Tommy J. DeBardeleben

Tres Rios Overbank Wetlands

Fast Flight Facts

Target Species:  An amazing variety of waterbirds, raptors, and songbirds

Elevation: 970'

Habitat:  Extensive ponds, marsh, wetlands, riparian habitats, fields, and farmlands

Overall Birding Rating: 5

Difficulty: 1 (Easy)

Birding Type: Easy to Moderate Hiking

Facilities:  Parking, Restroom

Fees/Ownership:  None/City of Phoenix

Closest Town or City/How far from Phoenix:  Tolleson /11 miles southwest of Phoenix

Getting there:  Parking area on the west side of 91st Avenue (by permit only)

Overview:  Recently, Tres Rios Wetlands has constructed a new and very large extension to their wastewater treatment plant on the west side of 91st Avenue.  The area is huge, and it has been made into a wildlife sanctuary.  There are large ponds surrounded by riparian habitat where abundant birdlife is found, including large numbers of American White Pelicans, wintering ducks, grebes, rails, Osprey, and many more.  This extensive area, which is called the Tres Rios Flow Regulating Wetlands,  is chained in by a fence that dosen't allow public access, due to the fact these newly constructed Tres Rios Wetlands are considered part of the wastewater treatment plant.  However, outside of this fenced in wetland area immediately south, are more created wetlands to be found.  These outside wetlands are known as the "Overbank Wetlands".  They have been built for overflow purposes, and the water from the main project flows into these wetlands and run eventually into the Salt River, which creates an amazing birding experience through marsh, wetland, and riparian habitats.  This area is going to eventually be open to the public, but as of now it is only accessed by obtaining a permit from Tres Rios personnel.  The Overflow Wetlands run all the way west from 91st Avenue to 115th Avenue, which is 2.5 miles in length.  "Pond after pond" is the feel the birder will get as they are birding in this area.  Besides marsh and open wetland habitat, the Salt River is also close by with it's cottonwood, willow, and mesquite habitat.  Farmlands and agricultural fields are also adjacent to the wetlands.  Birding in these surrounding habitats will also be rewarding.  Despite the fact that the main wetland project is closed to the public, the birds in that area can often be seen in flight and through the fence.  And of course, most of them can be seen in the Overbank Wetlands, because the birdlife is abundant.  Any outing in this extensive area will likely hold a very interesting day of birding.

Birding Tip:  To bird this area, you must obtain a permit from Tres Rios personnel during business hours.  Visit Tres Rios's website at for contact information on obtaining a permit.  Once at the Overbank Wetlands, park your vehicle in the designated area and walk west for as much as 2.5 miles on the paths through excellent marsh and wetland habitat.  Birding close to the Salt River to the south also holds productive birding opportunities.  To see a better overview on birding the area, see the maps page under the "Pages" category below.

Directions:  To access the Tres Rios area, an easy way to get there would be to take the 91st Avenue exit south if on the I-10 freeway.  Also, if coming from the Loop 101 south, one can merge east onto the I-10 freeway for a short distance to reach the exit for 91st Avenue.  Once on 91st Avenue, take it south for five miles to the Tres Rios area. It is just north of Baseline and 91st, and about a mile south of Broadway and 91st.  Once obtaining a permit from Tres Rios personnel, the parking area will be on the west side of 91st Avenue to access the Overbank Wetlands.  When coming south down 91st Avenue (just south of Broadway), a large fenced in area will soon come into view which surrounds a noticeable wetland habitat.  Once reaching the end of this fenced in area (which is the Tres Rios Flow Regulating Wetlands), the Overbank Wetlands can be reached just south of this fenced in area.  You will see a "no trespassing" gate preventing vehicle access, but once you have the permit, you have permission to park and bird the area by foot.  The Tres Rios-Hayfield Site's access is only 0.15 miles south of the access point to the Overbank Wetlands, but the Hayfield Site is accessed on the east side of 91st Avenue. 


Tres Rios Overbank Wetlands Maps

Tres Rios Overbank Wetlands eBird Data


Scenes and Sights from Tres Rios Overbank Wetlands:


Birdlife of Tres Rios Overbank Wetlands:

Northern Harrier

Bald Eagle

Red-shouldered Hawk (rare in Arizona)

Peregrine Falcon

Sharp-shinned Hawk

American Kestrel

Cooper's Hawk

American White Pelican

Tropical Kingbird (Rare in Maricopa County)

Cinnamon Teal

Blue-winged Teal

Swamp Sparrow

Palm Warbler (rare in Arizona)

Chestnut-sided Warbler (rare but annual in Arizona)

Bendire's Thrasher

Lark Sparrow (juvenile)

Abert's Towhee



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