Runoff from wildfire could damage many Pima County homes

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Cañada del Oro Wash at Edwin Road on July 15, 2020 (Pima County)

TUCSON, Ariz. (AP) — Many Pima County homes and businesses could face flood damage in the wake of the latest large wildfire in the Tucson area, according to authorities.

The lightning-caused Bighorn Fire started June 5 and charred about 187 square miles in and near the Santa Catalina Mountains before it was fully contained on July 23.

The Arizona Daily Star reports close to 1,000 homes and businesses lying along a number of washes could be flooded during a 100-year storm. That’s more than double the 431 landowners in those areas who got letters from the county in late June telling them their homes could be flooded during a big storm.

A county Regional Flood Control District hydrologist told the Star the risk to Tucson residents from monsoon flooding due to the wildfire could last up to five years because of the way the blaze altered the watershed.

It typically takes watersheds two to five years to recover from such severe burns.

County flood control officials used computer models to help calculate the risks to homes and businesses downhill of the fire.

They found 982 buildings facing flood risks including 834 in unincorporated areas of Pima County, 109 in Oro Valley, 38 in Tucson and one in Marana.