register help

Gillespie Dam and Bridge, AZ

no permit
90 7 0
Guide 7 Triplogs  0 Topics
Rated  Favorite Wish List AZ > Southwest > Buckeye W
3.3 of 5 by 4
clicktap icons for details
Difficulty 0.5 of 5
Route Finding 1 of 5
Distance Round Trip 2.17 miles
Trailhead Elevation 750 feet
Elevation Gain 10 feet
Accumulated Gain 41 feet
Avg Time Round Trip 30 min
Kokopelli Seeds 2.38
Interest Historic, Seasonal Creek & Perennial Creek
Backpack No
feature photo
Photos Viewed All Mine Following
Will recalculate on button tap!
14  2016-05-08 chumley
13  2016-05-08 johnlp
13  2016-05-08 trekkin_gecko
9  2015-11-27 skatchkins
19  2012-05-01
Gillespie Dam & Bridge
22  2012-03-03
Hwy 80 to 85 Loop
Author chumley
author avatar Guides 75
Routes 667
Photos 13,172
Trips 1,417 map ( 10,542 miles )
Age 46 Male Gender
Location Tempe, AZ
Historical Weather
Trailhead Forecast
Expand Map
Preferred   Feb, Nov, Mar, Dec → Any
Seasons   Autumn to Spring
Sun  6:19am - 6:28pm
Official Route
0 Alternative
It's a dam history walk!
by chumley

Gillespie Dam
The 1,768 foot long and 56 foot tall Gillespie Dam was built in 1921 by agriculturalist Frank A. Gillespie to supply water to his Paloma Ranch and aid thousands of acres of new farmland along the Gila River between Arlington and Gila Bend. At the time, it was the largest privately financed concrete irrigation diversion dam in Arizona. The concrete dam was the last of four dams built at this site. The others were made of earth, stone, or wood, and were washed out by floods on the Gila River.

The current dam was breached in 1993, which was one of the largest dam failures in Arizona History. Another site associated with the construction of the dam and bridge is the Gillespie Dam Construction Camp. The site contains remnants of the machinery and structures used to build the dam, including an innovative pulley system for delivering concrete during construction.

On January 9, 1993 after heavy rains and winter runoff caused flooding on the Gila River estimated to be 200,000 cubic feet per second a 180-foot section of the dam failed. The dam was never repaired, nor was the remaining structure dismantled. An earthen levee was built to direct river flow to a pond where the necessary irrigation water is now pumped into adjacent canals.

Historic Gillespie Dam Bridge
The historic Gillespie Dam Bridge spans the Gila River on Old US 80 Highway, between the communities of Arlington and Gila Bend. Opened in 1927, the bridge is a unique and elegant reminder of Arizona's rich past and America's transportation history. The bridge is listed on both the Arizona State and National Register of Historic Places. During the winter of 2011, the bridge underwent a $7.3 million rehabilitation effort by the Maricopa County Department of Transportation.

Highway Info:
Shortly after Arizona’s statehood in 1912, a major east-west transportation route was established between Clifton and Yuma. Several bridge and ford crossings of the Gila River were attempted in the early years and proved unreliable due to frequent washouts during rain and flooding.

In 1921, the highway route was realigned to ford the Gila River just below the newly constructed Gillespie Dam. Heading south towards Gila Bend, the new route was known as the Phoenix-Yuma highway. The following year, the Arizona Highway Department built a concrete apron on the downstream side of the Gillespie Dam to help automobiles to cross the Gila River. This crossing point also proved to be unreliable, as high water often made passage difficult. Between 1922 and 1926, large trucks, tractors, and horse teams were frequently used to pull automobiles across the apron of the dam.

The Arizona Highway Department set about designing an all-weather bridge structure in 1925 to span the Gila River. Construction of the Gillspie Dam Bridge began in February 1926 and later that same year, the American Association of State Highway Officials adopted our present day highway numbering system, when the new Gillespie Dam Bridge opened to traffic on August 1, 1927. It was officially designated part of the early southern transcontinental US 80 Highway.

The new bridge and US 80 Highway through the Arlington Valley became part of the National “Ocean-to-Ocean” Highway and carried US 80 transcontinental traffic from 1927 until 1956, when the route shifted east to Rainbow Valley and the Arlington Valley stretch was decommissioned. The old highway and the bridge were transferred from the state of Arizona to Maricopa County.

Bridge Facts:
Lee Moor Construction of El Paso, Texas built the nine-span steel truss bridge for a cost of $320,000. The 1,662-foot-long Gillespie Dam Bridge was unique for its time and one of the longest bridges and the largest steel structure in the state. All of Arizona's major bridges before this were built using reinforced concrete arches which proved to be no match for swollen, flooding rivers. The new design produced a more durable and flexible bridge that could better withstand the force of flood waters.

Bridge design elements include a connected series of rigid through trusses weighing 2.3 million pounds. The bridge has a total of nine steel truss spans - five 200-foot-long trusses centered over the river channel, flanked by two 160-foot long trusses at each end. Each steel truss features a camelback web configuration with a built-up box beam for the upper and lower steel members. The trusses are supported by solid concrete abutments and pier columns placed on bedrock at a depth of 25 feet, with the deepest pair extending 43 feet below the riverbed.

The bridge and dam area today is largely open to the public, with only a small fenced area near where the electric pumps deliver river water to the canal system. The dam and apron can be climbed, and a narrow walkway crosses the diversion channel gates to the concrete apron. There are abundant species of birds and excellent fishing opportunities.

On the west side of the river, on the hill above the dam, an impressive display of petroglyphs can be found at the base of the cliffs. Access may be easiest by driving a quarter mile west of the bridge, parking in the dirt pull-out and following the use paths that lead down to the numerous panels.

Source: Most of the text above was taken from the interpretive signage placed at the bridge during the 2011/2012 bridge rehabilitation project. Unfortunately, at the time of this writing, vandals had removed those signs and no information is currently available on site.

Check out the Official Route and Triplogs.

Gate Policy: If a gate is closed upon arrival, leave it closed after you go through. If it is open, leave it open. Leaving a closed gate open may put cattle in danger. Closing an open gate may cut them off from water. Please be respectful, leave gates as found.

Leave No Trace and +Add a Triplog after your walk/tour to support this local community.

2016-05-09 chumley
    WARNING! Hiking and outdoor related sports can be dangerous. Be responsible and prepare for the trip. Study the area you are entering and plan accordingly. Dress for the current and unexpected weather changes. Take plenty of water. Never go alone. Make an itinerary with your plan(s), route(s), destination(s) and expected return time. Give your itinerary to trusted family and/or friends.

    Most recent Triplog Reviews
    Gillespie Dam and Bridge
    rating optionrating optionrated 3rated 3rated 3
    chums knew this was nearby so we checked in out while in the area
    interesting bit of arizona history
    i liked that nothing was off limits to exploration
    see chumley's [ description ] and [ gps route ] for possibilities
    fun stop that i would never have known about
    Gillespie Dam and Bridge
    rating optionrated 4rated 4rated 4rated 4
    Just a little history exploration after an earlier hike. I'd seen photos of this before, but never been. It's nice that it's largely open to the public to explore. Cool old truss bridge now approaching 100 years old. The dam is almost more interesting because it breached in 1993, though I would have liked to see it intact too. Same flood that knocked out the new Mill Ave bridge while it was being built. (The original/old Mill Ave bridge was built 10 years after Gillespie!). Nice history out here.

    Good to see a healthy running river too. Amazing how fertile a farming valley it is along the Gila floodplain. Recommended day trip for those who don't live and die by AEG and mileage statistics. ;)
    Gillespie Dam and Bridge
    rating optionrating optionrated 3rated 3rated 3
    Hwy 80 to 85 Loop
    Felt like spending gas while I could.

    I took the Old Hwy 80 down from Buckeye driving through farm land and almost empty roads that reminded me of Louisiana. I pulled off the road and drove up the hill that overlooks Gillespie Dam and Bridge to get a better vantage point to decide what to do next. I ended up hiking around and down the hill to the dam to poke around for a bit. Then I walked out on it to the break.

    Once back in the vehicle I continued on down the road seeing the sights. Stopped at the Spring Mountain Ski Ranch which looked doomed to fail from the start. Hit up Dairy Queen in Gila Bend and then took 85 towards home.

    Closer to town I realized I had no where to be and the sun was not yet down so I eyed dirt roads until I ended up taking the one that skirted the Robbins Butte Wildlife area. Those 15mph signs are so hard to see when your tires are in the air most of the time.

    Racing the sun, I ended up at what I now know is Robbins Butte and decided that was far enough. I looked at the rocky hill and thought I might just make it to the top in time. The rocks of course look bigger once you're halfway up. The side I was on, you pretty much had to use them as stairs though because everything else was too loose. I figured if I ran it my mind wouldn't have too much time to complain while trying not to fall.

    Anyway I made it to the top and as soon as I sat down I realized I couldn't breathe much that way and then when I stood up again I realized I was pretty much surrounded by petroglyphs (and big honking mosquitoes). I shot a few pics up there as the sun went down and then hiked down with my headlamp.

    Permit $$

    Map Drive
    Paved - Car Okay

    To walk/tour
    Travel west from Phoenix on I-10 approximately 30 miles to US-85. Take US-85 South 5 miles and turn right onto Hazen Road. Follow Hazen Road west 2 miles and turn south onto Wilson Road. Follow Wilson south half a mile to Old Highway 80. Turn right and follow Old US 80 for 14 miles to the bridge.
    page created by chumley on May 09 2016 11:01 am
    help comment issue

    end of page marker