transport processes in a heterogeneous soil, through conceptualization of heterogeneous formation as an equivalent homogeneous formation. In this way, the heterogeneous system is replaced by an equivalent homogeneous medium (e.g., Rubin, 2003; Zhu & Mohanty, 2003a,b; Zhu & Mohanty, 2004; Zhu et al., 2007; Zhu, 2008; Zhu & Sun, 2009; Zhu & Sun, 2010). Hydraulic parameters that define the equivalent homogeneous medium are known as effective parameters.