Sand motion and dust emissions in arid environments contribute to increased amounts of fine particulate matter suspended in the atmosphere, with possible negative consequences for human health at the local and regional scale. Prior to implementation of dust control measures in 2002, dust emissions from Owens (dry) Lake, California were the single largest source of fine aerosol particulate matter with a diameter less than 10 μm (PM10) in the United States. Sarcobatus vermiculatus, a deep-rooted woody phreatophyte shrub, stabilizes the dune system surrounding Owens Lake and is highly effective at reducing sand motion and trapping wind-blown dust during high-wind events. Declines in S. vermiculatus growth or health due to drought or other disturbances that reduce resource availability could contribute to destabilization of the dune system and greater likelihood of erosion and poor air quality. Nonetheless, relationships between S. vermiculatus health and function and resource availability are not well understood in the Owens Lake vegetated dune system. The purpose of this study was to investigate the effects of surface water inputs (precipitation, runon) on the growth and function of S. vermiculatus after consecutive years of drought. The southwestern United States has been in the grips of a megadrought since 2000, with 2021 marking an exceptionally dry year. As surface conditions become increasingly dry, many plants invest in deeper roots for accessing water, assuming adequate carbon reserves are available for root growth. However, previous studies in S. vermiculatus have demonstrated strong co-limitation of plant growth by water and nutrients (which typically arrive from surface inputs), such that the species might maintain a mostly shallow root system to capture pulses of water and nutrients. Though, a complete shift in root distributions for S. vermiculatus is unlikely due to the presence and availability of regional shallow groundwater. To understand the vertical distribution of S. vermiculatus roots we collected soil cores across eight dune locations (depth range 1.8 to 7.6 m) and extracted roots at intervals of 30 and 45 cm. To understand spatiotemporal dynamics in soil moisture, especially in relation to surface water inputs, we carried out monthly neutron probe readings over 13 months across the same dune locations, with readings occurring at the same depth intervals as root sampling. Neutron probe data were converted to volumetric water content (VWC) using calibration equations. To understand spatiotemporal dynamics in shrub function, in relation to key environmental drivers, we collected predawn and midday stem xylem water potential (Ψ), predawn and midday chlorophyll fluorescence (Fv/Fm, ΦPSII) and midday leaf gas-exchange (net photosynthesis [Anet], stomatal conductance to water vapor [gs]) on 48 shrubs spread across eight dune locations (6 per dune location) at six timepoints. Fortuitously, our data collection spanned markedly different environmental conditions, capturing both the tail end of a multi-year drought and above-average summer precipitation. Across locations and timepoints, we found that VWC increased following precipitation and runon events and VWC in the top 0.9 m of soil was positively correlated (R2 = 0.76, p< 0.0001) with predawn stem water potential (Ψpd). This indicated that shrubs respond to and utilize surface soil moisture even after periods of prolonged drought. Increased Ψpd was associated with higher midday Anet, gs, and chlorophyll fluorescence, though leaf temperature and vapor pressure deficit (VPD) were the most important drivers of Anet regardless of Ψpd. Additionally, following a significant late summer rain event in September 2022, shrubs produced substantial new growth. This new growth and combined with increased C fixation could increase C availability for growth and reproduction leading into the next growing season. Collectively, our data suggest that surface water is a key resource for S. vermiculatus and, although shrubs access deep soil moisture and groundwater, precipitation events seem to be a key driver in their growth and function.