Maipo Valley
Maipo Valley is the iconic valley regarding the origin of the wines of Chile. In this valley were founded the first vineyards in the XVI century. Watered by the homonymous river, it is located between 32º55' and 34º19' latitude south, and between 69°47’ and 71°43’ longitude west. The areas of Santiago, Pirque, Puente Alto, Buin, Isla de Maipo, Talagante, Melipilla, Alhué and María Pinto belong to the Maipo Valley.
Following the course of the Maipo River we find the Maipo vine-growing zone, which is the same as the Metropolitan administrative region of the Republic, which is the only Mediterranean region of the country. It is located between 32º55′ and 34º19′ latitude south, and between 69°47’ and 71°43’ longitude west. The areas of Santiago, Pirque, Puente Alto, Buin, Isla de Maipo, Talagante, Melipilla, Alhué and María Pinto belong to the Maipo Valley.
Denomination of Origin: Maipo
Region: Central Valley
Sub-Region: Maipo
Complementary Areas:
- Lower or Costa or Coastal,
- Central or Middle or Entre-Cordilleras,
- Upper or Andean or Andes
Soils
The relief of this region is divided into three units, which are from east to west: the Andes, the basin of Santiago, located in the central sunken basin and the Coastal Range. Here, the Andes Range is high and massive; volcanic cones are the highest summits of the range. Among these we find the Tupungato 6,570 metres high, San José 5,856 metres, Maipo 5,264 metres, Nevado de los Piuquenes 6,010 metres, the Cerro Juncal 6,060 metres and the Cerro Plomo, 5,430 metres. The impressive heights of the Andes allow for the existence of permanent snows, which provide region with considerable water resources.
The Basin of Santiago is 80 kilometres long from north to south and 35 kilometres wide from east to west; it is located between the Coastal Range and the first foothills of the of the Andean precordillera. The Basin of Santiago is limited to the north by the Chacabuco Range and to the south by the Paine hills, and constitutes an important orographic unit. Part of the basin is occupied by the city of Santiago, at 520 m.a.s.l. of altitude. In this region, the Coastal Range is the natural boundary with the region of Valparaíso; it forms here a compact range from north to south and is the western boundary of the Santiago basin with summits over 2,000 metres. The Roble Mountain, 2,222 m.a.s.l., La Campana, 1,828 m.a.s.l., Vizcachas, 2,046 m.a.s.l., the Roble Alto with 2,185 m.a.s.l. and the Chicauma and Lipangue summits which frame the basin of Santiago to the west, they stop communications between Santiago and the coast. From the viticultural point of view, the Maipo region has a natural east-west slope; it has a mean eastern altitude of 1000 m.a.s.l. and goes down towards the west to an average of 500 to 600 m.a.s.l. Due to its topography, vine growing varies within these altitudes and is generally done on soft slopes.
From the viticultural-orographic point of view it is possible to outline three areas: Upper Maipo or Andes Maipo, Central Maipo or Entre Cordilleras Maipo and Lower Maipo or Costa Maipo Valley. All have different agroclimatic influences associated to their altitude above sea level and their greater or lesser distance from the Andes mountain range. The effects stemming from various climatic and orographic elements, such as the nocturnal wind that comes down the mountains and goes towards the west and which, has been called puelche since pre-Columbian times, have clear diverse influence in the vines active growing period. In the Upper Maipo (in the precordillera), also called Andes Maipo, and in sectors where the Andes have a stronger relief, there are coarse-grained soils derived from volcanic accumulation. Alluvial soils of moderate development are found in the zones known as Middle or Entre Cordilleras, or Central Maipo and Lower Maipo, also called Coastal Maipo or Costa Maipo Valley.
Climate
The influence of the Coastal Range and the distance from the sea are the main factors causing the continental characteristics of the Maipo Valley region climate. The Maipo Valley is characterised by a temperate Mediterranean type climate, with a long dry season and a short rainy winter. January is the hottest month in this area, with a mean temperature of 22,1 °C, and July is the coldest, with a mean temperature of 7,7 °C; the mean annual temperature is of 13.9 °C. Winter rains are a distinctive feature of this region; they cause rather precarious flood conditions and reach a mean annual rainfall of 356.2 mm. Rainfall decreases from the coast towards the sunken basin, and increases again in the Andes. In this way the general bioclimatic lines of the region and of the central zone of Chile are defined. Rainfall is irregular over the years: a year can be very rainy and the next one very dry. The Colina sector, and to a lesser degree, the zone near the city of Santiago, has climates that are more arid and have a wider thermal range, which reflect the influence of the northern steppe climate. This phenomenon is caused by the presence of the relatively high Coastal Range, which acts as a screen, and makes it difficult for the seafront climate conditions to enter the central basin. There are local climatic differences within the basin of Santiago, due to the effect of the relief and the eastern hills of the Coastal Range which acts as a climatic barrier, generating dry areas; some with semiarid characteristics.
The local climatic differences within the basin of the Maipo Valley can be clearly established: the Upper Maipo or Andes Maipo is located in the precordillera with sectors nearer to the Andes and of stronger relief; the transition zone of the Central Maipo or Entre Cordilleras Maipo, which is frankly Mediterranean and the Lower Maipo or Costa Maipo Valley zone further away from the mountain range and with a characteristic sunken basin relief, with a strong influence from the sea. In the Andes, above 3,000 metres, climatic conditions are those of a cold mountain climate, low temperatures and solid precipitation, thus accumulating snow and glaciers on the peaks and gullies of the high mountain range. The Maipo valley is conditioned by its surrounding hydrologic system, which is the Maipo River and its tributaries, the main water collecting system of the Maipo basin. The Maipo River extends from its birth in the slopes of the Maipo volcano down to its mouth in the Pacific Ocean. This river has a mixed flow pattern, and is in spate twice a year: in winter due to the rains and in spring because of the thaw of Andean snow and ice. In the cordilleran zone the Maipo River receives three large tributaries; these are the Volcán, Colorado and Yeso rivers. In the basin of Santiago it receives the Mapocho River, its main affluent, from the north which has an independent Andean basin. In the lower course its tributary is Puangue Brook, of coastal cordilleran origin and rains flow pattern, so it brings water to the Maipo only in winter. In its middle course the Maipo River receives the Clarillo and Angostura Rivers, the first drains a lateral depression where the Pirque reservoir was built. In the higher course other small brooks fall into the Maipo, such as the Popeta, El Sauce and San Juan. After a course of 250 kilometres the Maipo River falls into the sea at Llolleo, South of the Port of San Antonio.