Giant Salvinia is an exotic/non-native/invasive plant that is flowing into our system from the Colorado River. Giant Salvinia is actually a floating fern that does not root into the substrate (like Hydrilla), and can double its size in as little as two and a half days. There are reports that the weeds can grow to a size of about 40 square miles within a few months.

The plant has oblong floating leaves, ½ to 1 ½ inches long. As plants mature and aggregate, the leaves fold and compress into upright chains. Because it grows as a dense floating mat, giant Salvinia reduces oxygen content and degrades water quality for fish and other aquatic organisms.

Giant Salvinia is spread when fragments break off. Boats and jet skis moving from infected water can spread it.   

Salvinia, native to Brazil, was first found in the Palo Verde Irrigation system near Blythe in 1990 and has traveled downstream to infest the Colorado River and everything downstream (including national wildlife refuges and into Mexico).  A multi-agency task force was formed to coordinate efforts to rid/control Salvinia from the lower Colorado River system. 

Only individual plants or small patches of Salvinia have been found in the District's delivery system.  A couple years ago, Giant Salvinia was a major problem at Imperial Dam - clogging water intakes.

Giant Salvinia Plants Giant Salvinia has been known to cover entire lakes and can double its size every week or so in warm weather.

Mature Giant Salvinia In mature plants, underwater rootlike structures conceal stalks with egg-shaped spore cases attached.  These spores are infertile; vegetative reproduction is the norm.