SUBROUTINE INTERPWLV(NODE1,H,ARIV,WRIV,DWRIV)

      USE BLK1MOD
!	  INCLUDE 'BLK1.COM'

	  NLSEC11=NRIVCR1(node1)
      IF(NRIVL(NLSEC11) .EQ. 0) THEN
        IF(WTRIVCR1(node1) .gt. 0.) THEN
          ARIV=0.
          WRIV=0.
	      RETURN
	    ELSE
	      A11=0.
	      W11=0.
	      DW11=0.
	      GO TO 272
	    ENDIF        
      ENDIF
	  DO K=2,NRIVL(NLSEC11)
	    DEPL=CRSDAT(NLSEC11,K,1)-CRSDAT(NLSEC11,1,1)
          IF(DEPL .GT. H) THEN
            FRAC= (H+CRSDAT(NLSEC11,1,1)-CRSDAT(NLSEC11,K-1,1))/&
			(CRSDAT(NLSEC11,K,1)-CRSDAT(NLSEC11,K-1,1))
	      A11=CRSDAT(NLSEC11,K-1,2)*(1.-FRAC) +&
      	     CRSDAT(NLSEC11,K,2)*FRAC
	      W11=CRSDAT(NLSEC11,K-1,3)*(1.-FRAC) +&
      	     CRSDAT(NLSEC11,K,3)*FRAC
	      DW11=(CRSDAT(NLSEC11,K,3)-CRSDAT(NLSEC11,K-1,3))/&
            (CRSDAT(NLSEC11,K,1)-CRSDAT(NLSEC11,K-1,1))
	      GO TO 272
	    ENDIF
        ENDDO

!IPK MAY04   ALLOW FOR LEVEL ABOVE HIGHEST LAYER

	    W11=CRSDAT(NLSEC11,NRIVL(NLSEC11),3)
	    DW11=0.
        A11=CRSDAT(NLSEC11,NRIVL(NLSEC11),2)+W11*(H-DEPL)
     	      
 272    CONTINUE
 	    NLSEC12=NRIVCR2(node1)
        IF(NRIVL(NLSEC12) .EQ. 0) THEN
          IF(WTRIVCR2(node1) .gt. 0.) THEN
            ARIV=0.
            WRIV=0.
	        RETURN
	      ELSE
	        A12=0.
	        W12=0.
	        DW12=0.
	        GO TO 274
	      ENDIF
        ENDIF
	  DO K=2,NRIVL(NLSEC12)
	    DEPL=CRSDAT(NLSEC12,K,1)-CRSDAT(NLSEC12,1,1)
          IF(DEPL .GT. H) THEN
            FRAC= (H+CRSDAT(NLSEC12,1,1)-CRSDAT(NLSEC12,K-1,1))/&
            (CRSDAT(NLSEC12,K,1)-CRSDAT(NLSEC12,K-1,1))
	      A12=CRSDAT(NLSEC12,K-1,2)*(1.-FRAC) +&
      	     CRSDAT(NLSEC12,K,2)*FRAC
	      W12=CRSDAT(NLSEC12,K-1,3)*(1.-FRAC) +&
      	     CRSDAT(NLSEC12,K,3)*FRAC
	      DW12=(CRSDAT(NLSEC12,K,3)-CRSDAT(NLSEC12,K-1,3))/&
            (CRSDAT(NLSEC12,K,1)-CRSDAT(NLSEC12,K-1,1))
	      GO TO 274
	    ENDIF
        ENDDO
!IPK MAY04   ALLOW FOR LEVEL ABOVE HIGHEST LAYER
        W12=CRSDAT(NLSEC12,NRIVL(NLSEC12),3)
  	    DW12=0.
        A12=CRSDAT(NLSEC12,NRIVL(NLSEC12),2)+W12*(H-DEPL)
 274    CONTINUE
	  ARIV=WTRIVCR1(node1)*A11+WTRIVCR2(node1)*A12
	  WRIV=WTRIVCR1(node1)*W11+WTRIVCR2(node1)*W12
	  DWRIV=WTRIVCR1(node1)*DW11+WTRIVCR2(node1)*DW12

  300 RETURN
      END