The Navidad Watershed, also known as HUC 12100102, is located in central Chile and covers an area of approximately 1,300 square kilometers. The watershed is characterized by a Mediterranean climate with dry summers and wet winters. The hydrology of the watershed is dominated by surface water and snowpack, with the latter providing a significant portion of the water supply during the dry season. The Navidad Reservoir, which is located in the watershed, serves as a major source of drinking water and irrigation for the region. The reservoir is known to contain relatively high levels of arsenic and manganese, which are of concern to water managers. Climate change is expected to impact the hydrology of the watershed, with increasing temperatures and changes to precipitation patterns. In recent years, the region has experienced a decline in snowpack, which has implications for water supply and management.