<nav id="header_nav" class="clearfix">
    <?php wp_nav_menu(array('menu' => 'Header Menu','menu-class' => 'clearfix')); ?>
</nav>
<nav id="social_media" class="clearfix">
    <?php wp_nav_menu(array('menu' => 'Social Menu','menu-class' => 'clearfix')); ?>
</nav>