Patent ID: 8292117

Claim:
A water holding tank ( 1 ) that is designed to constitute, by assembly of tanks, a water holding device that is buried in the ground, the water holding tank comprising: an approximately rectangular bottom wall ( 2 ) having four sides and four corners; four support elements located respectively at each corner, each support element having a lower platform ( 40 ) that is longer along a first one of the sides than a second one of the sides; four side walls ( 3 ) connected respectively to the sides of the bottom wall, each side wall comprising: a plurality of upper support platforms ( 9 ) that are arranged periodically along one side of the bottom wall, a plurality of lower support platforms ( 8 ) that are arranged alternately relative to the upper support platforms at a distance from the bottom wall, and a plurality of connecting walls ( 30 ), each connecting wall connects an upper support platform to a lower support platform while allowing for a passage of water, each connecting wall comprises: a thickness portion ( 31 ) that connects a thickness side ( 38 ) of one of the upper support platforms ( 9 ) to a thickness side ( 39 ) of one of the lower support platforms ( 8 ), an inside portion ( 32 ) that connects one of the sides of the bottom wall ( 2 ) to an inner side ( 36 ) of one of the lower support platforms ( 8 ), and an outside portion ( 33 ) that extends from an outer side ( 37 ) of one of the upper support platforms ( 9 ); the upper support platforms of a first one of the side walls are arranged in mirror positions of the lower support platforms of a second one of the side walls; wherein the inside portion and the outside portion are inclined allowing for having an interlocking arrangement of the water holding tank ( 1 ) with a second identical water holding tank.