Along the left side of the hole bordered by fencing is OB. If the ball exits the golf course OB then PHGA Local Rule #2 - Alternative to Stroke and Distance applies.
The creek and conservation area are considered penalty areas with red markers. Your options for relief are found How to take Relief from a Red Penalty Area under the Rules of Play section of the website.
The bridges are considered in the penalty area. Balls coming to rest on the bridges should be played as if in the penalty area.