The disposal area was part of the natural bluff along Cook Inlet, and after being deposited, the vehicles were covered with sand and silt, and a moderate amount of vegetative cover was established on the disposal area.  Over time, erosion and unauthorized dumping has caused vehicles, vehicle parts, and sediment to be deposited in the ACWR.  Other potential slope instability features have also developed, which, if left unattended, may result in increased sediment deposition in the refuge, and exposure of more cars that could potentially be dislodged.  These features include a large ravine with a recent slump or 'blow-out', steep foot paths that have no vegetation and cross the fine granular soil covering the vehicles, and poor vegetation cover at the top of the slope.

Shannon & Wilson led a team of engineers, hydrogeologists, environmental scientists, and biologists to evaluate the cause of recent larger scale failures, characterize the nature and likely extent of the buried debris, evaluate the stability condition of the bluff, and to develop options for slope repair and stability improvements.  The selected design option included placement of fill on the slope (to fill recent erosional failures), establishment of tree vegetation on the slope that will thrive and help prevent future erosional failures, and reinforcement of the toe of the slope against tidal erosion using anchored logs.  The design limits impacts to the public as well as sensitive migratory bird habitat at the base of the slope.