Qazvin Province in northwestern Iran once relied on a dense network of underground water cisterns known as ab anbars, with historical accounts placing the total at more than 100. Only a small number remain intact today, including Sardar-e Bozorg, described as Iran’s largest preserved single-domed water reservoir.
For mason contractors and restoration teams, these cisterns are a clear reminder of what masonry does best when it is detailed for the job. The core storage tank sat below ground, capped by a substantial brick vault or dome. That buried layout reduced direct solar exposure, leaned on the earth’s thermal stability, and protected stored water from temperature swings.
Structurally, the ab anbars also highlight classic masonry behavior. Builders covered large square or rectangular reservoirs without modern steel or reinforced concrete by controlling loads, thrusts, and geometry. The dome carried weight primarily in compression and transferred forces down into supporting walls. Brick fit the work well because small units can form tight curves and complex vault shapes.
Durability came from more than shape. Qazvin’s cisterns depended on saruj, a traditional waterproof mortar made with ingredients including sand, clay, lime, ash, goat hair, and egg white. That waterproofing mattered because cistern walls faced constant moisture, hydrostatic pressure from stored water, and lateral pressure from surrounding soil, all while being cleaned and maintained over long service lives.
A computational study of four Qazvin cisterns also connected dome profile to performance. Researchers found shorter, low-rise domes absorbed more solar radiation than taller domes, and in Qazvin’s relatively cold climate, that geometry aligned with better thermal behavior for the reservoir environment. Ventilation details also varied, with some cisterns using windcatchers to move air and manage temperature and humidity.
Read the full, original article from Pars Today here.