|
<br />
<br />"~i:"": .
<br />fl,. ~._......,
<br />
<br /> 8.75
<br /> r:' + + + + + +
<br /> Z 8.70
<br /> ::l +
<br /> ~O + + + + +++++
<br /> -a: 8.65 + + +
<br /> I<( + + + +
<br /> "-0
<br /> Z +
<br /> i'" 8.60
<br /> oo
<br /> 8.55
<br /> 8,5 +
<br />Z + + \ + + +
<br />LU '
<br />C!}5Cf.l 8,0 + + 93 percent +
<br />~i=:2o: 118 percent
<br />o<c<(w of saturation +
<br />a:a:>- 7,5 of saturation + +\
<br />Ol-C!}- +
<br />wz::::i..J
<br />>w_H:L +
<br />5~~~ 7,0 + + + + + + + +
<br />~o~ +
<br />-0 6,5
<br />0
<br /> 24
<br /> ZOO +
<br /> -::l +
<br /> w"ii) 23
<br /> a:-' + + + + +
<br /> ::lLU + + +
<br /> >-0 22 + + +
<br /> <J:iB + +
<br /> LULU + +
<br /> <La: 21
<br /> "'" + + + +
<br /> LULU
<br /> >-0 + + +
<br /> 20
<br /> 1200 1600 2000 2400 0400 0800 1200
<br /> 25 26
<br /> AUGUST 1999
<br />Figure 11, Diurnal measurements at Yampa River at mouth, August 25-26, 1999,
<br />
<br />Reconnaissance Measurements in Dinosaur
<br />National Monument
<br />
<br />Reconnaissance field measurements taken on
<br />the Yampa River between Deerlodge Park (site II,
<br />46 miles upstream from the mouth) and at mouth
<br />(Echo Park) (site 12) during August 30 through
<br />September 3, 1999, show pH in the narrow range of
<br />8,43-8,77 (fig. 12), with a measurement mean of 8,63
<br />(or 8,62 as the mean of H+ activities), Measurements
<br />for the first 3 days indicate definite increases in pH
<br />values (0.2]; 0, ]5, and 0.33 unit) as each day
<br />progressed, indicating possible effects of photosyn-
<br />thesis, The smallest diurnal change (0,15 unit on
<br />August 31) occurred on a day that was cloudy, The sky
<br />gradually progressed from sunny to cloudy on the
<br />afternoon of August 30, with a moderately hard,
<br />30-minute rain at 2000 hours, and became sunny
<br />shortly before noon after clouds and light rain on the
<br />morning of September 1, On the fourth day, September
<br />2, the sky was sunny for the first measurement at 0805
<br />hours but cloudy thereafter, with a hard, 13-minute
<br />rain beginnillg at 1152 hours, causing brief runoff
<br />
<br />from the canyon walls; values of pH varied irregularly
<br />on this day from 8,65 to 8,77,
<br />
<br />These pH data indicate minor or no effects of
<br />photosynthesis of the Yampa River in Dinosaur
<br />National Monument between Deerlodge Park (site 11)
<br />and Echo Park at the mouth (site 12), Aquatic vegeta-
<br />tion was sparse and scattered in the rocky streambed of
<br />Yampa Canyon, The water had a greenish tint during
<br />the measurement period, possibly indicating entrained,
<br />microscopic plant cells (phytoplankton),
<br />
<br />Although the first 3 days of measurement appear
<br />to indicate diurnal increases in pH values (fig, 12),
<br />these increases probably were mostly the result of
<br />downstream depletion of reactive organic matter and
<br />gradual venting of oversaturated, dissolved CO2,
<br />Specific conductance (fig, 12) indicates that one rela-
<br />tively consistent parcel of water was measured during
<br />August 30-31, for which pH values increased regu-
<br />larly (allowing for a small diurnal effect) from 8,43 to
<br />8,74 as it flowed 15,4 miles downstream. There were
<br />no flowing tributaries or springs along this 15,4-mile
<br />reach of the river downstream from Deerlodge Park,
<br />
<br />16 Evaluation of Trends In pH In the Vampa River, Northwestern Colorado, 1950-2000
<br />
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