Research team discovers extensive water management...

Research team discovers extensive water management system at Great Zimbabwe

Great Zimbabwe was not only the largest city in southern Africa during the Middle Ages, researchers have unearthed an extensive water management system that made gave the city water stability in the drought prone region.

Researchers from Zimbabwe, South Africa, England and Denmark set out to find how the city -that housed populations of between 10 000 and 18 000 over a period of more than six centuries-flourished in the arid climate.

The research team comprising Innocent Pikirayi, Tendai Musindo, Shadreck Chirikure, Munyaradzi Elton Sagiya, Bongumenzi Nxumalo, Federica Sulas, David Stott and Søren M. Kristiansen shared their findings in an article published in Anthropocene journal.

The researchers wrote:

The environmental and archaeological records when integrated with historical and ethnographic information, do paint a new, convincing portrait of Great Zimbabwe: a landscape where human settlement, land and water were intimately linked for a long time and to some extent, continue to do so. Springs and rainwater fed an urban population of ruling elites, religious leaders, craftsmen, and merchants. Water storage facilities were strategically placed to maximise supply and demand.

The team used remote sensing methods and excavation to investigate a number of large depressions in the landscape, locally called “dhaka” pits.

The depressions had not been investigated before, as previous researchers had concluded that they were just a result of diggings for the clay used for building in the city.

The new investigations show that the pits must also have been used to store and manage water for the city.

The research team say that they discovered clear signs that the depressions have been excavated where they can collect surface water, and at the same time seep and store groundwater for use during the dry periods of the year.

The researchers found more “dhaka” pits than were known before, in places where small streams will naturally run through the landscape when it rains or where groundwater seeps out.

It is this strategic placement combined with the construction of the depressions that has led the researchers to conclude that the “dhaka” pits functioned as a clever system to ensure a stable water supply, by capturing surface water and storing groundwater that could be used outside the rainy season as well.

The people of Great Zimbabwe thus devised climate-smart methods for storing and managing water in an area that is characterized by having three different climates, with a very warm and dry season, a warm and wet season and finally a warm and dry winter. Such a water supply may have been essential in order to create an urban society that required a safe supply of water for its inhabitants, for livestock and for agriculture.

The researchers hope that the exploration of “dhaka” pits in other areas might also reveal how other medieval communities in the region dealt with water management issues.

Access to water is a key contemporary issue, not just in Zimbabwe, but most of Africa. Knowledge of indigenous systems can open up possibilities of sustainable and environment smart modern ways of ensuring water security for all today.