HOLLOW LIGHTWEIGHT PLASTIC DRAINAGE CHAMBERS WITH OPEN BOTTOMS USED TO FORM A DRAIN FIELD FOR USE IN DRAINAGE SYSTEMS FOR WASTE, CLEAR OR STORM WATER TREATMENT AND MANAGEMENT APPLICATIONS PROVIDING STORAGE AND INFILTRATIVE CAPABILITY OF THE WASTE, CLEAR AND STORM WATER, THE CHAMBERS ABLE TO BE AXIALLY ALIGNED IN END-TO-END RELATIONSHIP AND INTERLOCKED USING A LATCHING SYSTEM BASED ON OVERLAPPING END RIBS, EACH CHAMBER HAVING ONE END WITH A LARGER RIB AND THE OTHER END WITH A SMALLER RIB, THE CHAMBERS USED IN CONNECTION WITH A DELIVERY CONDUIT THAT EXTENDS TO AND INTRODUCES EFFLUENT INTO THE FIRST IN A SERIES OF THE CHAMBERS FORMING GALLERIES OF SUCH CHAMBERS, THE EFFLUENT THEN SEEPING INTO SURROUNDING EARTH THROUGH THE OPEN BOTTOMS OF THE CHAMBERS OR THROUGH INFILTRATION APERTURES IN THE WALLS OF THE CHAMBERS