Data Collection Report - Flood Control District of Maricopa County

Existing, natural vegetation in the Durango drainage area is characteristicof the Lower Colorado River Valley subdivision of the SonoranDesertscrub biome (Brown 1994), with various subdivisions and plantassociations described below.Photo V-1. Wetland vegetation and riparian woodland at 115 thAvenue and the confluence of the Gila and Salt rivers. Suchareas may provide breeding or foraging habitat for specialinterest species such as Yuma clapper rail, southwester willowflycatcher, western yellow-billed cuckoo, and western leastbittern.Photo V-2. North-northeast view from Van Buren Street andthe Agua Fria River. The banks are channelized, and utilitystructures are located in the riverbed.Photo V-3. Stabilized banks of the Agua Fria River near VanBuren Street.The Durango drainage area includes portions of the Agua Fria, Gila, andSalt rivers, as well as the confluences of the Salt and Gila rivers, and theGila and Agua Fria rivers. Much of the Agua Fria River has beenchannelized for flood control (Photo V-3). Permanent surface waterexists along portions of the Gila and Salt rivers. Late succession ripariangallery forest exists in the project area near the confluence of the Gilaand Salt rivers and provides potential habitat for several special interestspecies, and attracts many birds of prey. The Tres Rios constructedwetlands exist along the Salt River beginning at the City of Phoenix 91 stAve Wastewater Treatment Plant, and contain a variety of native andintroduced plant and animal species. The effluent is conveyed andrecharged to the Salt River. The Tres Rios project supports a diversearray of shore birds, song birds, and raptors, as well as muskrat andbeaver. However, native fishes are not likely to occur in the aquaticcommunity at and downstream of Tres Rios, because introduced speciessuch as tilapia (Tilapia sp.), mosquitofish (Gambusia affinis), sailfinmolly (Poecilia latipinna), common carp (Cyprinus carpio), largemouthbass (Micropterus salmoides), and bullfrogs (Rana catesbiana) are soabundant that they presumably prey on or outcompete native species(Minckely 1991).Upland Vegetation TypesSonoran Desertscrub, Lower Colorado River Valley Subdivision.Honey mesquite (Prosopis glandulosa), creosote bush (Larreatridentata), and foothill palo verde (Cercidium microphyllum) arecharacteristic species of the Sonoran Desertscrub biome existing in theDurango drainage area. Other common plants include burrobush(Hymenoclea salsola), snakeweed (Gutierrezia sarothrae), burro weed(Isocoma acradenia), various saltbush species (Atriplex spp.), brittlebush(Encelia farinosa), desert broom (Baccharis sarothroides), buckhorncholla (Opuntia acanthocarpa), white bursage (Ambrosia dumosa),mallows (Sphaeralcea spp.), and desert milkweed (Asclepias subulata).The Lower Colorado River subdivision is drier and hotter than theArizona Upland subdivision that lies chiefly to the south. Consequently,plant growth is relatively less complex and dense in the Lower ColoradoRiver subdivision. However, the composition of animal species differslittle - reptile species are relatively more abundant while bird species areless so.Aquatic and Riparian Vegetation TypesAquatic Communities and Wetlands. Both permanent andintermittent aquatic communities exist within the project area along theSalt, Gila, and Agua Fria rivers. Such communities include natural andconstructed wetlands. Apparently natural wetland communities exist at,DIBBLE & ASSOCIATES 37 DURANGO ADMPDATA COLLECTION REPORT