Description Usage Arguments Details Value References Examples

View source: R/induce_infiltration_time.R

Calculate the critical time at which stream transitions from gaining to losing.

1 | ```
induce_infiltration_time(d, S, Tr, Qa, Qw)
``` |

`d` |
distance from well to stream [L] |

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

`Tr` |
aquifer transmissivity [L2/T] |

`Qa` |
ambient groundwater inflow rate per unit length of stream [L2/T] |

`Qw` |
well pumping rate [L3/T] |

This calculates the critical time at which induced infiltration due to groundwater pumping begins, based on the glover model of streamflow depletion. Derived in Chen (2003) Eq. 4.

Assumptions:

Groundwater flow is perpendicular to stream

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 thicknessStream 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

Stream fully penetrates through aquifer

No streambed resistance to flow (see hunt or hantush for streambed resistance)

A numeric of `tc`

, the critical time at which induced infiltration begins [T].

Chen, X (2003). Analysis of Pumping-Induced Stream-Aquifer Interactions for Gaining Streams. Journal of Hydrology 275(1): 1-11. doi:10.1016/S0022-1694(02)00320-7

1 2 3 4 | ```
# recreate Figure 2 in Chen (2003)
Qa <- c(0.0001, 0.0003, 0.0005, 0.0008, 0.001)
tc <- induce_infiltration_time(d = 575, S = 0.2, Tr = 100*15, Qa = Qa, Qw = 2727)
plot(x = (pi * Qa * 100 * 15 * 575 / 2727), y = tc, log = "y")
``` |

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