General settings

Parameters with their default value and a description for the function kwb.wtaq::wtConfigureGeneral
Parameter Default value Description
title paste(“Input file generated by kwb.wtaq-functions on”, date()) Title of simulation; up to 70 characters in length. Leave this line blank if no title is specified.
format “DIMENSIONAL” Analysis format. Enter DIMENSIONAL.

Aquifer settings

Parameters with their default value and a description for the function kwb.wtaq::wtConfigureAquifer
Parameter Default value Description
aqtype “WATER TABLE” Type of aquifer being simulated. Two options are provided: AQTYPE = CONFINED or AQTYPE = WATER TABLE
bb 20 Thickness or saturated thickness of aquifer at beginning of simulation, in units of length.
hkr 4.10E-03 Horizontal hydraulic conductivity of aquifer, in units of length per time.
hkz 1.74E-03 Vertical hydraulic conductivity of aquifer, in units of length per time.
ss 3.76E-05 Specific storage of aquifer, in units of inverse length.
sy 0.25 Specific yield of aquifer, dimensionless. Enter 0 if AQTYPE = CONFINED.

Drainage settings

Parameters with their default value and a description for the function kwb.wtaq::wtConfigureDrainage
Parameter Default value Description
idra 2 Type of drainage at water table. Enter 0 if AQTYPE = CONFINED. Three options are provided: IDRA = 0: Instantaneous drainage. IDRA = 1: Gradual drainage. IDRA = 2: Drainage with unsaturated-zone characterization.
alpha c() Only used if idra = 1. Drainage constants, in units of inverse time. Maximum of 5 values is allowed.
acc 5.0 Only used if idra = 2. Soil-moisture retention exponent, in units of inverse length.
akk 31.7 Only used if idra = 2. Relative hydraulic-conductivity exponent, in units of inverse length. The value specified must be greater than or equal to that specified for ACC.
amm 100 Only used if idra = 2. Initial unsaturated-zone thickness above the capillary fringe, in units of length.
axmm 10 Only used if idra = 2. The unsaturated-zone thickness above the capillary fringe above which an assumption of an infinitely thick unsaturated-zone thickness is assumed, in units of length.

Time settings

Parameters with their default value and a description for the function kwb.wtaq::wtConfigureTimes
Parameter Default value Description
its 1 Time specification: ITS = 0: Log-cycle time steps (use to generate theoretical curves). ITS = 1: User-specified times.
tlast 0.0 Largest value of time. Enter 0 if ITS = 1.
nlc 0 Number of logarithmic cycles on the time scale for which drawdown will be calculated. Enter 0 if ITS = 1.
nox 0 Number of equally spaced times per logarithmic cycle for which drawdown will be calculated. Enter 0 if ITS = 1.

Solver settings

Parameters with their default value and a description for the function kwb.wtaq::wtConfigureSolution
Parameter Default value Description
isoln 2 Numerical-inversion solution type: ISOLN = 1: Solution by the Stehfest algorithm (must use this option for confined aquifers). ISOLN = 2: Solution by the de Hoog algorithm (must use this option for drainage with unsaturated-zone characterization [wtConfigureDrainage()$idra == 2]).
rerrnr 1.0E-10 Relative error for Newton-Raphson iteration and finite summations of drawdown for water-table aquifers. A value of 1.0E-10 is suggested. Enter 0.0D0 for AQTYPE = CONFINED.
rerrsum 0.0 Only used if isoln = 1. Relative error for finite summations of drawdown for confined aquifers. Suggested value is 1.0E-07 to 1.0E-08. Enter 0 if AQTYPE = WATER TABLE.
nmax 0 Only used if isoln = 1. Maximum number of terms permitted in the finite summations of drawdown for confined aquifers. Suggested value is 200. Enter 0 if AQTYPE = WATER TABLE.
ntms 30 Factor used to determine number of terms in the finite summations for drawdown for water-table aquifers. Suggested values are 20 or 30. Enter 0 if AQTYPE = CONFINED.
ns 8 Only used if isoln = 1. Number of terms used in the Stehfest algorithm. This must be an even integer, the value of which depends upon computer precision. If the computer holds 16 significant figures in double precision, let NS = 6 to 12. A value of 8 is recommended.
error 1.0E-04 Only used if isoln = 2. Relative error sought for the accuracy of the numerical inversion. A value of 1.0E-04 is suggested.
nnn 6 Only used if isoln = 2. Number of terms used in the summation of the Fourier series of the approximation to the inverse Laplace transform. A value of 6 is suggested.
method 3 Only used if isoln = 2. Indicates which method will be used to accelerate convergence of the Fourier series. Options are 1, 2, or 3. Only METHOD = 3 has been tested and was found to be satisfactory. Users can consult de Hoog and others (1982) and John Knight’s subroutine LAPADC for additional details if needed.

Pumping well settings

Parameters with their default value and a description for the function kwb.wtaq::wtConfigurePumpwell
Parameter Default value Description
ipws 0 Type of pumped well: IPWS = 0: Partially penetrating pumped well. IPWS = 1: Fully penetrating pumped well.
ipwd 1 Type of diameter of pumped well: IPWD = 0: Infinitesimal diameter (line-source theory). IPWD = 1: Finite diameter.
rw 1.0 Radius of pumped well screen, in units of length.
rc ifelse(ipwd == 0, 0, rw) Inside radius of pumped well in the interval where water levels are changing during pumping, in units of length. Enter 0 if IPWD = 0.
zpd 5.0 Depth below top of aquifer or initial water table to the top of the screened interval of the pumped well, in units of length.
zpl 10.0 Depth below top of aquifer or initial water table to the bottom of the screened interval of the pumped well, in units of length.
sw 0.0 Well-bore skin parameter, dimensionless.
qq 0.05 Pumping rate of well, in units of cubic length per time.
tspw data.frame(t = 60 * 1:3, dd = 2 * c(0.4, 0.6, 0.7)) data.frame with column containing the user-specified times for which drawdown at the pumped well will be calculated. If the data.frame has no rows, no drawdowns are calculated for the pumped well. The data.frame can (optionally) contain the drawdowns that have been measured for the pumped well at the corresponding times in an additional column .
pwname “PS” Name of pumping well. This parameter is not evaluated by WTAQ but will be used in the result data frame returned by wtRunConfiguration. We introduce it in order to be able to identify the well within a wellfield.
ipump 1 Option to suppress calculations of drawdown at pumped well: IPUMP = 0: Drawdown is not calculated at pumped well. IPUMP = 1: Drawdown is calculated at pumped well.
irun 1 Option to suppress drawdown calculations for the pumped well. Allows user to specify time-drawdown data, but those data are ignored during the simulation. Options are: IRUN = 0: Drawdowns not calculated. IRUN = 1: Drawdowns calculated.

Observation well settings

Parameters with their default value and a description for the function kwb.wtaq::wtConfigureObservationWell
Parameter Default value Description
obname “obs1” Name of observation well or piezometer; up to 10 characters in length.
r 30.0 Radial distance from axis of pumped well to observation well or piezometer, in units of length.
iows 0 Type of observation well or piezometer: IOWS = 0: Partially penetrating observation well. IOWS = 1: Fully penetrating observation well. IOWS = 2: Observation piezometer.
idpr 0 Options for delayed response of observation well. IDPR = 0: No delayed response. IDPR = 1: Delayed response.
rp ifelse(idpr == 0, 0, 0.1) Inside radius of the observation well (or piezometer) standpipe in the interval over which water levels are changing during pumping, in units of length. Enter 0 if IDPR = 0.
z1 ifelse(iows == 2, 0, 5.0) Depth below top of aquifer or initial water table to the top of screened interval of observation well, in units of length. Use for IOWS = 0 or 1. Enter 0 if IOWS = 2.
z2 ifelse(iows == 2, 0, 10.0) Depth below top of aquifer or initial water table to the bottom of screened interval of observation well, in units of length. Use for IOWS = 0 or 1. Enter 0 if IOWS = 2.
xll ifelse(idpr == 0, 0, z2 - z1) Length of screened interval of observation well or piezometer, in units of length. Enter 0 if IDPR = 0.
zp ifelse(iows == 2, 3.0, 0.0) Depth below top of aquifer or initial water table to center of piezometer in units of length. Use for IOWS = 2. Enter 0.0D0 if IOWS = 0 or 1.
tsobs data.frame(t = 60 * 1:3, dd = c(0.4, 0.6, 0.7)) data.frame with column containing the user-specified times for which drawdown at the observation well or piezometer will be calculated. If the data.frame has no rows, no drawdowns are calculated for the observation well or piezometer. The data.frame can (optionally) contain the measured drawdown for the observation well or piezometer at the corresponding times in an additional column .
irun 1 Option to suppress drawdown calculations for the observation well or piezometer. Allows user to specify time-drawdown data, but those data are ignored during the simulation. Options are: IRUN = 0: Drawdowns not calculated. IRUN = 1: Drawdowns calculated.