This subsection is on the lake plain of the Imperial Valley, which is southeast of the Salton Sea.  It has a very hot, arid climate.  MLRA 30h.

Lithology and Stratigraphy.   This subsection contains Quaternary, and some Pliocene, lacustrine deposits.  There are a few very small obsidian and pumice domes in a line from Obsidian Butte to Mullet Island at the southeast end of the Salton Sea.

Geomorphology.   This subsection is practically all nearly level dry lake bed.  The Imperial Valley is aligned toward the northwest.  The elevation range is from about -230 feet on the shore of the Salton Sea up to about sea-level on the old shore-line of Lake Cahuilla.  Fluvial erosion and deposition and eolian deflation and deposition are the main geomorphic processes.

Soils.  The soils are mostly Typic and Vertic Torrifluvents in coarse-loamy, coarse-silty, fine-silty, and fine families.  Also, there are some Typic Torripsamments and Typic Torriorthents.  The soils are well drained, except on poorly drained playas.  The soil temperature regimes are hyperthermic.  Soil moisture regimes are aridic.

Vegetation.   The predominant natural plant communities are Creosote bush - white bursage series and, around the Salton Sea, Allscale series. Mixed saltbush series and Mesquite series are common in riparian areas, and Iodine bush series and Saltgrass series are present around the margin of the Salton Sea.

Characteristic series by lifeform include:

Grasslands: Alkali sacaton series, Desert sand - verbena series, Indian ricegrass series, Pickleweed series, Saltgrass series.

Shrublands: Allscale series, Arrow weed series, Bush seepweed series, Fourwing saltbush series, Iodine bush series, Mixed saltbush series.

Forests and woodlands: Fremont cottonwood series, Mesquite series.

Surface Water.  Runoff is slow.  Drainage is to the Salton Sea.  The Alamo and New Rivers are the main conduits of overflow from the Colorado River.