They claimed that water would pond in front of the barrier, giving rise to potential leakage into the trenches. The Wilshire group questioned the purpose or function of the breakup berths and postulated that channelization at the end of the failed berms would force concentrated runoff toward the western edge of the main rip-rapped flood-protection barrier. Thus their two main concerns are: (1) the proposed flow diversion or breakup berms upslope to the west of the 70-acre LLRW site and (2) the proposed rip-rapped flood-protection barrier around the LLRW site. In addition, they predicted channelization of surface water at the ends of the diversion berms and consequent threats to the integrity of the trench cover. In their expanded report (Wilshire et al., 1993b), they referred to 'site evaluation documents that incorrectly claim' that the upslope diversion berms will protect the primary flood control berm against erosion. In their first memorandum (Wilshire et al., 1993a), referencing the draft EIR/S, they referred to possible failure of ''flood control devices'' without specifying which devices they were addressing.

The Wilshire group has expressed concern about the long-term stability of engineered flood and erosion control facilities.

Level 70 stone flood