Behind our apartment, right behind the patio, the complex's landscape dips sharply into a drainage ditch which we variously refer to as "the river" or "the moat".
Water tends to flow down along the east edge of the paved area of the property, picking up runoff from the short hill (and neighboring property), as well as vehicle spray from SUVs that bomb around the back pathway.
This runoff eventually collects into a drainage ditch which runs along this portion of the development. The moat is interrupted by a large tree which grows in "the hump" dividing the moat (which continues on to the west from here). Through the base of this hump is a 12-inch pipe to permit free water flow between the ditches.
In October 2003, during heavy fall rains, this pipe blocked up. By afternoon, the moat behind our apartment looked like this.