Halophytic Plant Establishment in Playa Settings to Promote Dust Control at the Salton Sea, CA
Chris Sanderson1* , Ondrea Hummel1, Sujoy Roy1
1Tetra Tech Inc., Albuquerque, NM, USA
The Salton Sea is a hypersaline inland lake situated in the Coachella and Imperial Valleys of Southern California. Over the past 20 years the lake surface elevation has decreased by approximately 12 ft, exposing the dry lakebed (playa) and accumulated lakebed sediments containing metals, salts and likely a suite of degradation products resulting from chemicals used in production agriculture. Soils within the playa are saline with salinity ranging from 33-67 deciSiemens/meter, which is near the observed limit halophytic plant species used in study. The ongoing recession of the lake and subsequent exposure of the dry lakebed poses potentially significant air quality problems for the nearby population as well as the region in general. The lake surface elevation is expected to drop another 18 feet over the next 20 years (CH2M Hill, 2018), thus exposing an additional 80,000 acres of lakebed. If no action is taken, the increase in exposed lakebed is anticipated to contribute to an increase in wind-blown dust (PM10) and exacerbate a regional air quality problem.
A multi-disciplinary team led by the California Department of Water Resources, along with Tetra Tech, is studying the use of halophytic plant species to promote dust suppression and vegetation enhancement over 2,500 acres. The primary aim of this plan is to prevent dust emissions through roughness-based dust control methods. Roughness-based dust control consists of the construction of natural physical structures and establishment of Allenrolfea occidentalis and other plant species in hyper-xeric halophytic settings. This study investigated the use of several plant establishment techniques designed by Tetra Tech for use on an 80-acre pilot site. Study results will be presented, including plant species survivorship rates for both seeded and planted stock under various irrigation systems and watering regimes, plant species response to the cessation of irrigation, and the edaphic and vegetative parameters associated with plant establishment.