Sea level rise (SLR) will cause shallow unconfined coastal aquifers to rise. Rising groundwater can emerge as surface flooding and impact buried infrastructure, soil behavior, human health, and nearshore ecosystems. Higher groundwater can also reduce infiltration rates for stormwater, adding to surface flooding problems. Levees and seawalls may not prevent these impacts. Pumping may accelerate land subsidence rates, thereby exacerbating flooding problems associated with SLR. Public agencies at all jurisdiction levels will need information regarding where groundwater impacts are likely to occur for development and infrastructure planning, as extreme precipitation events combine with SLR to drive more frequent flooding. We used empirical depth-to-water data and a digital elevation model of the San Francisco Bay Area to construct an interpolated surface of estimated minimum depth-to-water for 489 square kilometers along the San Francisco Bay shoreline. This rapid assessment approach identified key locations where more rigorous data collection and dynamic modeling is needed to identify risks and prevent impacts to health, buildings, and infrastructure, and develop adaptation strategies for SLR.

Designers and engineers are developing proposals for physical projects to adapt coastal sites to future sea level rise related threats. This puts pressure on local and regional decision makers to develop strategic frameworks for prioritizing, permitting and funding such projects. However, no systematic evaluation tools exist for the full range of these innovative designs. We build on the literature to develop an evaluation framework that synthesizes two different approaches to categorize these proposals and provide insight for coastal managers and decision makers. We apply this framework to physical projects that address sea level rise in their design around the San Francisco Bay Area, a leading region in sea level rise adaptation. We find that these projects demonstrate a shift toward more habitat-focused strategies, which likely marks the beginning of a larger transformation of the coastal zone. According to our five-part evaluation tool, we also find that the projects' scores have improved over time, indicating that state agency work may be helping communities implement more flexible adaptation initiatives. Despite these positive signs, we also find that none of the projects achieved high marks in all five of the evaluation criteria. This finding indicates that there is a critical need for improvement in physical planning for adaptation to higher sea levels and associated impacts. Most importantly, we find that an evaluation framework such as the one used here can provide critical insights into the likely risks and benefits of proposed adaptation projects and their long-term implications for coastal zones.