December 2023
Sea turtles depend on sandy beaches around the World for their nesting habitat. They face a major challenge in the flooding and erosion of their nesting beaches. High tides, storm surges, and wave runup can inundate or wash out incubating nests, significantly increasing egg mortality. Galveston Island’s beaches in Texas serve as important nesting habitat for the critically endangered Kemp’s ridley sea turtle. Due to its conservation status, all nests are excavated and moved to safer beaches or an incubation facility by the Gulf Center for Sea Turtle Research.
The coastal region around Galveston Bay, including the Houston metropolitan area, has suffered severe flooding and erosion from past hurricanes. In response, large-scale coastal protection infrastructure, including sand nourishments and engineered dune systems along Galveston Island, is planned. These planned interventions offer a unique opportunity to implement new multi-functional nature-based solutions in a large-scale coastal protection plan. Functional requirements of these future climate proof designs are improving flood safety and enhancing the ecosystem—for example through beach design that provides optimal nesting habitat for turtles.
This study aims to assess the risk of nest inundation for different beach profile shapes and hydrodynamic conditions. As a first step towards a predictive modelling tool, we set up a field experiment on Galveston Island to monitor the nearshore hydrodynamics, beach profile, and ground water table (Figure 1). We use an array of pressure sensors along the cross-shore profile, (i) in the nearshore to monitor the hydrodynamics of the surfzone, and (ii) inside a set of slotted wells along the emerged profile to monitor the groundwater table. Additionally, we take GPS measurements of the beach profile and recordings of wave runup.
The resulting dataset will be used to calibrate a hydrodynamic model to predict the sand moisture content along the cross-shore profile for different hydrodynamic conditions. This tool can be used (i) directly by coastal managers to make informed decisions regarding whether to relocate or leave turtle nests in situ; and (ii) in the long-term to help design and implement beach nourishment strategies that provide optimal nesting habitat for this critically endangered species.