Water quality response to the Angora Fire, Lake Tahoe, California

作者：Oliver Allison A^*; Reuter John E; Heyvaert Alan C; Dahlgren Randy A

来源：Biogeochemistry, 2012, 111(1-3): 361-376.

DOI：10.1007/s10533-011-9657-0

• Wildfire
• Water quality
• Streams
• Watershed response
• Nutrients

The Angora Fire (summer of 2007) was the largest and most severe wildfire in recent history within the Lake Tahoe basin of the Sierra Nevada. To determine the watershed response and to assess the potential for downstream impacts of nutrient and sediment delivery to Lake Tahoe, we monitored the post-fire hydrology and stream water chemistry for 2 years at four locations along the length of Angora Creek, a perennial stream draining the burned watershed. When compared with unburned streams, the hydrology of Angora Creek indicated an earlier and faster melting of the spring snowpack. Peak stream water concentrations of total N (TN) and ammonium occurred within the burned area, whereas peak concentrations of nitrate (NO3 (-)), total P, soluble reactive P, total suspended solids, turbidity, electrical conductivity (EC), and dissolved organic C occurred below the burned area. In comparison to pre-fire data, TN, NO3 (-), TP, total dissolved P, EC, and turbidity increased following the fire, particularly in the wetter second year. Yields for subwatershed areas suggest that the burned urban subwatershed was the largest source of nutrients and sediments, whereas the wet meadow subwatershed downstream of the burned area retained materials. Erosion control efforts, below-average annual precipitation and the timing of its arrival (absence of summer and fall rainstorms), and the existence of a wet meadow below the burned watershed likely reduced the negative impacts that would have been expected from such a severe wildfire.

• 出版日期2012-11