Peb qhov kev tiv thaiv dej nyab yog cov khoom lag luam tswj dej nyab tshiab, cov txheej txheem khaws dej tsuas yog nrog cov dej buoyancy kom ua tiav qhov qhib thiab kaw tsis siv neeg, uas tuaj yeem tiv taus nag xob nag cua thiab dej nyab, kom ua tiav 24 teev ntawm kev tswj dej nyab ntse. Yog li peb hu nws "hydrodynamic Tsis Siv Neeg Dej nyab lub qhov rooj", txawv ntawm Hydraulic Flip Up Flood Barrier lossis Electric Flood Gate.
