HR: 0830h
AN: H41D-1037    [PDF]
TI: Monsoon Season Surface Water Chemistry Response Following Wildfire: 2003 Aspen Fire in Sabino Canyon, Arizona
AU: * Einloth, S L
EM: seinloth@hwr.arizona.edu
AF: Hydrology and Water Resources, University of Arizona, 1133 E. North Campus Dr. Harshbarger Bldg., Tucson, AZ 85721 United States
AU: Chief, K D
EM: kchief@hwr.arizona.edu
AF: Hydrology and Water Resources, University of Arizona, 1133 E. North Campus Dr. Harshbarger Bldg., Tucson, AZ 85721 United States
AU: Ekwurzel, B
EM: ekwurzel@hwr.arizona.edu
AF: Hydrology and Water Resources, University of Arizona, 1133 E. North Campus Dr. Harshbarger Bldg., Tucson, AZ 85721 United States
AU: Nijssen, B
EM: nijssen@u.arizona.edu
AF: Hydrology and Water Resources, University of Arizona, 1133 E. North Campus Dr. Harshbarger Bldg., Tucson, AZ 85721 United States
AU: Nijssen, B
EM: nijssen@u.arizona.edu
AF: Civil Engineering and Engineering Mechanics, University of Arizona, P.O. Box 210072 CE Bldg., Tucson, AZ 85721 United States
AU: Ferr\'{e}, P A
EM: ty@hwr.arizona.edu
AF: Hydrology and Water Resources, University of Arizona, 1133 E. North Campus Dr. Harshbarger Bldg., Tucson, AZ 85721 United States
AB: The Aspen Fire in the Coronado National Forest north of Tucson burned in excess of 80,000 acres and destroyed more than 300 structures. Exposed, burned soils are highly vulnerable to intense monsoon rains, leading to increases in surface runoff, peak flows, and erosion rates. As part of an integrated investigation of the hydrologic impacts of this fire, we rapidly mobilized a field sampling campaign during the 2003 monsoon season that began immediately following the resolution of the fire. Stream water chemistry serves as an integrated signal of many watershed processes: precipitation, runoff, infiltration, soil hydrophobic layers, ash deposition in the stream, debris flows, and subsequent water/ash chemical equilibrium reactions. The portion of the watershed that has been burned by the Aspen fire covers a wide range of elevation and vegetation zones of the Santa Catalina Mountains. Many biogeochemical and hydrological processes within this area were altered by a sudden lack of vegetation and changes in soil properties following a fire: evapotranspiration, litter volume, organic decomposition, leaching, cation exchange, anion sorption, nutrient uptake, and soil hydrophobic layers. Surface water and precipitation samples were collected following an event-based sampling strategy, while soil samples were collected in each vegetation and burn severity regime. Precipitation samples were collected to characterize temperature and elevation effects on precipitation chemistry, in particular stable isotopes. The surface water chemistry changes measured throughout each hydrograph event can be linked to air permeameter results, a rapid measurement for soil hydraulic conductivity, for the different burn severity and vegetation zone regimes. Both nutrient and suspended sediment loads greatly increased following the fire. A debris flow mobilized large diameter boulders. Stream gauge flow event peaks were larger than expected given concurrent extensive precipitation gauge network recordings compared with flow history of this watershed before the fire.
DE: 1040 Isotopic composition/chemistry
DE: 1821 Floods
DE: 1860 Runoff and streamflow
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2003 Fall Meeting