Water constitutes about 14% of the city's total area, including Lewisville Lake, the Elm Fork of the Trinity River, and two local tributaries of the Elm Fork - Prairie Creek and Timber Creek. A riparian zone encompasses a portion of the city in the southeast. The intersection of the Elm Fork and Lake Lewisville has given rise to a delta at the southern end of the lake, extending south. The Federal Emergency Management Agency has labeled much of the area surrounding the delta as "Zone AE", meaning the area is subject to 100-year flood precautions.
Water constitutes about 14% of the city's total area including Lewisville Lake the Elm Fork of the Trinity River and two local tributaries of the Elm Fork - Prairie Creek and Timber Creek A riparian zone encompasses a portion of the city in the southeast The intersection of the Elm Fork and Lake Lewisville has given rise to a delta at the southern end of the lake extending south The Federal Emergency Management Agency has labeled much of the area surrounding the delta as "Zone AE" meaning the area is subject to 100-year flood precautions