🇮🇷 Iran · Hydraulic works
Band-e Darreh South Extension Dam (Birjand Darreh South Gravity Dam)
Khwarazmian Late Islamic 1210 CE (Birjand) · Khwarazmian South Khorasan Birjand oasis
South Darreh arch-gravity 42 m × 18.2 m 8 m radius: conjunctive wadi+qanat 28,000 m³ south branch with cistern 8 m.