subroutine set_hc(smtill,smutil,hour,bdtill,bdutil)
c
c     +++PURPOSE+++
c     This function is called from the "WINTER" function on an hourly
c     basis and its purpose is to initialize inputs for and to cal-
c     culate the values for Hydraulic Conductivities.
c
c     Authors(s):  John Witte, UofMn WCES @ USDA-ARS-NCSRL
c     Date: 10/27/93

c     Verified and tested by Reza Savabi, USDA-ARS, NSERL 317-494-5051
c                  August 1994
c
c     +++ARGUMENT DECLARATIONS+++
      real    smtill,smutil,bdtill,bdutil
      integer hour
c
c     +++ARGUMENT DEFINITIONS+++
c     smtill - The soil moisture of the tilled soil. (%/100)
c     smutil - The soil moisture of the untilled soil. (%/100)
c     hour   - Hour of the day that the model is running. (hr)
c     bdtill - Bulk density of the tilled soil layer. (Kg/m^3)
c     bdutil - Bulk density of the untilled soil layer. (Kg/m^3)

c     +++PARAMETERS+++
      include 'pmxpln.inc'
      include 'pmxnsl.inc'
      include 'pmxhil.inc'
      include 'pmxtls.inc'
      include 'pmxtil.inc'
      include 'pmxcrp.inc'
      include 'pmxpnd.inc'

c     +++COMMON BLOCKS+++
      include  'cstruc.inc'
c       read:  iplane
c
      include  'cwater.inc'
c       read:  ssc,st,fctill(mxplan),fcutil(mxplan)
c
      include  'cwint.inc'
c       read:  thetdr,ssc,hk
c
      include  'cparame.inc'
c       read:  ks

c
c     +++LOCAL VARIABLES+++
      save
      real    portil,adjtil,adjutl,kstill,
     1        ksutil,kutill,kuutil,temp,porutl
      integer count
c
c     +++LOCAL DEFINITIONS+++
c     portil  - Calculated porosity of the tilled soil layer. (%/100)
c     porutl  - Calculated porosity of the untilled soil layr.(%/100)
c     adjtil  - Calculated Hyd. Conductivity adjustment-tilled. (*)
c     adjutl  - Calculated Hyd. Conductivity adjustment-untilled. (*)
c     kstill  - Saturated Hyd. Cond of tilled layer. (m/hr)
c     ksutil  - Saturated Hyd. Cond of untilled layer. (m/hr)
c     kutill  - Unsaturated Hyd. Cond of tilled layer. (m/hr)
c     kuutil  - Unsaturated Hyd. Cond of untilled layer. (m/hr)
c     count   - Temporary counter. (*)
c     temp    - Temporary real variable. (m/s)
c
c
c     +++END SPECIFICATIONS+++


c -- Porosity values for both tilled and untilled.

      portil = (2650. - bdtill) / 2650.
      porutl = (2650. - bdutil) / 2650.


c -- Adjusted values for both tilled and untilled.

      adjtil = (hk(1) + hk(2)) / 2.

      temp = 0.
      do 100 count = 3, nsl(iplane), 1
        temp   = temp + hk(count)
  100 continue
c     adjutl = temp / (nsl(iplane) -2 )
c
c XXX For test data set 19 - only have 2 soil layers (nsl(iplane)=2)
c     Thus - nsl(iplane) - 2 = 0, and you get a divide by zero.
c     This needs to be examined and fixed properly.
c     Currently ADJUTL isn't used for anything anyway.  dcf 2/25/94
c
      if(nsl(iplane)-2 .gt. 0)then
        adjutl = temp / float(nsl(iplane) - 2 )
      else
        adjutl = hk(2)
      endif


c -- 1/3 bar water content values for both tilled and untilled.

c     wiltil = (thetdr(1,iplane) + thetdr(2,iplane)) / 2.
c     temp = 0.
c     do 200 count = 3, nsl(iplane), 1
c       temp   = temp + thetdr(count,iplane)
c 200 continue
c     wilutl = temp / (nsl(iplane) -2)
c
c XXX For test data set 19 - only have 2 soil layers (nsl(iplane)=2)
c     Thus - nsl(iplane) - 2 = 0, and you get a divide by zero.
c     This needs to be examined and fixed properly.
c     WILUTL is used in subroutine CALCHC.  Following needs fixed
c     as my value for WILUTL will not be correct.  dcf  2/25/94
c
c     if(nsl(iplane)-2 .gt. 0)then
c       wilutl = temp / float(nsl(iplane) - 2 )
c     else
c       wilutl = thetdr(2,iplane)
c     endif


c -- Saturated hydraulic conductivity for tilled and untilled soil.

      kstill = (ssc(1,iplane) + ssc(2,iplane)) / 2.

      temp = 0.
      do 300 count = 3, nsl(iplane), 1
        temp   = temp + ssc(count,iplane)
  300 continue
c     ksutil = temp / (nsl(iplane) -2)
c
c XXX For test data set 19 - only have 2 soil layers (nsl(iplane)=2)
c     Thus - nsl(iplane) - 2 = 0, and you get a divide by zero.
c     This needs to be examined and fixed properly.
c     KSUTIL is used in subroutine CALCHC.  Following needs fixed
c     as my value for KSUTIL will not be correct.  dcf  2/25/94
c
      if(nsl(iplane)-2 .gt. 0)then
        ksutil = temp / float(nsl(iplane) - 2 )
      else
        ksutil = ssc(2,iplane)
      endif

      kstill = kstill * 3600
      ksutil = ksutil * 3600
c --  We must change the above units from m/sec to m/hr.

c      kstill = 0.0084
c      ksutil = 0.0084

c -- Palous... kstill = 0.0036
c --           ksutil = 0.0036

c -- Morris... kstill = 0.0084
c --           ksutil = 0.0084

c -- Field capacity for tilled and untilled soil layers.

c     fctill = (thetfc(1,iplane) + thetfc(2,iplane)) / 2.

      temp = 0.
      do 400 count = 3, nsl(iplane), 1
        temp   = temp + thetfc(count,iplane)
  400 continue
c     fcutil = temp / (nsl(iplane) -2)
c
c XXX For test data set 19 - only have 2 soil layers (nsl(iplane)=2)
c     Thus - nsl(iplane) - 2 = 0, and you get a divide by zero.
c     This needs to be examined and fixed properly.
c     FCUTIL is used in subroutine CALCHC.  Following needs fixed
c     as my value for FCUTIL will not be correct.  dcf  2/25/94
c
c     if(nsl(iplane)-2 .gt. 0)then
c       fcutil = temp / float(nsl(iplane) - 2 )
c     else
c       fcutil = thetfc(2,iplane)
c     endif


      call calchc(smtill,portil,wiltil(iplane),
     1            kstill,kutill,fctill(iplane))

      call calchc(smutil,porutl,wilutl(iplane),
     1            ksutil,kuutil,fcutil(iplane))

      usatkt(iplane) = kutill
      usatku(iplane) = kuutil

      return
      end