A cooling system according to an embodiment includes: a forked passage cooling circuit, the forked passage cooling circuit including a first leg and a second leg; and an air feed cavity for supplying cooling air to the first leg and the second leg of the forked passage cooling circuit; wherein the first leg of the forked passage cooling circuit extends radially outward from and at least partially covers at least one central plenum of a multi-wall blade, and wherein the second leg of the forked passage cooling circuit extends radially outward from and at least partially covers a first set of near wall cooling channels in the multi-wall blade.