A method and apparatus for filtering a large volume fluid intake system using a modular immersed-filtration array that can be easily scaled for use in a wide variety of immersion filtering applications. The immersed-filtration array is composed of a plurality of individual filtration modules. Each filtration module has a mating end that allows the module to be coupled with a base unit or plenum via a common interface port located on the base unit. The array can be scaled in a plurality of ways.