While walking her dog on her 50th birthday, Juliet Stromberg viewed a bulldozer removing vegetation from the Salt River bed where Maricopa County health inspectors believe mosquitoes are breeding.
“Emotion took over and I stepped in front of a bulldozer and became an activist,” she recounts. The driver said he was just doing his job and she backed away. The bulldozing also has been part of river channeling to avoid flooding.
The incident involving efforts to change vegetation is part of her belief that if normal stream flows were occurring as Phoenix saw in the 1970s and 1980s, native species would be able to compete with the tamarisk, a bushy plant brought to the United States in the 1800s to control erosion.
River channeling also has been used to control flooding and along with the higher Roosevelt Dam 90 miles east of the metropolitan area as well as drought it is harder for the native cottonwoods and willows to survive.
The trees are becoming less common due to their need for spring flooding. Tamarisk has evolved to provide streamside vegetation, with little “knowledge” that it is now seen more and more widely.
Tempe Town Lake in the Salt River channel was recently drained to allow for building a new dam and now is being refilled. This is another example of the artificial changes to what was once a normal boom and bust flowing of a Southwest river.
A recent visit to the flowing Gila River at Riverside in Pinal County showed a number of tamarisk with pink blossoms, showing that the plant has spread to many parts of the Southwest.