Peru

I

Introduction

Peru, officially Republic of Peru, country in western South America, bordered on the north by Ecuador and Colombia, on the east by Brazil and Bolivia, on the south by Chile, and on the west by the Pacific Ocean. The area of Peru, including several offshore islands, is 1,285,216 sq km (496,225 sq mi), making it the third-largest South American country (only Brazil and Argentina are larger). Lima is the country’s capital and chief commercial centre.

II

Land and Resources

There are three main topographical regions: the coastal plain, the sierra, and the montaña.

The coastal plain is an arid, elongated stretch of land extending the entire length of the country and varying in width from about 65 to 160 km (40 to 100 mi). The plain has most of the cities and industries of Peru, but few adequate harbours. A number of rivers flow through the region to the Pacific.

Parallel to and lying east of the coastal plain is the sierra, an upland region with the towering mountain ranges of the Andes, lofty plateaux, and deep gorges and valleys. The main mountain range is the Cordillera Occidental; other ranges include the Cordillera Oriental, the Cordillera Central, and a number of lesser chains. The sierra, which covers some 30 per cent of Peru, traverses the country from south-east to north-west and varies in width from about 400 km (250 mi) in the south to about 240 km (150 mi) in the north; the average height is about 3,660 m (12,000 ft). Several of the highest peaks in the world are located in the various sierran cordilleras and plateaux, notably Huascarán (6,768 m/22,205 ft), the highest in Peru. Lake Titicaca is in the south-east. Earthquakes occur in the sierra.

In the north-east the sierra slopes down to a vast tropical plain, the selvas, which extends to the Brazilian border and forms part of the Amazon Basin. The forested sierran slopes and a somewhat less elevated region are collectively designated the montaña. The montaña attains a maximum width of about 965 km (600 mi) in the north and constitutes some 60 per cent of Peru; it is covered with thick tropical forests in the west and with dense tropical vegetation in the centre and east. As a result, the region remains largely unexplored and undeveloped.

A

Rivers and Lakes

Peru has three main drainage systems. One comprises about 50 torrential streams that rise in the sierra and descend steeply to the coastal plain. The second comprises the tributaries of the Amazon River in the montaña region. In the third the principal feature is Lake Titicaca, which drains into Lake Poopó in Bolivia through the Desaguadero River.

The Napo, Tigre, and Pastaza rivers rise in Ecuador and flow into Peru. The last two streams are tributaries of the Marañón River, and the Napo empties into the Amazon River. The border between Peru and Colombia is delineated by the Putumayo River.

B

Climate

The climate of Peru varies widely, ranging from tropical in the montaña to arctic in the highest mountains of the Andes.

In the coastal plain the temperature is normally equable, averaging about 20° C (68° F) throughout the year. The coastal climate is moderated by winds blowing from the cool offshore current known as the Peru, or Humboldt, Current. The coast receives less than 51 mm (2 in) of precipitation each year, largely because the cordilleras receive most of the rain carried by the trade winds from the east. Mist-laden clouds known as garúa shroud many of the slopes of the sierra from June to October, providing enough moisture to support grasslands.

In the sierra the temperature ranges seasonally from about -7° to 21° C (20° to 70° F). Rainfall is usually scanty, but in some localities heavy rains fall from October to April. In Cuzco, in the south-eastern sierra, annual rainfall averages some 810 mm (32 in).

The montaña region is extremely hot and humid, although at higher altitudes it is less so. The prevailing easterlies blowing across the region gather moisture that is later deposited on the eastern Andean slopes. Annual rainfall in some districts averages as much as 3,810 mm (150 in). Most of this rain, which principally falls from November to April, eventually drains back to the montaña.