<h2><a name="_description"></a>DESCRIPTION <a href="#_top"><img alt="^" border="0" src="../../../up.png"></a></h2>
<div class="fragment"><pre class="comment">sig_BFI calculates baseflow index (BFI).
   Calculates BFI, that is the ratio between baseflow (volume) and
   total streamflow (volume), with different baseflow separation methods 
   (Lyne and Hollick, 1979; UK Institute of Hydrology, 1980).

   INPUT
   Q: streamflow [mm/timestep]
   t: time [Matlab datetime]
   OPTIONAL
   method: which baseflow se