Data Tables for The Delta Islands Adaptation Strategy; Development of Regenerative Land Uses in the Sacramento-San Joaquin Delta Through Interdisciplinary Science and Co-Design

Key indicators of unsustainability in the subsided Sacramento-San Joaquin Delta include decreased arability, biodiversity declines, and increased water supply vulnerability. The Delta Islands Adaptation Strategy (DIA) sought through interdisciplinary science, codesign, ecocultural knowledge, public involvement, and structured decision making to assess the potential implementation of alternate land uses on four Delta islands, Bouldin Island, Webb Tract, Holland Tract, and Bacon Island. Collectively, the DIA islands represent the range of physical, ecological, and social conditions that predominate in the farmed subsided Delta.<br>Based on present-day subsidence rates and GHG emissions, levee failure risk reduction potential, opportunities to enhance or restore ecological habitats, potential for habitat and hydrologic connectivity and adjacency benefits, and suitable areas for paludiculture, rice, regenerative agriculture, and net revenue, Bouldin Island was selected for development of detailed island-wide landscape scenarios during Phase I During Phase II near-term and long-term scenarios were developed on Bouldin Island for subsidence mitigation, greenhouse gas emissions reductions, ecological and ecocultural restoration, water quality and supply benefits, creation of recreation and community, development of opportunities for learning and partnerships.<br>Implementation of the near-term scenario would result in subsidence reversal; we estimated an annual total net soil volume change from accretion and avoided subsidence of 439,000 m³ and a reduction of average annual GHG emissions by 75% and net revenue greater than baseline. For long-term scenarios, we allocated land uses to maximize diversity and maintain agriculture in the case of the Long Term 2 scenario. For the Long Term 3, Long Term 4, and Long Term 5 scenarios, agriculture was eliminated and replaced with wetlands. Long Term 4 was estimated to have the greatest subsidence reversal benefit; a volume change relative to baseline of 738,000 m³. Values for scenarios Long Term 2, 3 and 5, were 505,000, 560,000, and 670,000 m³, respectively.The attached file provides the Appendix data tables referenced in the text.