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Intent To Prepare a Draft Environmental Impact Statement (DEIS) for El Rio Antiguo

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Army Corps of Engineers, DoD.


Notice of intent.


The Los Angeles District of the U.S. Corps of Engineers (the Corps) will initiate analyses of foreseeable environmental impacts from actions potentially to be implemented on a reach of the Rillito River. The Corps will prepare an Environmental Impact Statement (EIS) to accompany the Feasibility Report. Pima County will participate in the Feasibility Study.

The Rillito River flows from east to west along the south face of the Catalina Mountains, and is tributary to the Santa Cruz River. The study area extends from the confluence of Pantano and Tanque Verde Washes, which happens to coincide with Craycroft Road, downstream to Campbell Road. About 4.8 river miles lie between those limits. Except for a region on the south side approximately one mile long, all existing banks have been stabilized with soils cement. The study area will extend on the north side to include uplands in a region known locally as “the bend”, and on the south side to encompass lands potentially to be acquired along Alvernon Way and at Campbell Road. Approximately 925 acres lie within the roughly defined study area, and of that about 525 acres would be called uplands. A habitat restoration project on the south bank of the Rillito (Continuing Authorities Program, section 1135 of the Water Resources Development Act of 1986, as amended) has been initiated within the proposed study area. Refinements of the study area, both additional inclusions and exclusions, can be expected during the course of the Feasibility Study as appropriate to the general study objectives.

The proposed project emphasizes opportunities to restore riparian habitat, address matters of surface and groundwater quality, explore aquifer recharge along the Rillito, restoration of natural riverbed conditions, fashion localized seasonal wetlands (known in the southwest by the Spanish noun cienegas) at opportune places in the river bottom, and create venues appropriate for recreational educational uses of the river. Flood damage reduction on the Rillito itself and washes entering it from foothills of the Catalinas will also constitute aspects of the Feasibility Study.


District Engineer, U.S. Army Corps of Engineers, Los Angeles District, ATTN: Dr. John E. Moeur, Regional Planning Section, CESPL-PD-RP, PO Box 532711, Los Angeles, California 90053-2325.

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Dr. John E. Moeur, Environmental Manager, telephone (213) 452-3874.

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1. Authorization

The Feasibility Study for El Rio Antiguo has two distinct Congressional authorities. The more recent, House Resolution 2425 (dated 17 May 1994), directs:

* * * the Secretary of the Army * * * to review reports of the Chief of Engineers on the State of Arizona * * * in the interest of flood damage reduction, environmental protection and restoration, and related purposes.

Congress previously authorized similar endeavors through section 6 of the Flood Control Act of 1938. The 75th Congress of the United States passed what became Public Law 761. This legislation states, in part:

* * * the Secretary of War [Secretary of the Army since 1947] is hereby authorized and directed to cause preliminary examinations and surveys * * * at the following locations: * * * Gila River and tributaries, Arizona, * * *

2. Background

The Rillito River now appears as a broad dry, wash most of the year. Summer thunderstorms in its watershed may cause it run modestly, or in genuine flood, but it soon reverts to a dry desert wash.

It environs were much different a century and a half ago. A description written in 1910 portrays it before the Civil War as an unbroken gallery forest along the Rillito dominated by cottonwoods, willows, Arizona ash, Arizona walnut, diverse underbrush species adapted to the Sonoran Desert, interspersed with grasslands of sacaton and big galleta grass. Beavers dammed the Rillito in many places. Where water infiltrated somewhat faster, cienegas formed along the riverbed.

Diversion of surface waters, and then extraction by pumps of water from subsurface strata caused profound regional changes in hydrology starting about the turn of the last century. Thereafter, the Rillito began to decline.

3. Proposed Action

No explicit proposed alternative has yet been identified. The Feasibility Study to be evaluated by this EIS will evaluate impacts of viable alternatives once they have been framed in light of the topography, hydrology, biotic communities, and preferences of the local sponsor. A No action Alternative will form the basis for comparison for these evaluations. The EIS will address at least sixteen diverse kinds of resources important to the Sonoran Desert biome: Aesthetics, agriculture, air quality, biology, cultural, geology, groundwater recharge, hazardous wastes, land use, physical environment, recreation and education, safety, socioeconomic, sound and noise, transportation and communications, and water quality. The public will be afforded ample opportunity to comment on these analyses prior to taking any action to implement any alternative that may then be under consideration.

4. Scoping Process

The Corps will conduct a scoping meeting to aid in determining the importance of pertinent environmental issues. Participation of all interested Federal, State, and County resource agencies, as well as Native American peoples, groups with environmental interests, and all interested individuals is encouraged. Public involvement will be most beneficial and worthwhile in identifying pertinent environmental issues, offering useful information such as published or unpublished data. direct personal experience or knowledge which inform decision making, assistance in defining the scope of plans which ought to be considered, and recommending suitable mitigation measures warranted by such plans. Those wishing to contribute information, ideas, alternatives for actions, and so forth can furnish these contributions in writing to the points of contact indicated above, or by attending public scoping opportunities.

The scoping period will conclude 60 days after publication of this NOI and concurrent publication in newspapers circulated in the greater Tucson area.

5. Public Scoping Meeting

The Corps and the local sponsor invite all interested parties to a public Start Printed Page 56661scoping meeting to discuss project goals and offer ideas essential to developing alternatives to achieve those goals. An initial public meeting for the proposed El Rio Antiguo study is scheduled for the evening of Tuesday, November 13, 2001. Please gather at 6 PM in the 1st Evangelical Free Church, located at 4700 N. Swan Road, in Tucson, Arizona. Individuals, organizations, and agencies who wish to offer information or data relevant to anticipated project objectives, alternatives, impacts, mitigation, or any similar consideration may do so by attending the public scoping meeting. If that means for communication proves infeasible, then kindly mail the information to any of the three addresses noted above.

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Luz D. Ortiz,

Army Federal Register Liaison Officer.

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[FR Doc. 01-28244 Filed 11-8-01; 8:45 am]