Abstract: A storm water retention or detention system is constructed to fit a desired land area from square shaped concrete modules. Each of the modules has at least one water passage and one air passage, and the water passages and air passages of adjacent concrete modules are in alignment to allow the free flow of water and air therebetween. The water passage may be circular, have a cross-sectional area less than 60% of the total area of a side of module, and be slightly above the bottom inside surface of the modules.

Abstract: A manufacturing process for a one piece tank that involves three steps results in a consistently watertight and structurally stronger unit than previous tanks. The three steps comprise a process for producing the body of the tank, a process for producing a preliminary lid, and a process for producing the final tank. An important step in the process for producing the body of the tank is extending reinforcing steel (rebar) a distance above the concrete walls of the tank. After the preliminary lid is placed into a groove of the tank, the rebar is bent over the lid and a water stop is applied between the walls of the tank and the preliminary lid. The water stop can be any of several forms. In one form, the water stop is in the form of butyl or rubber strip which projects from the walls of the tank above the walls with the rebar. In an alternate form, the water stop is in the form of a gasket of plastic or other suitable material inserted in a groove at the top of the tank.

Abstract: A manufacturing process for a one piece tank that involves three steps results in a consistently watertight and structurally stronger unit than previous tanks. The three steps comprise a process for producing the body of the tank, a process for producing a preliminary lid, and a process for producing the final tank. An important step in the process for producing the body of the tank is extending reinforcing steel (rebar) a distance above the concrete walls of the tank. After the preliminary lid is placed into a groove of the tank, the rebar is bent over the lid and a water stop is applied between the walls of the tank and the preliminary lid. The water stop can be any of several forms. In one form, the water stop is in the form of butyl or rubber strip which projects from the walls of the tank above the walls with the rebar. In an alternate form, the water stop is in the form of a gasket of plastic or other suitable material inserted in a groove at the top of the tank.