WATERSHED HYDROLOGY
Lauren Giggy, PhD
BIO
I am a hydrologist and geologist, with expertise in watershed processes, carbon and nitrogen export dynamics, impacts of wildfire and drought, and groundwater storage and movement.
My dissertation research was focused on exploring the role of geology, climate, wildfire, and drought on streamflow and water chemistry dynamics in headwater systems situated in the Northern/Central Coast of California.
I've been privileged to work across a range of environmental science spaces, including academic research and teaching roles, government agencies, non-profit groups, and environmental consulting. These experiences have instilled a commitment to stakeholder-engaged research and production of science products that supports the unique needs and interests of each community.
I am excited to be joining the ECOSHEDS Lab at the University of New Hampshire in Fall 2025 as a remote postdoctoral researcher focused on watershed hydrology and water quality dynamics. I will be based out of San Luis Obispo County, California and am eager to support surface water and groundwater conservation and restoration efforts locally on the Central Coast of California as well.
In my free time, I skateboard, surf, ride bikes, and dabble in film photography. I'm always happy to chat about those too!
MY RESEARCH
Broadly, my research sits at the intersection of hydrology, geology, and biogeochemistry. My research considers how geology and climate mediate water movement through landscapes and how various hydrologic pathways influence water availability and water chemistry.
Lithologic controls on the hydrology of headwater streams in central coastal California
Plain language summary:
We find that the streams prone to rapid changes in streamflow (one minute it's dry, the next it's flooding) can exist right next to streams that maintain consistent steady streamflow. These streams co-exist right next door to each other due to variations in rock type and the degree of weathering. We also found that streams with rapid changes in streamflow tended to export much higher volumes of nutrients, which can cause water quality issues especially in sensitive aquatic settings, reservoirs and coastal environments. Despite these differences, certain aspects of the stream water chemistry were suprisingly similar. This work highlights the role of bedrock geology on driving nutrient export dynamics, and improves our understanding of landscapes with high variability in rock types, soil, topography, and hydrology.
Related publications:
Giggy, L., & Zimmer, M. (2025). The role of lithology on concentration‐discharge relationships and carbon export in two adjacent headwater catchments. Water Resources Research, 61,e2024WR037086.
Surface water persistence across ephemeral streams in central coastal California
Plain language summary:
Intermittent and ephemeral streams (aka non-perennial or temporary streams) are streams that periodically dry down. Intermittent streams generally sustain flow seasonally, and ephemeral streams generally only flow during or shortly after precipitation events. This work aimed to understand the precipitation patterns that activate streamflow in intermittent and ephemeral streams and the physical traits of a watershed that support streamflow in some regions longer than others. Across a period of drought, we observed shifts in the relationships between the persistence of streamflow and physical landscape attributes, likely driven by shifts in water storage, precipitation characteristics, and the routes water took through the subsurface before emerging in the stream. This work suggests that during prolonged drought, streams can shift between supporting seasonal flow to only flowing during periods of high-intensity rainfall, which has important implications for water resources management, aquatic and riparian habitat, ecological interactions, and stream protection under current environmental regulations.
Export of carbon, nitrogen, and water from fire-effected headwater streams
Plain language summary:
In August 2020, the SCU wildfires impacted our study site at Blue Oak Ranch Reserve in Santa Clara County (along with nearly 400,000 surrounding acres). Fires are known to alter soil and vegetation which can alter hydrologic processes and water quality. Leveraging in-place hydrologic sensors, we examined the water quality in our wildfire impacted Oak savannah watersheds for several years following the fire. We observed distinct post-fire water quality in our two study watersheds likely due to differences in bedrock type and the routes water takes through the landscape. We also observed ongoing water quality impacts in high-intensity storm events over 400 days after the wildfire. These results highlight the role of hydrogeologic settings and weather patterns on post-fire water quality dynamics.
Geologic sources of salinity in the Dolores River watershed, SW Colorado
Plain language summary:
Southwestern Colorado has a very unique geologic history that causes modern issues with high salinity in several major rivers. This work aimed to build on previous research in the region to pin point different geologic sources of salt along the Dolores River, a tributary to the Colorado River. Results provide insight to whether changes in anthropogenic water use or climate change could further impact salinity in Dolores River.
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