Fadji Maina –
Hydrological Sciences Laboratory GESTAR –
NASA Goddard Space Flight Center
How California’s new normal (climate extremes and wildfires) shape its hydrology?
Understanding the evolution of water resources in response to a changing climate in California is essential for not only sustaining its economy and agriculture but also building resilient communities. With the onset of climate change, the region is increasingly subject to end-member fluctuations between periods of severe drought followed by extreme precipitation mainly caused by atmospheric rivers. Moreover, these extremes lead to conditions amenable to wildfires. In recent years, wildfires in California have occurred with increasing frequency and scale. Despite their significant impacts on redefining landscapes and hydrology, climate extremes and wildfire effects on watershed scale-hydrology are still highly uncertain. Understanding these impacts requires high-resolution physically based models which solve the transfer and movement of water and energy from the subsurface to the lower atmosphere. These models are crucial for a better understanding of the “new normal” where the unprecedented and increasingly frequent perturbations combined with the complexities of the watershed hydrodynamics have made the past historical trends less reliable indicators of future conditions. We, therefore, used an integrated hydrologic model to study the impacts of climate extremes and wildfires on a representative Californian watershed. The Cosumnes watershed hosts one of the last major rivers in California without a dam and offers a rare opportunity to isolate the effects of water management from a changing climate in the Golden state. Because projections show that these extremes conditions will characterize the future climate of California, we also assessed the impacts of both extremely dry and intensely wet conditions on the hydrology at the end of the century.