Aquifer Diffusivity and Stream Resistance from Varying Stream Stage

Estimation of layered aquifer diffusivity and river resistance using flood wave response model

“…The observed hydrograph is quite well matched to the calculated hydrograph except for B3(11). The estimated aquifer diffusivity is 18,636-81,151 m 2 /h, and river resistance is 479-1677 m through the ramp kernel method by Singh et al (2002). The estimated aquifer diffusivity and river resistance are 20,904-81,600 m 2 /h and 474-2886 m through the conventional convolution method presented by Hall and Moench (1972).…”

“…An overview of the derivation of the equations used in this study is presented here. The detailed mathematical expressions which are widely used as a conventional convolution are shown in Hall and Moench (1972), and the improved equations are shown in Singh et al (2002).…”

“…The river resistance, a, is derived from a head dependent flux boundary condition as expressed in Eq. (6), and is called as the retardation coefficient (Hall and Moench, 1972), which is the effective thickness of aquifer required to cause the same head loss as for the semi-pervious riverbank (Hantush, 1965 Singh et al (2002) uses discrete ramp kernel, and obtain more accurate and efficient results. They assume that the slope of the varying river stage is constant during a time step.…”

“…Table 1 flood wave response model. Both the conventional convolution equation by Hall and Moench (1972) and the discrete ramp kernel method by Singh et al (2002) were used to compare the calibration results to each other. The aquifer diffusivity, a and river resistance, a appear in a nonlinear form in Eqs.…”

“…They used the model of Zlotnik and Huang (1999), a model developed specifically for transient exchanges of water between an aquifer and a partially penetrating stream with semi-pervious bottom sediments. Singh et al (2002) presented an efficient method that uses discrete ramp kernel for obtaining the piezometric head in an aquifer due to an arbitrary variation in stream stage considering river resistance. The method assumes straight line variation between two consecutive points in representing the arbitrary river stage variation.…”