The aim of this project is to understand how eco-morphological nature-based solutions can stimulate nesting of sea turtles and contribute to preserving their nesting habitat, while still providing sound engineering solutions for improving flood safety of the hinterland. To reach this objective, the project TURTLE faces four major challenges: C1) the understanding of hydrodynamic and groundwater processes and timescales of flooding relevant for sea turtle nests on sandy beaches; C2) the analysis of preferential sediment characteristics for sea turtle nests; C3) the sound environmental characterization of sea turtle nesting beaches; C4) the development of engineering methods and guidelines to upscale findings to any regional management unit.

A major challenge to sea turtles is the degradation of their nesting beaches due to human and climate-induced effects, such as accelerated sea level rise, anomalous storm activity, and increased coastal development. Flooding and erosion of nesting beaches during events with high water levels and/or waves (e.g., storms and tropical cyclones) can inundate or even wash out incubating nests, significantly decreasing hatching success. Furthermore, storm erosion can significantly alter beach morphology, which may affect nesting over several seasons. On longer time-scales, structural erosion and coastal squeeze may gradually diminish the amount of nesting habitat available to sea turtles. Nature-based solutions—for example in the form of turtle-friendly design of sand nourishments or beach design along new land reclamations—may offer promising opportunities to preserve and even expand global habitats for turtle nesting. Galveston Bay (Texas, USA) in the Gulf of Mexico is sheltered by sandy beaches and barrier islands, which serve as nesting habitat for the critically endangered Kemp’s ridley sea turtle. These nesting beaches are characterized by frequent inundation and long-term erosion. As there is a lack of accurate information on flooding likelihoods, local coastal managers are preemptively relocating all turtle nests to other beaches in the region. In addition, the Houston metropolitan area, at the landward end of the bay, suffered severe flooding and damage during hurricanes Ike (year 2008) and Harvey (year 2017). In response, US national authorities are developing large-scale coastal protection plans, including sandy interventions on beaches, such as sand nourishments and dual dune systems. Next to the degradation of the nesting beaches, nature organizations and coastal managers are worried about the impact of the planned coastal interventions on these habitats, for example in the case of unsuitable sand nourishments.

TURTLE is organized around three major research activities, combining a regional case study in Galveston Bay (Texas, USA) and global data analysis:
A1- A fieldwork campaign focused on measuring groundwater processes and inundation/flooding of sea turtle nests.
A2- The analysis of global sea turtle nesting beaches.
A3- The upscaling and development of guidelines for short- and long-termed flood risk management at sea turtle nesting beaches.
Through the above activities, the project will provide: i) datasets on hydrodynamic processes; ii) datasets on preferential environmental and morphological characteristics of sea turtle nesting beaches; iii) new methods for assessing risk of nest inundation on sandy beaches; iv) a dedicated tool for coastal management to inform on short-term decisions on the relocation of turtle nests using seasonal forecasts; and v) engineering design guidelines to develop long-term flooding protection plans that enable sea turtle nesting beaches.

TURTLE will carry out for the first time, a fieldwork experiment designed to understand relevant hydrodynamic
processes and timescales of flooding of sea turtle nests on sandy beaches, and analyses of global beach sediment samples.
TURTLE will create a new global database of sea turtle nesting beach granulometry.
TURTLE will develop tools for aiding (short-term) decision makers on the relocation of turtle nests using seasonal forecasts, and guidelines on beach-dune design of sea turtle nesting beaches for (long-term) flood risk management. These probabilistic modelling tools will combine data with statistical and novel machine learning techniques, numerical and physical models, and uncertainty characterization.
TURTLE will upscale findings to other regional management areas, the new gathered data in this project will be
combined with remote sensing products, such as satellite imagery, and global databases of environmental
variables, such as reanalysis or future projections of waves, wind, surges, tides, and sea level rise.
TURTLE aligns with other TUD research projects such as, CHANCE on climate change impacts on extreme sea
levels, AdaptCoast on Adaptive monitoring, nowcast, and prediction of beach surface dynamics, and PhD research on the climate change impacts on sea turtle nesting beaches.

Activity 1: Fieldwork campaign for measuring groundwater and inundation processes at sea tutle
nesting beaches.
Activity 2: Analysis of global sea turtle nesting beaches.
Activity 3: Upscaling and development of guidelines for short- and long-termed flood risk management at sea turtle nesting beaches.

All products’ IP will belong to TUD and will be shared with the parties contributing to its development.
Additionally, we aim at making any publications and datasets open-access and shared according to the
FAIR principles (findable, accessible, interoperable, and reusable), whenever possible

Scientific publications will target Q1 journals, and they will acknowledge the TKI DT subsidie for its
support. Results will be published and communicated in the DIGISHAPE and ECOSHAPE Dutch
consortiums, and through other media dedicated to the general public. Additionally, the project
progress will be communicated through the TKI website. Regular meetings with the consortium
members will be carried out to ensure findings are shared and discussed timely. Open-source data will
be shared using FAIR principles, the channels for dissemination and links will be defined in a Data
Management Plan elaborated at the start of the project and these will be also included in the TKI
website.

Het consortium zal een samenwerkingsovereenkomst sluiten die aan de eisen van de regeling tegemoet
komt.