While the recent economic success of the Chicago Harbor was badly needed, such growth does not come without increased scrutiny. In this case, scrutiny fell on the breakwater system. The main breakwater problem, especially on the exterior portion, is that many segments were constructed over 100 years ago. This brings up two areas of concern. First, the Chicago coastline receives constant abuse from the strong Lake Michigan generated waves, placing breakwater durability in question. Second, record low water levels in the 1960s (as mentioned previously) exposed upper levels of the timber cribs to air and caused dry-rot to the breakwater supports, placing breakwater strength in question. Obviously, the effects of a breakwater failure would be economically devastating. As economic growth increases in the harbor area, the need to analyze possible failure increases. Two questions arise: "If the breakwater fails, what will be the system-wide impact on the other breakwaters?" and "Will a failure result in damage to the shoreline structures?" These are questions the U.S. Engineering Research and Development Center (ERDC) sought to answer.