An energy island system arranged related to a body of water with a seafloor, a surface and a depth over an underground is disclosed. The system comprises a structurally rigid shell (1) extending from the seafloor to above the water surface, inclosing a lagoon of the body of water, material with a negative buoyancy stacked around the shell (1) forming a gravity stabilized wall (2), and a tunnel (5) established in the wall (2), providing for hydraulic communication between the surrounding body of water and the interior of the shell (1). Further, a method for construction of an energy island is disclosed.

A low-impact water conserving dam includes a dam body and reinforcing ribs arranged on a rear portion of the dam body. The reinforcing ribs comprise transverse reinforcing ribs and vertical reinforcing ribs interlaced with the transverse reinforcing ribs. A front portion of the dam body is an inclined surface and a rear end of the dam body is a platform surface. A planting bin is arranged on the platform surface of the dam body for planting vegetation. A plurality of water flow through holes are arranged in a matrix manner at a bottom of the planting bin. A water storage bin is arranged in an interior of the dam body. The water flow through holes are communicated with the water storage bin. A water drainage channel communicated with the water storage bin is formed in a middle upper portion of the inclined surface of the dam body.

A low-impact water conserving dam includes a dam body and reinforcing ribs arranged on a rear portion of the dam body. The reinforcing ribs comprise transverse reinforcing ribs and vertical reinforcing ribs interlaced with the transverse reinforcing ribs. A front portion of the dam body is an inclined surface and a rear end of the dam body is a platform surface. A planting bin is arranged on the platform surface of the dam body for planting vegetation. A plurality of water flow through holes are arranged in a matrix manner at a bottom of the planting bin. A water storage bin is arranged in an interior of the dam body. The water flow through holes are communicated with the water storage bin. A water drainage channel communicated with the water storage bin is formed in a middle upper portion of the inclined surface of the dam body.

The invention relates to a stone, in particular a dam stone for a flood dam. In order to be able to build a stable flood dam in an easy way, according to the invention a cover surface is provided with at least two ribs and an opposing base surface is provided with at least two grooves corresponding to the ribs so as to create an indirect connection between two stones by means of a third stone that can be detached by applying a tensile force perpendicular to the base surface. The invention further relates to the use of such a stone. In addition, the invention relates to a method for manufacturing a mass retention structure, in particular a flood dam.

The invention relates to a stone, in particular a dam stone for a flood dam. In order to be able to build a stable flood dam in an easy way, according to the invention a cover surface is provided with at least two ribs and an opposing base surface is provided with at least two grooves corresponding to the ribs so as to create an indirect connection between two stones by means of a third stone that can be detached by applying a tensile force perpendicular to the base surface. The invention further relates to the use of such a stone. In addition, the invention relates to a method for manufacturing a mass retention structure, in particular a flood dam.