FLOOD02227 - Laserfiche WebLink

Home Browse Search

AUG-29-2000 rUE 10:03 AM FAX NO. p, 05 rainfall data from Mr, Hess and Mr. Ostransky suggest the recurrence interval of the August 16 rainstorm ranged from about 20 to 40 years. THE FLOOD Standard hydraulic methods were used to estimate peak discharge for streams in burned and unburned basins. Drainage basin at the location of the flood estimates also were determined. Unburned areas in the area of maximum rainfall (2 to 3 inches of rain) had little or no runoff. For example, an unbumed 0.2 sq. mi. tributary to Cedar Creek near Jug Court had no runoff. Similarly, the -1 sq. mi. unburned left bank tributary to Bobcat Gulch also had no runoff on August 16th. In contrast, a -0.04 sq. mi. (-25 acres) burned basin near Jug Court had a peak discharge 01 about 50 cIs. Likewise, the unnamed Wild Turkey Road (at street number #119) -0.1 sq. mi. (-60 acres) tributary had a peak discharge of about 100 cfs. The peak discharge in Bobcat Gulch was about 800 cubic feet per second (cfs) for the -3 square ~ '7 3 mile (sq. mi.) basin, but not all of the basin produced runoff. A representative channel cross .---=::;:;. section just upstream from the first hairpin turn along Bobcat Gulch is shown in figure 3. The runoff probably was generated Irom less than 1 sq. mi. corresponding to the burned area. Cedar Creek upstream from Cedar Springs Pond, which drains the area of maximum rainfall had a peak discharge 01 about 400 cfs from about 1.5 sq. mi., but much of this area was unburned (-1 sq, mi.) or the contributing drainage area was about 0.5 sq. mi. Cedar Creek at Cedar Cove had minimal runoff (less than 60 cIs), which drains the majority of the burned area (-8 sq. mi.). This reflects the limited rainfall even over the burned area. However, most of the upper Cedar Creek runoff from the 8/16 storm was contained in Cedar 4