Balochistan, the largest of the four provinces of Pakistan, spreads over an area of 347,190 Sq, Kms., forming 43.6 per cent of the total area of Pakistan. It has clustered population and is smallest in proportion as compared to that of other provinces. Its population, according to 1998 census, is xx million, having a low density per square kilometer. Physically, Balochistan is an extensive plateau of rough terrain divided into basins by ranges of sufficient heights and ruggedness. Broadly, Balochistan geographic area can be divided in to four distinct zones: Upper high lands, lower high lands, plains, and deserts.
The upper highlands, known locally as Khorasan, rise as high as 3,700 meters, with valley floors about 1,500 meters above sea levels.
The highlands include Makran, Kharan and Chaghi ranges in the West and Sulaiman, Pab, Kirther in the east. The Upper High Lands fall mainly in districts Zhob, Killa Saifullah, Pishin, Quetta, Ziarat and Kalat. It comprises a number of ranges such as Sulaiman, TobakKakari, Murdar, Zarghoon, Takatu, and Chiltan ranges.
The Lower High Lands have an altitude ranging from 1970 to 3940 ft (600 to 1200 M). They are located in the south-eastern Balochistan, except eastern part of Kachi, the southern end of Dera Bugti and Nasirabad districts. Some are extension of lower high lands that exist at boundaries of Gwadar, Turbat, Panjgur, Kharan and Chaghi districts.
Balochistan has relatively small area of plains as compared to its total land area. They include the Kachi plain, situated to the south of Sibi and extending into Nasirabad Division, the southern part of Dera Bugti district, and narrow plain area along the Mekran coast stretching from Kachi to the Iranian border. The plains of Kachi, Las Bela and that of river Dasht cover sizable area. Mountains dominate the terrain, and valley floors, and piedmont plain make up only 15% of the landscape.
The western part of the province, mostly in Kharan and Chaghi districts, consists of vast plains covered with black gravel surface and broad expanses of sand dunes.
The coastal-line is about 760 Kilometers long, with a number of peninsulas and promontories. The coastal area is not effectively connected with the interior; the steep hills rise abruptly beyond the narrow costal plain. Ports, such as Somiani, Pasni and Gwadar are unsheltered. Federal and provincial governments have comprehensive development plans that feature a deep sea port at Gwadar and a coastal highway.
The climate of the upper highlands is characterized by very cold winters and warm summers. Winters of the lower highlands vary from extremely cold in the northern districts to mild conditions closer to the Makran coast. Summers are hot and dry. The arid zones of Chaghi and Kharan districts are extremely hot in summer. The plain areas are also very hot in summer with temperatures rising as high as 120 degrees F (50 degrees C). Winters are mild on the plains with the temperature, never falling below the freezing point. The desert climate is characterized by hot and very arid conditions. Occasionally strong windstorms make these areas very inhospitable.
Average annual precipitation in Balochistan varies from 2 to 20 inches (50 to 500 mm). Maximum precipitation falls in the northeastern areas with annual average rain fall ranging from 8 to 20 inches (200 to 500 mm). It decreases in the south and the eastern parts and is minimum in Naukundi. Kharan and Dalbandin area, rainfall ranges between 1 to 2 inches (25 to 50mm). Evaporation rates are higher than the precipitation and generally vary from 72 to 76 inches (1830 1930 mm) per annum.
RIVERS AND STREAMS
All rivers and streams are part of three major drainage systems. Coastal drainage system is characterized by small, ephemeral streams and hill torrents. Rivers and streams that do not possess any significant perennial flow constitute Inland system that dominates the central and northwestern area of the province. Nari, Kaha and Gaj rivers are part of Indus drainage system located in the northeastern margins of the province. The flow in rivers is typified by spring runoff and occasional flash floods. The rivers beds are dry and look like small streams. Stream gradients are high and the rate of run off is very rapid. The Zhob River Basin drains towards the northeast into the Gomal River which ultimately joins the Indus River. Streams along the border of Punjab and Sindh provinces flow toward the east and southeast into the Indus River. Central and western Balochistan drains towards the south and the southwest into the Arabian Sea. Some areas located in districts Chaghi, Kharan, and Panjgur drain into playa lakes, locally called " Hamun" such as Humun-e-Lora and Hamun-e-Mashkel etc.
The important rivers in Balochistan are Zhob, Nari, Bolan, Pishin, Lora, Mula, Hub, Porali, Hingol, Rakshan and Dasht