Poor water quality is a growing problem in California and around the world, limiting resources for drinking water, food production, recreation, and harming ecosystems. Water quality issues range from chemical, bacterial, and viral contamination to excess nutrients from agricultural runoff causing harmful algal blooms and saltwater intrusion compromising coastal aquifers. Climate change is expected to exacerbate these challenges. Heavy rains will increase agricultural and urban runoff; increasing temperatures will accelerate the growth of bacteria and algae; and sea level rise will increase the risk of saltwater intrusion. These escalating water quality concerns are challenging the well-being of populations around the globe and putting pressure on already stressed natural systems.

We will bring together experts from a wide variety of fields in a two-day workshop on April 12-13, 2024. Our goal is to find places where tighter cooperation with scientists focused on measurement and forecasting and social scientists focused on mechanisms for human adaptation can yield both useful knowledge and more efficient social responses. The workshop will highlight recent scientific advancements in measuring and modeling water quality and new engineering solutions for addressing escalating water quality challenges in California and around the globe. We will also identify areas where the development of new measurement or modeling capabilities could enable more effective resource management and regulatory policy. The workshop will focus on the three topic areas outlined below. The hope is that these case studies will help drive a broader conversation about where new science can have the biggest impact on improving access to clean water.

1. Nature-based opportunities for improving water quality in managed aquifer recharge (MAR). MAR offers opportunities to replenish groundwater systems, but faces water quality challenges stemming from agricultural nutrient runoff and pollutants (e.g., heavy metals, PFAS) produced by cities. This topic area will explore challenges and potential solutions for sustainably managing water quality in MAR systems. 

2. Sea-level rise and saltwater intrusion into coastal aquifers. Sea-level rise, in combination with groundwater pumping, can cause saltwater intrusion in coastal aquifers, rendering groundwater wells unusable or increasing costs for water treatment facilities. This topic area will explore scientific advances, including recent and upcoming satellite missions such as SWOT and PACE,  in measuring local-level risk of saltwater intrusion, their link to coastal and inland water quality, and policy options for managing this risk. 

3. Nonpoint source pollution from agricultural runoff and algal blooms. An overabundance of nutrients from agricultural runoff can lead to excessive algae growth and deteriorating water quality. However, this type of pollution is difficult to regulate because its source is not directly measurable. This topic area will explore state-of-the-art methods for detecting algal blooms, tools for modeling the origins of the nonpoint source pollution causing these blooms, and regulatory options for addressing this challenge.