The Corpus Christi Bay is locate in the southern Texas Coastal Bend, in a semi-arid region. Freshwater inflow is very low and the only sources of freshwater drainage to Corpus Christi Bay include the Nueces River and Oso Bay, from Oso Creek. The recently approved re-opening of Packery Channel in the southern reaches of the bay will provide another source of exchange in the near future. The Corpus Christi Bay system includes three of seven estuaries in Texas: Aransas, Corpus Christi and upper Laguna Madre. The system is separated from the Gulf of Mexico by Mustang and North Padre Islands, with water exchange taking place almost exclusively through Aransas Pass.