Rio Salado Update April 2000

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

Construction of Low Flow Channel
What happened to residents who made their home in the River?
Groundwater Investigation Underway for Rio Salado Habitat Restoration Project

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Construction of Low Flow Channel

Wetlands in the Rio Salado Project will create a habitat for wildlife.

For all intents and purposes, the portion of the Salt River bed that cuts through Phoenix has been a low-flow channel since the last dam was constructed to collect water and generate power for a booming metropolis.

But there have been times when the riverbed has taken on the appearance of a raging flood. In 1993, for example, water from the usually dry Salt River inundated roadway crossings and lapped at bridges.

The “flood of ‘93” was a rare occurrence that resulted from heavy storms and runoff in the watershed along the upper Salt. Saguaro, Canyon, Apache, and Roosevelt lakes filled to the brim, forcing Salt River Project (SRP) to release water into the normally dry riverbed.

That’s why construction of an enhanced low-flow channel is so critical to the Phoenix Rio Salado Habitat Restoration Project, according to Donald Rerick of the Maricopa County Flood Control District. Scheduled to begin in May, construction of the low-flow channel is the restoration project’s first step.

“The intent of the project is habitat restoration, however, we don’t want to aggravate the flood control capacity of the river,” said Rerick. “The plan is to achieve a low-flow channel that follows the historic alignment of flows through the channel somewhat meandering and not a straight line.” The low flow channel is approximately 200’ wide and as deep as 10 feet below the existing channel bottom.

As is now, the Salt River is of little benefit to wildlife or the public.

The Salt River bed currently is an ugly urban scar of landfills, unauthorized dumping, and sand and gravel operations. Ultimately, the Rio Salado Project will transform it into what it was before the dams — a meandering stream and chain of ponds highlighted by native vegetation.

Rerick points out that the low-flow channel, which will be designed to carry flows of 12,200 cubic feet per second, will be at the bottom of a larger channel that could comfortably handle a 100-year flow rate of 166,000 cubic feet per second.

“In an extreme case, if we had a 100-year flood soon after the project is completed, you may lose some of the habitat improvements that will be installed.” Rerick said. “However, if initially we have enough years of consecutive low flows the habitat improvements will prosper and the river channel will take on the look of a meandering stream with backwaters and trees.”

The low-flow channel also will protect the terraced areas that will be where most of the habitat values are developed, he added.

The low-flow channel’s first phase from 19th Avenue to 7th Street should take about 10 months to complete. “At that point, the U.S. Army Corps of Engineers will begin the second phase from 7th Street to 28th Street,” Rerick said. “The Phase Two contract will advertise and be awarded so it will begin when Phase One ends. Plans call for the entire low-flow channel to be finished two years from this May.”

Habitat enhancements, according to Rerick, will follow the construction. The Rio Salado Project is a partnership between the U.S. Army Corps of Engineers, the City of Phoenix and the Maricopa County Flood Control District.

The City of Phoenix is sponsoring the project; the Corps of Engineers is designing and contracting for construction; and the Maricopa County Flood Control District is responsible for the flood control elements.

Congress authorized the $80 million federal grant for Phoenix Rio Salado in the Water Resources Development Act last August, paving the way for construction to begin.

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What happened to residents who made their home in the River?

Aerial view of the current condition of the Salt River.

Construction of the Rio Salado Project’s low-flow channel, which is scheduled to begin in May, involved awarding contracts, preparing construction schedules, and lining up people and machinery for the ambitious project. That appears to be the easy part when you consider what Bev Marsh of Phoenix’s Human Services Department and her team had to accomplish.

Marsh oversaw the effort to persuade about 25 homeless people living along the Salt River bed to move to safer surroundings.

“The Phoenix Police Department began monthly counts of the number of residents who made their home in the riverbed soon after we held our first public meetings on Rio Salado in April 1997. A concern expressed by the public was for individuals and families who lived in the riverbed. The city’s Rio Salado project coordinator Karen Williams was asking where would they go when the city starts construction on Rio Salado.

“We began back June and July by going to the river and handing out fliers that told the people living in the area that they would have to be relocated and would receive help from caseworkers who were assigned to the project,” said Marsh, casework services coordinator for the Community Services Division, which is under Human Services.

A few left immediately, but most — the “hardcore homeless” — refused.

“Initially, representatives from a number of homeless shelters set up a resource table and passed out information on alternatives to living in the riverbed,” said Marsh. “We didn’t have any takers. The people who were living down there just didn’t want to move.”

Rio Salado will have ponds lined with cottonwood trees.

Finally, a couple of the hardcore homeless individuals agreed to move and to be connected to an agency for help.

With the Phoenix Police Department’s help, outreach teams eventually accomplished their mission:

“The riverbed residents moved to safer ground,” said Marsh. “We know that some of the homeless opted for help from agencies … a couple of people were moved to houses or apartments, two were linked back to the mental-health system, and two or three moved on to the Phoenix Gospel Mission.”

The relocated individuals had been living in 19 makeshift campsites that were demolished to discourage others from taking up residence in them.

The following agencies provided outreach teams for the relocation project: Health Care for the Homeless, Tumbleweed, Standup, Home Base, Value Options Outreach, Project Hope, Alternative Behavior Service, and Terros.

“Actually,” Marsh said, “the whole project has gone very well.”

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Groundwater Investigation Underway for Rio Salado Habitat Restoration Project

Monitoring Well.

By Cortney C. Brand, Dames & Moore

Dames & Moore’s Phoenix office is currently conducting a groundwater quality and supply investigation for the Phoenix Reach of the Rio Salado Habitat Restoration Project. The first round of groundwater sampling and analysis on the first three monitoring wells has been completed, and four new monitoring wells have been installed.

Analytical results from the first three wells suggest good quality groundwater at these well sites. No volatile organic compounds (VOCs); semi-volatile organic compounds (SVOCs), pesticides or PCBs were detected in any samples.

The water supply for the Rio Salado Habitat Restoration project will be derived entirely from shallow groundwater beneath the general area of the project. The water will be used to support plant growth and a low flow channel. It is anticipated that the project will require up to six million gallons per day (MGD) of water continuously for these purposes.

Groundwater quality is a significant concern for the project. Water quality parameters such as nitrate and total dissolved solids (TDS) will have an impact on plant growth. Also, there is a concern for the potential for pumping water containing hazardous contaminants, which may be present in groundwater in the vicinity of the Salt River. At a minimum, groundwater pumped for the project must meet the U.S. Environmental Protection Agency’s (EPA) National Pollution Discharge Elimination System (NPDES) permit discharge limitations.

The monitoring well network will be used to monitor groundwater quality throughout the project area and to assess the potential for contaminated groundwater to migrate into the capture zone of the production wells. The first three groundwater-monitoring wells have been installed along the Salt River at Central Avenue, 16th Street and 24th Street. These well sites correspond with the proposed locations of the production wells, which will be constructed in pairs on either side of the river. Information collected from these wells will be used to decide whether wellhead treatment will be required to achieve adequate quality and to assist in design of the production wells. Design and permitting of the first production well for the project is currently underway. This well will be located near Central Avenue and the Salt River.

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