lling mean from the specified date, either by the first 
(<code>'left'</code>), last (<code>'right'</code>), or middle (<code>'center'</code>) day of the rolling n-day group of observations. 
Default <code>'right'</code>.</p></dd>


<dt>water_year_start</dt>
<dd><p>Numeric value indicating the month (<code>1</code> through <code>12</code>) of the start of water year for
analysis. Default <code>1</code>.</p></dd>


<dt>start_year</dt>
<dd><p>Numeric value of the first year to consider for analysis. Leave bla