of the Trans-Zambezi Railway a decade later, followed by the railroad bridge across the Zambezi at Sena, were steps in that direction. Nevertheless, eliminating the Cabora Bassa gorge as a barrier into the interior and constructing a dam on that site remained prerequisites to effective domestication of the river and exploitation of the Zambezi valley’s rich natural resources.
Local Perspectives:
“In the Past, the Zambezi Gave Us Wealth”202
For the Shona- and Chewa-speaking communities who had settled on the southern and northern margins of the Zambezi well before the arrival of the Portuguese (see map 2.1),203the river was neither a dangerous force of nature requiring domestication nor a form of wealth waiting to be tapped by scientists who, alone, knew the value of the riches it contained. While examples of livelihood insecurity—the river’s erratic character and the hardships that flooding, crocodiles, and hippopotami caused, for example—are embedded in their oral narratives of environmental harmony in the pre-Cahora Bassa period, their stories about the Zambezi emphasized the river’s positive meanings for the rural communities living near its shores.
From their perspective, for centuries the Zambezi had provided a safe and bountiful supply of fresh running water for drinking, cooking, washing, and bathing. It had nourished the reeds African men used to weave mats and baskets and the trees they needed to build homes and canoes. It was also an important waterway that facilitated local commerce in agricultural produce, honey, wax, fish, meat, iron, and indigenously produced cloth, and, even before the Portuguese arrived, a flourishing trade with Indian Ocean merchants. Additionally, the river yielded powerful medicines that combated illness and infection and was the location of many sacred sites. Above all else, it provided the nutrients needed to fertilize cultivators’ alluvial gardens and to support the fish populations that were a crucial source of protein in African diets.
In short, the Zambezi, despite its unpredictability, had “given wealth” to African communities by sustaining and providing life. Thus, despite the nostalgia that is evident in their recollections, representations of the river in contemporary oral narratives highlight its intrinsic benefits and life-giving properties, rather than the hazards—or development potential—stressed by outsiders, making them an important counter to European discourses about the Zambezi.
In the following section, we highlight how Africans living in the lower Zambezi valley described the river’s role in their everyday lives before the construction of Cahora Bassa. Based on oral and archival materials from the area stretching downriver from the dam to the Zambezi delta, this summary provides insights into the river’s history and its varied impacts on local communities, environments, and production systems. Oral accounts stress the extraordinary agricultural capacity, biodiversity, and livability of the Zambezi floodplains while the river remained in African hands and provide glimpses of the devastating microecological and economic consequences that followed for peasant households when the colonial state appropriated control over its life-sustaining waters.
The Lower Zambezi Ecosystem
The lower Zambezi extends from Cahora Bassa to the expansive delta and enters the sea through a mosaic of alluvial grasslands and swamp forest, covering an area of 225,000 square kilometers. In the mountainous area, from Cahora Bassa to Tete city, the river runs through a narrow valley (five hundred meters wide) with bedrock outcrops adjacent to the waterway. Downstream from Tete, it broadens to a width of several kilometers. Only at the fast-swirling Lupata gorge, 320 kilometers from its mouth, does the river narrow appreciably. Otherwise, the banks are low and fringed with reeds, with alluvial gardens located along both shores. The Shire River flows from Lake Malawi into the Zambezi about 160 kilometers from the sea. Just south is the fertile delta, a triangular area covering 1.2 million hectares. The rich delta floodplain, whose width can reach several hundred kilometers, historically supported hundreds of thousands of rural villages. The delta’s savanna and woodlands provided wood for fuel and housing along with wild fruits and medicinal plants and sustained a wide variety of wildlife, including the largest population of Cape buffalo in Africa.204
Before the construction of any upriver dams, the most important factor shaping the physical environment of the lower Zambezi valley—and the welfare of all species inhabiting the river and its neighboring lowlands—was the Zambezi’s annual flood cycle. The complex ecological dynamics of the lower Zambezi’s main channel, the associated floodplains, and the biologically rich delta and coastal estuary regions205 had coevolved, in the predam period, with a very particular flood regime connected to the bimodal pattern of annual rainfall.206
Under normal climatic conditions, Zambezi flow patterns were fairly predictable. Flooding occurred in two stages after the onset of the rainy season, in late November or December. A week or two later, flow rates began to increase, creating small peaks in response to local rainfall runoffs in the lower Zambezi basin. While flows in December could reach as high as 6,740 cubic meters per second, the principal flood normally began in January and peaked between late February and late March (see fig. 2.1). During this period, the river swelled to several times its normal size, overflowing its banks virtually every year between 1930 and 1958—the period for which records of the flow rate exist.207The floodwaters began to recede in April, leaving behind a rich deposit of organic and inorganic nutrients on the lowlands adjacent to the river. During the dry season, from late April through October, water levels diminished rapidly, until the river’s flow returned to its average low point of approximately 400 cubic meters per second. The flooding cycle began anew with the onset of the next rainy season.
The magnitude and duration of the seasonal floods varied over time and from one zone to another. For the forty years preceding Cahora Bassa’s construction, the maximum annual peak flow ranged from five to twenty thousand cubic meters per second , although the extremes were infrequent—occurring only twice.208Even at the lower end, however, the runoff was sufficient to inundate the plains and deposit valuable silt. Table 2.1 documents the maximum flood levels measured at two locations on the lower Zambezi before the construction of Kariba and Cahora Bassa. Mutarara is located about 150 kilometers downriver from the Cahora Bassa gorge, and Marromeu sits in the delta. Despite the annual variability of flood levels, at both sites they were always sufficient to overflow the river’s banks and inundate alluvial fields.
The Zambezi’s annual flooding critically affected the topography and natural-resource base of both the valley and the vast wetlands of the delta. The seasonal runoff ensured high groundwater levels throughout the region and fed channels, tributaries, and lakes—most dramatically in the delta, where it formed a wide riverine landscape with “open mosaics of marsh, pond, oxbows and shallow wetlands.”209During the rainy months of December through March, the width of the inundated floodplains varied from place to place. Carlos Churo of Chicoa Velha, for instance, remembered stretches of the river where floodwaters stretched for seven to nine kilometers on both banks.210In parts of the delta where the alluvial plains were much larger, the floodwaters could span twenty to thirty kilometers.211Some lowland areas, such as the northern floodplains near the confluence of the Zambezi and Shire Rivers, had a spillover that nourished more than eighty thousand hectares of land, while, in nearby Inhangoma, the Zambezi inundated fifty-five thousand choice hectares.212Many of the islands dotting the river also benefited from this extensive seasonal irrigation, as did lowlands adjacent to both the Zambezi’s tributaries and streams flowing into it.
These alluvial lowlands, particularly in the delta, contained some of Mozambique’s most biologically diverse ecosystems. For this reason, the delta itself has long been vital to Mozambique’s national economy and is a wetland of international significance.213A massive eighteen-thousand-square-kilometer zone of flooding and silt deposition, it stretches almost three hundred kilometers along the Mozambique coastline and 160 kilometers inland to the Zambezi’s confluence
