水の一日の必要量

Yamamoto (2000) did various hiking experiments in Japan, and measured

the amount of dehydration. He deduced an expression to estimate the

quantity of dehydration per time:

dehydration (gram/hour)= 5 X body weight ( kg )

Briefly, providing 8 hours hiking, the dehydration of 50 kg body

weight person is 2,000 gram, that of 60 kg person is 2,400 gram, ..

that of 70 kg person is 2,800 gram.

The bad effect of dehydration will appear at 1.5% dehydration of body

weight, then, for safety, we should suppress dehydration within 1% of

body weight. Therefore, the water needed for 8 hours hiking is 1,500

gram for 50 kg person, 1,800 gram for 60 kg person, 2,100 gram for 70

kg person.

Female is weaker than male on the dehydration.

J Environ Public Health. 2012;2012:760108. Epub 2012 Feb 21.

Impact of summer cattle grazing on the Sierra Nevada watershed: aquatic algae and bacteria.

Derlet RW, Richards JR, Tanaka LL, Hayden C, Ger KA, Goldman CR.

Department of Environmental Science and Policy and the John Muir Institute of the Environment, University of California, Davis, CA 95616, USA. rwderlet@ucdavis.edu

Abstract

We evaluated periphytic algal and microbial communities to assess the influence of human and cattle impact on Sierra water quality.

64 sites (lakes and streams from Lake Tahoe to Sequoia National Park, California) were sampled for suspended indicator bacteria and algae following standardized procedures. The potential for nonpoint pollution was divided into three categories: cattle-grazing areas (C), recreation use areas (R), or remote wildlife areas (W).

Periphyton was found at 100% of C sites, 89% of R sites, but only 25% of W sites. Eleven species of periphytic algae were identified, including Zygnema, Ulothrix, Chlorella, Spirogyra, mixed Diatoms, and Cladophoria. Mean benthic algae coverage was 66% at C sites compared to 2% at W sites (P < 0.05). The prevalence of E. coli associated with periphyton was 100% at C sites, 25% of R sites, and 0% of W sites. Mean E. coli CFU/gm of algae detected was: C = 173,000, R = 700, W = 0. (P < 0.05). Analysis of neighboring water for E. coli bacteria >100 CFU/100 mL: C = 91%, R = 8%, W = 0 (P < 0.05).

Higher periphytic algal biomass and uniform presence of periphyton-attached E. coli corresponded to watersheds exposed to summer cattle grazing. These differences suggest cattle grazing compromises water quality.

PMID: 22505950 [PubMed - in process] PMCID: PMC3312331 Free PMC Article

J Water Health. 2010 Jun;8(2):326-33. Epub 2009 Nov 9.

Reducing the impact of summer cattle grazing on water quality in the Sierra Nevada Mountains of California: a proposal.

Derlet RW, Goldman CR, Connor MJ.

University of California, Davis, 4150 V Street, PSSB Suite 2100, Sacramento, CA 95817, USA. rwderlet@ucdavis.edu

Abstract

The Sierra Nevada Mountain range serves as an important source of drinking water for the State of California. However, summer cattle grazing on federal lands affects the overall water quality yield from this essential watershed as cattle manure is washed into the lakes and streams or directly deposited into these bodies of water. This organic pollution introduces harmful microorganisms and also provides nutrients such as nitrogen and phosphorus which increase algae growth causing eutrophication of otherwise naturally oligotrophic mountain lakes and streams. Disinfection and filtration of this water by municipal water districts after it flows downstream will become increasingly costly. This will be compounded by increasing surface water temperatures and the potential for toxins release by cyanobacteria blooms. With increasing demands for clean water for a state population approaching 40 million, steps need to be implemented to mitigate the impact of cattle on the SierraNevada watershed. Compared to lower elevations, high elevation grazing has the greatest impact on the watershed because of fragile unforgiving ecosystems. The societal costs from non-point pollution exceed the benefit achieved through grazing of relatively few cattle at the higher elevations. We propose limiting summer cattle grazing on public lands to lower elevations, with a final goal of allowing summer grazing on public lands only below 1,500 m elevation in the Central and Northern Sierra and 2,000 m elevation in the Southern Sierra.

J Travel Med. 2008 Jul-Aug;15(4):209-15.

Backpacking in Yosemite and Kings Canyon National Parks and neighboring wilderness areas: how safe is the water to drink?

Derlet RW.

Department of Emergency Medicine, School of Medicine, University of California Davis, Sacramento, CA 95817, USA. rwderlet@ucdavis.edu

Abstract

The objective of this study was to determine the risk of acquiring disease from popular Sierra Nevada wilderness area lakes and streams. This study examines the relative risk factors for harmful waterborne microorganisms using coliforms as an indicator.

Water was collected in the backcountry Yosemite and Kings Canyon National Parks and neighboring wilderness areas. A total of 72 sites from lakes or streams were selected to statistically differentiate the risk categories: (1) natural areas rarely visited by humans or domestic animals; (2) human day use-only areas; (3) high use by backpackers; (4) high use by pack animals; and (5) cattle- and sheep-grazing tracts. Water was collected in sterile test tubes and Millipore coliform samplers during the summer of 2006. Water was analyzed at the university microbiology lab, where bacteria were harvested and then subjected to analysis using standardized techniques. Statistical analysis to compare site categories was performed using Fisher's exact test.

Coliforms were found in none of the 13 wild sites, none of the 12 day hike sites, and only 3 of 18 backpacker sites (17%). In contrast, 14 of 20 sites (70%) with pack animal traffic yielded coliforms, and all 9 sites (100%) below the cattle-grazing areas grew coliforms. Differences between backpacker versus cattle or pack areas were significant, p <or= 0.05. All samples grew normal aquatic bacteria. Sites below cattle grazing and pack animal use tended to have more total heterotrophic bacteria.

Alpine wilderness water below cattle areas used by pack animals is at risk for containing coliform organisms.Water from wild, day hike, or backpack areas showed far less risk for coliforms.

Wilderness Environ Med. 2008 Summer;19(2):82-90.

Risk factors for coliform bacteria in backcountry lakes and streams in the Sierra Nevada mountains: a 5-year study.

Derlet RW, Ger KA, Richards JR, Carlson JR.

Department of Emergency Medicine, University of California, Davis, School of Medicine, Sacramento, CA, USA. rwderlet@ucdavis.edu

Abstract

To provide a 5-year longitudinal assessment of risk of acquiring disease from Sierra Nevada Wilderness area lakes and streams. This study examines the relative risk factors for harmful water microorganisms, using coliforms as an indicator.

Streams and lakes in the backcountry of Yosemite and Kings Canyon National Parks and neighboring wilderness areas were selected and water was analyzed each year over a 5-year period. A total of 364 samples from lakes or streams were chosen to statistically differentiate the risk categories based on land usage, as follows: 1) areas rarely visited by humans (Wild), 2) human day-use-only areas (Day Hike), 3) areas used by backpackers with overnight camping allowed (Backpack), 4) areas primarily impacted by horses or pack animals (Pack Animal), and 5) cattle and sheep grazing tracts (Cattle). Water was collected in sterile test tubes and Millipore coliform samplers. Water was analyzed at the university microbiology lab, where bacteria were harvested and then subjected to analysis using standardized techniques. Statistical analysis to compare site categories was performed utilizing Fisher exact test and analysis of variance.

A total of 364 sampling sites were analyzed. Coliforms were found in 9% (4/47) of Wild site samples, 12% (5/42) of Day Hike site samples, and 18% (20/111) of Backpacker site samples. In contrast, 63% (70/111) of Pack Animal site samples yielded coliforms, and 96% (51/53) of samples from the Cattle areas grew coliforms. Differences between Backpacker vs Cattle or Pack Animal areas were significant at P <or= .05. All samples grew normal aquatic bacteria.

Surface water from watersheds below cattle areas and those used by pack animals is at high risk for containing coliform organisms. Water from Wild, Day Hike, or Backpack sites poses far less risk for contamination by coliforms.

Wilderness Environ Med. 2006 Spring;17(1):15-20.

Coliform bacteria in Sierra Nevada wilderness lakes and streams: what is the impact of backpackers, pack animals, and cattle?

Derlet RW, Carlson JR.

Department of Emergency Medicine, University of California, Davis, School of Medicine, Sacramento, CA, USA. rwderlet@ucdavis.edu

Abstract

The presence of coliform bacteria indicates a watershed risk for harboring microbes capable of causing human disease. We hypothesized that water from watersheds that have different human- or animal-use patterns would have differing risks for the presence of coliform bacteria. METHODS; Water was collected in wilderness areas of the Sierra Nevada range in California. A total of 60 sites from lakes or streams were selected to statistically differentiate the risk categories: 1) high use by backpackers, 2) high use by pack animals, 3) cattle- and sheep-grazing tracts, and 4) natural areas rarely visited by humans or domestic animals. Water was collected in sterile test tubes and Millipore coliform samplers during the summer of 2004. Waterwas analyzed at the university microbiology lab, where bacteria were harvested and then subjected to analysis by standardized techniques. Confirmation was performed with a Phoenix 100 bacteria analyzer. Statistical analysis to compare site categories was performed with Fisher exact test.

Only 1 of 15 backpacker sites yielded coliforms. In contrast, 12 of 15 sites with heavy pack-animal traffic yielded coliforms. All 15 sites below the cattle-grazing areas grew coliforms. Differences between backpacker and cattle or pack-animal areas were significant (P < or = .05). Only 1 of the 15 wild sites rarely visited by humans grew coliforms. All coliforms were identified as Escherichia coli. All samples grew normal aquatic bacteria of the genera Pseudomonas, Ralstonia, and Serratia and nonpathogenic strains of Yersinia. No correlation could be made with temperature or elevation. Sites below cattle-grazing tracts and pack-animal usage areas tended to have more total bacteria.

Alpine wilderness water below cattle-grazing tracts or areas used by pack animals are at risk for containing coliform organisms. Areas exclusively used by backpackers were nearly free of coliforms.