TWO

WATER AND EMPIRE

ALONG THE BANKS OF THE GODAVARI RIVER, CLOSE TO THE MIDSIZED city of Rajahmundry on the eastern coast of India, stands a museum dedicated to Sir Arthur Thomas Cotton. Pointing the way to the museum, a bronze statue of the man watches over a busy bridge across the river; he is mounted on a horse, head cocked, eyes on the horizon.

Arthur Cotton was born in Surrey, one of eleven children. He joined the East India Company’s forces in 1819, as second lieutenant in the Madras Engineers. Two years later, he was seconded to the chief engineer of Madras, and developed his lifelong fascination with water. He was an evangelical Christian, a stern and devout man. His career began with a marine survey of the Pamban channel, off the coast of Madras. In the 1840s, Cotton renovated and restored the ancient dam at Kallanai, along the Kaveri River that flows east from the Western Ghats mountain range to the Bay of Bengal; the Kaveri’s fertile delta was, and still remains, the agrarian heartland of Tamil-speaking South India. Cotton’s attention moved north of the Kaveri, to the Krishna and Godavari rivers that meet the Indian Ocean in the region of Andhra, farther up India’s eastern seaboard.¹ In 1852, Cotton completed a barrage, or dam, over the Godavari River at Dowleswaram, which regulated the flow of the river using large gates. Henry Morris, the district’s chronicler, described the barrage as the “noblest feat of engineering skill which has yet been accomplished in British India.” It was a “gigantic barrier thrown across the river from island to island, in order to arrest the unprofitable progress of its waters to the sea.”² The Godavari delta gets scarcely a mention in most general histories of British India. It witnessed no major battles or massacres; it was home to few members of India’s nationalist intelligentsia; its urban centers were relatively small. But the region epitomizes the transformation of India’s waters in the nineteenth century.

Statue of Sir Arthur Cotton at the Arthur Cotton Museum, near Rajahmundry, India. CREDIT: Sunil Amrith

The Cotton museum, close to the barrage, conveys both unaffected enthusiasm and palpable neglect. The photographs are faded. Monuments of water technology from the 1850s—pulleys and simple pumps—are dotted around the complex. There is something almost accidental in their placement, as if they had been forgotten there. But the museum is well attended by groups of schoolchildren and by young couples. Most of the explanatory text in the museum is in Telugu. The message is unambiguous: Arthur Cotton saved the Godavari delta. His bold engineering skill turned it from a poor region into an expanse of irrigated fertility. Frescoes on the wall tell the story: before Cotton, this land was stalked by famine and leached by drought; thanks to his munificence it became the “rice bowl” of India, secure from the fluctuations of climatic fortune. On a local bus the next day, my neighbor turned to me and—prompted by nothing more than the lush landscape around us, and a sense that I was a visitor—told me the story again. “Everything here,” he said, his arm sweeping across the horizon, “is here because of Cotton dora (‘Boss Cotton’); he was a very great person.” A Telugu language biography of Cotton was published a few years ago. Farmers’ associations are named after him. Every year on his birthday, cultivators gather to garland his statue. In 2009 a small delegation from Andhra, including a former cabinet minister, traveled to England to locate his grave, which they found in a quiet corner of Dorking, Surrey. Such veneration of a colonial Englishman is unusual in contemporary India: curiously at odds with the movement to rename cities and streets and buildings to erase the stain of imperialism. It reflects a sense that water has a value beyond ideology, beyond politics—beyond history.

Fresco inside the Arthur Cotton Museum showing Andhra at the mercy of the elements before Cotton’s engineering feats. CREDIT: Sunil Amrith

Boat on the Godavari River. CREDIT: Sunil Amrith

The geography of empire in India was sculpted by wind and water. Until the nineteenth century, the only India that Europeans knew, the only India they were interested in, was the India that was wet. They sailed to India’s coasts, swept there by the direction of the monsoon winds; in the eighteenth century, they moved upriver into the Ganges valley, heartland of the successive Indian empires of the Mauryas, the Guptas, the Afghans, and finally the Mughals. By 1800, the English East India Company had defeated its remaining Indian challengers: the Marathas in the west, and Tipu Sultan’s kingdom of Mysore in the south. Following the Napoleonic Wars, British power commanded the Indian Ocean. But the British faced the same hydraulic dilemmas of every South Asian empire before them. The sea routes between India and the world were governed by the reversal of the winds. Communication between the coasts and the interior was slow; India’s mighty rivers could only be traveled up at certain times of the year; roads were poor. The East India Company’s revenues were tied to the cycle of planting and harvesting. Only gradually did the Company incorporate arid zones into its domain—the Deccan and the southeastern edge of the Peninsula by 1800; and then, by the middle of the nineteenth century, India’s northwest frontier.

Over the next half century British engineers and administrators and investors sought to master nature, as a step toward connecting India’s interior more closely to its coastal ports and from there to the rest of the world. The quest to understand water in India fused the efforts of adventurers and engineers, mariners and scientists. They were driven by curiosity and by necessity. Some sought profit and renown. Others followed their private enthusiasms. Not all of them served the colonial state. Their work would not have been possible without the ingenuity of Indian assistants, observers, draftsmen, recorders, porters, and soldiers, whose achievements have been effaced, for the most part, from the historical record. Women were scarce in this scientific world, but the few who were involved made contributions of lasting significance. The science of water in nineteenth-century India traced the descent of the rivers, the tracks of the storms, and the path of the rains. Each of these crossed the borders of British India. Knowledge of each brought awareness of interdependencies and inequalities on a regional scale. Each provoked new kinds of political intervention.

I

The word “monsoon” appeared in English first in the late sixteenth century, derived from the Portuguese monção. It comes from the Arabic mawsim (for “season”), which also provides the word for “season,” mausam, in Urdu and Hindi. In its simplest definition, it is a weather system of regularly reversing winds, characterized by pronounced wet and dry seasons. There are many monsoon systems around the world, but the Asian monsoon is by far the greatest in scale and consequence, and the Indian subcontinent is its zone of most intensive activity.

South Asia lies at the heart of the monsoon system because of the geological history that has left the Indian peninsula protruding from Eurasia into the vastness of the Indian Ocean. India lies at the edge of the continental landmass that dominates the northern hemisphere, facing a southern hemisphere that is mostly water. The monsoons have evolved over tens of millions of years. They have left an archive of their natural history on the seabed and on land. Tiny algae, diatoms, and single-celled marine plants called radiolara show that the monsoons first appeared in the Miocene era, soon after the Himalayas irrupted from the collision of the island Indian peninsula and the Eurasian landmass. Traces embedded in tree rings tell us that the Asian summer monsoon has strengthened during warm interglacial periods, as during the Medieval Warm Period up to the fourteenth century, and weakened during periods of planetary cooling, as during the Little Ice Age that lasted from the middle of the sixteenth to the early eighteenth centuries.

As early as 1686, English astronomer Edmund Halley identified the basic driving force of the monsoon as the differential heating of the sea and the land—he saw it as a gigantic sea breeze. In the summer months, land temperatures rise more rapidly than the sea warms. Winds are driven from areas of high pressure over the sea to areas of low pressure over land. “The Air which is less rarified or expanded by heat and consequently more ponderous,” Halley wrote, “must have a Motion towards those parts thereof, which are more rarified, and less ponderous, to bring it to an Equilibrium.” Halley’s understanding missed one crucial dimension, which was understood by George Hadley in the eighteenth century—Earth’s rotation affects the winds, causing them to veer right in the northern hemisphere and left south of the equator.³

So as the Asian landmass begins to heat up in the spring, the warming air above it rises, and cooler, moist ocean air moves in to take its place. The monsoon winds blow from the southwest, curving and doubling back to grip India, pincerlike, from both the Arabian Sea and the Bay of Bengal. The air sweeping in from the ocean contains vast stores of solar energy in the form of evaporated water, which is released as the vapor condenses as rain: the release of this stored energy sustains the power of the monsoon. The monsoon makes landfall in Kerala and Sri Lanka in late May or early June, reaching the Bengal delta by the end of the month and moving steadily inward. The arrival, or “burst,” of the monsoon is presaged by a period of unsettled weather and frequent thunderstorms. When it comes it can be spectacular. It brings welcome relief after months of building heat; it sustains the land’s capacity to feed India.

Torrential rainfall cools the earth’s sodden surface as the peaks of temperature and rainfall move steadily inland, finally petering out as they reach the far northwest of India and Pakistan. The Himalayas are a crucial part of the monsoon system. The elevation of the Tibetan Plateau leads it to warm rapidly and so drives the differentials of pressure and temperature that power the monsoon system; but the mountains themselves act as a colossal barrier to the winds, essentially sealing India off from the rest of Asia, and concentrating the monsoon rains to the south of the mountains, along the Gangetic plain.

As the temperature contrast between land and sea begins to even out, the system returns to equilibrium, and another period of transition begins. As winter advances the Asian landmass cools more rapidly than the ocean. The winds now reverse to blow from the northeast, creating dry conditions over much of Asia between November and March. But neither in summer nor in winter is the monsoon uninterrupted. The wet season is characterized by frequent suspensions in rainfall, known as “breaks”; the “dry” winter monsoon brings the bulk of the year’s rainfall for a few regions, including the Tamil Nadu coast in southeastern India.⁴ The periods of transition, as the winds reverse, are prime time for the devastating cyclones that visit the Bay of Bengal regularly. As we will see throughout Unruly Waters, the quest to understand the monsoon, which began in earnest in the second half of the nineteenth century, has been riddled with obstacles. The study of the monsoon remains filled with uncertainty.

IN THE LONG SWEEP OF INDIAN HISTORY THE MONSOON IS BOTH an internal and an external frontier. The monsoon has shaped the limits of cultivation and the distribution of crops. It has facilitated communication between some places and barred it between others. Its ecological niches have created economic unevenness—the stuff of which political power is made. The reach of the monsoon also marks the junction, the ecological nexus, between two very different ideas of India. One is as a settled agrarian empire; the other, as the outward-looking heart of the Indian Ocean world. The pattern of the monsoon draws a rough vertical line down the middle of the Indian subcontinent, dividing the drier west—part of a Eurasian “arid zone” stretching across Central Asia and as far as the Sahara—from the wet, marshy east, which stretches beyond, to Southeast Asia, to form a region that twentieth-century geographers called “monsoon Asia.”⁵ The bulk of India’s population has always lived to the east of that line.

The line dividing wet and dry zigzags across the subcontinent. The arid zone reaches down from Rajasthan in the northwest to the Deccan plateau at the heart of central India. The Deccan lies in the “rain shadow” created by the hulking Western Ghats mountain range—the rain clouds that sweep in from the Arabian Sea collide with the high mountains and disgorge their contents, leaving little for the plains beyond. From there arid bands snake down to the very far southeast of India, interspersed with more fertile coastal or riverine belts. The frontier corresponds to the ancient division—still visible today, though now modified by technology—between the major staple crops that have fed Indians for centuries: rice in the monsoon zone, and wheat or millet in the drier region.

The great rivers of South Asia modify the patchwork of wet and dry. They interact with the monsoon in a hydraulic cycle of colossal proportions. Because of their fertility, their ability to sustain life and to produce a surplus, the Gangetic plains have been the heart of every Indian empire. Their rich alluvial soils have supported a large population for centuries. The river system watered crops and provided an artery of transportation and trade, if never on the same scale or with the same reach as the Yangzi River system in China and its ancient complex of canals.⁶

Given their immense power both to sustain and to destroy life, India’s rivers have been among the most revered on Earth. The river Ganges—often styled as “mother,” or “Ma Ganga”—is the archetypical sacred river, spiritual source of all of India’s rivers, writes scholar of Hinduism Diana Eck. In some sense, all of India’s other rivers are microcosms of the Ganges. For millennia, the Ganges has been a site of pilgrimage, most especially at the point of its confluence with the Yamuna River at Prayag. For many Hindus, moksha—liberation from the cycle of rebirth—has been believed to come from bathing in the waters of the Ganges, or being cremated on it banks. The purity of the waters of the Ganges (gangajal) has long been accepted and valued by people across India. Hindu scriptures contain many versions of the origin myth of the Ganges, known as the avatarana, or descent to Earth. In the version of the story in the Ramayana and the Mahabharata, the unruly Ganges tumbles from heaven, tamed as it flows through the serpentine locks of Shiva’s hair before it spills onto the plains of India. In all of these stories, the Ganges epitomizes liquid shakthi, the energy that sustains the universe. The Ganges is not alone, it stands at the apex of a land of sacred waters. In many regions of India, rivers have been personified; their flow helps people to imagine how distant places are connected to one another. In many spiritual traditions in South Asia, the rivers have been thought to channel the power of all the water in the world, from the clouds to the oceans.⁷

THE LINE BETWEEN PLENITUDE AND SCARCITY MIRRORED THE trajectory of the rain-bearing winds and followed the paths of the rivers. Over centuries India’s rulers built irrigation canals, storage tanks, channels, and dams. These shifting arrangements bore little resemblance to Wittfogel’s ideal type of a “hydraulic society.” Regional leaders and imperial administrations spearheaded construction projects, but so too did local lineages, temple complexes, and landowners. In the pre-modern period the most widespread infrastructures of irrigation were found in Sri Lanka and in central and southern India. The biggest of them were elaborate hydraulic systems, individual waterworks linked in a larger web. And some of the dams, like the sixteenth-century Daroji reservoir in arid northern Karnataka, were large even by modern standards. Spurts of hydraulic ambition alternated with stasis, construction with disrepair. The power that arose from the control of water spread unevenly, liable to seizure or decay.⁸

Water was never far from the minds of the mounted conquerors from the highlands of Inner Asia who stormed their way to the Gangetic plain in the second millennium to forge a new political power in India. The heart of their power lay at the frontier between the monsoon and the arid lands. They harnessed the benefits of both. Established in 1206, the Delhi Sultanate was the first Persian-Islamic state in South Asia.⁹ Though it collapsed in the second half of the 1300s, riven by internal division and threatened by fresh invasions from the northwest, the reach of the sultanate’s power into the heartland of the Indian subcontinent was a prelude to the Mughals’ even greater empire.

The Mughals were a Turko-Mongol dynasty with roots in present-day Uzbekistan. They unified much of the Indian subcontinent during the two centuries when they were at the height of their powers. Zahir-ud-din Muhammad Babar (1483–1530), known as Babur, was the first Mughal emperor. He claimed descent from Timur (Tamerlane), the Turkic conqueror, and on his mother’s side from Chingghis Khan. Driven from Samarkand, Babur established a new kingdom in Kabul, Afghanistan. From there he launched an assault on the Indian subcontinent, where he established the Mughal Empire in 1526. From the age of twelve, he kept a diary from which he later composed the Babur Nama, one of the earliest autobiographies in the Islamic tradition. He was a meticulous observer. He was driven by naked ambition. He was not averse to brutality. He was a lover of nature. The Babur Nama is filled with references to water. Babur’s primary interest was in water as both ornament and practical necessity in constructing the gardens that he loved. In the Mughal tradition of landscape architecture, gardens played both a symbolic and an aesthetic role: they were places of beauty and sensual pleasure. Their proportions embodied the principles of order and harmony.

Babur’s interest in water went beyond the requirements of his exquisite gardens. He commented on the entire system of irrigation at work as he advanced into North India. The cultivation of gardens and the sustenance of agriculture were related endeavors.¹⁰ “The greater part of the Hindustani country is flat,” he observed of the Yamuna valley. “Many though its towns and cultivated lands are, it nowhere has running waters”—by “running waters,” Babur meant the canals well known in the Central Asian lands of his birth. Rather, “rivers and, in some places, stagnant waters” in wells or tanks, irrigated the Indian plains. He saw that “autumn crops grow by the downpour of rain themselves,” but that “some vegetables” had to be “watered constantly.” Babur observed cultivators at work. He was struck particularly by the method that the British would later dub the Persian Wheel. “In Lahore, Dibalpur and those parts people water by means of a wheel,” he wrote:

They make two circles of ropes long enough to suit the depth of the well, fix strips of wood between them, and on these fasten pitchers. The ropes with the wood and attached pitchers are put over the well-wheel. At one end of the wheel axle a second wheel is fixed, and close to it another on an upright axle. This last wheel the bullock turns. Its teeth catch in the teeth of the second, and thus the wheel with the pitchers is turned. A trough is set where the water empties from the pitchers and from this the water is conveyed everywhere.

Further down the Yamuna valley, toward Agra, he noticed that “people water with a bucket”—leather buckets lifted by yoked oxen—which he described as “a laborious and filthy way.”¹¹

The Mughal realm expanded ceaselessly between 1560 and 1605, and again between 1630 and 1690. Its territories stretched from Gujarat in the west to Bengal in the east, and far into South India.¹² The Mughals mobilized long-distance trading networks that followed the caravan routes to the western edge of central Asia and beyond. They stored wealth in precious metals. Once the Mughals conquered the Gangetic plains, they filled the state’s coffers from productive, densely settled agrarian lands and large populations. The Mughals inaugurated a rigorous system of land taxation. The administration relied on an interlocking system of larger landowners (zamindars), who served as tax collectors, and, below them, subordinate holders of rights to the land. The state used land grants to reward its loyal officials and to co-opt local elites into the system.¹³

Mughal military and financial prowess came from the mounted martial traditions of dry lands. As many as one in five men served in local military forces, often as seasonal labor in a climate where agriculture was uncertain and horses were plentiful.¹⁴ But India’s unruly waters had a bearing on Mughal military strategy, as they would later constrain the options of the British. As they approached the Bengal delta, Mughal armies struggled beyond Rajmahal—their horses were ineffective in the humid conditions; they had to use boats. The Akbar Nama, Abul Fazl’s account of the Emperor Akbar’s reign (1556–1603), describes the challenge of climate. In 1574, as Akbar’s forces captured the city of Patna—near the site of the ancient Ganges River port of Pataliputra—they “chose the river route, in this season full of turbulence, and with constant rain and tempest.”¹⁵

Aside from military campaigns, the instability of India’s rivers were a source of woe to local inhabitants. Historian Irfan Habib’s An Atlas of the Mughal Empire—a painstaking work of recovery—pieced together, from the minutiae of Persian sources and European travel accounts, how often, how abruptly, rivers changed course. This turmoil came from the huge loads of silt the rivers carried down from the Himalayas—when the rivers were in full force they threw up sandbanks and islands as obstacles around which the waters found a new path; silt deposits raised riverbeds and pushed the rivers into new channels. At other times, sudden changes in course were driven by violent earthquakes. The only response was flight—abandoned settlements lined the banks of vanished rivers, as when the Ganges “deserted” the once-flourishing town of Kanauj in the early sixteenth century. People had no choice but to move with the migrating waters. Beginning in the early seventeenth century, the Ganges began to shift eastward. A major earthquake in 1762 and another in 1769–1770 jolted the river away from its channel, forcing it into contact with new tributaries: the Tista and the Jamuna, the Jelangi and the Mathabhanga, the Kirtinasa and the Naya Bhangini. Even the names that rivers bore could be a testament to their instability: “Naya” means new, suggesting memories of an old Bhangini. The coastline shifted with the rivers: Habib reconstructs the coast of Gujarat through “decaying ports”: places that had once been on the coast, that now lay silted up.¹⁶

As their realm expanded to reach India’s coasts, the Mughals incorporated within their realm port towns that faced the eastern and western Indian Ocean. Long before the arrival of Europeans, merchants in India had trading links that spanned the Indian Ocean rim. Indian textiles filled marketplaces across Southeast Asia and China, the Mediterranean and West Africa. Many regions of India—Gujarat, Bengal, and the Coromandel coast—thrived on long-distance trade. Textiles brought forth medicinal products, spices, local crafts, and large quantities of precious metals. On one estimate the Indian economy absorbed 20 percent of the world’s supply of silver between 1600 and 1800.¹⁷ Throughout Southeast Asia’s era of commercial expansion in the sixteenth century, Indian traders from the coasts of Gujarat, Madras, and Bengal shipped cloth to Pegu and Tennasserim in Burma, to the thriving port of Melaka on the Malay peninsula, and to the Indonesian islands of Sumatra and Java.¹⁸

The Portuguese apothecary Tomé Pires observed in Melaka in 1512 that ships from Bengal brought “five white cloths, seven kinds of sinabafos, three kinds of chautares, beatilhas, beirames and other rich materials. They will bring as many as twenty kinds.” In their holds came “very rich bed-canopies, with cut-cloth work in all colors and very beautiful,” and “wall hangings like tapestry.” Pires concluded that “Bengali cloth fetches a high price in Melaka, because it is a merchandise all over the east”—from Melaka these textiles would make their way to markets across the Indonesian archipelago. In return, Indian traders exported from Melaka “camphor and pepper—an abundance of these two—cloves, mace, nutmeg, sandalwood, silk, seed-pearls a large quantity, copper, tin, lead, quicksilver, large green porcelain ware from the Liukiu [Japan’s Ryukyu islands], opium from Aden… white and green damasks, enrolados from China, caps of scarlet-in grain and carpets; krises and swords from Java are also appreciated.”¹⁹ The variety of Indian cloth gave rise to a lexicon that seeped into languages of trade everywhere: longcloth and salemporis, moris and gingham, dungarees and guinea cloth and kaingulong. Indian weavers targeted diverse markets. Their weaves, patterns, colors, and designs were all adapted to local tastes.²⁰

The Indian Ocean’s trading world reached deep into the interior. It intersected with circuits of commercial exchange that went overland to Central Asia. In India, as elsewhere, the sixteenth and seventeenth centuries saw the deepening commercialization of the countryside. From 1500, South India saw the rise of a merchant class whose diversified business included overseas trade, collecting and keeping a share of local tax revenues, and financing local rulers’ military ambitions. Global demand for Indian cotton set up a chain of transactions that linked the cotton-growing countryside to the port towns. Cultivators became more dependent on credit from urban merchants to finance the next year’s crop; gold and silver currency came into more widespread use. Agrarian commercialization fed the Mughal state’s treasury. The state’s demand for cash taxes, historian Victor Lieberman observes, “acted like a giant pump, sucking foodstuffs from the countryside into towns and cites.”²¹

This was the world that European trading companies entered; initially, they were players among many others. The monsoon winds brought the first Portuguese ships to India at the end of the fifteenth century. Arriving at Malindi on the eastern coast of Africa, Vasco da Gama sought advice from Indian traders there. They counseled him on the pattern of the winds that would take him across the Indian Ocean to Calicut. A local pilot guided his voyage. Chartered companies from Europe’s western edge took to the sea because the landed power of the three great Islamic empires—the Ottoman, the Safavid, and the Mughal—blocked their path across central Eurasia. So they found an alternative route to the profitable cotton textiles of India, the spices of the Indonesian archipelago, and the ceramic manufactured goods of China. Their ships rounded the Cape of Good Hope and crossed the Indian Ocean. They arrived on the coast of western India to find a region already open to the world, tied by commerce to the littoral of the Indian Ocean right up to the Mediterranean. Coastal India already, in the sixteenth century, faced both ways: connected to the far reaches of the Indian Ocean, but also to mountainous Central Asia.²²

Successive invaders of South Asia had come on horse from the northwest. Now, parvenu claimants to power approached by sea. Conquest was neither easy nor initially attractive. Monopoly was what the Europeans sought. In staking a claim to exclusivity they militarized the Indian Ocean’s sea lanes in a new way. Roiled by the Dutch revolt against the Spanish crown at home, the Portuguese soon met competition from the Dutch and English East India Companies in the Indian Ocean. European power was concentrated in a scattering of “factories” along the Indian coast. Each served as a dormitory, a trading post, and a warehouse all in one. European power rested on relationships delicately negotiated with local rulers. Competition among Europeans fueled the companies’ expansion—armed conflict at home and rivalry on the high seas heightened commercial contests in India.

By the eighteenth century European chartered companies had mobilized relationships and resources that spanned the globe.²³ They paid for their purchases in Asia with silver from the mines of Potosí (in present-day Bolivia). They transported Indian cottons to the coast of West Africa, and exchanged them for enslaved human beings. Europeans possessed many advantages as they inserted themselves into the fissiparous politics of regional kingdoms that had risen to fill the political void of a declining Mughal Empire. As well as precious metals, they could offer their local allies the security promised by the sophisticated weaponry at their disposal. The companies raised a lot of capital, quickly, aided by their structure as joint-stock firms. They intervened in local succession disputes. They did deals with bankers and zamindars. British, French, and Dutch companies became enmeshed at the frontier between the coast and the interior.²⁴

The transformative moment came in the second half of the eighteenth century. British maritime power pushed inland. Not long after the Battle of Plassey in 1757—which stabilized the British “bridgehead” in Bengal—the East India Company received the diwani, or the right to the land revenues of Bengal, the most fertile province of the Mughal Empire. Bengal’s agrarian wealth funded a violent cycle of English expansion. The Company’s army rose to become one of the largest military forces in the world. The English were the first truly to harness both of the monsoon frontiers, welding maritime and landed wealth. Between 1757 and 1857, British control expanded up the Ganges valley from Bengal; the most rapid period of expansion came in the 1790s and 1800s, as British confidence and ambition were fueled by the worldwide war against France. The Company subdued the proudly independent southern Indian kingdom of Mysore in 1799, the Gangetic kingdom of Awadh and the southern domain of Arcot in 1801, the Dutch-dominated island of Sri Lanka by 1815, the Maratha lands in western India by 1818, and the coast of Burma by 1826. The late Christopher Bayly, whose early work on the merchants and markets of North India is unsurpassed, observed that at all times the Ganges valley remained “the main axis of Britain’s Asian Empire.” The valley’s commerce “pointed northward to the high regions of Central Asia,” while “huge quantities of cotton, opium, and indigo bound for China and Europe” flowed downriver to Calcutta, along with hides, oilseeds, and the saltpeter used to make gunpowder. Shipments of rice, opium, and tobacco went upstream toward India’s northwest frontier.²⁵

As British power forced its way into the interior, into southern and western India, the distribution of water created different possibilities for agricultural, fiscal, and therefore political expansion. For scientists and travelers, mastering the map of India’s water became a matter of curiosity; for revenue administrators it was a matter of urgency.

II

One of the earliest maps of the British domains in India was the work of James Rennell (1742–1830), surveyor-general of Bengal. Given the centrality of the Ganges to British power in India, Rennell set out to map the Ganges, from its source to the Bengal delta. He described the descent of the river from the “vast mountains of Thibet” to the Indian plains, where it “serves the capacity of a military way through the country,” before reaching the ocean in “a labyrinth of rivers and creeks.” Rennell was impressed by the power of India’s rivers: “next to earthquakes,” he wrote, “perhaps the floods of the tropical rivers produce the quickest alterations in the face of our globe.” He described the “extensive islands” of silt (known locally as chars) formed “during an interval far short of that of a man’s life.” Rennell saw that “it is no new thing for the rivers in India to change their course.” He described how the confluence of the Kosi and the Ganges had migrated forty-five miles in a short span of time. The mighty Brahmaputra, India’s second-largest river, had “varied its course still more.” Rennell described the Brahmaputra as unknown, forbidding, and turbulent. Where the Brahmaputra met the Ganges, in the Bengal delta, he described “a body of running fresh water, hardly to be equalled in the old hemisphere.” Its governing influence was the monsoon. The characteristic pre-monsoonal storms, known as northwesters, were “the most formidable enemies that are met with in this inland navigation.” Of enemies there were plenty. Traveling upriver, he wrote, a regular “budgerow” (bajra)—large boats with cabins that covered their length, most common along the Ganges—“hardly exceeds 8 miles a day, at ordinary times.”²⁶