Administrative Order for RI/FS. The first two amendments provided for the defendants to conduct additional studies; the third amendment, effective 4/27/16, provides for them to perform pre-design studies. The objectives of the Fourth Amendment are to: 1) design the remedy for river mile 3.0 to river mile 5 of Lower Duwamish Waterway Site (the LDW Upper Reach ), consistent with the Lower Duwamish Waterway ROD and CERCLA; 2) incorporate and supersede the work being carried out under the Third Amendment to this AOC in support of the development of seafood consumption institutional controls for the Site; and (3) provide for timely periodic monitoring of selected site conditions, as necessary.