Badwater Basin, located in Death Valley National Park, often appears dry, but water presence is rare and temporary. This landscape is the lowest point in North America, sitting at 282 feet below sea level. Although the vast salt flat is usually bone-dry, a small, permanent spring-fed pool of highly saline water exists near the roadside boardwalk. The basin occasionally transforms into a shallow, short-lived lake following heavy precipitation events, contrasting its typical arid state.
The Cycle of Temporary Surface Water
The appearance of water in Badwater Basin is tied to infrequent, intense rainfall in the surrounding region. The basin is endorheic, meaning water flows into it from the vast 9,000 square-mile drainage system but has no outlet. When significant rain falls on adjacent peaks, it generates flash floods that rush down the alluvial fans, collecting on the valley floor.
This runoff temporarily creates a shallow lake, sometimes called Lake Manly, which can stretch for miles across the salt flat. The water is typically only a few inches deep. The annual evaporation rate in Death Valley is immense (around 150 inches), dramatically outstripping the average annual rainfall of about 2 inches. Due to the extreme heat, surface water quickly disappears, sometimes lasting only a few weeks, leaving behind newly deposited salt.
The Geochemistry of the Salt Flats
The salinity of Badwater Basin is due to the process of evaporite formation. As water flows into the basin from the surrounding mountains, it dissolves minerals from the rock and soil. These dissolved solids, primarily sodium chloride (table salt), calcite, gypsum, and borax, are carried into the basin.
The water collects and is subjected to intense evaporation. As the water vaporizes, the dissolved minerals become increasingly concentrated, forming a dense brine. Eventually, the minerals precipitate out, crystallizing to form the thick, white salt crust that covers nearly 200 square miles of the basin floor. Repeated cycles of flooding and evaporation cause the salt crust to expand and fracture, creating the distinctive polygonal patterns visible on the flats.
Life Adapted to Hypersaline Conditions
Despite the hypersaline environment, life has adapted to survive in Badwater Basin. The organisms that thrive here are often extremophiles, such as halophilic (salt-loving) bacteria and archaea that live in the mud and brine pools, sometimes lending a reddish hue to the water.
The Badwater snail, an endemic species, is found only in the permanent water sources around the periphery of the salt flats. Salt-tolerant plants, known as halophytes (like pickleweed), grow around the margins of the permanent pool. Temporary life, including aquatic insects and brine shrimp, appears when the temporary lake forms.