Nav menu walker depth

Hi, How can I override the roots nav walker depth ? I would like to set the depth to 1 without changing the roots base code.

function roots_nav_menu_args($args = '') {
  $roots_nav_menu_args['container'] = false;

  if (!$args['items_wrap']) {
    $roots_nav_menu_args['items_wrap'] = '<ul class="%2$s">%3$s</ul>';
  }

  if (current_theme_supports('bootstrap-top-navbar') && !$args['depth']) {
    $roots_nav_menu_args['depth'] = 2;
  }

  if (!$args['walker']) {
    $roots_nav_menu_args['walker'] = new Roots_Nav_Walker();
  }

  return array_merge($args, $roots_nav_menu_args);
}

Manually set the depth argument when you call the menu, as you would with any other theme.