geotech (version 1.0)

wellHydraulics: Well Hydraulics

Description

These functions are used to calculate flow rate to wells (wellFlow), drawdown to wells (wellDrawdown), and hydraulic conductivity from pumping tests (kPump).

Usage

wellFlow(k, H = NA, h0, hf, r0, rw)
wellDrawdown(Q, k, H = NA, h0, r0, rw, r)
kPump(Q, H = NA, h1, h2, r1, r2)

Arguments

Q

flow rate into well

k

hydraulic conductivity of aquifer

H

thickness of aquifer

h0

initial total head in aquifer (before pumping)

hf

final total head in well casing (after pumping)

r0

radius of influence

rw

radius of well

r

radius of interest (for drawdown calculations)

h1

total head in farthest observation well (kPump

h2

total head in nearest observation well (kPump)

r1

radius from pumped well to farthest observation well (kPump)

r2

radius from pumped well to nearest observation well (kPump)

Value

• wellFlow outputs the flow rate to the well (Q)
• wellDrawdown outputs a two-element list containing:
  1. h = height of groundwater surface a distance r from the well
  2. dd = h0 - h = drawdown of groundwater surface a distance r from the well
• kPump outputs the estimated hydraulic conductivity of the aquifer from the pumping test

Details

• Datum for total heads is the bottom of the aquifer.
• Note the following classifications of aquifers as unconfined, confined, or mixed (which start as confined prior to pumping and finish as unconfined after pumping is complete):
  • For unconfined aquifers, H > h0 (or specify as NA) in wellFlow and wellDrawdown, and H > h1 (or specify as NA) in kPump.
  • For confined aquifers, H >= hf in wellFlow and wellDrawdown, and H >= h2 in kPump.
  • For mixed aquifers, H < hf in wellFlow and wellDrawdown, and H >= hf in kPump.

See Also

hydraulicConductivity

Examples

##  Example code for Flow rate to well
wellFlow(k = 0.065, H = 10, h0 = 21, hf = 15, r0 = 20, rw = 2)

##  Example code for Well Drawdown
wellDrawdown(Q = 14.5, k = 0.065, H = 10, h0 = 21, r0 = 20, r = 2,
             rw = 2)

##  Example code for Hydraulic Conductivity from pumping tests
kPump(Q = 14.5, H = 10, h1 = 20, h2 = 16, r1 = 16, r2 = 8)