Atturbury Wash Riparian Stewardship Project
Atturbury Wash, an ephemeral channel that meanders through Lincoln Regional Park in Tucson, is undergoing down-cutting and there has been die-off of native vegetation along the stream corridor. This die-off has coincided with the down-cutting and the ongoing drought and periods of abnormally high temperatures that have occurred in recent years. Conversely, upstream of Lincoln Park, within the Fred Enke Golf Course, excess sediment is being deposited due to a combination of over-widened golf cart crossings that decrease flow velocity and act as grade-control.
In order to address these problems, principles and methods of natural channel design were utilized to stabilize habitat conditions within the wash both in Lincoln Regional Park and the downstream portion of the golf course. The goals of the project are to stabilize the bed of the wash through installation of grade control at several locations and to prevent loss of the current distributary channel network that reduce high velocities and associated channel erosion. As part of the project a series of low impact stream stabilization improvements were installed, including one rock dams, Zuni bowls, media lunas, rock run-downs, and boulder vanes, j-hooks, and cross-vanes. The adjustment will assist in inducing a stable rate of sediment transport with the result of reducing flow velocity and encouraging aggradation of sediment on the bed of the channel. Preventing further down-cutting will help preserve the already drought-stressed riparian vegetation.
The following is a summary of George F. Cathey’s technical contribution to the project (as an employee of Natural Channel Design, Inc.):
- Engineer of Record for all civil works associated with the restoration project.
- Topographic/Geomorphic Survey – Coordinated and oversaw a supplemental survey of the stream reach, conducted by EIT staff, using a survey grade RTK GPS system to augment the LIDAR data of the site with additional topographic and geomorphic data (profiles, cross-sections, and bankfull features).
- Permitting Assistance – Assisted the development of the permitting package for the project including USACE 404 permit, ADEQ 401 Certification, City of Tucson Floodplain Use Permit, and Stormwater Pollution Prevention Plan (SWPPP).
- Design – Coordinated with Watershed Artisans, Inc. on the design and placement of multiple stream and floodplain structures, including one rock dams, rock run-downs and Zuni-bowls, and boulder cross-vanes, vanes, and j-hooks.
- Construction & Permitting Package – Oversaw the development of the construction and permitting drawings and reports.
- Construction Phase Services – Developed a staking plan for the earthmoving operations in coordination with the contractor and laid out the construction using RTK GPS equipment.
- Record Drawings – Completed the as-built survey and associated Record Drawings of the constructed stream improvement project. Used RTK GPS equipment to survey all above ground/visible structures including rock cross-vanes, vanes, Zuni-bowls, and one-rock dams. Monumented and surveyed permanent cross-section monitoring locations. Drafted revisions and created Record Drawings for the project.