Wednesday, December 19, 2007

Physiography of Sindh

Physiography of Sindh
Sindh comprises about 3% land mass of the Indo-Pak Subcontinent. It lies largely in the delta of the lower Indus basin, connected on three sides with areas of marked geographical contrasts. On the west, it rests against the slopes of Kirthar mountains bordering the Iranian tableland. Towards the east, it passes into the great desert of Thar, beyond which lie the Aravalli Range. At the base of the deltaic triangle it has the Arabian Sea-bed. In the North, narrow apex of Sindh penetrates into the plains of the Five rivers of Punjab. Sindh is about 360 miles long from North to South and nearly 275 miles in its exteme breadth (175 miles average). It covers an area of about 53,000 sq. miles.
Sindh is essentially a gift of the River Indus (Sindhu Darya). Its flowing length in Sindh is about 580 miles. It bisects Sindh, overflowing on both east and west valley regions to form the rich alluvial areas with forests and agricultural lands. The Indus delta region has been continuously growing reclaiming lands during historic times.
Sindh has a flat low-level country topography with some hills in the distance ( i.e. Halar and Sulaiman ranges of Kirthar) in the west and Aravalli in the east. Some isolated limestone rock formations are also evident near Sukker, Hyderabad and other areas. Its soils are deltaic valley soils, with sands more and more prominant as one goes towards the sea-board. Its rock are marine, with plenty of proofs of the presence of a sea which once lay between the two hilly regions of geologically different formations and age, viz., the Khirthar and the Aravallis ( also called as Karonjhar in the Sindhi folklore).
Phisiographically, Sindh can be divided in three vertical almost parallel sections:
I) Western highlands- comprising of the Kirthar Mountains and Sindh Kohistan extending from Sulaiman range in the North all the way to sea-board in the South.
II) Lower Indus valley- consisting of western and eastern valley sections and the deltaic area.
III) Eastern Desert- including Pat section and the Thar area.
A subtropical region, Sind is hot in the Summer and cold in winter. Temperatures frequently rise above 115 F (46 C) between May and August, and the minimum average temperature of 36 F (2 C) occurs during December and January. The annual rainfall averages about seven inches, falling mainly during July and August.The southwesterly monsoon wind begins to blow in mid-February and continues until the end of Semptember, whereas the cool northerly wind blows during te winter months from October to January.
Sindh is said to be between the two monsoons - the southwest from the Indian Ocean and the Northeast or the retreating monsoon, deflected towards it by Himalayan mountains- and escapes the influence of both. The average rainfall in Sindh is only 6 to 7 inches per year. But what is lost by the region during the two seasons is, however, regained for it by the Indus, in the form of inundation, caused twice a year, by the spring and summer melting of Himalyan snow and by rainfall in the monsoon season. It should be noted that these natural patterns have since been somewhat changed due to man-made dams and barrages that have been constructed on Sindhu Darya.
Climatically, Sindh is divided in three sections - Siro (Upper section centered at Jacobabad), Wicholo (Middle section centered at Hyderabad), and Lar (Lower section centered at Karachi). In Upper Sindh, the thermal equator passes through Sindh. The highest temperature recorded was 127 Degrees F in 1919. The air is generally very dry. In winter frost is common.
In MiddleSindh, average monsoon wind speed is 11 miles/hour in June. Temperature is lower than Upper Sindh but higher than the Lower Sindh. Dry hot days and cool nights are summer characteristics. Maximum temperature reaches 110-112 Degrees F. The Lower Sindh is effected by the coastline and is damper, humid, SW winds in summer and NE winds in winter and generally the climate is maritime with rainfall little less than the Middle Sindh. The maximum temperature reaches 95-100 Degrees F. In the Kirthar range at 6,000 ft and higher on the Gorakhnath and other peaks in Dadu district, temperatures near freezing have been recorded and brief snow fall is received in winters.
The Landscape
From north to south, Sind assumes a pattern of three parallel belts. A central stretch of rich alluvial plain bisected by the long, winding, silvery line of the Indus, flanked on the west by the rocky range of the Khirthar Range and bounded on the east by a sandy desert belt.
The Khirthar Range consists of three parallel tiers of ridges. The easternmost section is steep on the west but has a long gradient to the east. The central ridge has flat tops and rounded sides broken by deep ravines and fissures, whereas the westernmost tier consists of a vast plateau or tableland with some beaks rising above 7,000 feet. This mountainous belt has little soil and is mostly dry and barren. The easterly desert region first appears in the north as low dunes and vast flats. Continuing southward, the Achhrro Thar (White Sand Desert) occurs in the middle of the belt and is followed by the Thar Desert (q.v.) in the southeast.
The central riverine belt - 360 miles long and about 20,000 sqare miles in area - constitutes the Valley of the Indus. The fertile plain, gradually sloping down from north to south, in its long gradient forms the three flat regious known as siro (the upper), vichole (the middle), and larr (the lower). The variety of soils includes pakki, or patt, the flat level land of old alluvial forming the northern strips of the Sukkur, Jacobabad, and Larkana districts; reti-wari, the soft reddish rocky soil of the belt skirting the northwesterly rocky range; kacho, the fertile silt alluvial in the narrow inundated belt of the Indus; wariasi, an admixture of soft clay and sand; chiki, the composite fine clay and soft sand on both sides of the inundated belt; and kalar, or alkaline soil, found mostly in the larr region.
Vegetation And Animal Life
Except fot the irrigated Indus Valley, the province is arid and has scant vegetation. The dwarf palm, kher (Acacia rupestris), and lohirro (Tecoma undulata) trees are typical of the western hill region. In the central valley, the babul tree is the most dominant and occurs in thick forests along the Indus banks. The nim (Azadirachta indica), ber (Zizyphys vulgaris) or jujuba, lai (Tamarix orientalis) and kirirr (Capparis aphylla) are among the more common trees.
Mango, date palms, and the more recently introduced banana, guava, orange, and chiku are the typical fruit-bearing trees. The coastal strip and the creeks abound in semi-aquatic and aquatic plants, and the inshore Indus deltaic islands have forests of timmer (Avicennia tomentosa) and chaunir (Ceriops candolleana) trees. Water lilies grow in abundance in the numerous lake and ponds, particularly in the lower Sind region.
Among the wild animals, the sareh (Sind ibex), urial or gadh (wild sheep) and black bear are found in the western rocky range, where the leopard is now rare. The pirrang (large tiger cat or fishing cat) of the eastern desert region is also disappearing. Deer occur in the lower rocky plains and in the eastern region, as do the charakh (striped hyena), jackal, fox, porcupine, common gray mongoose, and hedgehog. The Sindhi phekari, red lynx or caracal cat, is encountered in some areas.
Phartho (hog deer) and wild bear occur particularly in the central inundation belt. There is a variety of bats, lizards, and reptiles, including the cobra, lundi (viper), and the mysterious Sind krait of the Thar region, which is supposed to suck the victim's breath in his sleep. Crocodiles are rare and inhabit only the backwaters of the Indus and its eastern Nara channel. Besides a large variety of marine fish, the plumbeous dolphin, the beaked dolphin, rorqual, or blue whale, and a variety of skates frequent the seas along the Sind coast. The Pallo (sable fish), though a marine fish, ascends the Indus annually from February to April to spawn

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