~ ~ ~ PURPOSE ~ ~ ~
this subroutine finds the effective lateral hydraulic conductivity
and computes drainage or subirrigation flux
~ ~ ~ INCOMING VARIABLES ~ ~ ~
name |units |definition
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
drain_co(:) |mm/day |drainage coefficient
ddrain(:) |mm |depth of drain tube from the soil surface
latksatf(:) |none |multiplication factor to determine conk(j1,j) from sol_k(j1,j) for HRU
pc(:) |mm/hr |pump capacity (default pump capacity = 1.042mm/hr or 25mm/day)
sdrain(:) |mm |distance between two drain tubes or tiles
stmaxd(:) |mm |maximum surface depressional storage for the day in a given HRU
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~ ~ ~ OUTGOING VARIABLES ~ ~ ~
name |units |definition
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
qtile |mm H2O |drainage tile flow in soil profile for the day
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~ ~ ~ LOCAL DEFINITIONS ~ ~ ~
name |units |definition
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
ddarnp |mm |a variable used to indicate distance slightly less
|than ddrain. Used to prevent calculating subirrigation
|when water table is below drain bottom or when it is empty
i |none |counter
w |mm |thickness of saturated zone in layer considered
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~ ~ ~ SUBROUTINES/FUNCTIONS CALLED ~ ~ ~
Intrinsic:
SWAT: depstor
~ ~ ~ ~ ~ ~ END SPECIFICATIONS ~ ~ ~ ~ ~ ~
find effective lateral hydraulic conductivity for the profile in hru j calculate parameters hdrain and gee1 calculate Kirkham G-Factor, gee calculate drainage and subirrigation flux section
Determine surface storage for the day in a given HRU (stor)
ddranp=ddrain(j)-1.0