The Natural Environment of the Riparian Area
Riparian Area
These steps were built to lead visitors over to the “lake” created behind the dam. At that time, the water could be as deep as 8 feet and fishing and swimming were possible. Today, this is the entrance to the riparian area which refers to the green vegetated area on each side of streams and rivers. Notice the difference between the desert that you just left and the area you are about to enter.
As you go down the steps in front of you above the dam, notice how much cooler it is and observe the large deciduous trees such as Gooding’s Willows, Velvet Ash, Freemont Cottonwoods and Arizona Sycamores. These trees have large leaves that provide shade most of the year. They are able to grow much larger than the trees in the nearby desert because of their proximity to water.
If you went down the same steps in 2010 or several years before that, instead of seeing only the native vegetation, you would have observed mostly an invasive plant called Arundo donax (Giant Reed), a grass that looks much like bamboo. More about this later.
Moving along the path you will note a large Ash tree on the right. There is a large nest in the tree outlined by the red rectangle in the photo, built by a male Cooper’s Hawk.
Last April (2018) four eggs were laid in this nest. The female incubates the eggs for 30 – 36 days while the male brings her food. When the eggs hatch, the female continues to brood the young for about two weeks while the male brings food. The photo shows all four chicks in the nest with the adult feeding them after I saw her bring in the food on June 3, 2018.
The young leave the nest 28 to 32 days after hatching and go out on the tree branches. This is referred to as branching. They will return to the nest for some time after leaving. This photo was taken on June 9, 2018.
Within 2 months the juveniles become independent and no longer need their parents. This photo was taken on June 28, so the adults are still involved in their care. They are now quite adept at flying. Note the blue eyes. As they get older and become independent, the eye color will change to yellow and then to red as they become adults.
The adult hawks may re-use the nest next season or not. There are two other nests in this area that have been used successfully over the last several years. This one was built, but not used last year.
As you pass the tree with the nest, you will come to the top of the dam. In 2006 there was a huge flood in Sabino Canyon. Had you been standing where you are now, you would have been under water. A good part of the year, the creek dries up and you can walk across to the other side.
When Sabino Dam was built, the citizens of Tucson hoped for a lake that could be used for recreational purposes. However, Sabino Lake soon became a silted in version of itself and is now only a small pond at the best of times. You will notice the presence of aquatic plants such as cattails, rushes and sedges that love to be in standing water. This area still provides a cool, shady respite from the desert just a few yards away.
As I mentioned earlier, the view was very different before 2010. Between 2008 and 2010, volunteers led by Sabino Canyon Volunteer Naturalists and Arizona Master Watershed Stewards removed an infestation of an invasive plant, Arundo donax (Giant Reed), from here and along 1-1/4 miles of Sabino Creek. Arundo uses 10-20 times as much water as any native plant and can grow 2-4” a day, crowding out all native plants. More than 300 community volunteers donated 6,300 hours during the winter months of 2008-2010 clearing out the 20-ft.-tall Arundo canes. Today you see healthy habitat here with young Mesquite, Willow, Black Walnut and Cottonwood trees reclaiming the area.
Spend as much time as you wish exploring this area. Keep in mind that there may be rattlesnakes around so stay on the trails and keep your eyes open. Your chances of actually seeing one are slim as they like to avoid people and are well camouflaged. This advice applies anywhere in the Canyon or in Tucson for that matter.
If you go back to the top of the steps and turn left, the trail will take you back to the traffic circle and you can retrace your steps to the Visitor Center.
Another option is to turn right at the top of the steps and follow the trail to the Bluff Trail. Following this trail will lead you across to the main tram road. Turn left and you can return to the Visitor Center that way.
Thank you for visiting. I hope you enjoyed your tour.
If you are retracing your steps, watch for the rock on the left at the end of the Bear Canyon Trail. As the sign indicates, turning left onto the trail will take you back to the Visitor Center and parking lot.