Drainages & Floodplains
DRAINAGES & FLOODPLAINS
The Study Area’s drainage is characterized by washes (ephemeral streams) that drain out of the Superstition Mountains into the valley floor through fan shaped areas of alluvial (sand, mud. gravel, etc} deposits.
Washes within the alluvial fans are not always clearly defined, and have a tendency to meander. As a result, their floodplains are not easily determined. The direction of drainage is generally southwesterly.
Several of these drainages are considered areas of potential flood hazard by the Federal Emergency Management Agency (FEMA).
ZONE A FLOOD AREAS
FEMA designates “Zone A” drainages as 100 year flood prone, of where flooding has a one percent chance of occurring in any given year. The Zone A drainages in the Study Area are Queen Creek. Whitlow Wash, Navajo Wash, and Peralta Wash.
ZONE B FLOOD AREAS
FEMA designates “Zone B” drainages as between the limits of the 100 year floodplain and the 500 year floodplain; or those subject to 100 year flooding that is less then one foot in depth; or, in an area where contributing drainage is less than one square mile; Or, protected by levees from a base flood. The only Zone B area in the Study Area is the Queen Valley area, which is protected by Whitlow Ranch Dam. Queen Valley’s Zone B covers parts of Donna Drive, Queen Valley Drive, and Diane Drive.
ZONE C FLOOD AREAS
The remainder of the Study Area is designated “Zone C” by FEMA. These are areas of minimal flooding.