Several attempts by the Louisiana Department of Transportation and Dev~ lopment to protect the shoreline and Louisiana Highway 82 are discussed. To identify the important factors needed for proper design of shore protection structures, failures of earlier efforts, as well as the success of recent efforts, are evaluated. An emphasis should be placed on the acquisition of wave data, as well as a survey of the offshore profile. Porosity of the revetments, underlayers, and geotextiles seems to be important in the stability? f the. structure. Scour at the toe is another design consideration m d. es1gn of revetment structures. Project cost of shoreline protect10n was considerably reduced by providing alternates through competitive bidding. The 1984 and 1988 cabled and noncabled blocks and cast-in-place revetments have been exposed to several storms and have performed satisfactorily. The only damage to the roadway has been associated with landside foreslope at the time of overtopping.

Shoreline stabilization to stop erosion is an uncommon problem for most state transportation agencies. Occasionally, however, such corrective measures are needed to protect highways threatened by erosion in coastal areas. Identification and elimination of the cause of erosion is normally the best approach for solving the problem, but cannot always be accomplished. The second-best approach for solving the problem is the construction of coastal structures (1). Of these structures, revetments for shore stabilization is the most common. In order to avoid adverse results, revetment projects should be designed cautiously, and may require supplemental measures such as breakwaters or beach nourishment (2). Over 36 mi of seawalls and shoreline revetment are located in Louisiana, primarily along Lake Pontchartrain and East Timbalier Island (3). Louisiana has experienced accelerated coastal erosion in recent years. One of the few coastal areas in the state directly accessible by car is located along Louisiana Highway 82 (LA-82) in Cameron Parish. Between Peveto Beach and Holly Beach, LA-82 roughly parallels the Gulf of Mexico shoreline. Along this section of highway, the roadway embankment foreslope is under frequent wave attacks. Storm occurrences and their associated stages measured inland at the US Coast Guard station are presented in Table 1. Initial efforts by the Louisiana Department of Transportation and Development to protect the shoreline and LA-82 were unsuccessful. However, recent efforts have been successful, to date. Figure la shows the failure of the initial shoreline protection efforts; Figure lb shows one of several recent revetment projects along LA-82. The major goal for these projects was to