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 changesEcosystem changes –Water –Riparian vegetation –Sediment –Native and non-native fish. –Native American cultural and archeological sites.

Effects on the Water in the Colorado River BeforeBefore –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. –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. AfterAfter –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.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.Vegetation permitted to develop at lower elevations in new zones. More than 1,000 acres of additional habitat for native wildlife.More than 1,000 acres of additional habitat for native wildlife. Marshes now occur that enhance plant diversity in the river corridor.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.Loss of sand from camping beaches. –Sand gets trapped behind dam. Build-up of rapids at tributary mouths.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.Silting up of fish habitats. –Decrease in yearly flooding has allowed silt to build-up in back cannels used as 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 species3 native species * Colorado squawfish, bony chub and roundtail chub have disappeared. 2 native species2 native species * humpback chub and razor back sucker, endangered. 1 native species1 native species * flannelmouth sucker is a candidate for listing under the endangered species act. 2 native species2 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.Majority of the non-native species – Coldwater trout. Declines due to habitat changes, competition and predation.Declines due to habitat changes, competition and predation. A controlled flood was held in March and April * Researchers hope that the flood cleaned silt out of backwater channels used as habitats by native fish.A controlled flood was held in March and April * 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 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 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 virusHepatitis A virus –Estimated 1.4 cases worldwide. –37,000 per year in the US. –Primers * capsid protein. –192 bp product –192 bp product. EnterovirusEnterovirus –includes poliovirus, coxsackievirus, echovirus, enteroviruses –Viruses most often detected in polluted water. –Primer * conserved region of nonstructural protein. –197 bp product

Results HAVPolio

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.