Great Zimbabwe’s residents turned old clay quarries below the Hill Complex into reservoirs that could hold at least 4.9 million gallons of water, and nearby clans still manage springs around the old stone city

Earlier writers, starting with Richard Hall in 1905, saw the hollows as old clay quarries. Builders dug mud there for house walls. Pikirayi’s group, writing in the journal Anthropocene, says many of them were later dammed to catch runoff from the granite hills.

Clay quarries that held water

The work involved Great Zimbabwe University, the University of Cambridge and Aarhus University in Denmark. It “has identified dhaka pits, which were part of the ancient city’s water infrastructure,” Pikirayi said in a University of Pretoria research update on February 19, 2026.

Between 2014 and 2019, the team interviewed elders who live on the edge of the site. They also dug test pits and sent soil off for chemical analysis.

Two of the pits lie at the southern foot of the Hill Complex, about 330 feet (100 meters) apart. The paper gives them as about 213 by 66 feet (65 by 20 meters) and 6.5 feet (2 meters) deep. A 2-foot-square trench in Pit 1 hit a dark, peat-like silt that the paper says is unique to the dhaka pits.

Water features at Great Zimbabwe: Dhaka Pit 1 (left) and Mungwini well (right), as labeled in the study. (Image: Pikirayi et al. / Anthropocene, CC BY 4.0)

Surveys, soil samples and LiDAR, a laser scan that maps bare ground from an aircraft, “revealed that these depressions were part of a very complex, ‘climate-smart’ water management system,” Pikirayi said. Other old cities also had hidden water systems, like the ancient water channels found beneath Hagia Sophia.

Meisie Rasakanya, who wrote the update with Pikirayi, pointed to the slope itself. “The damming of water in a hilly place such as Great Zimbabwe is indicative of the ability by the ancients to minimise water losses,” she said.

Laser maps of the Hill Complex

The laser survey was flown in 2016 and 2017. Its terrain model, sharp to about 1.3 feet (0.4 meters), picked out a scatter of closed hollows. Most of them had never been mapped before.

Some have earth banks piled on the downhill side. Natural wetlands in the area lack them, so the team reads these hollows as the work of people. According to the paper, the city’s walls also seem to mark off some of the largest pits and protect the reservoirs.

Thirteen springs within 3 miles

Within about 3 miles (5 kilometers) of the ruins, the researchers logged 13 present-day springs and their wells. Chisikana spring lies about 720 feet (220 meters) northwest of the Great Enclosure. The Nemamwa clan still holds rituals there.

In Mungwini, about 2 miles (3 kilometers) south of the hill, one spring serves roughly 30 homesteads. People there plant banana trees to keep the soil damp. They fence off trickles from browsing animals and ring wells with stone.

Locals told the team that the 1947 drought spared Mungwini. In 1996 the well went dry and cattle died.

Pikirayi, deputy dean of humanities at Pretoria, wants today’s towns to treat water as one system, from harvesting to discharge. “Key to this integrated approach is involving communities,” he said. The paper argues that water supply alone does not explain why old cities lasted or declined, a point also raised by research on why the Maya left their cities.

Credit handed to outsiders

UNESCO put Great Zimbabwe National Monument on its World Heritage List in 1986. Its record lists the property near Masvingo at 722 hectares (about 1,780 acres). Excavations there turned up glass beads and porcelain from China and Persia, plus Arab coins from Kilwa on the East African coast.

Finds like these help archaeologists trace ancient trade routes.

For decades, settlers gave the credit to someone else. Peter Garlake, writing in the journal Africa in 1982, said Cecil Rhodes saw propaganda value in proof of ancient foreign settlement. It would make the British South Africa Company’s 1890 occupation look respectable, Garlake wrote, and promise wealth to settlers.

Rhodes later had Hall, a believer in Biblical origins for the ruins, named curator. In 2017, Shadreck Chirikure, another co-author of the water study, led a PLOS ONE paper on the city’s size. It found the total population likely never topped 10,000, half the 20,000 archaeologists had pictured at its peak.

Undated reservoirs and uncertain volumes

When the reservoirs were dug, and how long they worked, is still open. The authors write that “precise dating of the construction and functioning of dhaka reservoirs at Great Zimbabwe remains a priority.”

The team treats its volume estimate as a minimum, because it could not measure how much water soaked away or evaporated. Someone still has to check on the ground that each hollow seen from the air was really dug by people.

The full study was published in Anthropocene.

National Museums and Monuments of Zimbabwe runs the ruins today. UNESCO lists soil moisture, tourism pressure and invasive plants such as lantana among the threats to the site.

Photo: Fanny Schertzer / Wikimedia Commons, CC BY 3.0