Alias question for frank

gistfile1.php

<?php
$params = array(
      'body' => $reach->img_shortcodes . $reach->description . "\n\n" .
        $reach->shuttledetails . "\n\n" . $reach->gaugeinfo,
      'fields' => array(
        'legacy_id' => array(
          'type' => 'text',
          'value' => array(
            $reach->reach_id,
          ),
        ),
      ),
      'format'    => 'filtered_html',
      'log'       => 'Imported from legacy Postgres database (table: reaches) on ' . date('Y-m-d'),
      'path'      => array('alias' => "content/River/detail/id/{$reach->reach_id}"),
      'title'     => $reach->name,
      'type'      => 'river_section',
      'uid'       => $uid,
    );
?>