Groundwater is in contact with surface water. However, traditionally, groundwater and surface water used to be considered as separate water resources (Winter, 1998). Because of that, management of groundwater and surface water resources poses a risk of allocating the same water twice in the water budget (Geosciences Australia, 2013). Not only two resources are in close contact rather they do interact. So, Winter (1998) considered groundwater and surface water as a single resource.
Surface water commonly is hydraulically connected to ground water, but the interactions are difficult to observe and measure (Winter, 1998). Interaction depends upon understanding the effect of topography, geology and climate of the groundwater flow system (Toth, 1970). Besides that, biotic factors are also responsible for the interaction (Sophocleous, 2002). Because of the complexity, the study of groundwater and surface water interaction has been studied for more than a century. The study was started using analytical method developed by Boussinesq (1877). Still today, study of groundwater-surface water interaction is the most common topic of research studying stream-aquifer interaction (Winter, 1995). In spite of difficulties observing and measuring the interactions directly, different techniques have been developed understanding the interaction. For example, measurement of hydraulic heads, temperature of water in the aquifer etc.
The study of groundwater-surface water interaction is not limited to methods related to physical properties of aquifer but it is rather extended to chemical and numerical methods and some have even taken a statistical approach to quantify interaction. Statistical methods like Principal Component Analysis (PCA) and end-member mixing analysis (EMMA) was applied with major ion chemistry and the stable isotopes of water and of dissolved inorganic carbon estimate mixing proportion among three sources (Hooper and Shoemaker, 1986; Doctor, 2006, Solis, 2007). Guggenmos et al. (2011) concluded that the multivariate statistics can be used as a rapid method to identify groundwater-surface water interaction at a regional scale using existing hydro-chemical dataset. The chemical approach measures degree of connectivity between the aquifer and the surface water using chemical and isotopic tracers from surface water, shallow aquifer, deep aquifer as well as rain water (Katz, 1997, Negrel et al., 2003, Baskaran et al., 2009). The common practice in measurement of interaction is using linear mixing models to partition two sources with a single isotopic signature or three sources with two isotopic signatures (Phillips and Gregg, 2001). Krabbenhoft (1990) concluded that the stable isotope method provides a way to integrating the spatial and temporal complexities of the flow field and thereby offer an alternative to the traditional time and labor intensive methods using seepage meters and an extensive piezometer network. Another approach...