anchor.diff:    return
   end subroutine update_velocities_for_barotropic_tendency
   
  -! -----------------------------------------------------------------------------
  +! ---------------------------------------------------------------------------
   !> Check that the free surface anomaly and layer thicknesses are consistent
   
  -subroutine enforce_moderate_free_surface(h, eta, depth, freesurfFac, thickness_error, nx, ny, layers)
  +subroutine enforce_moderate_free_surface(h, eta, depth, &
  +    freesurfFac, thickness_error, nx, ny, layers)
     implicit none
   
     double precision, intent(inout) :: h(0:nx+1, 0:ny+1, layers)
  
positive.code:   ! - The model then solves for the tendencies at the current step
    !   before solving for the fields at the next time step.
  
    !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    !!! MAIN LOOP OF THE MODEL STARTS HERE                                    !!!
    !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  
    do n = 1, nTimeSteps
  
  
negative.code:   return
  end subroutine evaluate_dhdt
  
  ! ---------------------------------------------------------------------------
  !> Calculate the tendency of zonal velocity for each of the active layers
  
  subroutine evaluate_dudt(dudt, h, u, v, b, zeta, wind_x, fu, &
  