The General Directorate of Water subdivides or brings together the basins of Chile according to the needs of study and management. There are two inventories that have managed to be accepted as main, the one of the basin inventory of the National Water Bank "Annex: Inventory of basins of Chile (BNA)") (BNA) of 1978, of greater use, and the inventory of basins of the Department of Water Resources Administration "Anex: Inventory of basins of Chile (DARH)") (DARH) of 2014 of better cartography that has forced to redefine some limits, sometimes with major changes, but also due to some redefinitions of the concept of subbasin.

Under the BNA the item code is 025 and with the DARH it is 0205.

The subdivision of the BNA is as follows:[5]​.

The layout of basins in the DARH inventory is as follows:[6]​.

From a geological point of view, in the subsoil of the basin there are 3 concentric sectors that have been formed over the course of millions of years. The central part, called the core, a ring around it called (with respect to the core) the marginal zone and an outer ring, called the alluvial zone.

The core of the salt flat is where the sediments left by the evaporation of water have accumulated. These are the evaporitic deposits. Its main component is halite, which in some places has a depth of up to 900 m.

The marginal zone (with respect to the core) is an intermediate zone, in which alluvial elements are mixed with salts and sedimented minerals.

The surface of the alluvial zone is practically the slopes of the elevations that surround and enclose the basin. Under it, the remains of the erosion of the Andes mountain range and the Domeyko mountain range have accumulated, that is, gravel, sand, clay and silt.[7]​ The thickest remains in the highest parts and the finest manages to be deposited at the lowest levels.

Contenido

Sus principales características morfométricas y climatológicas son:[8]​.

• - altura: 2300 m.

• - superficie de la cuenca: 18 100 km².

• - superficie del salar: 3000 km².

• - superficie de las lagunas: 12,6 km².

• - precipitaciones: 25 mm/año (salar) - 300 mm/año (Cordillera).

• - evaporación potencial: 2000 mm/año (salar) - 1600 mm/año (Cordillera).

• - temperatura media: 14 °C (salar).

La base de equilibrio del salar tiene un área húmeda de 1500 km², un 10% del área total del Salar, en una altitud media de 2.400 , que es alimentada por una profusa red de drenaje, cuyas principales cauces desembocan en la cabecera norte del salar a través de los ríos San Pedro de Atacama y Vilama. El primero es el principal aporte superficial al salar de Atacama. Existen también corrientes subterráneas en todo el límite oriental, un gran número de pequeños aportes generados en vertientes que caen desde el oriente y también por el extremo sur.[3]​[9]​.

Se puede dividir la afluencia al salar en dos zonas que son la norte y la oriental. Los caudales asociados a cada cauce son los publicados por un informe de la DGA.[9]​.

Tributaries coming from the north

The San Pedro de Atacama sub-basin, or Atacama, which includes the San Pedro River and the Vilama River, has a rainfall regime, the product of summer rains and to a lesser extent winter rains. In humid years the highest flows occur in summer, between January and February, and in winter, between July and August. In dry years the highest flows occur between June and July. The period of lower flows is observed in the quarter given by the months of September, October and November.[3]​.

1. • San Pedro de Atacama River, previously called simply the Atacama River, flow 1021 l/s;

1. Río Salado "Río Salado (San Pedro de Atacama)")

1. Pelon River

2. Río Grande "Río Grande (San Pedro de Atacama)")

1. Machuca River

2. Putana River

1. Incahuasi River

3. Jauna River.

2. • Vilama River, flow 218 l/s

1. Puritama River

2. Puripica River.

Bodies of water to the west

• - Aguada de La Escalera.

Tributaries coming from the east

The eastern sub-basin of the Atacama Salt Flat includes all the channels that flow into the eastern part of the Atacama Salt Flat. These contributions have fluviometric stations that only have gauges with information on specific flows, with a monthly record. With this information, the behavior of this subbasin can be determined in a general way, in order to broadly establish its regime. Very even flows are observed throughout the year, with slight increases in the winter and summer months. Due to the lack of information, it is not possible to properly determine the dry period of this sub-basin.[3]​ The tributaries of the salt flat to the east are, following Hans Niemeyer's description:[2]​.

On the west side, Niemeyer does not mention tributaries.

Lagoons and lagoon systems

The lagoons of the Atacama salt flat are the accumulation in the lowest parts of the basin of runoff (surface) and the appearance on the surface of layers of water from the alluvial zone that until that place were underground. During the descent, both superficial and underground, the waters pass through areas rich in soluble minerals, which are dissolved, absorbed and transported to the lowest places in the basin, the lagoons.[7]​.

A DGA report establishes the following aquatic systems in the core of the salt flat, that is, where water, salts and brines accumulate:[10]​.

Soncor hydrological system:

1. • Dead Donkey Channel.

2. • Laguna Puilar").

3. • Chaxa Lagoon.

4. • Barros Negros Lagoon.

Quelana Water System:

1. • Quelana Waters.

Comb System:

1. • Internal Lagoon").

2. • Saladita Lagoon").

3. • Laguna Salada (Salar de Atacama) "Laguna Salada (Salar de Atacama)").

La Punta-La Brava-Tiloposo System:.

1. • Laguna La Punta").

2. • Laguna Brava (Salar de Atacama)&action=edit&redlink=1 "Laguna Brava (Salar de Atacama) (not yet written)").

3. • Vegas Tyloposo.

Tebenquiche System:

1. • Laguna Tebenquiche (Tebinquiche on the map of the Armed Forces of the United States of America, Tebenquinche in the cited work).

The Baltinache and Cejar lagoons are also located in the north of the plain.

There is between the Chaxa and Barros Negros lagoons the Burro Muerto canal, which flows between the San Luis bridge and the entrance to the Chaxa lagoon.[11]​ In this way, the Soncor system is formed, which includes the Puilar, Chaxas, Barros Negros lagoons and the canal itself, which some consider to be the most important ecosystem in the basin.[12]​.

The location of some of the lagoons can be seen in the following map of the area.

Glaciers

The public glacier inventory of Chile 2022 records a total of 19 glaciers in the basin. The total area covered is 1.8 km² and the volume of water stored in the glaciers is estimated at 0.015 km³.

hot springs

The Puritama Baths are hot springs with facilities for visitor service.

Wetlands

The biodiversity information and monitoring system of the Chilean Ministry of the Environment does not register wetlands of any type in the basin.[4]​.

There are artificial irrigation canals in the basin.

To have an approximation at the basin level (local cases are not reflected) of consumption compared to water availability, it is defined as:.

Following intricate definitions of consumption and demand that consider surface water, groundwater, minimum sustainability flows, and consumption that is not returned to the original channel, all according to standards of international organizations, the results have been classified into four cases:[13]​.

• - High water gap, more than 40% of the available water is consumed: there is strong pressure on the water resource and a maximum urgency to organize supply and demand. In these cases, the low availability of water is a limiting factor in economic development.

• - Average water gap, between 20% and 40% of the available water is consumed: there is pressure on the water resource that must be managed, establish priorities, optimize its use and protect ecosystems, also through investments.

• - Moderate water gap, between 10% and 20% of the available water is used, the availability of water is a limiting factor for development.

• - Low water gap, less than 10% of the supply is used, there are no significant pressures on the water resource..

Applied this classification to the Atacama salt flat basin, the study estimates a moderate water gap with a use of 10% of the available water.[13]​.

The Agroclimatic Atlas of Chile distinguishes six climate districts in the salt flat:

• - 15-3-4 High altitude desert and xeric humidity regime (BWHXe) with temperatures between a January maximum of 20 °C and a July minimum of -0.1 °C. It has an average of 0 consecutive frost-free days. An average of 157 frosts are recorded during the year. The period of temperatures favorable to vegetative activity lasts 5 months. It annually records 700 degree days and 1,311 hours of cold accumulated until July 31. The average annual precipitation is 38 mm and a dry period of 12 months, with a water deficit of 2,058 mm/year. The wet period lasts 0 months during which a water surplus of 0 mm is produced.

• - 2-1 Interior desert and xeric humidity regime (BWXe) with temperatures between a January maximum of 28.3 °C and a July minimum of 3.3 °C. It has an average of 0 consecutive frost-free days. An average of 68 frosts are recorded during the year. The period of temperatures favorable to vegetative activity lasts 12 months. It annually records 1,528 degree days and 730 hours of cold accumulated until July 31. The average annual precipitation is 23 mm and a dry period of 12 months, with a water deficit of 2,273 mm/year. The wet period lasts 0 months during which a water surplus of 0 mm is produced.

• - 15-3-5 Cold high altitude steppe with xeric humidity regime (BSkXe) with temperatures between a January maximum of 11.4 °C (max of 20 °C and min of 5 °C within the district) and a July minimum of -7 °C (max of -2 °C and min of -9 °C within the district). It has an average of 0 consecutive frost-free days. An average of 360 frosts are recorded per year. The period of temperatures favorable to vegetative activity lasts 0 months. It annually records 81 degree days and 1,889 hours of cold accumulated until July 31. The average annual precipitation is 108 mm and a dry period of 12 months, with a water deficit of 1,559 mm/year. The wet period lasts 0 months during which a water surplus of 0 mm is produced.

• - 15-2-4 Cold high altitude steppe with arid humidity regime (BSkAr) with temperatures between a January maximum of 7.7 °C and a July minimum of -11.1 °C. It has an average of 0 consecutive frost-free days. An average of 365 frosts are recorded during the year. The period of temperatures favorable to vegetative activity lasts 0 months. It annually records 14 degree days and 1,800 hours of cold accumulated until July 31. The average annual precipitation is 211 mm and a dry period of 10 months, with a water deficit of 1,189 mm/year. The wet period lasts 0 months during which a water surplus of 0 mm is produced.

• - 2-3-4 Cold high altitude steppe with xeric humidity regime (BSkXe) with temperatures between a January maximum of 11.8 °C and a July minimum of -10.3 °C. It has an average of 0 consecutive frost-free days. An average of 365 frosts are recorded during the year. The period of temperatures favorable to vegetative activity lasts 0 months. It annually records 61 degree days and 1,800 hours of cold accumulated until July 31. The average annual precipitation is 119 mm and a dry period of 12 months, with a water deficit of 1,511 mm/year. The wet period lasts 0 months during which a water surplus of 0 mm is produced.

• - 2-3-3 Cold high altitude steppe with xeric humidity regime (BSkXe) with temperatures between a January maximum of 15.4 °C and a July minimum of -4 °C. It has an average of 0 consecutive frost-free days. An average of 321 frosts are recorded during the year. The period of temperatures favorable to vegetative activity lasts 0 months. It annually records 211 degree days and 1,909 hours of cold accumulated until July 31. The average annual precipitation is 61 mm and a dry period of 12 months, with a water deficit of 1,798 mm/year. The wet period lasts 0 months during which a water surplus of 0 mm is produced.

During the autumn and winter months of the southern hemisphere, there is practically no rain in the area due to the influence of the South Pacific anticyclone. When this front moves south, in the spring and summer months of the southern hemisphere, it allows rains from the tropical rain belt to reach the highlands.[9]​.

The Walter Lieth diagrams show with a blue area the periods in which precipitation exceeds the amount of water that the heat of the sun evaporates in the same period of time, (an average of 10 °C per month evaporates 20 mm of fallen water) leaving a humid climate. On the contrary, the yellow areas indicate that during that time the fallen water can be evaporated by the heat of the sun. The gray area indicates very humid months.

Se accede a la zona por la ruta internacional 23-CH, asfaltada desde Calama hasta el kilómetro 220 y luego con ripio hasta el Paso de Sico hacia Argentina.[14]​.

Agricultural holding

The San Pedro de Atacama River irrigates with its waters from the upper course the aillus of Condeduque (which includes the town of San Pedro), Solor, Larache, Yaye, Checar, Sequitor, Cucter and Coyo. In its lower course the aillus Machuca, Río Grande, San Bartolo, Cuchabrache, Catarpe, Tambillo, Guáchar and Quitor.[2]​.

Guatín is irrigated with the waters of the Vilama River, and the Vilama canal, which takes in the entire river, irrigates Purico, Vilama and the Poconche, Beter and Tulor aillus.

To improve the infrastructure of 1700 hectares. Agricultural projects were built in the 1960s, a total of 50 km of irrigation canals with prefabricated slabs. The San Pedro Alto canal is 9.8 km long and

capacity of 1.4 m/s; The Vilama canal is 14.2 km long and has a capacity of 0.5 m/s.

The 60,000 m³ Toconao pond that regulates the night waters of the Honar stream irrigates an area of ​​up to 33 hectares. which include more than 60 km of lined ditches.

The water from the Aguas Blancas stream is taken through a lined canal to terraced land located in the valley of the town of Toconao where it is used to irrigate pastures. In Socaire, up to 300 hectares of alfalfa and corn are irrigated through a 5 km long canal that runs into the stream of that name.

The other oases such as Zapar, Camar and Peine are smaller, although in Peine up to 50 hectares are irrigated with the water stored in a tank.[2]​.

Lithium exploitation

The salt flat has 25% of the world's lithium reserves and large quantities of borax and potassium salts.

The Sociedad Química y Minera de Chile (SQM) and others[15]​ have exploitation rights over salts and minerals from the salt flat, which they exploit by extracting brines from the subsoil and evaporating them in extensive shallow pools. These pools are visible from space.[16]​.

To extract the salts and minerals from the brine stored under the salt flat, the brine is pumped to the evaporation pools (the pools visible from space), exposed to the heat of the sun until the water evaporates, leaving the sediments that are collected and sent to other plants for subsequent treatment.[7]​.

Tourism

The area has acquired a great role in tourist offers of various kinds, among which the Church of San Pedro "Iglesia de San Pedro (San Pedro de Atacama)"), the R.P. Archaeological Museum stand out. Gustavo Le Paige, Tatio geysers, Valle de la Luna "Valley of the Moon (Chile)"), Baños de Puritama Hot Springs, Pukará and the village of Quitor, Aldea de Tulor, the Atacama salt flat itself, ALMA astronomical observatory, Los Flamencos national reserve, etc. There are many companies that offer tours to these tourist attractions, through them you can easily access all these places. Most are found around the central square of San Pedro de Atacama.

The basin has only one area under official protection belonging to the National System of Wild Areas Protected by the State (SNASPE):[3]​.

• - Los Flamencos National Reserve, has an area of 20,806 hectares[3]​ and includes

• Tebenquiche nature sanctuary;

• Valle de la Luna "Valley of the Moon (Chile)"), declared nature sanctuaries;

• Soncor hydrological system[17]​.

There are 5 priority sites in the regional biodiversity strategy: the ayllus of San Pedro de Atacama, the Tatio geysers, the Atacama salt flat, the Licancabur Volcano sector and according to law 19300 "Protected wild areas of Chile") the Lejía lagoon.[4]​.

The General Directorate of Water subdivides or brings together the basins of Chile according to the needs of study and management. There are two inventories that have managed to be accepted as main, the one of the basin inventory of the National Water Bank "Annex: Inventory of basins of Chile (BNA)") (BNA) of 1978, of greater use, and the inventory of basins of the Department of Water Resources Administration "Anex: Inventory of basins of Chile (DARH)") (DARH) of 2014 of better cartography that has forced to redefine some limits, sometimes with major changes, but also due to some redefinitions of the concept of subbasin.

Under the BNA the item code is 025 and with the DARH it is 0205.

The subdivision of the BNA is as follows:[5]​.

The layout of basins in the DARH inventory is as follows:[6]​.

From a geological point of view, in the subsoil of the basin there are 3 concentric sectors that have been formed over the course of millions of years. The central part, called the core, a ring around it called (with respect to the core) the marginal zone and an outer ring, called the alluvial zone.

The core of the salt flat is where the sediments left by the evaporation of water have accumulated. These are the evaporitic deposits. Its main component is halite, which in some places has a depth of up to 900 m.

The marginal zone (with respect to the core) is an intermediate zone, in which alluvial elements are mixed with salts and sedimented minerals.

The surface of the alluvial zone is practically the slopes of the elevations that surround and enclose the basin. Under it, the remains of the erosion of the Andes mountain range and the Domeyko mountain range have accumulated, that is, gravel, sand, clay and silt.[7]​ The thickest remains in the highest parts and the finest manages to be deposited at the lowest levels.

Contenido

Sus principales características morfométricas y climatológicas son:[8]​.

• - altura: 2300 m.

• - superficie de la cuenca: 18 100 km².

• - superficie del salar: 3000 km².

• - superficie de las lagunas: 12,6 km².

• - precipitaciones: 25 mm/año (salar) - 300 mm/año (Cordillera).

• - evaporación potencial: 2000 mm/año (salar) - 1600 mm/año (Cordillera).

• - temperatura media: 14 °C (salar).

La base de equilibrio del salar tiene un área húmeda de 1500 km², un 10% del área total del Salar, en una altitud media de 2.400 , que es alimentada por una profusa red de drenaje, cuyas principales cauces desembocan en la cabecera norte del salar a través de los ríos San Pedro de Atacama y Vilama. El primero es el principal aporte superficial al salar de Atacama. Existen también corrientes subterráneas en todo el límite oriental, un gran número de pequeños aportes generados en vertientes que caen desde el oriente y también por el extremo sur.[3]​[9]​.

Se puede dividir la afluencia al salar en dos zonas que son la norte y la oriental. Los caudales asociados a cada cauce son los publicados por un informe de la DGA.[9]​.

Tributaries coming from the north

The San Pedro de Atacama sub-basin, or Atacama, which includes the San Pedro River and the Vilama River, has a rainfall regime, the product of summer rains and to a lesser extent winter rains. In humid years the highest flows occur in summer, between January and February, and in winter, between July and August. In dry years the highest flows occur between June and July. The period of lower flows is observed in the quarter given by the months of September, October and November.[3]​.

1. • San Pedro de Atacama River, previously called simply the Atacama River, flow 1021 l/s;

1. Río Salado "Río Salado (San Pedro de Atacama)")

1. Pelon River

2. Río Grande "Río Grande (San Pedro de Atacama)")

1. Machuca River

2. Putana River

1. Incahuasi River

3. Jauna River.

2. • Vilama River, flow 218 l/s

1. Puritama River

2. Puripica River.

Bodies of water to the west

• - Aguada de La Escalera.

Tributaries coming from the east

The eastern sub-basin of the Atacama Salt Flat includes all the channels that flow into the eastern part of the Atacama Salt Flat. These contributions have fluviometric stations that only have gauges with information on specific flows, with a monthly record. With this information, the behavior of this subbasin can be determined in a general way, in order to broadly establish its regime. Very even flows are observed throughout the year, with slight increases in the winter and summer months. Due to the lack of information, it is not possible to properly determine the dry period of this sub-basin.[3]​ The tributaries of the salt flat to the east are, following Hans Niemeyer's description:[2]​.

On the west side, Niemeyer does not mention tributaries.

Lagoons and lagoon systems

The lagoons of the Atacama salt flat are the accumulation in the lowest parts of the basin of runoff (surface) and the appearance on the surface of layers of water from the alluvial zone that until that place were underground. During the descent, both superficial and underground, the waters pass through areas rich in soluble minerals, which are dissolved, absorbed and transported to the lowest places in the basin, the lagoons.[7]​.

A DGA report establishes the following aquatic systems in the core of the salt flat, that is, where water, salts and brines accumulate:[10]​.

Soncor hydrological system:

1. • Dead Donkey Channel.

2. • Laguna Puilar").

3. • Chaxa Lagoon.

4. • Barros Negros Lagoon.

Quelana Water System:

1. • Quelana Waters.

Comb System:

1. • Internal Lagoon").

2. • Saladita Lagoon").

3. • Laguna Salada (Salar de Atacama) "Laguna Salada (Salar de Atacama)").

La Punta-La Brava-Tiloposo System:.

1. • Laguna La Punta").

2. • Laguna Brava (Salar de Atacama)&action=edit&redlink=1 "Laguna Brava (Salar de Atacama) (not yet written)").

3. • Vegas Tyloposo.

Tebenquiche System:

1. • Laguna Tebenquiche (Tebinquiche on the map of the Armed Forces of the United States of America, Tebenquinche in the cited work).

The Baltinache and Cejar lagoons are also located in the north of the plain.

There is between the Chaxa and Barros Negros lagoons the Burro Muerto canal, which flows between the San Luis bridge and the entrance to the Chaxa lagoon.[11]​ In this way, the Soncor system is formed, which includes the Puilar, Chaxas, Barros Negros lagoons and the canal itself, which some consider to be the most important ecosystem in the basin.[12]​.

The location of some of the lagoons can be seen in the following map of the area.

Glaciers

The public glacier inventory of Chile 2022 records a total of 19 glaciers in the basin. The total area covered is 1.8 km² and the volume of water stored in the glaciers is estimated at 0.015 km³.

hot springs

The Puritama Baths are hot springs with facilities for visitor service.

Wetlands

The biodiversity information and monitoring system of the Chilean Ministry of the Environment does not register wetlands of any type in the basin.[4]​.

There are artificial irrigation canals in the basin.

To have an approximation at the basin level (local cases are not reflected) of consumption compared to water availability, it is defined as:.

Following intricate definitions of consumption and demand that consider surface water, groundwater, minimum sustainability flows, and consumption that is not returned to the original channel, all according to standards of international organizations, the results have been classified into four cases:[13]​.

• - High water gap, more than 40% of the available water is consumed: there is strong pressure on the water resource and a maximum urgency to organize supply and demand. In these cases, the low availability of water is a limiting factor in economic development.

• - Average water gap, between 20% and 40% of the available water is consumed: there is pressure on the water resource that must be managed, establish priorities, optimize its use and protect ecosystems, also through investments.

• - Moderate water gap, between 10% and 20% of the available water is used, the availability of water is a limiting factor for development.

• - Low water gap, less than 10% of the supply is used, there are no significant pressures on the water resource..

Applied this classification to the Atacama salt flat basin, the study estimates a moderate water gap with a use of 10% of the available water.[13]​.

The Agroclimatic Atlas of Chile distinguishes six climate districts in the salt flat:

• - 15-3-4 High altitude desert and xeric humidity regime (BWHXe) with temperatures between a January maximum of 20 °C and a July minimum of -0.1 °C. It has an average of 0 consecutive frost-free days. An average of 157 frosts are recorded during the year. The period of temperatures favorable to vegetative activity lasts 5 months. It annually records 700 degree days and 1,311 hours of cold accumulated until July 31. The average annual precipitation is 38 mm and a dry period of 12 months, with a water deficit of 2,058 mm/year. The wet period lasts 0 months during which a water surplus of 0 mm is produced.

• - 2-1 Interior desert and xeric humidity regime (BWXe) with temperatures between a January maximum of 28.3 °C and a July minimum of 3.3 °C. It has an average of 0 consecutive frost-free days. An average of 68 frosts are recorded during the year. The period of temperatures favorable to vegetative activity lasts 12 months. It annually records 1,528 degree days and 730 hours of cold accumulated until July 31. The average annual precipitation is 23 mm and a dry period of 12 months, with a water deficit of 2,273 mm/year. The wet period lasts 0 months during which a water surplus of 0 mm is produced.

• - 15-3-5 Cold high altitude steppe with xeric humidity regime (BSkXe) with temperatures between a January maximum of 11.4 °C (max of 20 °C and min of 5 °C within the district) and a July minimum of -7 °C (max of -2 °C and min of -9 °C within the district). It has an average of 0 consecutive frost-free days. An average of 360 frosts are recorded per year. The period of temperatures favorable to vegetative activity lasts 0 months. It annually records 81 degree days and 1,889 hours of cold accumulated until July 31. The average annual precipitation is 108 mm and a dry period of 12 months, with a water deficit of 1,559 mm/year. The wet period lasts 0 months during which a water surplus of 0 mm is produced.

• - 15-2-4 Cold high altitude steppe with arid humidity regime (BSkAr) with temperatures between a January maximum of 7.7 °C and a July minimum of -11.1 °C. It has an average of 0 consecutive frost-free days. An average of 365 frosts are recorded during the year. The period of temperatures favorable to vegetative activity lasts 0 months. It annually records 14 degree days and 1,800 hours of cold accumulated until July 31. The average annual precipitation is 211 mm and a dry period of 10 months, with a water deficit of 1,189 mm/year. The wet period lasts 0 months during which a water surplus of 0 mm is produced.

• - 2-3-4 Cold high altitude steppe with xeric humidity regime (BSkXe) with temperatures between a January maximum of 11.8 °C and a July minimum of -10.3 °C. It has an average of 0 consecutive frost-free days. An average of 365 frosts are recorded during the year. The period of temperatures favorable to vegetative activity lasts 0 months. It annually records 61 degree days and 1,800 hours of cold accumulated until July 31. The average annual precipitation is 119 mm and a dry period of 12 months, with a water deficit of 1,511 mm/year. The wet period lasts 0 months during which a water surplus of 0 mm is produced.

• - 2-3-3 Cold high altitude steppe with xeric humidity regime (BSkXe) with temperatures between a January maximum of 15.4 °C and a July minimum of -4 °C. It has an average of 0 consecutive frost-free days. An average of 321 frosts are recorded during the year. The period of temperatures favorable to vegetative activity lasts 0 months. It annually records 211 degree days and 1,909 hours of cold accumulated until July 31. The average annual precipitation is 61 mm and a dry period of 12 months, with a water deficit of 1,798 mm/year. The wet period lasts 0 months during which a water surplus of 0 mm is produced.

During the autumn and winter months of the southern hemisphere, there is practically no rain in the area due to the influence of the South Pacific anticyclone. When this front moves south, in the spring and summer months of the southern hemisphere, it allows rains from the tropical rain belt to reach the highlands.[9]​.

The Walter Lieth diagrams show with a blue area the periods in which precipitation exceeds the amount of water that the heat of the sun evaporates in the same period of time, (an average of 10 °C per month evaporates 20 mm of fallen water) leaving a humid climate. On the contrary, the yellow areas indicate that during that time the fallen water can be evaporated by the heat of the sun. The gray area indicates very humid months.

Se accede a la zona por la ruta internacional 23-CH, asfaltada desde Calama hasta el kilómetro 220 y luego con ripio hasta el Paso de Sico hacia Argentina.[14]​.

Agricultural holding

The San Pedro de Atacama River irrigates with its waters from the upper course the aillus of Condeduque (which includes the town of San Pedro), Solor, Larache, Yaye, Checar, Sequitor, Cucter and Coyo. In its lower course the aillus Machuca, Río Grande, San Bartolo, Cuchabrache, Catarpe, Tambillo, Guáchar and Quitor.[2]​.

Guatín is irrigated with the waters of the Vilama River, and the Vilama canal, which takes in the entire river, irrigates Purico, Vilama and the Poconche, Beter and Tulor aillus.

To improve the infrastructure of 1700 hectares. Agricultural projects were built in the 1960s, a total of 50 km of irrigation canals with prefabricated slabs. The San Pedro Alto canal is 9.8 km long and

capacity of 1.4 m/s; The Vilama canal is 14.2 km long and has a capacity of 0.5 m/s.

The 60,000 m³ Toconao pond that regulates the night waters of the Honar stream irrigates an area of ​​up to 33 hectares. which include more than 60 km of lined ditches.

The water from the Aguas Blancas stream is taken through a lined canal to terraced land located in the valley of the town of Toconao where it is used to irrigate pastures. In Socaire, up to 300 hectares of alfalfa and corn are irrigated through a 5 km long canal that runs into the stream of that name.

The other oases such as Zapar, Camar and Peine are smaller, although in Peine up to 50 hectares are irrigated with the water stored in a tank.[2]​.

Lithium exploitation

The salt flat has 25% of the world's lithium reserves and large quantities of borax and potassium salts.

The Sociedad Química y Minera de Chile (SQM) and others[15]​ have exploitation rights over salts and minerals from the salt flat, which they exploit by extracting brines from the subsoil and evaporating them in extensive shallow pools. These pools are visible from space.[16]​.

To extract the salts and minerals from the brine stored under the salt flat, the brine is pumped to the evaporation pools (the pools visible from space), exposed to the heat of the sun until the water evaporates, leaving the sediments that are collected and sent to other plants for subsequent treatment.[7]​.

Tourism

The area has acquired a great role in tourist offers of various kinds, among which the Church of San Pedro "Iglesia de San Pedro (San Pedro de Atacama)"), the R.P. Archaeological Museum stand out. Gustavo Le Paige, Tatio geysers, Valle de la Luna "Valley of the Moon (Chile)"), Baños de Puritama Hot Springs, Pukará and the village of Quitor, Aldea de Tulor, the Atacama salt flat itself, ALMA astronomical observatory, Los Flamencos national reserve, etc. There are many companies that offer tours to these tourist attractions, through them you can easily access all these places. Most are found around the central square of San Pedro de Atacama.

The basin has only one area under official protection belonging to the National System of Wild Areas Protected by the State (SNASPE):[3]​.

• - Los Flamencos National Reserve, has an area of 20,806 hectares[3]​ and includes

• Tebenquiche nature sanctuary;

• Valle de la Luna "Valley of the Moon (Chile)"), declared nature sanctuaries;

• Soncor hydrological system[17]​.

There are 5 priority sites in the regional biodiversity strategy: the ayllus of San Pedro de Atacama, the Tatio geysers, the Atacama salt flat, the Licancabur Volcano sector and according to law 19300 "Protected wild areas of Chile") the Lejía lagoon.[4]​.