Sabino Canyon's steep walls prevent the creek from getting wide. Especially during the summer monsoon storms, Sabino Creek experiences sudden and sometimes dangerous floods. These are some of the reasons flooding is very important in the *riparian* woodlands.

* Flooding scrapes the ground to make bare patches for seeds to grow.

* Flooding moves seeds and helps rub the seed coat so they can grow.

* Floods wash away the salts that crust on the earth's surface and bring nutrients to improve the soil.

* Flooding moves seeds away from parent plants so new plants don't have to compete for water and sun with older plants.

* Floods break off tree limbs and remove dead wood, clearing more space for sunlight.

* Floods also raise the water table which helps plants, animals, and people get enough to drink.

On July 15th, 1999 Sabino Creek flooded. The day before, on July 14th, 6 inches of rain fell on top of Mount Lemmon. Between 6:15 a.m. and 6:30 a.m. on July 15th, the rain gauge that measures the flow of water into Sabino Creek rose from 218 cubic feet per second to 1,700 cubic feet per second. One hour later, at 7:30 a.m., the flow was 10,650 cubic feet per second. 16 people were stranded in Sabino Canyon because they couldn't cross the bridges. (Water was rushing over the bridges at up to 4 feet high!) The hikers were rescued by heliocopter. This was the fastest rising flashflood in the past 50 years. Fortunately, no one was injured. For the complete story, read The Arizona Daily Star article entitled "Sabino, Rillito Flooded: Incessant Mountain Rains Deliver Soggy Surprise" (Friday, July 16, 1999).

These are photographs taken in the canyon two days after the flood on July 17th.