streamDepletr (version 0.1.1)

hantush: Streamflow depletion in partially penetrating stream with semipervious streambed.

Description

Streamflow depletion in partially penetrating stream with semipervious streambed.

Usage

hantush(t, d, S, Kh, b, Kriv, briv, prec = 80)

Value

A numeric of Qf, streamflow depletion as fraction of pumping rate [-]. If the pumping rate of the well (Qw; [L3/T]) is known, you can calculate volumetric streamflow depletion [L3/T] as Qf*Qw

Arguments

t

times you want output for [T]

d

distance from well to stream [L]

S

aquifer storage coefficient (specific yield if unconfined; storativity if confined)

Kh

aquifer horizontal hydraulic conductivity [L/T]

b

aquifer saturated thickness [L]

Kriv

streambed semipervious layer hydraulic conductivity [L/T]

briv

streambed semipervious layer thickness [L]

prec

precision for mpfr package for storing huge numbers; 80 seems to generally work but tweak this if you get weird results.

Details

This function is described in Hantush (1965). As the leakance term (b*Kh/Kriv) approaches 0 this is equivalent to glover. It contains numerous assumptions:

• Horizontal flow >> vertical flow (Dupuit assumptions hold)

• Homogeneous, isotropic aquifer

• Constant Tr: Aquifer is confined, or if unconfined change in head is small relative to aquifer thickness

• Stream is straight, infinitely long, and remains in hydraulic connection to aquifer

• Constant stream stage

• No changes in recharge due to pumping

• No streambank storage

• Constant pumping rate

• Aquifer extends to infinity

References

Hantush, MS (1965). Wells near Streams with Semipervious Beds. Journal of Geophysical Research 70(12): 2829-38. doi:10.1029/JZ070i012p02829.

Examples

hantush(t = 1826, d = 1000, S = 0.2, Kh = 86.4, b = 100, Kriv = 0.0864, briv = 1)

Qf <- hantush(t = seq(1, 1826), d = 1000, S = 0.2, Kh = 86.4, b = 100, Kriv = 0.0864, briv = 1)
plot(x = seq(1, 1826), y = Qf, type = "l")