A portable, water-filled barrier system includes a barrier internally divided into cells that emulates a section of a sandbag dike or wall. Automatic valves can seal openings between the filled cells, so that a punctured cell will not cause cells below and behind to deflate. In embodiments the barrier can be initially filled with air, positioned, and then filled with water while the air escapes through a pressure valve. The system further includes a base with water inflatable front and back panels. The side panels and bottom panel of the base can be water inflatable or flat. The base can be used to increase friction with the ground, protect against stones, and/or to support a leveling wedge or leveling material such as sand or spray foam when located on a sloped surface. A plurality of adjacent bases and barriers can provide an extended barrier system.

A portable, water-filled module suitable for use as a barrier or inclusion in a barrier is internally divided into cells and emulates a section of a sandbag dike or wall without requiring sand or intensive labor to install. Automatic valves can seal openings between the filled cells, so that a punctured cell will not cause cells below and behind to deflate. Cells can project below the base into a stabilizing trench. Some embodiments can be initially filled with air, positioned, and then filled with water while the air escapes through a pressure valve. Side structures of the module can enable interlocking with adjacent modules. In embodiments, rigid steps span the module to provide structural support and enable traversing of the module. The steps can be attachable to the module. The light, flexible walls of the module can include nanofiber.