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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 – – – – 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. • • 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: – – – – Don not drink untreated river water. Isolate ill individual. Keep off of trip for 10 days. Filter water and disinfect. Wash hands frequently.