Arundo Donax Removal in the Santa Ana River Watershed
Orange County Water District (OCWD) was awarded the Ruth Anderson Wilson Award by the Santa Ana Watershed Project Authority for its collaborative efforts in a program to remove Arundo donax (arundo) from the Santa Ana River watershed. The arundo removal program is also one reason the U.S. Environmental Protection Agency selected OCWD as a Clean Water Partner for 2003.
Arundo donax, or the giant cane, is a non-native, abundant bamboo-like grass that invades the habitats of native flora and fauna, all the while consuming enormous amounts of water. In addition, it is extremely flammable, it clutters beaches, and it clogs up streams and waterways, causing flooding and even bridge damage. Eight thousand acres of arundo use 20,000 to 30,000 acre-feet (about 10 billion gallons) of water per year more than does native habitat, enough water for 100,000 people.
Arundo, nicknamed 'Ihe plant from hell,' was introduced into Orange County from Europe in the late 1800s as a means of preventing erosion of irrigation ditches. It is a member of the grass family, although it looks more like bamboo. It is primarily found along the Santa Ana River and its tributaries, but can also be found in neighborhoods throughout Orange County and all the way down to the beach. Given sufficient sunlight and water, it can grow up to 10 inches per day in the summer and reach a height of more than 25 feet. Arundo grows so densely in pure stands that it is virtually impenetrable.
An estimated 8.000 to 10,000 acres of arundo inhabit the Santa Ana River watershed. To date, about 1,500 acres have been removed. Initial removal of one acre of arundo costs S5,000 to $9,500, but removing the plant by cutting it off above ground only stimulates additional growth from its massive root system. Full control requires decades of follow-up treatment of the regrowth by additional manual cutting and treatment with herbicides. Removal of the root systems is impractical. Furthermore, arundo removal must be initiated at the top of each watershed because the persistent plant has the ability to break off and transplant itself downstream. However, after the long battle against arundo is waged, native willows, sycamores, and cottonwoods can be replanted or regenerate.