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Urban Areas 283in high-fire-zone areas (Pincetl et al. 2008). Less evident impacts are also likely. For example,in the Los Angeles National Forest Station Fire, vegetation burned that had notburned since before the introduction of air pollution controls. Stormwater samples takenafter the Station Fire showed high levels of heavy metals that had been deposited beforeClean Air Act requirements were imposed (Burke et al. 2011). Water from the front rangeof the Los Angeles National Forest is a key source of groundwater recharge, and infiltrationbasins have been inundated with these post-fire pollutants. Except for the study ofthe L.A. Station Fire, little or no monitoring of such impacts has been done. Increasedincidents of urban-fringe fires will require improved post-fire monitoring and managementand treatment of stormwater runoff to reduce impacts to city water supplies anddownstream ecosystems (see also Chapter 3, Section 3.2.1, and Chapter 8, Section 8.4.2).Figure 13.12 Total acres burned in wilderness/urban interface zones of six Southwesterncities. Source: U.S. Department of the Interior’s Geospatial Multi-Agency Coordination Group(GeoMAC) Wildland Fire Support (http://www.geomac.gov), State of California Fire and ResourceAssessment Program (http://frap.cdf.ca.gov).The built environmentThe built environment itself can be a conduit for climate impacts. High percentages ofimpermeable surfaces like asphalt—which is commonly used in cities—increase surfacetemperatures, amplify heat waves, and reduce stormwater infiltration, contributing to