The impact of urban groundwater upon surface water - eTheses ...

REVIEW
have been used to determine river discharge accretion and characterise river subsurface water
exchange (Harvey et al., 1996, Kimball, 2002).
Piezometers and piezometer nests have been used in several studies to obtain water samples
and head measurements within the groundwater/surface water interface (Dean et al., 1999,
Cey et al., 1998, Lee, 1980, Henry, 2000). Other in situ sampling devices have also been
developed such as the colonisation corer (Fraser et al., 1996) and the bead tube sampler
(Moore, 2000). Passive sampling techniques based on diffusive gradients across semi-
permeable membrane devices have been used to detect both hydrophobic organics and heavy
metals in aquatic environments (Vroblesky et al., 1997; Church et al., 2000). A number of
devices have been developed to measure the seepage across a lake or riverbed (Lee, 1977;
Carr et al., 1980; Isiorho, 1999) although the methods often encounter errors when used in
fast-flowing river environments (Libelo et al., 1994). The temperature gradient across the
groundwater/surface water interface has been used to determine flow rates (Silliman et al.,
1995, Evans et al. 1997). Several of the investigative methods identified in the literature
review were adapted for use in the present study.
2.5 Modelling methods
A review of analytical and numerical methods of modelling river-aquifer interactions are
presented by HRU (2001), Winter (1995) and Younger (1989). Analytical solutions have been
developed from early simulations of 1D groundwater interaction with fully penetrating
streams (Rorabaugh, 1964) to meet a range of applications. These include the simulation of
bank storage and groundwater fluctuations during river flood events (Serrano and Workman,
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