A troublesome invasive species is
the quagga mussel, a tiny freshwater mollusk that attaches itself
to water utility infrastructure and reproduces at a rapid rate,
causing damage to pipes and pumps.
First found in the Great Lakes in 1988 (dumped with ballast water
from overseas ships), the quagga mussel along with the zebra
mussel are native to the rivers and lakes of eastern Europe and
western Asia, including the Black, Caspian and Azov Seas and the
Dneiper River drainage of Ukraine and Ponto-Caspian
The Quantification Settlement Agreement (QSA), signed in 2003,
defined the rights to a portion of Colorado River water for San
Diego County Water Authority, Coachella Valley Water District,
Imperial Irrigation District and the Metropolitan Water District
of Southern California.