Atturbury Wash is located on the east side of Tucson and is a tributary of Pantano Wash. Our project area is in the part of the wash in Lincoln Regional Park. Many washes in Tucson have lost their natural vegetation and hydrology due to development on thier floodplains, but Atturbury is largely undeveloped and has a wonderful, wide floodplain filled with dense riparian vegetation. This vegetation (netleaf hackberry, mesquite, blue palo verde, desert hackberry, graythorn, condalia, etc.) is kept alive exclusively by rainwater and stormwater (groundwater here is too deep for roots to reach it).
Stormwater flows occur mostly during heavy summer thundershowers. Historically, it would have spilled out of the shallow wash bed and spread across the floodplain, flowing slowly and infiltrating into the ground. However, erosion--originating upstream in Fred Enke Golf Course--have resulted in deepening of the main wash channel and capture of much of the stormwater that flowed across the floodplain. This caused most of the stormwaters to flow fast and deep, leaving the site quickly, and has resulted in die-off of some of the vegetation.
Arizona Water Protection Fund (AWPF)--Tucson Audubon received a $390,000 grant from the Arizona Water Protection Fund Commission. that has allowed us to address the hydrological issues through "natural channel design" and to revegetate some of the areas of the floodplain that have experienced die-off of vegetation. Contractors built one-rock dams and other structures--larger ones in the main wash and smaller ones in smaller side channels--to slow and spread water, contributing to greater infiltration of water on the floodplain and more availability of moisture to vegetation. Contractors were Dryland Solutions (Santa Fe, NM), Natural Channel Design (Flagstaff), Lil' John's Excavating (Tucson), and Ethos Rainwater Harvesting and Erosion Control (Tucson). The structures were placed in the wash and in the wash's floodplain, both in the lower part of the golf course reach and in the Atturbury-Lyman Bird and Animal Sanctuary.
The Natural Channel Design work accomplishes three things. The larger one-rock dams in the main wash act as grade-control structures, raising the wash bed slightly and stabilizing the level of channel incision. Second, they are placed in areas experiencing bank erosion, moving water away from stream banks. Third, they tend to push floodwaters onto the floodplain and prevent it from flowing back into the main wash channel, increasing the infiltration of water into the ground.
Conserve to Enhance (C2E)--Tucson Audubon received an $11,000 grant from C2E to enhance and publicize the work we are doing at Atturbury Wash. Whereas the AWPF grant funded work throughout the floodplain--much of it in less visible places--the C2E grant funded rainwater harvesting and revegation in a more public area where many people will see it. A sign was dedicated on May 9, 2014 further publicizing the work (photos here). Conserve to Enhance is a program developed at the University of Arizona's Water Resources Research Center as a way to convert real water conservation into tangible benefits for the environment.
A key to this process has been working closely with Tucson Parks and Recreation, which manages Lincoln Park, and the Tucson Golf Program that manages Fred Enke Golf Course. We also work closely with the Groves-Lincoln Park Neighborhood Association, which for decades has worked to preserve the natural open space in Lincoln Park. All these groups have strongly supported the our work and have contributed significant resources toward making it a success.
Part of Tucson Audubon's work at Atturbury Wash is public outreach regarding the importance of riparian habitat and healthy floodplain function. One of our key messages to the public is that natural open space in our city and county parks should not be seen as an "unused" portion of the park; the future site of a ball field or recreation center. That natural open space is a recreation area for bird watchers, hikers, dog walkers and many others. It is habitat for a wide variety of creatures—birds and more—that "wildlife watchers" enjoy seeing. Wildlife watching is a major source of income in Arizona, with an annual $1.4 billion "total economic impact."
Look in Tucson Audubon's calendars for site tours, birding field trips, volunteer work days and other opportunities to visit the project site and learn more.