Characterizing Post-fire Hydrologic Response Using End Member Mixing Analysis
Abstract
The study of Devil's Canyon watershed, located in the San Bernardino Mountains in southern California, is undertaken to further understanding of watershed response and recovery in the wake of wildfires. After the fire, increased hydrophobicity alters hydrologic flowpaths by increasing overland flow and decreasing infiltration to the subsurface. Watershed chemistry is utilized to characterize the subsequent change in hydrologic processes and explore the mixture of representative streamwater components. Geochemical data collected from streamwater, springs, soilwater and precipitation are used to determine the distribution of water and solutes in the contributing flowpaths within the watershed. Chemistry analysis shows an increase in cations (Ca, Mg, K, and Na), and a decrease in chloride in streamwater samples after the fire. An End Member Mixing Analysis (EMMA), capturing 96 percent of the variance, predicts the contribution of three components (soil water, groundwater and overland flow) in Devil's Canyon from both pre- and post-burn periods during the rainy season (December to April). Stream water samples from the pre-burn period are similar to the groundwater end member while immediate post-burn samples indicate components more similar to the precipitation end member. Gradual recovery of the watershed is being evidenced by a return to soil and groundwater compositions. Results from the EMMA-based hydrograph separation are used to optimize parameters within a conceptual model by isolating model flow components and calibrating related parameters to contributing portions of the hydrograph.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFM.H51J..02J
- Keywords:
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- 1816 Estimation and forecasting;
- 1836 Hydrological cycles and budgets (1218;
- 1655);
- 1846 Model calibration (3333);
- 1848 Monitoring networks;
- 1879 Watershed