where, K(T) is the hydraulic conductivity at a temperatureT°C,\(K_{\text{ref}}\) is the hydraulic conductivity at a reference
temperature ( \(T_{\text{ref}}\)) and f is the kinematic fluidity of
water which is also a function of temperature.
The mean temperature of infiltration water is
15 °C. The upper quartile
(3rd quartile) of pond water temperature provides the
reference for the average hydraulic conductivities in summer and the
lower quartile (1st quartile) provides reference for
the winter conductivities. The upper quartile of pond water temperature
is at 9.3 °C and the lower quartile is at 21 °C. After fitting these
values to equation 8, it is observed that the hydraulic conductivity
increases by 15 % in summer and decreases by 14.7 % in winter. In
other words, there is a 30% increase in hydraulic conductivity of the
pond bed in summer as compared to that in winter. The change in
hydraulic conductivity is not constant through the entire soil profile
since the temperature variation with depth is not uniform. According to
(Vandenbohede & Houtte, 2012), the temperature of water changes as it
moves down, which is influenced by the existing groundwater residing in
the aquifer. Temperature becomes constant after a depth of 25 m below
the ground surface. Hence, the influence of temperature is predominant
only close to the ground surface.