Leveraging the open-source sandpiper toolchain to evaluate how shallow compaction affects land-building and delta sustainability

Delta sustainability is threatened by rising sea levels, diminishing sediment supplies, and widespread environmental change. Addressing these challenges requires integrating science and engineering approaches across vast spatial and temporal scales, for example, from individual bars to the entire delta system, and from years to millennia. Open-source models and software development offer a strategic opportunity to accelerate this collaboration. In this paper, we demonstrate how community-built tools can be chained together to rapidly evaluate delta sustainability. As a case study, we leverage the extensibility of the pyDeltaRCM numerical model to evaluate how shallow subsidence, driven by delta sediments compacting unconsolidated bay muds, affects land-building processes. Central to this workflow is sandsuet, a shareable data schema designed to package and share rasterized geomorphology data, and a core component of the sandpiper toolchain. This schema integrates with sandplover, a Python package for reproducible spatiotemporal analysis of depositional environments. With the sandpiper toolchain, we identify the specific conditions under which delta substrate compaction does, and does not, hinder land-building projects. We then apply these insights to the Mississippi River Delta, and find that its substrate and surface network characteristics respond similarly with and without shallow subsidence. While compaction is likely, it is unlikely to diminish the land-building potential of restoration projects. This example illustrates that a community-driven, open-source approach can facilitate the long-term conservation of global deltaic systems.