Graduation date: 2001
Stabilization structures are the most commonly used form of shore protection along the Oregon coast. Eighty-five percent of the hard stabilization structures built in Oregon
from 1976 – 1999 were riprap revetments. An evaluation was conducted of 143 riprap
revetments in the northern three counties of Oregon. Clear trends exist in the distribution and demand for shore protection structures in Oregon with 78% of structures evaluated built immediately following an El Nino event and 55% of structures built in southern ends of littoral cells, indicating that erosion is not entirely unpredictable. The Oregon Parks and Recreation Department (OPRD) has the ultimate responsibility of issuing permits for the construction of riprap revetments. Although previous studies have shown that adverse impacts may be associated with the improper design of structures, OPRD does not regulate the structure design. The question has been raised whether design standards are practiced if not regulated and if design should be regulated. Sample sites were individually evaluated based on five criteria that have been identified as critical to the structural integrity of a structures: height of structure, size of rock, slope of structure,
texture and shape of material, the use of filter material and a toe trench, and whether the material was placed in an interlocking structure. Variations exist in the compliance with the individual elements. An analysis of overall structure stability, as determined by the evaluation of permit applications, revealed that 59% of structures are built according to the minimum necessary requirements while 14% were designed to a higher set of standards. There is some variation in the quality of structures designed by specific groups with contractors slightly more likely than engineers to design structures to higher standards and both engineers and contractors far more likely than individual homeowners to respect engineering recommendations. Little change in compliance with recommended engineering standards has been seen throughout time. In general, not enough information is given during the application process for shore protection structures to determine if engineering standards are implemented.