CLIMATE

In the Atacama region, the regional climate is mainly influenced by the following phenomena (Cepeda et al., 2004):

The southeast Pacific anticyclone, which blocks the frontal precipitation systems. As a consequence of the persistency of this atmospheric circulation system the Coquimbo Region is characterized as an arid climatic zone;
the cold Humboldt current along the Pacific coast,
the Andes mountains which create a longitudinal barrier to westerly winds,
El-Niño Southern-Oscillation, which causes increased precipitation on a 3 to 7 year time-scale.

According to the Koeppen classification, the Huasco valley is situated in a cold-arid desert climate (Kottek, Grieser, Beck, Rudolf, Rubel, 2006), characterized by winter rainfalls and hydrological deficits more than half year-long. Precipitation in the valley occurs almost exclusively as snowfall. Episodic rainfall events can occur during summer but do not represent a significant amount of the annual precipitation (Gascoin et al., 2010). One main characteristic for the valley, as for the whole region, is a strong variation of precipitation throughout the year and a strong altitude temperature gradient. At the coast, weather is foggy half the year and air humidity high, which changes with increasing altitude where temperatures and precipitation increases and air humidity decreases (Juliá et al., 2008).

Precipitation & Temperature

Precipitation is unevenly distributed, showing a clear altitude gradient. At Vallenar City (400 masl), mean annual precipitation is at 40mm/yr, compared to nearly 150 mm/yr in the high Andean mountains. Due to the low mean annual precipitation in the lower ranges of the valley, water availability relies nearly solemnly on snow melt (Squeo et al., 2008).

Temperatures in the valley are recorded with a minimum of 5°C (in July) and a maximum of 28°C (in January). 11 months of the year are frost-free up to Alto del Carmen. The following figures show climate variability with rising altitude gradients:

References and further reading:

Agrosuper (2006) Declaracion de Impacto Ambiental - Modificación Proyecto Agroindustrial del Valle del Huasco: Planta Rendering, Planta, Vallenar.

Aguilera, G., Pouilly, M. (2011) Iniciativa Agua y la Naturaleza (WANI), Vallenar, Huasco, Chile

Bitar, S., Weisner, R., Atenas, M., Musalem, M., Zenteno, P., López, A., Mardones, C., et al. (2009) Análisis de Impacto Económico y Social de Anteproyecto de Normas Secundarias de Calidad - Cuenca Río Huasco, Santiago.

Cepeda, J., Fiebig, M., Morales, H., Salas, S. (2004) Description of the Elqui River Basin, La Serena.

DGA (2004) Cuenca del Rio Huasco: Diagnostico y clasificacion de los cursos y cuerpos de agua segun objectivos de calidad, p. 105.

Fernández, J., Novoa, E., Córdova, A., Salvatierra, A., Sierra, C., Vásquez, C., Jimena, C., et al. (2008) Caracterización Textural de Suelos: Valle del Río Huasco, La Serena.

Gonzáles Aravena, V. (2011) Embalse Santa Juana y la Administración de las Aguas de la Cuenca del Río Huasco, Vallenar.

NSW (2010) Returning environmental flows to the Snowy River: An overview of water recovery, management and delivery of increased flows, Office, Sydney.

Núnez, J., Cortés, A. (2011) Modelo Para la Gestion Hidrica e la Cuenca de Huasco: Evaluacion de Caudal Ambiental y Valoracion de Servicios Hidrologicos, La Serena, Chile.

Núñez, J., Soto, G., Guitierrez, S., Barrera Martínez, L., Pizarro, I., & Wagnitz, P. (2012) Proyecto Desarrollo de un Modelo Para La Gestión Hídrica Sustentable del Valle del Huasco, Mediante la Evaluación de Caudales Ambientales y la Valoración Económica-Social de los Servicios Hidrológicos, Informe Final, La Serena, Chile.

Pizarro Barraza, I. (2012) Geomorfologia Cuenca Huasco, La Serena.

Pouilly, M., Aguilera, G. (2012) Evaluación preliminar de caudales ecológicos en la cuenca del río Huasco (Chile) mediante la simulación del hábitat físico del pejerrey Basilichthys microlepidotus y el camarón de río Cryphiops caementarius, Paris.

Pti (2010) Agricultura en el valle del huasco, Vallenar.

Pti-CORFO (2008) Plan Terretorial Estratégico en el àmbito Productivo en la Provincia de Huasco: Informe Final, Vallenar.

Stehr, D., Álvarez, G., Chávez, A., Isensee, P., Canepa, B., Acevedo, J., Bórques, M., et al. (2006) Aplicación de Metodologías para Determinar la Eficiencia de Uso del Agua: Estudio de Caso en la Región de Coquimbo, Coquimbo: Gobierno Regional - Region de Coquimbo.

Wagnitz, P. (2012) Cost-benefit analysis regarding environmental flow implementation in the semi-arid Huasco watershed, northern Chile, La Serena.

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