A water barrier system, comprising: a first mobile water barrier, comprising: a first sidewall; a first side sealing element positioned along an end of the first sidewall; a first bottom sealing element positioned along a first bottom edge of the first sidewall; and a first lowering mechanism (55, 56, 57, 58) for lowering the first sidewall to abut the first bottom sealing element against a surface to form a first bottom seal between the first sidewall and the surface; a second mobile water barrier, the second mobile water barrier connected to the first mobile water barrier with a coupler, the second mobile water barrier comprising: a second sidewall; a second side sealing element positioned along an end of the second sidewall; a second bottom sealing element positioned along a second bottom edge of the second sidewall; and a second lowering mechanism (55, 56, 57, 58) for lowering the second sidewall to abut the second bottom sealing element against the surface to form a second bottom seal between the second sidewall and the surface; and a translation mechanism for translating the first mobile water barrier and the second mobile water barrier toward each other to abut the first side sealing element against the second side sealing element to form an upper water seal between the first sidewall and the second sidewall, characterized in that the translation mechanism comprises an inner sill controlling cylinder coupled to the coupler, wherein the inner sill controlling cylinder is configured to longitudinally move the coupler relative to one or both of the first mobile water barrier or the second mobile water barrier to translate the first mobile water barrier and the second mobile water barrier toward each other. a first mobile water barrier, comprising: a first sidewall; a first side sealing element positioned along an end of the first sidewall; a first bottom sealing element positioned along a first bottom edge of the first sidewall; and a first lowering mechanism (55, 56, 57, 58) for lowering the first sidewall to abut the first bottom sealing element against a surface to form a first bottom seal between the first sidewall and the surface; a first sidewall; a first side sealing element positioned along an end of the first sidewall; a first bottom sealing element positioned along a first bottom edge of the first sidewall; and a first lowering mechanism (55, 56, 57, 58) for lowering the first sidewall to abut the first bottom sealing element against a surface to form a first bottom seal between the first sidewall and the surface; a second mobile water barrier, the second mobile water barrier connected to the first mobile water barrier with a coupler, the second mobile water barrier comprising: a second sidewall; a second side sealing element positioned along an end of the second sidewall; a second bottom sealing element positioned along a second bottom edge of the second sidewall; and a second lowering mechanism (55, 56, 57, 58) for lowering the second sidewall to abut the second bottom sealing element against the surface to form a second bottom seal between the second sidewall and the surface; and a second sidewall; a second side sealing element positioned along an end of the second sidewall; a second bottom sealing element positioned along a second bottom edge of the second sidewall; and a second lowering mechanism (55, 56, 57, 58) for lowering the second sidewall to abut the second bottom sealing element against the surface to form a second bottom seal between the second sidewall and the surface; and a translation mechanism for translating the first mobile water barrier and the second mobile water barrier toward each other to abut the first side sealing element against the second side sealing element to form an upper water seal between the first sidewall and the second sidewall, characterized in that the translation mechanism comprises an inner sill controlling cylinder coupled to the coupler, wherein the inner sill controlling cylinder is configured to longitudinally move the coupler relative to one or both of the first mobile water barrier or the second mobile water barrier to translate the first mobile water barrier and the second mobile water barrier toward each other.