Rio Salado Update June 1999

The following also is provided in Spanish. Lo siguiente también es provisto en Español.

Introduction
75,600 Plants for Phoenix Rio Salado
The Mesquite Bosque
Cottonwood/Willow
Wetlands
Rio Salado Project Timeline

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Introduction

The Rio Salado Project represents a long-held vision of many Phoenicians to turn the blighted Salt River into a community, environmental and recreational asset. A partnership between the Army Corps of Engineers and the city of Phoenix, the Rio Salado Project will bring enough water into the Salt River to support native shrubs and grasslands, trees and wildlife while preserving the river's flood capacity.

This newsletter is to keep interested persons informed of the project and to encourage public participation in the process.

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75,600 Plants for Phoenix Rio Salado

Did you know approximately 76,500 plants will be needed for the Phoenix Rio Salado Habitat Restoration Project that spans 550 acres through the Salt riverbed? The project will restore three primary habitats including 58 acres of wetlands, 99 acres of cottonwood/willow trees and 130 acres of mesquite bosques. Where will the plant materials come from? It's not like you or I going to a plant nursery and picking out trees. The project involves a contract with a nursery to grow very specific species of plant stock. In our attempt to recreate an authentic Salt River riparian habitat, the plants used must be indigenous to a Sonoran Desert river environment. Vegetation types selected for the project include Fremont cottonwood, Gooding willow, blue palo verde, desert willow, Arizona ash and sycamore, velvet and screwbean mesquite, elderberry and greythorn.

Cottonwood and mesquite near the Verde River.

Because the plants must be native to the river, the contracted grower/nursery is required to select seeds of the plant species from within a half-mile of the Salt River corridor. Over the next two years, the nursery will use these seeds to produce plants of sufficient quantity, uniform size and similar appearance. Upon completion of the growing period and during the best planting seasons, the nursery will provide the Phoenix Rio Salado Project with 15 gallon and 24-inch-box sized mesquite, cottonwood and willow trees that are weed, insect and disease free. Future growing contracts will be awarded for a variety of plant sizes and species to be ready for installation in 2001 as part of the first of three construction phases.

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The Mesquite Bosque

One of the most common trees found in the desert, mesquite is found in old floodplains, especially in areas of major watercourses and large tributaries. Annual and perennial grasses, plants and salt bushes compile the undergrowth of mature bosques.

Bosque is Spanish for woodlands. At one time, mesquite bosques were so thick throughout southern Arizona that they were known as mesquite forests. It was so lush and green that the interiors were park-like supporting a variety of different wildlife.

Native to deserts in the Southwest, Mexico and South America, mesquites are among the toughest and most useful trees for the desert. Mesquites hybridize (crossbreed) freely, causing differing characteristics, making accurate identification of the various species difficult. However, all varieties have dark bark and spreading, picturesque umbrella-like branches that provide light, airy shade. Leaves are composed of many tiny leaflets. Tiny, greenish yellow flowers in spikes are followed by flat seedpods. Typically, trees have many trunks and look like large desert shrubs. These drought tolerant trees will be allowed to grow and naturalize the upper banks of the Salt River corridor.

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Cottonwood/Willow

Cottonwoods and willows have become so accustomed to flooding that their seeds germinate only when covered by water. When flooding occurs, they sprout vigorously from their roots, trunks, branches and twigs. This habitat is found along streams, arroyos, lakes and in the Sonoran Desert, but is restricted to elevations below 3,900 feet. The Gooding willow is native to desert washes and streambeds below 5,000 feet. Trees of great size, especially the Fremont cottonwood and Gooding willow, characterize this habitat. The air is cool and shaded under the broad leaves of these trees, and saturated with lush undergrowth.

Cottonwoods line this pond in the lower Salt River.

Cottonwoods are known for rapid growth and suitability in riparian habitats where fast growth, toughness and low maintenance are considerations. The roots are invasive, therefore the cottonwood is not for city streets, lawns, small gardens or near sewer lines. The Freemont cottonwood can reach heights of 60 feet with thick, glossy yellow green triangular leaves that turn bright lemon yellow in fall. Small greenish yellow flowers in long slender clusters appear before leaves. The cottonwood gets its name from the female trees that bear masses of cottony seeds that blow about. The bark is gray, thick and deeply furrowed. The Gooding willow can grow to 45 feet tall. It has a gray furrowed trunk that may be three feet in diameter. Twigs are yellowish-brown with long slender green or yellowish-green leaves.

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Wetlands

Wetlands are found adjacent to rivers and streams and characterized by thick underbrush of cattails, bull rush and reeds and lush canopies formed by cottonwoods and willows. Wetlands have a high concentration of wildlife not found anywhere else in the desert and serve as a stop for many types of migratory birds, reptiles, fish and amphibians.

Wetlands in Tres Rios.

In more common language, wetlands are areas where the frequent and prolonged presence of water at or near the soil surface drives the natural system, meaning the kind of soils that form, the plants that grow and the fish and wildlife communities that use the habitat.

Wetlands are some of the most diverse ecosystems on earth. Reptiles such as turtles and snakes are common in wetlands. Many amphibians live in wetlands during at least part of their life cycle. A large number of fish species require wetland habitat for spawning and feeding, and birds use wetlands for nesting, resting and feeding. Mammals and birds that use wetlands include raccoons, beavers and clapper rails. Many threatened or endangered species in the United States are associated with wetlands. The 58 acres of wetlands in the Phoenix Rio Salado Project will provide valuable habitat for a variety of wildlife.

Mixed wetland vegetation.

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Rio Salado Project Timeline

Spring 1999 Congress authorizes project construction (Water Resources Development Act funding approved)

1999 through 2000 Project engineering and design

2000 Low flow channel construction begins

Early 2001 19th to Seventh Avenues Habitat Construction

2002 Seventh Avenue to 16th Street Habitat Construction

2003 16th Street to I-10 Habitat Construction

2003 Rio Salado Project opens

For more information, call Karen Williams at (602) 262-4717. This publication is available in the following alternative formats: Large print, Braille, audiotape or computer diskette by calling the ADA Liaison, Neighborhood Services Department, at (602) 495-5459, TDD: (602) 495-0685.

Visit us on the Internet

The Phoenix Rio Salado Habitat Restoration Project may be viewed on the Internet at: phoenix.gov/NBHDPGMS/rioproj.html.

If you have any questions or comments or would like to meet with our staff to discuss the project, call Karen Williams at (602) 262-4717.

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