Invasive species, also known as exotics, are plants, animals,
insects, and aquatic species introduced into non-native habitats.
Without natural predators or threats, these introduced species
then multiply.
Often,invasive species travel to non-native areas by ship,
either in ballast water released into harbors or attached to the
sides of boats. From there, introduced species can then spread
and significantly alter ecosystems and the natural food chain as
they go. Another example of non-native species introduction
is the dumping of aquarium fish into waterways.
Invasive species also put water conveyance systems at risk. Water
pumps and other infrastructure can potentially shut down due to
large numbers of invasive species.
Water users in Western Colorado are awaiting results of
ramped-up testing efforts to control invasive zebra mussels
after they were found in the Colorado River and an irrigation
canal near Grand Junction. The mussels spread quickly, and can
cause wide-reaching harms such as damage to irrigation
equipment and disruptions to river ecosystems for native fish.
Ongoing testing is aimed at finding the source of the young
zebra mussel larvae and stopping them before they become fully
established. “It’s really kind of looking for a needle in a
haystack,” said Rachel Gonzales, a spokeswoman for Colorado
Parks and Wildlife.
In an effort to prevent smallmouth bass — an invasive,
voracious predator that feasts on native fish, including the
threatened humpback chub — from establishing populations below
Glen Canyon Dam, the U.S. Bureau of Reclamation in early July
began releasing colder water from Lake Powell via the river
outlet works (which are 100 feet lower in a cooler part of the
water column) in addition to the hydropower penstocks. …
Reclamation chose this option with the goal of keeping water
temperatures below the dam under 15.5 degrees Celsius (60
degrees Fahrenheit), which is too cold for smallmouth bass to
thrive. But a report by a group of scientists at the
Center for Colorado River Studies at Utah State University says
that factors other than temperature should be taken into
consideration when trying to manage the nonnative
species.
Invasive zebra mussels are causing issues for the Western
Slope’s ecosystem and the situation could create damage to
regional agriculture. The species was discovered in both the
Colorado River and Government Highline Canal in mid-July.
Following the discovery, Colorado Parks and Wildlife initiated
an Invasive Species Rapid Response Plan, which includes
increased testing of the waters. On Friday, Colorado Parks
and Wildlife announced that more zebra mussel veligers, or
larvae, were found in the Colorado River and Government
Highline Canal with the increased testing. With the detections,
both bodies of water are considered positive for zebra mussels.
… Situated at the confluence of the Central Valley’s two main
river systems and just upstream of the San Francisco Bay, the
Delta is an important hub for both commercial and recreational
boat traffic, leaving it highly susceptible to non-native
species invasion. The Delta is not the only waterway dealing
with invasives – other popular California lakes and rivers used
for recreational activities like boating, camping, and fishing
are fighting similar battles. Non-native species of flora that
take root in important California waterways not only compromise
the native plant and fish communities that live there, but can
also impede human agricultural, industrial, and recreational
activity that rely on clear and healthy channels.
Colorado Parks and Wildlife announced Tuesday that it has
discovered zebra mussels in the Colorado River and the
Government Highline Canal, nearly two years after the invasive
species was first detected in the state. The small,
freshwater mussels are native to lakes in Russia and Ukraine,
but they are known globally for their rapid reproduction rate.
Wildlife officials say the species poses an extreme risk to
local ecosystems because zebra mussels kill off native plankton
that native species rely on for food. Infestations can also
devastate water infrastructure because the mussels attach
themselves to surfaces in large clusters, clogging waterways
and drainage systems. CPW said they discovered the newly
confirmed zebra mussel population through routine plankton
samples taken in early July.
In the vast labyrinth of the West
Coast’s largest freshwater tidal estuary, one native fish species
has never been so rare. Once uncountably numerous, the Delta
smelt was placed on state and federal endangered species lists in
1993, stopped appearing in most annual sampling surveys in 2016,
and is now, for all practical purposes, extinct in the wild. At
least, it was.
This tour guided participants on a virtual journey deep into California’s most crucial water and ecological resource – the Sacramento-San Joaquin Delta. The 720,000-acre network of islands and canals support the state’s two major water systems – the State Water Project and the Central Valley Project. The Delta and the connecting San Francisco Bay form the largest freshwater tidal estuary of its kind on the West coast.
Nutria are large, beaver-like
rodents native to South America that have caused alarm in
California since their rediscovery along Central Valley rivers
and other waterways in 2017.
The growing leadership of women in water. The Colorado River’s persistent drought and efforts to sign off on a plan to avert worse shortfalls of water from the river. And in California’s Central Valley, promising solutions to vexing water resource challenges.
These were among the topics that Western Water news explored in 2018.
We’re already planning a full slate of stories for 2019. You can sign up here to be alerted when new stories are published. In the meantime, take a look at what we dove into in 2018:
Sixty percent of California’s developed water supply
originates high in the Sierra Nevada mountains. Our water
supply is largely dependent on the health of our Sierra forests,
which are suffering from ecosystem degradation, drought,
wildfires and widespread tree mortality.
We headed into the foothills and the mountains to examine
water issues that happen upstream but have dramatic impacts
downstream and throughout the state.
GEI (Tour Starting Point)
2868 Prospect Park Dr.
Rancho Cordova, CA 95670.
For more than 100 years, invasive
species have made the Sacramento-San Joaquin Delta their home,
disrupting the ecosystem and costing millions of dollars annually
in remediation.
The latest invader is the nutria, a large rodent native to South
America that causes concern because of its propensity to devour
every bit of vegetation in sight and destabilize levees by
burrowing into them. Wildlife officials are trapping the animal
and trying to learn the extent of its infestation.
Estuaries are places where fresh and
salt water mix, usually at the point where a river enters the
ocean. They are the meeting point between riverine environments
and the sea, with a combination of tides, waves, salinity, fresh
water flow and sediment. The constant churning means there are
elevated levels of nutrients, making estuaries highly productive
natural habitats.
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
Sea.
This 24×36 inch poster, suitable for framing, explains how
non-native invasive animals can alter the natural ecosystem,
leading to the demise of native animals. “Unwelcome Visitors”
features photos and information on four such species – including
the zerbra mussel – and explains the environmental and economic
threats posed by these species.
This 24×36 inch poster, suitable for framing, explains how
non-native invasive plants can alter the natural ecosystem,
leading to the demise of native plants and animals. “Space
Invaders” features photos and information on six non-native
plants that have caused widespread problems in the Bay-Delta
Estuary and elsewhere.
The 24-page Layperson’s Guide to the Delta explores the competing
uses and demands on California’s Sacramento-San Joaquin Delta.
Included in the guide are sections on the history of the Delta,
its role in the state’s water system, and its many complex issues
with sections on water quality, levees, salinity and agricultural
drainage, fish and wildlife, and water distribution.