Abstract: An erosion control structure having a plurality of undivided flow passages. The structure may be constructed from concrete block bonded together, a single cast module, a plurality of pipes bonded together or other suitable construction materials.

Abstract: A wall comprising concrete blocks each having a longitudinally extending, wedge-shaped groove in one side thereof, the groove communicating with a pair of bores that extend through the block. The block is molded in a hollow shell or frame open at its top and bottom, the frame removably mounting a support from which depends a pair of cores by means of which the block bores are formed. Associated with the frame is a compactor and ejector member having at its lower end a base adapted to be accommodated snugly within the frame and having on its lower surface elongate, wedge-shaped grooving means that forms the groove in the block. The grooving means is longitudinally slotted to accommodate the core support and the grooving means and the base also are bored to accommodate the cores.