Estimation of Stream Conductance
The R. Herbert's stream conductance and the reach transmissivity constant are applicable for confined flow if the stream section conforms approximately to a semicircular section. The reach transmissivity constant is specific for the piezometer at which the potential difference is measured. The seepage from the stream under steady as well as quasi-steady-state flow is estimated by multiplying the difference in hydraulic heads at the stream boundary and at a piezometer or at an observation well in the vicinity of the stream with the corresponding reach transmissivity constant. The modified stream conductance derived preserving the depth of penetration and stream width or the one derived preserving the wetted perimeter of the stream and depth of penetration should be used in stream aquifer interaction studies. Herbert's stream conductance is applicable to streams with width about one-tenth of the aquifer thickness. The stream conductance derived maintaining the depth of penetration is the appropriate parameter for stream aquifer interaction study.