c$Author: fredfox $
c$Date: 2001-09-27 20:37:46 $
c$Revision: 1.2 $
c$Source: /weru/cvs/weps/weps.src/hydro/volwat_matpot_bc.for,v $

      real function volwat_matpot_bc(matricpot,thetar,thetas,
     1                                 airentry,lambda)
c     computes the volumetric water content at a matric potential

c*** Argument declarations ***
      real matricpot, thetar, thetas, airentry, lambda
c     matricpot  - soil water matric potential (pressure units of airentry)
c     thetar     - volumetric water content where hydraulic conductivity becomes zero
c     thetas     - saturated volumetric water content
c     airentry   - Van Genuchten parameter (1/pressure) (modify to set units returned)
c     lambda     - Brooks adn Corey pore size interaction parameter 

c*** Local variable declarations ***
      real  satrat
c     satrat     - conductivity relative saturation ratio

      satrat = (airentry/matricpot)**lambda
      volwat_matpot_bc = (thetas-thetar)*satrat + thetar
      return
      end