Home / About / Projects / Louisiana Highway 77 at Bayou Plaquemines, CAP Section 14

Louisiana Highway 77 at Bayou Plaquemines, CAP Section 14

  • Non-Federal Sponsor: The Louisiana Department of Transportation and Development (LADOTD).
  • Authorization:   Section 14 of the Flood Control Act of 1946, (P.L. 79-526), as amended 33 U.SC. 701r: for emergency stream bank and shoreline protection for public facilities and services.
  • Location:  The Study Area is located along the banks of Bayou Plaquemine and Louisiana Highway 77, which runs parallel to the Bayou in the city of Plaquemine, in Iberville Parish, Louisiana. The city of Plaquemine is located approximately 15 miles from Baton Rouge and approximately 70 miles from New Orleans, Louisiana. Bayou Plaquemine is an approximately 7-mile-long channel that runs from the Plaquemine Historic Lock, located at the latitude of River Mile 209 of the Mississippi River to the Gulf Intracoastal Waterway (GIWW) – Port Allen to Morgan City Alternate Route (the GIWW Alternate Route). The Bayou intersects the GIWW Alternate Route channel at approximate channel mile 46. The Bayou Sorrel Lock is located to the south of the Study Area and the lock operations were considered in the evaluation of the Alternatives. 
  • Problem:  The banks of Bayou Plaquemine are eroding which is undermining the shoulders of the Highway and threatening the structural integrity of the Highway. The Louisiana Department of Transportation and Development (LADOTD) has performed emergency work by installing sheet pile along 900 linear feet of the Highway in August 2016, but the highway and bank area is still vulnerable to failure. The bank may fail catastrophically with the next major rainfall causing imminent danger to the highway. In the event of a failure of Highway 77, thru traffic would be diverted to Highway 3066.  In 2020 approximately 537 vehicles used Highway 77 daily based on traffic monitoring data published by LADOTD.  Using an average of the years 2018-2020 it is estimated that 1,594 vehicles would be impacted by a Highway failure and experience an additional 1.17 miles diversion.  This would result in an average daily additional vehicle operating cost of $369, with an annual cost of $134,663
  • Purpose: The Recommended Plan consists of 3000 continuous linear feet of erosion protection and bank stabilization from Station 61+45 to Station 91+45 including the placement of stone over most of the area and installation of high performance turf reinforcement (HPTRM) to ease the existing bank slope and eliminate future bank line erosion at the mean high-water line.