| NSF Org: |
EAR Division Of Earth Sciences |
| Recipient: |
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| Initial Amendment Date: | November 4, 2020 |
| Latest Amendment Date: | November 4, 2020 |
| Award Number: | 2100269 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Hendratta Ali
heali@nsf.gov (703)292-2648 EAR Division Of Earth Sciences GEO Directorate for Geosciences |
| Start Date: | November 15, 2020 |
| End Date: | October 31, 2022 (Estimated) |
| Total Intended Award Amount: | $14,312.00 |
| Total Awarded Amount to Date: | $14,312.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
110 8TH ST TROY NY US 12180-3590 (518)276-6000 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
110 8th Street Troy NY US 12180-3522 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): |
Hydrologic Sciences, Geobiology & Low-Temp Geochem, Ecosystem Science |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
Wildfire magnitude and frequency are increasing across the western US. These wildfires are drastically altering Earth?s surface by burning vegetation and surface soils and destabilizing hillslopes, making them more prone to erosion. Together, these alterations impact how precipitation and other material is transported to rivers. Rivers are the main conduit for transferring water and materials from headwaters further downstream and ultimately to oceans. However, given the challenges of capturing unpredictable wildfire events, there is a lack of understanding of the composition, concentration, and timing of material export out of watersheds immediately following fires. Included in the material being transported is soot and charcoal (called pyrogenic carbon) and essential nutrients, such as nitrogen. These materials are important for local ecosystem function, global biogeochemical cycles, and for the water quality of downstream drinking water resources. This study proposes to collect water and soil samples from burned watersheds following the fires of the Santa Clara Unit Lightning Complex. The watersheds were instrumented prior to the fires and provide an opportunity to analyze hydrologic and biochemical data previous to and after the fire. This study will generate data that will help to understand the impacts of wildfires on water resources used for drinking water purposes and provide valuable information for mitigation of these impacts.
The goal of this research is to reveal how altered hillslope hydrology and streamflow in newly burned landscapes will impact the in-stream storage and export of ecologically and biogeochemically critical material, with specific focus on nitrogen and pyrogenic carbon. This research will be conducted in a headwater catchment in central coastal California, which experiences non-perennial streamflow due to its Mediterranean climate. Researchers will couple measurements of nutrient and pyrogenic carbon concentrations at the outlets of five nested watersheds to assess how previously identified differences in dominant streamflow generation processes influence observed material transport. Through deployment of automated samplers and a spectrophotometer, this work will develop a rich dataset of in-stream pyrogenic carbon and nutrient concentrations from the very first post-fire precipitation event to the summer dry down. This is critical for constructing an integrative view of hydrologic and biogeochemical processes in fire- impacted watersheds. The project will provide train undergraduate and graduate students and generate data that will inform the Santa Clara Valley Water District on the export of materials from burned watershed into drinking water sources.
This project is jointly funded by the Hydrologic Sciences and Geobiology and Low-Temperature Geochemistry programs in the Division of Earth Sciences and the Ecosystem Science Cluster program in the Division of Environmental Biology.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The main goal of this project was to determine how low severity fire affects the amount and flow paths of water in non-perennial headwater catchments, and how altered hydrology influences the mobilization and export of critical material in-stream. In August 2020, the Santa Clara Unit Lightning Complex Fires burned two experimental headwater catchments in the Diablo Range in central coastal California (USA). The paired catchments have different underlying geologies, which influence critical zone structure (e.g., subsurface thickness, hydraulic conductivity) and overall hydrologic behavior. Specifically, one watershed is dominated by shallower hydrologic flowpaths in hillslopes, producing larger streamflow responses to precipitation. To achieve our project goal, we collected stream water samples and hydrometric data at the watershed outlets at high temporal resolution from the first post-fire winter flush through summer drydown and during most storm events during the second post-fire year. Samples were analyzed for black (fire-derived) carbon, nutrients, and other major ions. Major research findings include:
- In-stream carbon, including dissolved organic carbon as well as particulate and dissolved black carbon, concentrations were highest in the watershed dominated by shallow hydrologic flowpaths in hillslopes.
- Within the first post-fire year, total dissolved nitrogen was depleted from both watersheds more rapidly than dissolved organic carbon.
- Overall, relationships between hydrology and material export indicate that carbon and nutrient export is driven primarily by underlying geology, rather than low severity fire, in these types of watersheds.
This study was the first known attempt to measure pulses of carbon, charcoal, and other material exported immediately after and through the year following a watershed burn event. Project findings are essential for constructing an integrated view of how wildfire affects water flow and elemental cycling in headwater catchments, particularly those in the fire-prone western United States.
This work supported two early career researchers, Margaret Zimmer and Sasha Wagner, and provided them with experience in the successful planning, leadership, and completion of a major funded project. Project funds also supported two female graduate students, who gained valuable fieldwork and analytical experience, participated in a highly collaborative and cross-disciplinary research team, and developed skills in data interpretation and science communication. Project results have been shared at international conferences, a US Congressional Staff briefing on wildfires in the western United States, and with local communities, such as the Capitola Rotary Club. Wagner has also incorporated wildfire science modules into her regularly taught courses.
Last Modified: 02/28/2023
Modified by: Sasha Wagner
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