Drainage Overview - Maricopa County Department of Transportation

CAP- 5 WEST
ACCESS ROAD
Figure GR-97. The CAP-5 West Wash has captured the power line access road and
changes its flow path
To identify areas with high avulsion potential, the parameter dv 2 was
calculated for the overbanks using the HEC-RAS hydraulic models. The
necessary hydraulic parameters for Trilby Wash, Iona East Wash, Iona
West Wash, and CAP-1 West Wash are shown in Table GR-31, Table
GR-32, Table GR-33, and Table GR-34, respectively. The overbanks
of the various washes were examined for areas in which the dv 2
parameter was greater than 18 ft 3 /s 2 . These areas were flagged as areas
of high avulsion potential. The dv 2 parameter was not the only thing
considered when identifying areas of high avulsion potential; the other
15 indicative characteristics listed from above were also considered.
Using these characteristics, areas of high avulsion potential were
identified as shown in Figure GR-111 for the Trilby/Iona system and in
7-166