How does near-surface groundwater form evaporite crusts on playas?

On playas, near-surface groundwater plays a critical role in the formation of evaporite crusts through the process of rigorous evaporative concentration.1

In closed basins where groundwater flow is a primary water source, moisture is transported to the lowest portions of the playa. As this groundwater reaches the surface, the high rate of evaporation—which consistently exceeds the rate of precipitation and surface runoff in these arid environments—causes the water to evaporate, leaving behind concentrated dissolved minerals. This process leads to the precipitation and crystallization of salts, which accumulate to form evaporite crusts.2341

The physical nature of these crusts can vary significantly:
* Rugged crusts: Thick salt accumulations can create uneven, rugged surfaces, such as those found at the Devil’s Golf Course in Death Valley.1
* Smooth surfaces: Regular flooding and subsequent evaporation of thin layers can result in very smooth surfaces, like those at the Bonneville Salt Flats.1
* Salt karst: Fluctuations in the water table can lead to the dissolution of these soluble crusts, creating solution cavities and salt karst topography.1