Skunk Creek, a dry arroyo for most of the year, runs through the cities of Glendale, Peoria, and Phoenix, AZ. As in much of the arid Southwest, the susceptibility to flash flooding is a very real threat; and as in much of the greater Phoenix area, development had altered the channel and placed people in harm’s way. The Flood Control District of Maricopa County undertook a project to stabilize the channel with the intention of taking as much property out of the 100-year floodplain as possible while preserving a naturally vegetated environment and public-use amenities such as walkways and equestrian trails.
Excavation, grading, and the placement of erosion control protection measures along Skunk Creek was a big project on a tight schedule. Only 270 days were allowed for the completion of the project, which included 38,000 cubic yards of special excavation; 700,500 cubic yards of open-channel earthwork; 36,900-cubic yards placement of 9-in.-deep reno mattresses for bank protection and scour aprons; 28,100 cubic yards of 12- and 18-in. gabion placement; and shotcrete installation over a 30,700-square yard area.
Falling within the jurisdiction of Glendale and Peoria, this project was carried out under the aegis of the Flood Control District of Maricopa County. Simons, Li and Associates (Tempe, AZ) were responsible for the design, and the general contractor was D.H. Blattner & Sons (Phoenix, AZ). The exceptional partnering arrangements among all the responsible participants from county officials, designers, contractors, subcontractors to suppliers, and the inspection team made it possible to complete this ambitious project on schedule. As one observer put it, “I’ve been to 14 county fairs and several dogfights, but I’ve never seen anybody move dirt like you boys!”
Rob Myers, area manager with Maccaferri Gabions’ Phoenix office, worked closely with the contractor and the subcontractor, Specialty Contractors of Arizona, to ensure a smooth and uninterrupted flow of materials to the site. In order to speed installation of the gabion material, special Gabion Mats, or rollouts, were used. “These are 6- or 9-foot-wide, 99-foot-long gabions designed to reduce assembly time and allow for quicker stone placement,” explains Myers. To further reduce assembly and installation time, a pneumatic fastening system called the “Spenax” was developed by Stanley Fastening Systems and is available through Maccaferri. This system consists of a hand-held gun loaded with wire rings that are squeezed closed by a set of jaws, and it allowed the contractor to eliminate much of the hand-lacing associated with traditional gabion assembly.
Most of the loose rock filling for the Gabion Mats was screened from onsite excavations and provided an economical and well-integrated source of material. After the gabions were placed, they were covered with 1 ft. of topsoil and seeded with native plant materials. The result is a stabilized channel that provides recreational opportunities while preserving the natural vegetation of its surroundings.
