apparatus for containment and / or equalization of effluent flow and runoff includes a plurality of compartments situated in a receiving body of water in a manner which prevents leakage of undiluted , polluted water into the receiving body of water . an inner , central compartment receives effluent flow or runoff and is surrounded or substantially surrounded by other compartments which allow sequential , generally radially outward flow of the effluent material from the central compartment to the receiving body of water . leakage is further prevented through improved manners of sealing flexible wall compartments from water leakage under the lower edges of the compartment walls .