Transcript Glen Canyon Dam and the Colorado River: Diseases in the Grand

Glen Canyon Dam and the
Colorado River: Diseases in
the Grand Canyon.
By Stephanie Boone
Effects of the Glen Canyon Dam on
the Colorado River
• Ecosystem changes
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Water
Riparian vegetation
Sediment
Native and non-native
fish.
– Native American
cultural and
archeological sites.
Effects on the Water in the
Colorado River
• Before
– Flow rates, sediment loads,
and water temperatures varied
from year to year and season
to season.
– Heavy runoffs ( snow from
Rocky Mountains) produce
flows greater than 100,000 cfs
during late spring and early
summer.
– Flows in late summer , fall and
winter less than 3,00 cfs.
– Water temperatures ranged
from near freezing in winter to
more than 80 F in late
summer.
• After
– Daily variations instead of
seasonal variations.
– Mean daily flows exceed
30,000 cfs about 3% of the
time and less than 5,000 cfs
about 10% of the time.
– Minimum and maximum daily
releases range from 12,000 to
16,000 cfs. * Fluctuations
mean the difference of 10 feet
between low and high water
on a given day.
Effects on the Riparian Vegetation
in the Colorado River
• Before the dam riparian
vegetation was scoured from
the river banks during
seasonal high water flows.
• Vegetation permitted to
develop at lower elevations in
new zones.
• More than 1,000 acres of
additional habitat for native
wildlife.
• Marshes now occur that
enhance plant diversity in the
river corridor.
Effects on the Sediment in the
Colorado River
• Loss of sand from
camping beaches.
– Sand gets trapped behind
dam.
• Build-up of rapids at
tributary mouths.
– Drop in flow reduced ability
to move debris. Build-up
makes it more dangerous.
• Silting up of fish habitats.
– Decrease in yearly flooding
has allowed silt to build-up
in back cannels used as
fish habitats.
Effects on the Fish in the Colorado
River
• 3 native species * Colorado
squawfish, bony chub and roundtail
chub have disappeared.
• 2 native species * humpback chub
and razor back sucker, endangered.
• 1 native species * flannelmouth
sucker is a candidate for listing under
the endangered species act.
• 2 native species * bluehead sucker
and speckle dace are relatively
common.
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Effects on the Fish in the Colorado
River
• Majority of the non-native
species – Coldwater trout.
• Declines due to habitat
changes, competition and
predation.
• A controlled flood was
held in March and April
1996. * Researchers
hope that the flood
cleaned silt out of
backwater channels used
as habitats by native fish.
Diseases on the in the Colorado
River
• Since 1972 there have
been ongoing outbreaks
on the river.
• Outbreaks in 1994 to
2000 involved more than
200 persons- river rafters.
Symptoms consistent
with norovirus infection.
• 2 Outbreaks in 2002 and
2003 were found to be
positive for norovirus.
Environmental Samples
Ben
*Samples were obtained portable
toilets of ill rafters and hikers.
*Samples were also obtained from
the Colorado River, Lees Ferry,
Phantom Ranch, sewage treatment
plant inside Glenn Canyon Dam.
*Water sample collection by filtration
with 1MDS filters.
*Volumes collected - 100 gallons.
*Samples transported on ice and
frozen at -20 C.
*Water samples were eluted from the
filter using beef extract followed by
organic flocculation and
reconcentration
Viruses Investigated
• Hepatitis A virus
– Estimated 1.4 cases
worldwide.
– 37,000 per year in the
US.
– Primers * capsid
protein.
– 192 bp product.
• Enterovirus
– includes poliovirus,
coxsackievirus,
echovirus,
enteroviruses 68-71.
– Viruses most often
detected in polluted
water.
– Primer * conserved
region of nonstructural
protein.
– 197 bp product
Results
HAV
Polio
Conclusions
• Don’t go rafting in the grand canyon.
• Need more research in area to determine
causative agents of outbreaks. Could be
parasitic in nature.
• CDC recommends:
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Don not drink untreated river water.
Isolate ill individual. Keep off of trip for 10 days.
Filter water and disinfect.
Wash hands frequently.