Reef Ball Foundation Photos and Project Description Database

State of Louisiana Department of Natural Resources Coastal Restoration Division Monitoring Plan for Terrebonne Bay Shore Protection Demonstration State Project Number TE-45 Priority Project List 10 September, 2005 Terrebonne Parish Prepared by: Todd Folse, Monitoring Section (CRD) LDNR/Coastal Restoration and Management Project Description The Coastal Wetlands Planning, Protection and Restoration Act (CWPPRA) of 1990 (PL 101-646, Title III) included the Terrebonne Bay Shore Protection Project (TE-45) as part of the 10th Priority Project List authorized on January 10, 2001. The TE-45 project is located southeast of Chauvin, Louisiana in Terrebonne Parish along the rapidly eroding northwest shore of Lake Barre, which is part of the Terrebonne Basin system (Figure 1). The project will evaluate six fabricated structures, placed along the shore, for their effectiveness in abating shoreline erosion including their ability to develop and sustain an oyster reef. The project examined five potential shoreline reaches during the engineering and design phase with the purpose of selecting three (3) reaches for the demonstration project based on several criteria (Hebert 2002); reaches A, B and E (Figure 1) were selected. The project?s monitoring life is eight (8) years post-construction. In Louisiana, coastal land loss has been estimated at approximately 25 square miles (64.7 square kilometers) year-1 (Dunbar et al. 1992) to 35 square miles (90.6 square kilometers) year-1 (Barras et al. 1994). More specifically, the average shoreline erosion rate for the five proposed reaches along the north shore of Lake Barre are 4.95 feet (1.51 meters) year-1 for the period of 1932 to 1983 (May and Britsch 1987). Due to high rates of erosion along the north shore and salinities conducive for oysters, this project location was chosen to evaluate the effectiveness of the six different structure types including the oyster?s ability to provide additional protection. The eastern oyster, Crassostrea virginica (Gmelin), is the dominant reef-building estuarine organism along the northern Gulf of Mexico. Because of Louisiana?s climate, it has the ability to spawn almost year round, but usually exhibits bimodal peaks of mass spawning in spring-early summer and again in early-late fall (Butler 1954). When waters are warm in summer, planktonic larvae require less than two weeks to metamorphose through several life stages before they are ready for settlement and a benthic life (Galtsoff 1964). Newly settled oysters often experience high mortalities in the first six months of life (Roegner and Mann 1995). At the time of setting, oyster larvae are usually less than 0.5mm in size, and are very vulnerable to predation and to burial due to sediment overburden. A hard substrate that provides refuge from predators and provides vertical relief from sediments is of significant importance to assure a chance for survival. Once the larva has set, it will become known as a ?spat oyster? until it is 25mm (1 inch) in shell length. The juvenile stage is short-lived with oysters maturing with functioning gonads within 4-12 weeks of settlement in summer water temperatures (Menzel 1951). Young oysters grow rapidly and can reach 75mm (3 inches) in shell length within 12-15 months in Louisiana waters. After an oyster is approximately 8 years old, somatic.....