A containment structure having a central elevated portion and an open bottom end, comprising: (i) a textile containment sheet substantially impervious to a first fluid; (ii) a central hub situated centrally on said textile containment sheet and having an outer periphery; (iii) a support for supporting said textile containment sheet in a downwardly-curved hemispherical dome-shape extending downwardly from the central hub, the support comprising: a plurality of elongate inflatable beam members, first longitudinal ends of the plurality of elongate inflatable beam members arranged circumferentially around said outer periphery of said central hub, said inflatable beam members each extending radially outwardly and in a downwardly-extending manner from said central hub and each underlying or overlying said textile containment sheet and each coupled to said textile containment sheet at one or more intervals or continuously along a longitudinal length of each of said inflatable beam members and thereby supporting said textile containment sheet; and (iv) one or more anchor members, each of said plurality of inflatable beam members proximate a second longitudinal end thereof opposite said first longitudinal end being tethered, via rope, cable, or chain members, to said one or more anchor members; and (v) a fluid exit port located in or at said central hub, for removing said first fluid from within said containment structure; wherein said inflatable beam members, when inflated with a second fluid and when said second longitudinal ends thereof are tethered to said one or more anchor members, together support said textile containment sheet in the downwardly-extending shape extending downwardly from said central hub, to form an enclosure having an open bottom end, wherein, when said inflatable beam members are inflated, said containment structure is resiliently deformable from said open bottom end to said central hub, wherein said central hub comprises: a plurality of ports spaced about the outer periphery and corresponding in number to the number of inflatable beam members, each port being coupled to and in fluid communication with the first longitudinal end of a respective one of the inflatable beam members, the plurality of ports being configured to provide said second fluid to an interior of each of said inflatable beam members for simultaneously inflating said inflatable beam members; and an inlet spigot arranged to couple to a supply hose to provide a supply of said second fluid. (i) a textile containment sheet substantially impervious to a first fluid; (ii) a central hub situated centrally on said textile containment sheet and having an outer periphery; (iii) a support for supporting said textile containment sheet in a downwardly-curved hemispherical dome-shape extending downwardly from the central hub, the support comprising: a plurality of elongate inflatable beam members, first longitudinal ends of the plurality of elongate inflatable beam members arranged circumferentially around said outer periphery of said central hub, said inflatable beam members each extending radially outwardly and in a downwardly-extending manner from said central hub and each underlying or overlying said textile containment sheet and each coupled to said textile containment sheet at one or more intervals or continuously along a longitudinal length of each of said inflatable beam members and thereby supporting said textile containment sheet; and (iv) one or more anchor members, each of said plurality of inflatable beam members proximate a second longitudinal end thereof opposite said first longitudinal end being tethered, via rope, cable, or chain members, to said one or more anchor members; and (v) a fluid exit port located in or at said central hub, for removing said first fluid from within said containment structure; a plurality of ports spaced about the outer periphery and corresponding in number to the number of inflatable beam members, each port being coupled to and in fluid communication with the first longitudinal end of a respective one of the inflatable beam members, the plurality of ports being configured to provide said second fluid to an interior of each of said inflatable beam members for simultaneously inflating said inflatable beam members; and an inlet spigot arranged to couple to a supply hose to provide a supply of said second fluid.