Sand Dams for Drought-Season Water Security — Shashe Catchment, Zimbabwe

In Zimbabwe's semi-arid Shashe catchment (Matabeleland South), the NGO Dabane Trust has built sand dams — low masonry/rock-and-concrete barriers across seasonal sand rivers that trap sand and store water within it, shielded from evaporation — to give rural communities a dry-season water source.

A 2024 peer-reviewed evaluation by the International Water Management Institute (IWMI), conducted with Dabane Trust under the NEXUS Gains initiative, assessed 20 sand dams used by 19 villages in the Zimbabwean part of the catchment. It found water available at dam sites for an average of 4.4 additional months per year compared with unmodified riverbeds, still 3.9 additional months in a drought year, and an average increase of about 58 litres of household water collected per day.

The same technique, pioneered at larger scale in Kenya's Kitui, Machakos and Makueni counties, has independently documented reductions in water-collection time from over three hours to as little as 15 minutes per trip, suggesting the Zimbabwe results are consistent with a wider, transferable evidence base rather than a one-off finding — though the Shashe evaluation itself relied on a mixed methodology of dam-site observation and community self-reported survey data.

Read the full analysis: https://iwmi.cgiar.org/2022/12/satisfying-the-growing-need-for-water-storage-the-role-of-sand-dams-in-an-integrated-storage-framework