Funds are awarded to carry out a costal morphology study on Gran Isle State Park, Louisiana, where undergraduate students will be quantifying the rates of beach erosion and deposition. The presence of Grand Isle at the mouth of Barrataria Bay represents a major component in the natural storm surge defenses of metropolitan New Orleans; but like most of the Louisiana Gulf coast, Grand Isle is suffering from rapid subsidence and significant beach erosion. This RAPID project will focus on evaluating the role that oil/tar buried in beach sand and clean up efforts have on erosion rates. To reach this goal, students will measure the elevation of the beach along standardized transects stretching from the highest point in the dunes or artificial levees to approximately 1 meter water depth along 3 km of the beach and spit in Grand Isle State Park. These monthly measurements and digital photographs will be used to keep a thorough record of the conditions along the transects allowing for a detailed reconstruction of the island's evolution at each location. The data on erosion and deposition rates generated by this RAPID award will be used to inform visitors to the state park and to create curricula materials. The investigation will be carried out by students from Tulane University and the University of New Orleans, under the mentorship of faculty from the University of Massachusetts - Dartmouth and their home institutions.
The Grand Isle Project, partially funded during the period of the BP Oil Spill by NSF Grant 1057681, built upon a pre-existing beach erosion and student training (REU) project in Grand Isle State Park on Grand Isle, Louisiana. This inhabited barrier island is home to over 2000 residents, contains significant infrastructure for the oil, fishing and tourism industries and serves as part of the natural storm surge protection system for greater New Orleans. Results collected prior to this grant quantified the erosion rate on Grand Isle prior to and following a beach nourishment project by the Army Corps of Engineers in summer 2008 and subsequent hurricane strikes by Gustav and Ike shortly thereafter. Funds from this grant were used to examine the effects of a second beach nourishment (winter 2010) and the impact of the BP Oil Spill and clean up for the period from summer 2010 - summer 2011. During this period 5 undergraduate students from Louisiana universities collected beach profile data for use in calculating sand erosion and deposition rates in an area heavily impacted by BP oil and the intensive cleanup which followed. The results thus far indicate that the sand provided by the 2010 beach nourishment project continues to erode from the beach as observed after the 2008 beach nourishment...though at a much slower rate than following the hurricane strikes of 2008. A pulse of sand from this system moved eastward along the spit and was lost into greater Barrataria Bay with heavy loss of land on the spit occuring starting spring 2011. Areas of the spit which had survived 2 hurricanes are now under water! The BP oil spill and clean up appears not to have played a significant long term role in this process at the shoreline despite significant removal of oiled sand for off site cleaning. Data from the project were used during the sutdy period to guide BP contractors in returning the sand to appropriate places on the beach and to guide cleanup operations in areas where rapid erosion threatened oil retention booms. Despite the best efforts of BP, some oil does remain buried below the water line and in the marshes in the lagoon behind the spit, though members of the general public are unlikely to see it without guidance on what to look for. Further disturbance of the system to attempt to remove this oil is not recommended as it would disrupt the recovery of vegetation needed to stabilize the system from erosion, which remains the primary problem threatening the shore of Grand Isle. Our results do indicate a significant effect of the BP clean up operation on the upper areas of the beach, however. During the period of intensive clean up, the beach was heavily impacted by the presence of booms, fencing and vehicle traffic. All these barriers erected parallel to the shore had the unintended effect of inhibiting aeolian (wind borne) processes that normally build up sand along the dune line. While such dune growth had begun following the 2010 beach nourishment, the oil spill clean up halted this process for approximately 9 months. Once the BP presence was reduced back to monitoring level, the winds were able to mobilize the beach sand allowing for significant dune growth behind the wind fences originally installed by the Army Corps of Engineers and on the drier parts of the open beach. This process is acting both on the managed public beach and on the wild spit without such fencing. Natural vegetation is moving into these areas and growing far better than in the artificial dune/levee constructed by the Army Corps. In the long term, establishing well vegetated dunes is the approach most likely to protect Grand Isle State Park from gradual erosion and storm driven events. The data from this project were used by park officials to request a second line of wind fencing as a parting gift from BP to enhance this process. This project resulted in furthering the education of 5 undergraduate students including a senior thesis by one student. High school students from the METALS program for recruitment of underserved populations into the geosciences participated via other funding during the summer of 2011 and gained benefit of working in the oil spill arena. 1 student poster, 1 faculty poster and 2 oral faculty presentations have been made on these data at meetings of the Geological Society of America. Course materials using these data have been used by the PI at Rochester Community & Technical College and at the Minnesota Mineral Education Workshop for in-service Earth Science teachers. We are in the process of preparing 3 publications based on the Grand Isle work. Materials on this project will be included in displays at the Grand Isle Park visitor center.
