Sindh

The rivers that join the Indus at the Panjnad are all substantial, perennial watercourses, carrying large volumes of water, with the result that the Indus is swelled to a mighty river south of the Panjnad. After this meeting, the river turns westward and eventually splits, its main branch running in a southwesterly direction roughly parallel to the Kirthar Hills of southern Baluchistan, with an eastern branch, the Eastern Nara, running parallel. While the Indus enters the Arabian Sea south of the mountains of Baluchistan in a fan of distributaries, the Nara debouches into the Rann of Kutch. The gentle gradient of lands in Sindh is sufficient to maintain a rapid flow of water in the Indus but inadequate to prevent the river from meandering. The river's course has changed in detail on many occasions, as the annual floods cause it to cut new channels or as meanders are cut off to form oxbow lakes, and there have also been several major changes in its course since the end of the Pleistocene. The Indus and the Eastern Nara Rivers flow through land that receives little rainfall and is essentially desert, overlaid by alluvial deposits renewed by the annual inundation; in places these deposits are hundreds of meters thick. During the winter months, when there is little rain, the Indus is confined to its bed, often flowing along a levee. However, swollen in the spring by snowmelt in the Himalayas and in the summer by the rains of the southwest monsoon, the waters carried by the river increase five-, eight-, or even twelve-fold; massive floods on the latter scale now occur on average every five to fifteen years. The floodwaters overflow the levee banks and spread out over a wide area on both sides of the river, depositing first their heavy sediments on the levee banks and adjacent areas, then progressively finer sediments as the waters spread away from the river. Beyond the annually inundated active floodplain are areas that often also receive floodwater. Periodically the river breaks through the levee banks and cuts a new channel through the alluvium of its flood plain. One or both banks may be affected, so the annual provision of water and alluvial silts in any particular area is not entirely reliable, although the fluctuations do not cause prolonged hardship, due to the fertility of the soil and the abundance of the crops grown there (mainly wheat but also barley, pulses, and other crops). These are winter sown; some summer crops are also cultivated, including cotton and sesame. The most favored places for cultivation are patches of deep sediment left behind in channels carved out by the floodwaters: These can generally be sown directly, without breaking the soil with a plow. These fertile patches change their location annually and therefore must be searched for; other areas, watered and provided with fresh alluvium by the inundation, are plowed before planting, after the waters have receded. Cattle and water buffaloes are the main livestock kept by Sindhi farmers, whereas the fringes of the plain (the western piedmont and the margins of the Thar Desert) provide grazing for sheep and goats and, in the west, for wild sheep, wild goats, and onagers.

Oxbow lakes, where meanders of the river have been bypassed, are fertile habitats for wildlife. Seasonal lakes are also formed in levees abandoned by the river. Around the lakes grow reeds and palms as well as grasses. Many species of fish, shellfish, turtles, crocodiles, and birds abound in the lakes and rivers, and fishing is a major occupation of a number of groups in the region. Wild water buffalo, swamp deer, and wild boar were once also found in these wetland locations. Vegetation along the rivers is restricted to plants that can tolerate being immersed annually by the inundation, but substantial gallery forest grows in the meander plain of the river, beyond the active flood plain. Though reduced over the last century, the natural vegetation of the region includes a range of trees, such as acacia, pipal, sissoo, neem, tamarisk, and jujube. These forests and grassland have been home to tigers and lions, rhinos and elephants, peafowl, and other birds including the francolin.

Settlements are concentrated where water is available but where their inhabitants are not threatened by the annual inundation, such as on the banks of oxbow lakes and islands. Indus cities were often constructed on an artificial platform, to raise them above the danger of flooding, or were protected with massive brick walls.

To the west of the Indus River a piedmont plain edges the Kirthar Range of the mountains of Baluchistan and Sindh Kohistan to its south; through this run passes leading to the Baluchi uplands. In the summer this zone is watered by seasonal streams and torrents pouring down the mountainsides that deposit alluvium along their foot. The majority of these western watercourses peter out on the plain, but some may in the past have flowed into the Indus. North of the Kirthar Range and west of the Marri-Bugti Hills lies the Kachi plain, a substantial extension of the Indus plain into the mountains of Baluchistan. The Bolan River flows through the center of the plain and is the main access route to the west from the central Indus region. The valley is also watered by rivers flowing from the mountains on both sides, of which the Mula and the Nari are the most important. Unlike Sindh, this plain is also watered by rainfall, mainly in the summer from the southwest monsoon but also in the winter. Cultivation is now mainly in the summer (kharif) though some winter (rabi) cultivation also takes place: In the Indus period, rabi cultivation predominated, making use in some cases of small-scale irrigation using bunds (small dams) and small channels. The Kachi plain is a region transitional between the mountains of Baluchistan and the more challenging Indus plains, and it was occupied by farmers (at Mehrgarh) by the eighth millennium BCE.

In winter, when the Indus keeps to its bed, it is navigable by large boats; during the summer floods it is often too turbulent for navigation but at other times during the summer country boats with a shallow draught can be used on it. West of the Indus, a smaller river, the Western Nara, flows along an abandoned former bed of the Indus, the Sindh Hollow, and empties into Lake Manchar, a substantial lake on the west side of the Indus. Less violent than the Indus, the Western Nara can be used for navigation for part of the inundation season, as well as for irrigation. Lake Manchar increases in extent by around 10,000 hectares during the inundation and is a bountiful source of fish and birds. Its inhabitants have developed methods of coping with the floods by living in boats or in huts raised above the waters on platforms or by moving from houses to platforms during the floods. Lake Manchar today is considerably larger than it was in Indus times.

The main resource of the Indus Valley is its alluvium for agriculture. But, unlike the rivers of Mesopotamia and Egypt, the Indus also has important mineral resources. In central Sindh its current course passes through a major outcrop of limestone, the Rohri and Sukkur Hills, which have extensive deposits of high-quality flint, exploited by the region's inhabitants since Palaeolithic times. Alum, gypsum, and building stone are also available and in the Kachi plain there is bitumen, used by the early inhabitants of Mehrgarh to waterproof baskets.

To the east of the Indus and Eastern Nara is an arid region, somewhat higher than the Indus plain, giving way to the Great Indian, or Thar, Desert. The desert fringes and the arid Tharparkar region to the southwest receive some summer rainfall from the southwest monsoon, transforming these areas into a rich grassland into which cattle, goats, and sheep from the Indus Valley are driven for summer pasture. The limited rain falling on the desert accumulates in hollows to form seasonal lakes and pools, which provide water for people and animals.

Gujarat

The Tharparkar forms a corridor, used particularly in the summer when it is grassland, between the Indus Valley and the southern region of Gujarat. This region receives more rainfall than the desert and Indus Valley but still only around 400-800 millimeters per year, falling during the summer monsoons. Kharif dry farming is the norm today in the region, along with animal husbandry utilizing the thickets of scrubby vegetation, such as acacia, euphorbia, and caper, and grasses. Large numbers of cattle and goats are kept, as well as some sheep, both by farmers and by pastoral nomads who may move to Sindh during the driest months in the spring. Water buffaloes are also important in northern Gujarat and are kept in smaller numbers elsewhere. On the higher ground there is forest, often including the economically valuable teak, and in antiquity the forest cover was much greater. The area is home to many herbivores, such as wild water buffalo, boar, blackbuck, spotted deer, onager, and nilgai, and probably in the past bison (gaur), as well as elephants, rhinos, and lions. It also attracts many flocks of migratory and perennial birds, such as waterfowl, particularly in the Ranns but also in pools created by the rivers. The indented coastline has mudflats and deep estuaries, treacherous to those unfamiliar with their perils but offering good natural harbors. Fishing was and is a major activity in the Gujarat region and along the coast to its north. Fish caught in these waters include pomfret, mullet, grunt, shark, Bombay duck, sole, and many other species, as well as cuttlefish and a great range of shellfish, the shells from the latter being particularly esteemed as a raw material for making bangles and other artifacts. Pearl oysters are also known in the Gulf of Kutch.

The northern and northeast edge of the region is occupied by the Great and Little Ranns of Kutch, sandy salt mudflats that become marshes when they are flooded during the summer months. In the Indus period it seems likely that the Ranns were open water throughout the year. Settlement here is concentrated on patches of high ground, islands during the Indus period, on the largest of which, Kadir Island, was situated the major Indus city of Dholavira.

South of the Great Rann is the Kutch peninsula, a great island in Indus times. A substantial area of grassland south of the Great Rann provides rich pastures for large numbers of cattle, and pastoralism is the main way of life on the peninsula, which has little agriculture due to its low rainfall and lack of perennial rivers. Compensating for these dry conditions to some extent are underground water sources retained in sandstone, which mitigate the effects of periodic droughts.

The Little Rann curves round the east and south of Kutch and separates it from Saurashtra (Kathiawar), a large peninsula, much of which is taken up by a hilly plateau, surrounded by a belt of fertile alluvial soils. The many streams and small rivers draining the high ground carry a little water year round but are torrential and destructive after the monsoon rains. Saurashtra's soils are predominantly the water-retentive black cotton soils, suitable for dry farming, and crops are also irrigated from wells.

The Little Rann continues into the Nal Depression, an area of low-lying ground extending to the Gulf of Khambhat (Cambay), which fills with water during the monsoon season. In its center is the Nal Lake, a seasonal body of water. Pollen evidence shows this to have been a freshwater lake in the Indus period, greater in extent than the present-day lake. The important Indus town of Lothal is situated near the southern end of the Nal Depression.

The adjacent lands of the Indian mainland were also important to the Indus people. The North Gujarat plain is fertile but arid sandy alluvium with thorn forest. The Indus people apparently avoided the plain for settlement, and it has been argued that they did so because it was inhabited by well established hunter-gatherer groups with whom the Indus people enjoyed mutually beneficial relations. To the south, the coast of the Gulf of Khambhat is also alluvial, but the soils are salty and the plain is dissected by a number of seasonal river valleys, including the deeply entrenched Narmada and Tapti Rivers; it receives more rainfall than the areas to its north and west, tending to heavy flooding in the monsoon period. Fertile black cotton soils occur in parts of the region, and there is some cultivation but much of the region is grassland. The coastal strip is backed by the mountains of the Western Ghats.

Gujarat has important deposits of gemstones, particularly agate, which were obtained from the rivers and plateaus of Saurashtra and were mined at Rajpipla on the Narmada. Steatite and alabaster were also available. There was some copper in North Gujarat, and a little tin may have been obtained in North Gujarat and the Panch Mahal Hills to the east.

The Aravallis and the Thar Desert

A number of seasonal rivers flow into the Ranns or enter the sea through the Gulf of Khambhat. The most northerly is the Luni River, which flows into the northeast corner of the Great Rann. It originates among the Aravalli Hills, as do the Banas, which flows into the Little Rann; the Sabarmati, which empties into the Gulf of Khambhat; and other rivers. The Aravallis are a range of low hills situated on the southern edge of the Thar Desert. The vegetation of this area includes drought-resistant acacia and tamarisk. The area receives adequate rain in the summer to support agriculture in the lowland areas and to provide pasture on the uplands. The monsoon rains also fill the beds of seasonal streams, rivers, and lakes. It was home in Indus times to groups who lived mainly by fishing, hunting, and gathering. These hills are rich in minerals, including steatite, and were one of the main sources of the copper used by the Indus people; they may also have provided tin, gold, silver, and lead.

North and northwest of the Aravallis lies the Thar Desert, a rocky plateau of ancient alluvial clays overlain by shifting sand dunes and by patches of hills. Although potentially fertile, the soils depend on rainfall, which is generally low, with less than 100 millimeters in some parts. Fossil channels of ancient watercourses have been detected in parts of the Thar Desert, some blocked by sand dunes to form lakes. During the summer months these fill with runoff water from the hills and dunes but soon become saline and dry up. This region supports some wild fauna such as blackbuck, Indian gazelle, and desert foxes, and it is exploited today by pastoralists and in antiquity by hunter-gatherers; it may have been more hospitable in the past than it is today.

The Indo-Gangetic Divide and the Saraswati River Valley

Between the northeastern edge of the Thar Desert and the Himalayas lies the flat, fertile alluvial plain of the Indo-Gangetic divide, the region between the Punjab rivers and the Ganges. In its southern part, the Yamuna and Ganges rivers descend from the Himalayas to run in parallel south and east to their confluence at Allahabad and thence to the river's great delta on the Bay of Bengal. The Ganges-Yamuna doab (the land between the rivers) is an area of high rainfall; in antiquity this was covered by thick forests, including sissoo and sal, and by dense thickets, including acacia, all providing useful timbers. The abundant and varied flora and fauna, including Indian jungle fowl (the wild ancestor of the domestic chicken), supported hunter-gatherer communities, particularly around lakes. The Indus people moved into the northern part of the doab, penetrating as far east as the western bank of the Ganges, probably using fire to clear limited areas of forest, but, until the development in the first millennium BCE of iron tools for effective forest clearance, farmers from the north were unable to penetrate farther into the Ganges region. In the regions once settled by Indus farmers, winter-grown wheat is the main crop today, using irrigation.

Farther north, numerous streams and rivers descend from the Siwalik Hills, a low range forming part of western edge of the Himalayas and bordered by sal forest, and gradually converge to form a single river, known today as the Ghaggar or Hakra, now generally dry beyond the modern settlement of Hanumangarh. In antiquity it was called the Saraswati, a name confined today to one of the small rivers rising in the Siwaliks. These rivers are dry for most of the year but carry water seasonally, bringing alluvium to the plains between the Sutlej and Drishadvati (modern Chautang) Rivers. However, the existence of dry ancient riverbeds and the heavy concentration of Indus and other prehistoric sites along the existing and dried-up rivers indicate that in the past the rivers carried far more water and extended their flow farther west, perhaps as far as the Arabian Sea. While the rivers carry water only during the monsoon season, groundwater is also available from wells. Floodwaters from the Sutlej River to the north also sometimes fill portions of the dry riverbeds, creating lakes. The eastern area, with its numerous seasonal watercourses, is prime agricultural land, growing mainly wheat during the winter. Farther west the perennial vegetation is desert scrub with some trees, such as euphorbia and acacia. However, during the rains that fall in small quantities in both winter and summer, the region is transformed into rich grassland offering excellent pasture both for domestic herds of cattle, camel, and sheep, often brought here from Sindh during the annual Indus floods, and for wild game such as Indian gazelle, blackbuck, and, in the past, onager. Other local fauna in antiquity included wild boar, tigers, and lions. Modern irrigation permits some productive cultivation, and there is also considerable high-risk and low-yielding rain-fed agriculture in the river valleys.