The remains of Great Zimbabwe, the first major city in South Africa, can be found in the mountains of southeast Zimbabwe. The name “Zimbabwe” is translated as “big stone house” in the Shona language, and the country got its name from the name of the ancient city. Great Zimbabwe was the 11th-century capital of the Shona Kingdom, which covers parts of modern-day Zimbabwe and Mozambique, known for its large stone houses and hedges.

The city prospered and many people lived here until it was abandoned in the 17th century. So how did the people living there meet their needs? Water was a particular challenge – Greater Zimbabwe is located in a climate-sensitive region, so providing a stable water supply for so many people and cattle would be difficult.

This mystery was explored by a team of researchers from South Africa, England, Zimbabwe and Denmark in their paper Climate Smart Water Harvesting and Storage: Legacy of the Dacian Pits in Great Zimbabwe. Using remote sensing and excavation techniques, they discovered a series of large depressions in the terrain, locally known as “daka” pits. The depressions had not been explored before because they were thought to have been built solely to collect the clay used to build the city. But new research shows that this may not be the whole truth.

Research shows that the pits were also used to store and manage water for the city. There are clear indications that depressions have been dug where they can collect surface water and also infiltrate and store groundwater for use during dry periods of the year. Researchers have found more “dhak” pits than previously known, and they are found where small streams naturally flow during rain or where groundwater seeps in. This, combined with the location and design of the depressions, convinced the researchers that the “Dhaka” pits function as an intelligent system to provide a stable water supply, by storing more surface and groundwater that can be used outside of the rainy season.

Thus, the people of Greater Zimbabwe developed climate-wise methods of water storage and management in a region characterized by three different climates: a very hot and dry season, a warm and rainy season, and finally a warm and dry winter. Such a water source may be necessary to create an urban society that needs a safe source of water for its inhabitants, animals and agriculture.

It was impressively designed and shows that the management of the natural hydrological system in the city was under control, much earlier than previously thought. Maybe they’ve done it so well that other parts of the world can now learn from how they did it in Greater Zimbabwe hundreds of years ago?