The presence of wetlands in the altiplano of northern Chile is due to azonal1 conditions (soil type, hydric dynamics, etc.), which allow vegetation to develop locally and limited to the geographic space that meets these conditions. In Chile, these systems are known as Azonal Terrestrial Hydric Vegetation Systems (SVAHT, by its Spanish initials).
Although this type of system shares the characteristic of requiring a permanent water supply with a strong seasonal influence (liquid precipitation and snowmelt), each SVAHT has its own particular dynamics. It is therefore necessary to understand their hydrogeological conditions in order to avoid impacts caused by industrial activity to be carried out in nearby areas.
Groundwater is usually the basal hydric component of SVAHTs, with a stable supply flow throughout the year. Therefore, characterizing the aquifer 2 that feeds the vegetation system is essential for environmental assessments and subsequent water-resource management strategies.
From a hydrogeological perspective, the study of a SVAHT requires identifying the water inputs that sustain its occurrence, which can be approached using two concepts:
1. Piezometric surface: This corresponds to the upper boundary of an aquifer, that is, the depth from the ground surface at which the water level is found. The piezometric surface makes it possible to recognize flow directions and hydraulic gradients.
Piezometry is determined by monitoring the depth of the water level in wells and/or shallow wellpoints [BL3] around the area of interest. Usually, shallow levels tend to show seasonal and even daily variations, so proper data collection is essential to understand these types of variations.
