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CLimmOLOGICRL HDD ITER QUALITY DflTfl - -
CARIBOU • POKER CREEKS RESEARCH WATERSHED
U. S. ENVIRONMENTAL PROTECTION AGENCY
CORVALLIS ENVIRONMENTAL RESEARCH LABORATORY
ARCTIC ENVIRONMENTAL RESEARCH STATION
COLLEGE, ALASKA 99701
-------
CLIMATOLOGICAL AND WATER QUALITY DATA
CARIBOU-POKER CREEKS RESEARCH WATERSHED
by
Frederick B. Lotspeich
Arctic Environmental Research Station
Robert L. Jackson
Arctic Environmental Research Station
Austin E. Helmers
Institute of Northern Fprestery
AERS WORKING PAPER NO. 30
CERL NO. 014
U.S. ENVIRONMENTAL PROTECTION AGENCY
CORVALLIS ENVIRONMENTAL RESEARCH LABORATORY
ARCTIC ENVIRONMENTAL RESEARCH STATION
COLLEGE, ALASKA
May 1976
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TABLE OF CONTENTS
PAGE
INTRODUCTION 1
FIELD STATION 1
Description 1
Instrumentation 3
CLIMATOLOGICAL MEASUREMENTS 11
WATER DATA 15
Field Measurements 15
Summer 17
Winter 17
Laboratory Analysis 25
Schneider Continuous Monitor 30
DISCUSSION AND CONCLUSIONS 39
REFERENCES 41
iii
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LIST OF TABLES
NUMBER PAGE
1 Daily Precipitation (Inches Water Equivalent) 16
2 Field Data (1971) 18
3 Field Data (1972) 19
4 Dissolved Oxygen (1974) 26
5 Laboratory Analytical Data (Summer 1971) 27
6 Laboratory Analytical Data (Summer 1972) 28
7 Laboratory Analytical Data (1974) 29
8 Schneider Monitor (Summer 1973)-pH 33
9 Schneider Monitor (Summer 1973)-Specific Conductance 34
10 Schneider Monitor (Summer 1973)-Temperature & D.O.
IV
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LIST OF FIGURES
NUMBER PAGE
1 Topographic map of the Caribou-Poker Creeks
Research Watershed 2
2 Confluence of Caribou and Poker Creeks; trailer site 4
3 Airlifting the laboratory trailer by Chinook
helicopter 5
4 Unloading the Chinook at the field site 6
5 Laboratory trailer and generator shelter established
on timber foundation; tracked vehicle (Thiokol) 7
6 Interior of field laboratory in late 1974 9
7 Caribou Peak in winter showing antenna.and the
shelter for radio relay gear 10
8 Summer water temperatures for Caribou and Poker
Creeks (1973) and precipitation from breakup to
freezeup at field station 12
9 Air temperatures at the field station (1973) 13
10 Air temperatures at the field station (1974) 14
11 Interior of Thiokol tracked vehicle while measuring
conductivity, pH, and total alkalinity by field
chemistry methods; titration and alkalinity underway 21
12 Icings in late winter before breakup 22
13 Ice auger used to drill through 12' of ice prior
to breakup when overflow has caused maximum ice
depth 23
14 Conductivity and alkalinity data comparing summer
and winter values 24
15 One day's data from the monitor on Poker Creek to
illustrate diverse ranges in various parameters 31
v
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INTRODUCTION
The Caribou-Poker Creeks watershed was selected in 1969 as a site
where agencies and individuals with Interests in water and related re-
search could conduct studies within a coordinated framework. Research
watersheds are important areas for obtaining basic information on relation-
ships between land, water and climate. This particular research watershed
is rather unique because one of the two basins has been set aside for "planned
disturbances," while the other basin will be preserved in its natural state
as a control. Slaughter (1973) describes these basins in detail and presents
the rationale and history of their selection. Figure 1 shows the topography
and distribution of the various sub-basins comprising the entire watershed,
and lists the stations and their respective numbers. "Planned disturbances"
such as oil spills, road construction, forest fires, etc., under controlled
and carefully monitored conditions will provide resource managers and regula-
tory officials with sufficient information to minimize the environmental
impact of large-scale disturbances. A recent paper (Slaughter and Helmers,
1974) presents a broader overview and stresses the need for hydrological
research in subarctic regions.
The Arctic Environmental Research Station (AERS) has been involved in
water quality research in these basins since the basins were established.
In 1971, Laboratory personnel sampled all tributaries monthly throughout
the summer. Field chemistry and stream discharge measurements (11 in all)
were accomplished at the sampling site. Chemical and biological samples
were collected for laboratory analyses. Three similar sampling runs were
completed in the summer of 1972. Jinkinson et al. (1973) report on the
biological findings and present water quality data for the mainstreams
of Poker and Caribou Creeks. More complete data for all stations are
included in this report.
All data collected before fall 1972, represent summer conditions. To
collect the necessary year-round data in 1972, a permanent field site was
established as a cooperative venture with the U.S. Forest Service, Institute
of Northern Forestry, Fairbanks, Alaska, and the U.S. Army Cold Regions
Research and Engineering Laboratory, Ft. Wainwright, Alaska. This field
station provides the capability for continuous water quality monitoring
of Poker and Caribou Creeks and the collection of some climatological
data. This report describes the establishment of the field station;
presents some climatological data; discusses the water chemistry data
from 1971 and 1972; includes the monitoring data for 1973, the winter
data for 1974; and briefly considers future plans and modifications for
the field station.
FIELD STATION
Description
A 20-foot laboratory trailer, two robot water quality monitors, a
3-KW heavy-duty, diesel-powered generator and some climatological instru-
ments were acquired as a preliminary step in establishing a field station
1
-------
ro
Figure 1. Topographic map of the Caribou-Poker Creeks Research Watershed. Heavy solid lines outline
the entire basin; dashed lines outline sub-basins which are designated as C for Caribou
and P for Poker Creek; number below each sub-basin designation is the area of that basin
in square miles.
CARIBOU-POKER CREEKS RESEARCH WATERSHED
inter-Agency Technical Committee for Aloska
m cooperation with
U S Bureau of Land Monagemer
Aiosko Stole O'wision of Lands
Foirbanks North Stor Borough
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independent of commercial power. The confluence of Caribou and Poker
Creeks was selected as the site which would permit continuous sampling
of both streams with minimal effort. Figure 2 shows the summer appear-
ance of the site before the trailer was installed. The trailer was
equipped with a propane furnace and conventional laboratory furniture. The
total weight was approximately 4 tons. Since the nearest road is more than
2 miles from the site, the trailer was airlifted by an Army Chinook heli-
copter (Figure 3) from a staging area at the University of Alaska Poker
Flat Rocket Range. Three additional helicopter loads (Figure 4) brought
in timbers and building material to construct housing for the generator, a
500-gallon fuel tank, the diesel-generator unit, and 12 drums of fuel.
All equipment was flown in on October 19, 1972.
Ground access to the field station is over a trail that permits a
tracked vehicle to reach the/Site from the Steese Highway, about 2 miles
away. Although the trail fords the Chatanika River 0.5 miles from the
highway, there are no problems during normal flow or in winter. However,
during spring breakup and fall freezeup, a vehicle cannot be used to cross
the river. During these periods visitors must walk in from the river
after crossing it on foot or in a small boat.
Both the generator housing and the laboratory trailer were placed on
timber foundations about 3 feet above ground to avoid icings common to this
area in late winter and early spring. The generator shelter was insulated
with 1 inch of styrofoam on the walls and 2 inches overhead. Figure 5 shows
the site as it appeared in November 1972. Although the 1972-1973 winter was
rather mild, below zero temperatures coupled with the short day-length, pro-
longed the time required to complete the installation. Thus, it was not
until March 1973 that water was actually flowing through the water quality
monitor.
In 1974 the Witte diesel-generator unit was moved to another shelter
across Poker Creek opposite the utiliduct. This move reduced the fire
hazard and will allow the old engine house to be used for storage. A
second diesel unit (Onan, two-cylinder, air-cooled) was also placed in
the engine shelter to provide a backup power source and for supplementary
power during brief periods.
Instrumentation
A standard "Cotton Region" instrument shelter was erected December 12,
1972, and a set of maximum-minimum thermometers installed. From that date,
weekly maximums, minimums, and temperature at time of observation were re-
corded. A Friez wind speed and direction recording anemometer was installed
but, because of various delays, continuous records were not available until
February 1973. Similar delays prevented the operation of a heated tipping
bucket precipitation gauge. Thus, records of precipitation were not col-
lected until May 1973 when an event recorder was installed which functioned
satisfactorily. A Forest Service 8-inch diameter aluminum rain gauge, also
installed in May 1973, supplemented the recording gauge.
A general description of the Schneider Water Quality Monitor and its
installation follows: The instrument takes in water continuously through
an inmersion pump suspended in the stream, passes it through several sen-
sors in its lower bay, and returns the sampled water to the stream via a
3
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Figure 2. Confluence of Caribou and Poker Creeks; Caribou on the left, Poker on the right. Trailer
site is just above this confluence and within 40-50 feet of each creek.
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£
Figure 3. Airlifting the laboratory trailer by Chinook helicopter. This trailer weighed 4 tons and was
placed within 5 feet of the marked landing area. Caribou-Poker Creeks Research Watershed.
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Figure 4. Unloading the Chinook at the field site. Caribou-Poker Creeks Research Watershed.
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Figure 5. Laboratory trailer and generator shelter established on timber foundation. The tracked
vehicle is a Thiokol owned by the U.S. Forest Service. Caribou-Poker Creeks Research
Watershed.
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gravity drain. The instrument analyzes the water with electronic processing
units located in the middle bay and can continuously record up to seven para-
meters (pH, temperature, turbidity, dissolved oxygen, temperature, radiation,
and redox potential). A-multipoint recorder is mounted at the top of the
unit giving a total height of about 5 feet; floor space requirements are
about 4 square feet.
A utiliduct was constructed of 1-inch lumber to connect the monitor
with the stream. It was lined with 2 inches of styrofoam for insulation,
with resulting interior dimensions of 3 x 4 inches. A 1-inch diameter
plastic intake line carries.the pumped water to the monitor and a 2-inch
plastic pipe acts as the gravity drain. The intake line was wrapped with
heat tape to protect against freezing. Poker Creek's utiliduct is about
50 feet long and Caribou Creek's is 110 feet. Immersion pumps are sus-
pended beneath the utiliducts with their intakes located several inches
above the stream bottom to avoid drawing in bottom sediments. A power
cord leads from the trailer through the utiliduct to the pump.
Although a monitor was installed and operating by March 13, 1973, con-
tinuous records were not obtained until after April 6 because of a heat tape
failure which resulted in a frozen intake line. After April 6, the monitor
ran continuously, with some temporary clogging during high water, until
October 12 when the pump stopped running. The pump was restarted but some-
time between October 29 and November 2,- the propane used for trailer heat
was exhausted which caused the trailer to get cold enough to freeze the
drain line. From this time, no monitoring data were generated for a
variety of reasons, including frozen pipes, stream icing and engine failure.
The second monitor (Figure 6) was installed in June 1974 to monitor
Caribou Creek. Five parameters were measured in the initial installation:
conductivity, temperature, dissolved oxygen (D.O.), solar radiation, and
pH. Although the monitor was outfitted with turbidity and redox potential
modules, they were never used because of calibration problems. An experi-
mental bubbler stream stage recorder was installed in Caribou Creek to
obtain a continuous record of stream stage. However, electronic problems
developed and the record is brief.
In September 1973, a data logger and transmitter (purchased by the
U.S. National Weather Service) were installed in the laboratory trailer
and a micromet station established nearby (Slaughter, Hofeditz, et'al.).
Data from this station will be transmitted by radio to the U.S. Forest
Service Laboratory on the University of Alaska Campus via a radio repeater
station (Figure 7) on Caribou Peak. Because of design problems and delays
in installation of equipment, no data have been collected through the
system to the date of this report. Ultimately, all data generated at
the trailer site will pass through the system at the Forest Service base
station in a standardized form permitting computerized analysis and
storage. Eventually data from additional meteorological stations also
will be transmitted through the system. All data generated within the
watersheds will be in a mode facilitating electronic data processing and
storage, thereby eliminating strip chart recorders and manual data reduc-
tion except as backup.
8
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Figure 6. Interior of field laboratory in late 1974; both monitors on the right, data logger at extreme left,
and several recorders on bench in the background. Caribou-Poker Creeks Research Watershed.
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Figure 7. Caribou Peak in winter showing antenna and the shelter for radio relay gear. Caribou-Poker
Creeks Research Watershed. (Photo by U.S. Forest Service)
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CLIMATOLOGICAL MEASUREMENTS
Weekly observations of stream and air temperatures, precipitation, and
winds at the field station provide some interesting data included in this
section as figures with brief dicussion.
Water temperatures, measured at monthly intervals in 1971, indicated
that during the summer, Poker Creek was consistently warmer than Caribou
Creek. Figure 8, which summarizes weekly measurements from breakup to
freezeup in 1973, demonstrates that Poker Creek remains warmer throughout
the summer. Ice on Poker Creek went out during the week of May 10-17 and
the water temperature in both creeks was first measured on May 29; at that
time the temperature of Poker Creek was 5.4°C, compared to 3.6°C for Cari-
bou. Similar differences persisted until late August when the creeks were
within one degree of each other. In late September, water temperatures of
both creeks were the same with freezeup occurring by October 16 when tempera-
tures for both streams reached 0.0°C. Water temperature under ice in this
environment remains within 0.2°C of freezing until breakup.
Without water temperature data for the tributaries, any explanation
of the temperature difference between these streams is speculative and
tentative. However, one possible explanation is the orientation of each
stream to insolation. Poker Creek flows generally in a south-westerly
direction in a flat valley and is exposed to afternoon sunlight throughout
much of its length. Caribou Creek, on the other hand, flows mostly east-
ward; hence, it receives less direct insolation. Tributaries of Poker
Creek, except P-l, also have a more favorable orientation to receive
insolation than do those of Caribou Creek.
Figure 9 presents weekly maximum-minimum air temperatures from Janu-
ary 1 to December 21, 1973. The minimum recorded during this period was
48°C below zero and the maximum was 23°C. The maximum temperatures did
not rise above freezing until the end of March and dropped below freezing
during the last of October; thus, for about 5 months, maximum temperatures
were below freezing. Minimum temperatures did not rise to freezing until
the second week in June and then only for a two-week period; they again
dropped below freezing in June and July. A second brief period of frost-
free temperatures occurred in the second and third weeks of July, giving
a total of about one month of frost-free weather throughout the summer.
Even when minimums were above freezing, they never exceeded 2°C.
Figure 10 presents similar data for 1974; these curves closely follow
those for 1973. Fairbanks data show that minimum temperatures are above
freezing for about a 2-month period each year. Caribou-Poker Creeks
watersheds definitely have a colder temperature regime than does Fairbanks
which is situated on the broad Tanana Valley.
Continuous wind data are not available at this time. However, visual
observations of the anemometer indicate that winds are light and variable
except during passage of major fronts.
The direction of the light winds tends to alternate back and forth
down the two stream valleys. Even when no velocity is being recorded,
one notices the vane facing up one valley and then the other; seldom
11
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12
10
8
(Si
hi
X
8 y
_ 6
o
o
111
IT
Z>
6
q:
Ld
Q_
2
UJ
Poker
Caribou
PPtn.o——o Trailer site
<
cc
Cd
ID
CO
2 §
3
2
3
o
o
, <
J uly
A ugust
Sept.
1973
Figure 8. Summer water temperature for Caribou and Poker Creeks (1973) and precipitation from breakup
to freezeup at field station. Caribou-Poker Creeks Research Watershed.
-------
+30
+20
o +10
MAX.
MIN.
-40
-50
Figure 9. Air temperatures at the field station (1973). Caribou-Poker Creeks Research Watershed.
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Figure 10. Air temperatures at the field station (1974). Caribou-Poker Creeks Research Watershed.
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was it facing downstream toward the south. These generally light winds
are in sharp contrast to the stronger winds on the surrounding peaks at
2400-2700 feet (Slaughter et al., 1974).
Rainfall measurements are also summarized in Figure 8 for 1973 as an
accumulative curve from late May until freezeup in October. Total rainfall
for that period was about 12 inches which is greater than the normal yearly
rainfall for Fairbanks (the nearest weather station with long records). The
only dry period that summer occurred in September; otherwise rainfall was
well distributed. Data collected for 1974 show a similar pattern; however
the total was only about 7 inches.
Table 1 shows the daily readings of the tipping bucket recording rain
gauge for the summer of 1973 and for July 1974 through February 1975. These
data clearly indicate that June, July and August 1973 were rainy with a
relatively dry September. Accumulated rainfall measured with this gauge
for a five-month period was about 2 inches more than measured with the non-
recording gauge. No explanation for this discrepancy is offered at this
time. The record for the period of December 1973 through June 1974 was
not available for inclusion in this report. Accumulation for July through
October 1974 was 5.2 inches.
The sketchy data presented here suggest that the climate at the
Caribou-Poker watershed is considerably different from Fairbanks. These
variations from the considered regional norm are valid reasons for con-
ducting climatological research in small watersheds. The small, consistant
differences in water temperature.between the main stems of these streams
clearly suggest that what may appear as a constant for small streams is
not truly constant and small variations to orientation can cause significant
temperature differences. This hypothesis needs to be verified by continued
observations and expansion of the climatological and water sampling network.
WATER DATA
Field Measurements
Temperature, pH, conductivity, alkalinity, and dissolved oxygen were
measured as soon as possible after collection. Whenever possible, samples
were transported to a small tracked vehicle (Thiokol Imp) or the field
station for analysis.
pH was measured with a Model 401 Orion Specific Ion Meter. Conduc-
tivity measurements were made using a Beckman Model RB3-338 bridge with
an epoxy dip cell with a constant of 0.2. Alkalinity was measured by
substituting methyl purple for the methyl orange indicator and then
following the procedures specified in Standard Methods. Titration for
alkalinity was performed with a 10 ml pipet control led by a safety filler
which allows drop-sized control. Dissolved oxygen was measured by two
methods: a YSI D.0. meter and the Hach dry chemical pillow method using
300 ml bottles. In the Hach method, D.0. was fixed immediately, after
sampling and transported to the laboratory for final titration..
Discharge measurements were made using a Price type AA current
meter and standard techniques outlined by the U.S. Geological Survey.
15
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NTH
ay
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
AL:
TABLE 1
DAILY PRECIPITATION (INCHES WATER EQUIVALENT)
CARIBOU-POKER CREEKS RESEARCH WATERSHED
Station: Confluence of Caribou and Poker Creeks
Elevation Approximately 725' ms/
1973
1974
1975
May June July Aug. Sept.
Oct.
Nov. Dec.
July Aug. Sept. Oct. Nov. Dec.
Jan. Feb.
.47
.18
,24
.35
.06
.47
.03
.01
.01 .09
.01
.02
.01 .04
.01
.29
.26
.67
.02
.07
.02
.01
.05
.01
.01
.13
.10
.01
.17
.01
.88
.03
.50
.16
.16
.54
.02
.02
.45
.21
.01 .86
.48
.03
o
LO
.05
.02
.02
.48
CM
O
.01
.01
.12
,11
.16
.78
.07
.01
.15
.06
.03
ro
00
.82
.01
.37
.04
.04
.05
.06
.10
.01
.24
*3"
o
.01
.01
.55
.02
.14
.03
.01
.58
.10
.11
.09
.02
.02
.02
.02
.08
C TO
.01
o o-i
.01
.28
.18
.07
.09
.04
.17
,10
.01
.32
.02
.06
.09
.05
.03
.20
.03
.03
.04
.02
.02
.01
.01
.11
.16
.57
.17
.25
.07
.15
.14
.02
.01
.03
.01
.16
.02
.01
.06
.04
.14
.10
.01
.19
.10
.08
.01
.11
.05
.20
.22
.04
.01
.04
.11
.05
.01
.01
.15
.01
.04
.01
.22
.16
.01
.29
.40
.06
—
.01
.09
CO
o
.08
1.18
2.45
.86
.72
.71
.35
.64
,08
.08
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Summer
Similarities and differences among the tributaries are apparent in
scrutinizing the summer field data for 1971 (Table 2). Water temperatures
for 1973 were discussed earlier but these were from one site on each stream
at weekly intervals. Temperature data in Table 2 show that tributaries of
Caribou Creek are not consistently cooler than those of Poker Creek but, at
the confluence of the streams, Poker Creek remains warmer than Caribou
Creek until the end of the summer. At this time, all temperatures were less
than 1.0°C except at station C-4 which remained above freezing at 1.8°.
Similar trends occur in the summer data for 1972 (Table 3).
The pH range was within 2.0 units for all streams during both summers
with no apparent trends or recurring patterns. This narrow range is indica-
tive of the absence of unusual chemical factors and is nearly ideal for
aquatic life.
Dissolved oxygen during the summer of 1971 was found to be high in all
streams at the time of measurements. Data are insufficient to detect any
seasonal trends or patterns among tributaries.
The waters of Caribou-Poker Creeks are quite clear at all times. Even
at maximum discharge, suspended sediment was generally low. Discharges among
streams show a considerable range which is a reflection of basin size. Sea-
sonal range was considerable with maximums present in August 1971 and in May
1972; discharges measured in June and August 1972 were the minimum recorded.
Conductivity and alkalinity appear to be useful diagnostic tools to
detect waters with different characteristics. Early in the course of the
field work it was noted that Poker Creek appeared to have a higher con-
ductivity and alkalinity than did Caribou Creek. The same was true for the
tributaries although there was a wide range in the values among various
basins with stations P-l and P-6 usually higher than the others. An excep-
tion to this observation occurred on August 8, 1972, when conductivity and
alkalinity were higher in Caribou than in Poker Creek at their confluence.
Winter
Systematic winter sampling for water quality was first attempted in
these watersheds in the winter of 1974-1975. Because a trail network existed
for only Caribou Creek, no attempt was made to sample Poker Creek except at
the field station site. The winter schedule planned for monthly sampling
of four tributaries of Caribou Creek, starting in October, and biweekly
sampling of the mainstems of Caribou and Poker Creeks at the field station.
No difficulty was experienced through December in sampling any of the small
streams; however, by January, all of the tributaries exhibited heavy icings.
Since the water surface under the deep ice might be shallow and only a few
inches wide, an ice auger was an uncertain way of reaching the flowing water
to extract samples. Therefore, no attempt was made to sample these small
streams after December. Sampling of P-Main and C-Main was continued through-
out the winter; however, the data after December are not reported here.
Field measurement methodology was the same as for the summer work except
that dissolved oxygen was measured by the Winkler procedure using dry chemi-
cals instead of solutions or a D.O. meter as in previous years. Samples
17
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TABLE 2
FIELD DATA (1971)
CARIBOU-POKER CREEKS RESEARCH WATERSHED
WATER
SPECIFIC
SUSP.*
TEMP.
CONDUCTANCE
ALK.
D..0.
SEDIMENT
DISCHARGE
STATION
DATE
°C
pmho/cm
pH
mg/1
mg/1
mg/1
cfs
P-l
07/20/71
4.9
135
7.8
45
10.8
1
7.9
P-2
II
4.3
110
8.2
38
11.6
4
7.4
P-4
II
5.0
78
7.6
29
10.6
3
6.2
P-6
II
5.0
115
7.0
41
10.8
4
3.1
C-l
07/21/71
4.7
49
6.8
19 .
9.2
2
C-2
II
4,1
78
7.2
27
1.1.7
5
C-3
II
3.9
62
6.9
19
11.7
7
C-4
II
4.6
100
7.7
39
11.6
6
P-Main
II
8.6
103
8.2
41
11.0
3
C-Main
II
6.6
84
7.5
32
11.3
4
P-C
07/20/71
8.1
100
7.0
39
10-2-
2
43.9
P-l
08/14/71
3.2
95
7.4
38
2
14.1
P-2
II
3.1
105
7.3
38
4i
13.5
P-4
M
2.9.
70
6.9
28
1
8.3
P-6
II
2.9
105
7.3
38
5
4.4
C-l
II
3.6
29
7.2
15
3
5.5
C-2
II
4.1
63
7.1
22
7
7.9
C-3
II
3.0
50
6.7
15
3
4,3
C-4
II
4.2
95
7.3
35
11
5.6
P-Main
II
6.2
92
7.1
36
10
40.5
C-Main
II
4.9
36
7.1
32
6
25.2
P-C
II
6.0
85
6.6
32
5
58.2
P-l
09/08/71
2.3
125
7.2
49
_ _ _ —
2
8.1
P-2
II
2.5
' 54
7.4
43
3
3.9
P-4
II
2.5
80
7.1
32
3
5.6
P-6
It
2.3
120
7.5
54
--
3.2
C-l
II
2.6
46
7.1
18
14
3.1
C-2
II
3.5
75
6.1
26
2
2.6
C-3
¦ II
2.3
60
6.7
20
3
3.0
C-4
II
3.5
98
6.3
41
7
6.0
P-Ma i n
It
5.3
110
6.7
45
2
26.3
C-Main
II
3.9
80.
6.1
31
7
20.4
P-C
II
4.8
98
7.1
38
2
44.8
P-l
09/28/71
0.4
125
7.3
53
13.2
2
5.4
P-2
II
0.8
105
7.7
42
12.8
1
2.2
P-4
II
0.8
80
7.4
36
14.0
4
4.0
P-6
II
0.6
120
7.0
46
13.3
4
2.1
C-l
09/29/71
0.6
46
___•
19
13.2
—
1.8
C-2
/ II
0.9
70
—
28
13.8
2
C-3
09/28/71
0.6
65
—
23
14.1
3
1.7
C-4
II
1.8
95
—
41
13.6
3
4.1
P-Main
09/29/71
0.0
120
—
47
13.2
2
8.6
C-Main
II
0.1
83
—
36
12.7
2
6.4
.18
-------
TABLE 3
FIELD DATA (1972)
CARIBOU-POKER CREEKS RESEARCH WATERSHED
WATER
SPECIFIC
SUSP.*
TEMP.
CONDUCTANCE
ALK.
SEDIMENT
DISCHARGE
STATION
DATE
°C
nmho/cm
pH
mg/1
mg/1
cfs
P-l
05/31/72
1.6
55
7.1
17.5
15
17.6
P-2
II
1.8
75
7.2
21.0
38
11.2
P-4
II
2.5
63
19.0
15
9.7
P-6
06/01/72
1.9
76
7.3
25.0
16
4.3
C-l
II
1.1
35
6.1
12.0
7
4.9
C-2
II
1.6
54
6.6
17.5
12
3.4
C-3
II
0.8
30
6.8
8.0
9
4.1
C-4
II
2.0
80
7.2
29.0
21
5.5
P-Main
05/31/72
4.5
75
23.5
25
49.3
C-Main
II
4.2
55
17.0
27
27.7
P-C
II
5.9
65
22.5
54
76.4
P-l
06/29/72
5.2
100
M
49.0
„
4.3
P-2
11
3.8
100
38.0
2.8
P-4
II
3.4
81
32.0
--
4.1
P-6
II
3.6
119
42.0
2.2
C-l
II
3.2
50
20.0
--
2.2
C-2
11
3.2
78
23.0
1.9
C-3
II
3.0
75
21.0
1.0
C-4
II
4.2
98
39.0
--
2.5
P-Main
II
8.5
114
46.0
--
17.6
C-Main
II
6.2
85
36.0
9.2
P-C
.11
8.8
110
42.0
27.2
P-l
08/21/72
4.4
140
8.0
54.0
5.0
P-2
II
3.9
124
7.8
43.0
1.3
. P-4
II
3.8
90
7.4
35.0
3.8
P-6
II
3.8
133
7.2
49.0
--
2.0
C-l
II
5.3
59
6.9
22.0
1.9
C-2
II
5.3
60
6.9
29.0
1.1
C-3
II
3.9
69
6.9
23.0
1.3
C-4
08/22/72
2.7
105
7.1
42.0
2.4
P-Main
II
4.9
78
7.3
35.0
..
14.2
C-Main
II
3.4
95
7.3
50.0
--
12.0
P-C
II
5.3
120
7.3
45.0
27.1
This analysis was performed in the laboratory but is listed here for convenience.
19
-------
for lab analyses were collected at the same stations where the field chemistry
was done. Chemical measurements were made in the heated, rear compartment of
the Thiokol and consisted of conductivity, pH and total alkalinity in addition
to D.O. Figure 11 shows the inside of the Thiokol with the field gear assembled.
One objective of the field chemistry was to make the measurements (as nearly
as possible) at ambient water temperatures to which aquatic life is exposed.
Conductivity was measured at +1°C, alkalinity at 2-4°C, and pH about 5°C.
The pH meter was standardized to compensate for temperatures over the pH
range of 7.0 to 9.2.
Sampling of the mainstems of Poker and Caribou Creeks became more dif-
ficult as winter progressed because overflow greatly increased the ice thick-
ness. During the winter of 1973-1974, the entire area surrounding the
confluence of Caribou-Poker Creeks was one expanse of ice averaging 8-10
feet thick over the stream channels. Unless one knows in advance where to
drill in these small streams, the chances of hitting water instead of gravel
is quite small because nothing remains above the ice to mark the channel.
If gravel is hit, the auger bit cannot be reused without resharpening.
Figure 12 shows these icings in March 1974; compare with Figure 5. Figure
13 shows the ice auger used to drill through 12 feet of ice. Since the
location of the channel was known, excellent samples were obtained.
Variability among streams and seasonal trends for conductivity and
alkalinity are shown in Figure 14. In plotting these curves, data from
previous summers were used to show the seasonal trends as summer passed
to winter. Freezeup is sometime in October when the stream water has
cooled to 0°C and a continuous ice cover is present except in limited
reaches with fast water.
Summer data for these two parameters were discussed earlier and will
not be described here other than to point out the variability among
streams of Caribou Watershed. Some of the variability among'streams with
respect to conductivity appears to be related to discharge, with low
values at high flows and high values at low flows, when ground water has
more influence with its higher electrolyte content. Data for Poker Creek
tributaries are not plotted because winter data are nonexistent; only
P-Main is shown on these curves. As noted earlier, Poker was always
higher in conductivity than was Caribou Creek and this condition persisted
into the winter. All streams tended to increase in conductivity as winter
progressed, although C-4 showed a slight decrease from November after a
marked increase in October. This continued increase in conductivity
probably reflects the influence of ground water as winter progresses.
By the end of the winter, the conductivity of Poker Creek exceeded 200
umho/cm.
Alkalinity showed similar trends with an abrupt increase at freezeup
which later dropped but still remained higher than the summer values.
That rather spectacular, surprising increase may be related to some
phenomena associated with changes as winter conditions approach. The
increase in alkalinity at freezeup requires validation and a concerted
effort will be made to intensively sample these streams next year at
freezeup.
20
-------
Figure 11. Interior of Thiokol tracked vehicle while measuring
conductivity, pH, and total alkalinity by field chemistry
methods; titration for alkalinity underway.
21
-------
Figure 12. Icings in late winter before breakup. Compare with Figure 5 to get some measure of the ice
depth. Caribou-Poker Creeks Research Watershed.
-------
Figure 13-A
Figure 13-B
Figure 13. Ice auger used to drill through 12' of ice prior to breakup when
overflow has caused maximum ice depth. Caribou-Poker Creeks
Research Watershed.
23
-------
no -
i 1 1 1 1 r
6/1 6/29 729 8/14 8/21 9/B 9/29 ICV25 11/22 12/18
DATE
28 9 25 12 20 6
-• CI
-k C2
-o C3
C4
CM
-a PM
CONDUCTIVITY
DATE
discharge (cfs)CM
49 18
40 14 26 9
discharge (cfs) PM
t 1 1 1 1 1 1 1 r
6/29 T2\ 8/14 8/21 9/B 9/29 10/25 11/22 12/18
x C2
ALKALINITY
DATE
DATE
Figure 14. Conductivity and alkalinity data comparing summer and winter
values. Summer values are from 1971 and 1972; winter data
are from October-December 1974. Caribou-Poker Creeks
Research Watershed.
24
-------
Data for dissolved oxygen (Table 4) clearly show that all these streams
were near saturation (12-V3 mg/1) at freezeup and remained high as ice
cover became continuous. Stations P-Main, C-Main, and C-4 were still near
11 mg/1 or more in December; however, the remaining small streams decreased
in D.O. as winter progressed with station C-l at 6.9 mg/1 in December. Such
depletion in D.O. as winter progresses has been reported earlier (Schallock
and Lotspeich, 1974) and is related to a thick, continuous ice cover. The
icing phenomena with its attendant overflow is apparently a significant
factor in winter D.O. levels.
pH remained relatively static or tended to decrease under winter condi-
tions with most stations indicating near neutrality, the lowest being C-4
with 6.6 in December. All of the streams are near.the optimum pH for aquatic
life. These small variabilities suggest that no adverse effects should be
caused by small changes in this parameter.
Laboratory Analysis
During 1971 and 1972, water samples were collected at the same stations
where field chemistry was performed. These samples were analyzed in the
laboratory for nutrients and trace elements (Tables 5 and 6). Additional
samples were taken in 1974 (Table 7). Several ions were determined that do
not appear in the tables. These ions where near the lower limits of detec-
tion and showed only slight variability in time or among streams. They
included Mn, NO2-N, O-PO4-P, and NH3-N: and will not be discussed further in
this report.
Five elements, copper, lead, arsenic, manganese, and zinc were present
in very low concentrations near the lower detection limits of our instru-
mentation. Three of these, copper, manganese and zinc are essential minor
elements for aquatic life and their presence in all samples indicates that
they should not limit life in these waters.
The two essential nutrients of the nitrogen cycle, phosphate and nitrate,
were very low in these waters but they did show variability among streams,
especially nitrate. Concentration levels of both ions were similar over
the 3-year sampling period. Such similarity in data for widely spaced
sampling periods suggests a high degree of reliability in sampling and
analytical procedures.
Iron, another essential element, is present in low concentrations but
does not show real trends among streams or with time. Chloride appears in
these waters but in modest to low concentrations with Poker Creek being
higher than all others; chloride seems to be highest in October just at
freezeup.
A Technicon Auto-Analyzer I was used to determine NH3-N, NO2-N,
NO3-N, O-PO4-P, T-PO4-P, CI and SiO2 by EPA approved methods for automated
analyses as found in Methods for Chemical Analysis of Water Wastes, 1971.
The procedure for the sulfate determination is found in Standard Methods
for the Examination of Water and Wastewater, 13th edition, p. 334, method
156C (1971). Total carbon was determined with a Beckman Model 915 Total
Organic Carbon Analyzer. The remaining elements were determined with a
Perkin-Elmer 303 Atomic Absorption Spectrophotometer and a Perkin-Elmer
HGA-2000 graphite furnace.
25
-------
TABLE 4
DISSOLVED OXYGEN (1974) mg/1
CARIBOU-POKER CREEKS RESEARCH WATERSHED
STREAM
DATE
C-l
C-2
C-3
C-4
C-M
P-M
* 4/12
....
11.3***
13.8
** 6/13
12.7
12.5
10/25
12.4
13.0
13.3
10/30
13.3
12.6
12.6
11/14
12.2
12.8
11/22
9.1
12.0
12.6
11/26
12.4
12.1
12.3
12/10
11.0
12.2
12/18
6.9
10.0
9.5
12.1
12/24
— — - —
10.6
12.2
* Pre-breakup.
** Post-breakup.
*** Includes C-l and C-2 only.
26
-------
TABLE 5
LABORATORY ANALYTICAL DATA (SUMMER 1971) mg/1
CARIBOU-POKER CREEKS RESEARCH WATERSHED
STATION
DATE
SO 4
Si 02
Ca
Mg
K
Na
Fe
T-PO4-P
NOrN
CI
TC
P-l
07/20/71
10.0
6.1
12.9
4.26
0.45
0.81
0.07
<0.01
0.24
16.8
14.4
P-2
II
9.0
6.3
11.7
3.68
0.38
0.70
F0.01
0.01
0.56
3.8
8.6
P-4
II
5.0
6.2
10.6
1.85
0.38
0.98
0.09
<0.01
0.31
2.0
8.3
P-6
II
12.0
6.6
17.2
2.94
0.42
1.10
0.21
<0.01
0.24
1.1
8.1
C-l
07/21/71
4.0
6.5
7.89
1.63
0.45
0.74
0.04
<0.01
0.21
1.2
7.2
C-2
II
6.0
6.7
9.32
3.09
0.27
0.79
. 0.04
0.02
0.44
1.1
7.9
C-3
II
8.0
5.0
15.0
1.66
0.25
0.96
0.08
0.03
0.29
0.1
14.9
C-4
II
7.0
7.0
14.5
3.79
1.09
5.73
0.06
0.02
0.54
1.0
8.4
P-Main
II
9.0
6.6
16.1
3.32
0.40
0.87
0.12
0.02
0.26
1.1
10.1
C-Mairi
II
7.0
6.8
12.4
2.51
0.38
1.04
0.14
0.02
0.26
0.9
11.6
P-C
07/20/71
8.0
6.6
14.2
2.96
0.47
0.89
0.08
0.01
0.29
1.1
9.7
P-l
08/14/71
8.0
5.7
5.56
3.97
0.55
0.21
0.16
0.06
0.22
0.34
15.5
P-2
II
9.0
6.6
6.22
5.06
0.57
0.23
0.11
0.04
0.56
0.44
13.3
P-4
II
4.0
5.5
4.36
2.28
0.63
0.22
0.18
0.06
0.30
0.29
13.8
P-6
II
11.5
5.4
4.88
3.32
0.61
0.27
0.20
0.06
0.30
0.34
12.4
C-l
II
2.5
4.0
2.38
1.79
0.34
0.15
0.20
0.07
0.24
0.35
7.8
C-2
II
4.0
5.6
3.28
2.98
0.48
0.18
0.06
0.05
0.66
0.88
6.7
C-3
II
8.0
2.8
3.35
0.75
0.37
0.24
0.06
0.06
0.33
0.63
10.9
C-4
II
6.0
6.7
5.97
3.10
0.67
0.31
0.09
0.07
0.34
0.37
6.8
P-Main
II
7.0
6..1
5.64
3.85
0.66
0.27
0.13
0.07
0.30
0.20
10.1
C-Main
II
5.0
4.4
3.34
2.45
0.52
0.23
0.11
0.08
0.26
0.29
8.3
P-C
II
8.0
5.7
4.08
3.32
0.58
0.27
0.10
0.09
0.29
0.29
12.1
P-l
09/08/71
5.0
7.1
10.50
4.66
0.75
0.77
0.34
<0.01
0.25
0.38
18.2
P-2
II
10.0
7.5
8.55
5.00
0.57
0.77
0.24
0.06
0.47
0.17
17.1
P-4
II
6.0
7.7
6.61
2.25
0.64
0.82
0.18
0.07
0.29
0.22
11.7
P-6
II
13.0
8.2
11.40
3.48
0.68
0.91
0.21
0.08
0.58
0.21
11.2
C-l
II
4.0
7.0
4.62
1.56
0.40
0.63
0.15
0.05
0.40
0.73
18.8
C-2
II
6.0
7.8
5.49
3.03
0.53
0.73
0.08
0.06
0.43
0.21
9.5
C-3
II
7.5
6.1
5.49
1.74
0.45
0.73
0.13
0.08
0.33
0.24
12.2
C-4
II
6.0
8.5
7.99
3.29
0.76
0.86
0.14
0.06
0.36
0.27
14.0
P-Main
II
8.0
7.8
9.36
3.94
0.70
0.82
0.18
0.07
0.26
0.22
14.0
C-Main
II
6.0
7.6
5.74
2.76
0.59
0.82
0.23
0.08
0.28
0.78
11.7
P-C
09/08/71
7.0
7.9
8.55
3.41
0.67
0.77
0.19
0.07
0.24
0.24
15.2
P-l
09/28/71
9.4
7.8
18.40
3.90
0.87
0.11
0.05
<0.01
0.26
0.26
17.5
P-2
II
9.1
7.9
17.40
4.50
0.80
0.11
0.28
0.10
0.43
0.30
21.8
P-4
II
3.9
8.5
13.20
1.90
0.75
0.12
0.20
0.06
0.27
0.27
14.3
P-6
II
11.6
8.6
21.3
3.00
0.83
0.14
0.16
0.06
0.28
0.30
15.8
C-l
09/29/71
3.0
8.0
8.3
1.40
0.44
0.09
0.28
0.04
0.22
0.30
13.6
C-2
II
4.4
8.1
9.60
2.70
0.63
0.97
0.09
0.04
0.41
0.30
10.1
C-3
09/28/71
7.2
7.6
16.80
1.80
0.56
0.11
0.12
0.04
0.36
0.30
19.6
C-4
II
6.1
8.7
13.9
2.80
0.88
1.30
0.29
0.07
0.40
0.30
18.6
P-Main
09/29/71
8.2
8.0
16.60
3.40
0.85
0.12
0.64
0.06
0.28
0.30
16.0
C-Main
II
5.4
8.4
12.30
2.50
0.75
0.14
0.20
0.07
0.27
0.30
20.8
27
-------
TABLE 6
LABORATORY ANALYTICAL DATA (SUMMER 1972) mg/1
CARIBOU-POKER CREEKS RESEARCH WATERSHED
ro
oo
STATION
DATE
S04
Si02
Ca
Mg
K
Na
Fe
t-po4-p
N03-N
CI
TC
P-l
05/31/72
7.2
1.2
7.6
2.2
0.6
0.7
0.79
0.08
0.15
3.8
15.2
P-2
It
8.6
3.3
9.2
3.6
0.6
1.1
0.94
0.07
0.49
0.5
14.4
P-4
II
3.8
3.1
11.7
1.7
0.7
1.1
0.47
0.05
0.34
10.3
10.3
P-6
06/01/72
9.7
2.8
11.8
2.4
0.7
1.3
1.21
0.09
0.25
0.4
12.0
C-l
II
3.0
2.0
5.9
1.4
0.4
1.2
0.40
0.07
0.24
0.3
9.8
C-2
II
3.8
3.3
6.6
2.3
0.5
1.3
0.21
0.08
0.60
1.7
7.8
C-3
II
5.5
0.6
4.4
1.0
0.4
0.8
0.33
0.07
0.13
5.2
12.2
C-4
II
5.7
3.5
11.3
2.4
0.7
1.6
0.56
0.07
0.44
6.0
9.6
P-Main
05/31/72
7.4
2.6
10.5
2.7
0.7
1.2
0.86
0.07
0.34
16.2
12.8
C-Main
II
5.7
2.1
7.1
2.1
0.6
1.2
0.86
0.09
0.24
2.7
12.0
P-C
II
6.6
2.5
8.9
2.5
0.6
1.1
1.23
0.08
0.28
0.4
12.0
P-l
06/29/72
10.0
2.8
21.8
4.3
0.6
1.4
0.06
0.04
0.32
11.2
P-2
II
12.0
2.9
18.9
4.0
0.4
1.3
0.09
0.05
0.78
11.1
P-4
i;
6.4
1.4
17.9
2.0
0.5
1.5
0.11
0.05
0.31
7.6
P-6
II
13.0
3.9
19.7
3.0
0.6
1.8
0.22
0.05
0.30
4.5
C-l
ii
4.1
1 .5
9.6
1.1
0.4
1.9
0.07
0.03
0.19
0.2
C-2
ii
6.9
3.2
13.6
3.1
0.4
1.3
0.04
0.03
0.52
2.4
C-3
ii
9.6
2.0
10.8
1.8
0.4
1.5
0.03
0.04
0.32
1.0
C-4
ii
7.6
3.2
17.1
2.9
0.6
1.8
0.11
0.03
0.47
10.4
.
P-Main
ii
11.0
3.8
18.4
3.3
0.6
1.7
0.09
0.05
0.34
7.9
C-Main
ii
15.0
3.5
17.1
2.8
0.6
2.0
0.52
0.06
0.29
6.2
P-C
ii
11.0
3.9
22.5
3.2
0.6
2.6
0.19
0.06
0.30
0.3
P-l
08/21/72
4.0
8.5
19.1
3.8
0.6
1.3
0.17
0.11
0.38
0.2
8.0
P-2
M
5.0
8.2
15.2
4.1
0.5
1.3
0.09
0.07
0.61
0.2
6.0
P-4
11
4.0
9.1
12.8
2.0
0.6
1.6
0.13
0.12
0.37
0.3
7.0
P-6
II
7.8
9.4
19.4
3.2
0.7
1.9
0.60
0.09
0.27
0.5
8.0
C-l
II
3.8
8.6
7.9
1.6
0.4
1.3
0.06
0.13
0.17
0.3
6.0
C-2
11
3.8
8.8
9.6
3.0
0.5
1.3
0.41
0.14
0.42
0.2
5.0
C-3
II
4.4
8.2
9.9
1.6
0.4
1.5
0.08
0.11
0.42
0.4
7.0
C-4
08/22/72
5.4
8.9
15.1
2.8
0.7
1.8
0.11
0.13
0.52
1.6
8.0
P-Main
II
5.4
8.7
18.1
3.5
0.7
1.7
0.06
0.12
0.22
0.2
7.0
C-Main
II
5.6
3.7
13.0
2.6
0.6
1.7
0.19
0.12
0.27
5.0
6.0
P-C
II
4.7
3.5
17.5
3.2
0.6
1.8
1.03
0.12
0.34
0.9
8.0
-------
TABLE 7
LABORATORY ANALYTICAL DATA (1974) mg/1
CARIBOU-POKER CREEKS RESEARCH WATERSHED
TOTAL
STATION
DATE
so4
Si02
Ca
Mg
K
Na
Fe
N03-N
CI
TC
HARD.
t-po4-p
C-Main
04/12/74*
7.5
8.8
13.4
3.3
1.0
1.5
1.16
0.21
3.0
143
0.01
11
06/13/74
4.5
8.9
14.1
2.6
0.9
1.3
0.13
0.25
12.0
44
0.02
II
10/30/74
9.5
8.0
17.1
3.3
0.7
2.1
0.12
0.38
0.8
30
0.02
II
11/14/74
8.6
8.0
17.8
4.1
0.9
2.2
0.15
0.38
0.4
54
0.03
II
11/26/74
9.0
8.0
18.3
4.0
0.7
2.2
0.34
0.39
0.5
13.6
62
0.02
II
12/10/74
8.9
8.0
18.5
4.3
0.8
1.8
0.43
0.39
0.5
13.8
62
0.03
II
12/24/74
8.7
7.8
19.2
4.3
1.0
1.9
0.40
0.38
0.5
13.6
66
0.03
P-Main
04/12/74**
14.4
8.0
22.0
4.0
1.3
1.7
0.19
0.20
3.0
295
0.01
II
06/13/74
9.0
6.1
16.3
2.9
1.0
1.3
0.42
0.24
15.0
46
0.01
II
10/30/74
10.8
7.5
23.6
4.1
0.8
2.2
0.24
0.44
1.4
51
0.02
II
11/14/74
11.5
7.0
23.3
4.9
0.9
2.1
0.08
0.43
5.7
84
0.02
II
11/26/74
11.2
7.5
22.6
4.9
0.8
2.1
0.08
0.90
1.1
16.9
73
0.02
II
12/10/74
11.1
7.2
23.8
5.1
0.9
1.7
0.14
0.45
1.9
16.9
79
0.03
II
12/24/74
10.9
7.2
23.5
5.0
1.0
1.8
0.16
0.50
0.9
15.9
75
0.03
C-l
10/25/74
4.3
8.0
9.0
1.9
0.4
1.4
0.19
0.48
1.8
41
0.02
II
11/22/74
5.6
7.5
9.4
2.6
0.4
1.5
0.26
0.23
0.7
36
0.02
II
12/18/74
4.9
7.3
9.7
2.7
0; 4
1.3
0.56
0.21
0.6
7.0
32
0.02
C-2
10/25/74
6.6
8.0
10.7
3.3
0.5
1.3
0.08
0.98
1.1
46
0.02
II
11/22/74
7.4
7.5
10.0
4.0
0.4
1.4
0.16
0.64
0.4
44
0.02
II
12/18/74
6.6
7.2
10.0
4.0
0.4
1.1
0.11
0.58
0.3
7.6
40
0.03
C-3
10/25/74
14.1
7.0
17.1
2.4
0.6
1.8
0.20
0.53
0.5
24
0.03
II
11/22/74
15.1
7.0
18.5
3.0
0.6
1.8
0.05
0.52
0.6
54
0.02
II
12/18/74
15.6
7.0
19.4
3.0
0.6
1.4
0.20
0.94
0.6
9.1
56
0.02
C-4
10/30/74
7.1
8.0
17.3
3.1
0.7
2.0
0.12
0.65
0.8
27
0.04
II
11/26/74
6.6
8.0
18.4
3.8
0.7
2.1
0.08
1.4
0.4
14.0
57
0.03
II
12/18/74
7.2
7.9
18.7
4.0
0.8
1.5
0.26
0.64
0.5
13.8
67
0.03
* Data from C-l and C-2 at bridge.
** Includes all tributaries, 2 miles above trailer.
-------
Of the trace elements measured in these basins, only calcium and mag-
nesium are present in high enough concentrations to influence conductivity.
Calcium concentrations were always several times higher than were those of
magnesium; however, the pattern of variability among streams and with time,
was very similar. This high degree of similarity enables a simplification
of analytical methods by substituting an EDTA total hardness titration for
the complex instrumental procedures. This titration measures the sum of
Ca and Mg which is adequate for baseline characterization once the relative
levels have been established. Total Ca and Mg for the basins comprising
Poker Creek Watershed was higher at all seasons than for the basins com-
prising Caribou Creek Watershed. There was a trend toward increasing con-
centration of these elements as winter progressed. However, considerable
variability did exist with the basins of each watershed and with season.
Calcium and magnesium were always higher in Poker than in Caribou Creek
and validated the conductivity measurements. Evidently these two ions
were the chief contributors to this simple measurement.
Total carbon content was moderate with little or no variablity pattern.
Based on more recent analyses, it has been established that most of the
total carbon present in these waters is the carbonate-bicarbonate form;
dissolved organic carbon was very low. Total hardness is a summation of
calcium and magnesium concentrations and should show close correlation
among calcium, magnesium, and conductivity. Two values stand out: those
measured in April, before breakup, in Caribou and Poker Creeks. These
concentrations need validating but this high value in late winter, with
an immediate decrease after breakup would indicate dilution of the ground-
water flow during winter with runoff water at breakup.
Potassium, another essential trace element, was present in low con-
centrations and did not show any clear cut trends although Poker Creek
appears to be somewhat higher than all others. Sodium, about double the
concentration of potassium, showed no trends among streams or with time.
Analyses from samples later in the winter might require a modification
of this interpretation.
Although silica content was moderate for all streams of these basins,
variability was very low and showed no pattern with time or season. Chlo-
rides were present in all streams but there did not appear to be any vari-
ability pattern. Sulfate appeared to be the major anion in all these waters
and ranged in concentration from a low of 3 mg/1 to a high of 15 mg/1 with
considerable variability. Sulfate content was moderately high in both
watersheds with Poker Creek consistently higher than Caribou Creek.
Schneider Continuous Monitor
Figure 15 is an example of daily recording by the monitor. Little or
no differences are observable in conductivity or pH, whereas the diurnal
changes in solar radiation, dissolved oxygen and temperature are readily
apparent. As the summer progressed, the dissolved oxygen and temperature
curves approached straight lines. Solar radiation gradually diminished in
both intensity and duration, reflecting shorter days and lowering of the
sun angle.
30
-------
r Solar Raciation
(Cd/cm2/mm) x 10
Conductivity. rnicromhos/cm/5Q
Temperature. F/10 \
Dissolved oxygen, mg/L/2
1
1
1
1600
2000 2400 0400
6/28/73
0800 1200
TIME, HOURS
1600 2000 2400 0400
6/29/73
Figure 15.
One day's data from the monitor on Poker Creek to illustrate diverse ranges in various
parameters. Dots and the dashed line for solar radiation show how values bounce around
during cloudy days.
o
a>
O
O
0800
o o
o
in ca
CO Oj M
^ 5 ^
ft L;! o
~ ~ 3
Wo?
1—
~ != 7
sr 3-
o
o
w o'
fD —«
C*
-------
Stream data generated by the Robot monitor is best interpreted in terms
of relative changes rather than absolute values. Calibration problems, sys-
tem failure or malfunction and transport of the stream water to the monitor
contributed to error. These will be discussed where applicable. Periods
of down time for the monitor are indicated in the tables by gaps in the
daily recordings.
pH (Table 8) was difficult to calibrate because of electrode problems.
Suspect data has been footnoted indicating that the unit was not responding
properly at the time of calibration, but apparently stabilized sometime later.
These data still permit inspection of daily changes even if some numbers were
inaccurate. Less than 1 pH unit difference was observed over the entire
monitoring period. No daily trends were found except a 0.1-0.2 pH unit
change, with highs usually occurring in the afternoon. This variability
is not considered significant enough to discuss in terms of stream changes
because instrumentation or other errors might have been the cause.
Conductivity (Table 9) also exhibited little change over the monitoring
period, ranging from about 100-125 umhos/cm. Again, no trends were found;
the highs and lows did not occur in any pattern.
Solar radiation highs of about 0.6-0.7 cal/cm /min were observed through
June to early August, decreasing to about 0.1-0.2 cal/cm /min by mid-
October. The highs usually occurred at noon, but there could be great
fluctuation during the day depending on the cloud cover. Solar radiation
has an effect on stream measurements, especially temperature and D.0. How-
ever, no tables have been assembled for solar radiation data and it will be
correlated only in a general manner.
In analyzing the temperature and dissolved oxygon data, it should be
noted that the monitor measured these parameters after pumping the water
50 feet from Poker Creek. At times this affected these data (Table 10).
Pump clogging or malfunction would result in elevated temperatures and
correspondingly depressed D.0. Even under optimum conditions, heat transfer
in the utiliduct system had an apparent effect. Calibration of the D.0.
probe was carried out by drawing water from the monitor and performing a
Winkler D.0. analysis. Difficulty was encountered with stability, especially
when a probe was replaced, during the period from June 27 to August 16. It
was never determined if the D.0. unit was properly calibrated within that
period. In addition, excessively high temperatures indicated that a great
deal of heat transfer was occurring within the utiliduct.
Of particular interest was the period of July 4-11 when the highest
water temperatures were recorded. This period corresponded to a time when
the highest solar radiation was recorded. The chart indicated the skies
were clear or had very scattered clouds. Days at that time of the year are
approximately 22 hours long. Since there was no indication of the pump
malfunctioning, heat transfer seemed to be the most probable cause of the
high temperatures and low D.0. recorded at the monitor. On July 10, the
highest water temperature for the summer (20°C) was recorded by the monitor.
This was undoubtedly erroneous since the highest temperature ever obtained
with a thermometer in the stream was about 9°C. These data from the moni-
tor are useful because they do show definite diurnal and seasonal changes,
although the values for temperature and D.0. are not always accurate with
respect to insitu conditions.
32
-------
TABLE 8
S Cm EIDER MONITOR (SUMMER 1,973)
CARIBOU-POKER CREEKS RESEARCH WATERSHED
PH
DATE
HIGH
LOW
DATE
HIGH
LOW
DATE
HIGH
LOW
*5/30
7.6
_ _ _
7/14
7.1
7.0
8/27
7.6
7.5
5/31
7.6
—
7/15
7.1
6.9
8/28
7.5
6/1
7.6
7.5
7/16
7.2
6.9
*8/30
6/2
7.6
— .
7/17
7.2
7.0
8/31
7.4
7.2
6/3
7.6
6.9
7/18
7.2
7.1
9/1
7.5
7.2
*6/11
7.4
**7/26
9/2
7.5
7.2
6/12
7.4
7.3
7/27
7.9
7.7
9/3
7.5
7.2
6/13
7.5
—
7/28
7.8
7.7
9/4
7.5
7.3
6/14
7.5
7.1
7/29
7.7
7.6
9/5
7.5
7.3
6/15
7.4
7.2
7/30
7.7
7.4
9/6
7.5
7.3
6/16
7.5
7.4
7/31
7.7
7.5
9/7
7.5
7.3
6/17
7.6
7.5
**8/1
7.5
7.4
9/8
7.5
7.3
6/18
7,6
7.5
8/2
7.1
6.9
9/9
7.5
7.3
6/19
7.6
8/3
7.0
6.9
9/10
7.5
7.3
*6/20
7.3
—
8/4
7.0
6.8
9/11
7.5
7.3
6/21
7.4
7.3
8/5
7.0
6.8
9/12
7.3
---
6/22
7.4
7.3
8/6
7.0
6.8
*9/18
7.5
6/23
7.4
7.3
*8/7
6.8
—
9/19
7.4
6/24
7.4
7.3
8/8
7.8
7.6
9/20
7.4
—_
6/25
7.4
7.3
8/9
7.8
7.6
*9/26
7.5
—
6/26
7.4
7.3
8/10
7.8
7.7
9/27
7.4
*6/27
7.4
—
8/11
7.5
7.4
9/28
7.4
7.3
6/27
7.5
7A
8/12
7.5
7.4
9/29
7.4
7.3
6/28
7,5
7.4
8/13
7.6
7.3
9/30
7,4
—
6/29
7.5
7.4
8/14
7.6
7.5
10/1
7.4
6/30
7.5
7.4
8/15
7.7
7.5
10/2
7.4
—
7/1
7.4
7.3
*8/16
7.6
7.5
*10/3
7.4
—
7/4
7.3
7.1
8/17
7.8
7.6
10/4
7.5
—
7/5
7.3
7.1
8/18
7.7
7.6
10/5
7.5
—
7/6
7.3
7.2
8/19
7.8
7.6
10/6
7.5
—
7/7
7.2
7.0
8/20
7.9
7.6
10/7
7.5
—
7/8
7.3
7.1
*8/21
7.7
7.6
10/8
7.5
—
7/9
7.4
7.2
8/22
7.4
7.3
10/9
7.5
—
7/10
7.4
7.2
8/23
7.5
7.3
10/10
7.5
—
7/11
7.4
7.3
8/24
7.6
7.4
*10/11
7.5
**7/12
7.3
7.3
8/25
7.6
7.5
10/12
7.5
—
7/13
7.2
7.0
8/26
7.7
7.5
Calibration
~~Calibration - Accuracy in doubt due to stability problems with electrodes.
33
-------
TABLE 9
SCHNEIDER MONITOR (SUMMER 1973)
CARIBOU-POKER CREEKS RESEARCH WATERSHED
SPECIFIC CONDUCTANCE ymhos/cm
DATE
MAX.
MIN.
DATE
MAX.
MIN.
DATE
MAX.
MIN.
*5/30
«» * m
...
7/14
98
93
8/26
108
105
5/31
110
108
7/15
98
88
8/27
108
95
6/1
113
110
7/16
98
88
8/28
95
—
6/2
113
110
7/17
105
98
*8/30
103
*6/11
98
7/18
108
8/31
103
100
6/12
100
95
*7/26
9/1
103
100
6/13
105
103
7/27
120
115
9/2
110
108
6/14
108
80
7/28
118
115
9/3
no
110
6/15
95
85
7/29
118
95
9/4
113
110
6/16
105
98
7/30
103
95
9/5
113
110
6/17
108
105
7/31
108
105
9/6
113
—
6/18
115
110
8/1
108
9/7
113
—
6/19
115
—
*8/1
9/8
115
113
*6/20
118
8/2
115
113
9/9
115
—
6/21
118
—
8/3
118
115
9/10
115
—
6/22
120
118
8/4
118
—
9/11
115
—
6/23
120
120
8/5
120
118
9/12
115
—
6/24
120
120
8/6
120
120
*9/18
118
118
6/25
120
120
8/7
120
—
9/19
115
—
6/26
123
120
*8/7
9/20
113
—
6/27
123
123
8/8
120
120
*9/26
118
^6/27
125
8/9
120
—
9/27
118
115
6/28
125
—
8/10
120
—
9/28
115
113
6/29
125
—
8/14
100
95
9/29
115
—
6/30
125
—
8/15
105
100
9/30
118
115
7/1
118
115
*8/16
105
—
10/1
115
113
7/4
108
98
8/17
110
—
10/2
115
113
7/5
113
108
8/18
110
—
10/3
118
—
7/6
113
103
8/19
110
—
10/4
118
115
7/7
103
100
8/20
113
no
10/5
115
—
7/8
no
105
*8/21
113
—
10/6
115
—
7/9
115
110
8/21
1 TO
10/7
118
—
7/10
120
115
8/22
95
88
10/8
120
118
7/11
120
120
8/23
98
90
10/9
120
118
*7/12
120
120
8/24
103
98
10/10
120
—
7/13
98
90
8/25
105
103
10/11
10/12
10/13
120
123
120
120
~Calibration
34
-------
TABLE 10
SCHNEIDER.MONITOR (SUMMER 1973)
CARIBOU-POKER CREEKS RESEARCH WATERSHED
DATE TEMPERATURES DISSOLVED OXYGEN mg/1
1973 mtm may ttmf mtm may
1973
MIN.
MAX.
TIME
MIN.
MAX.
TIME
*5/30
6.7
1900
11.4
2000
5/31
1-7
0600
12.2
0700
5/31
. —
8.3
1900
11.0
2000
6/1
3.3
0600
11.8
0700
6/1
7.2
1800
10.3
1900
6/2
3.3
0600
11.6
0700
6/2
—
5.0
1800
11.6
1900
*6/11
7.2
1900
11.2
1000
6/12
3.9
0600
6/12
—
8.3
1700
11.6
1700
6/15
2.2
0600
11.6
0700
6/15
8.9
1700
10.2
1800
6/16
3.9
0600
11.2
0700
6/16
—
7.8
1700
10.2
1800
6/17
3.9
0600
11.2
0700
6/17
—
10.0
1800
9.6
1800
6/18
4.4
0700
10.4
0800
6/18
—
6.7
1900
10.6
2000
6/19
3.9
0600
11.4
0700
6/19
—
10.6
1700
10.2
1800
*6/20
4.4
0500
11.4
0500
6/20
—
10.0
1800
10.4
1900
6/21
4.4
0600
11.2
0700
6/21
—
10.0
1700
10.0
1800
6/22
5.0
0600
10.2
0700
6/22
—
10.0
1700
10.0
1700
6/23
5.0
¦
0800
10.6
0900
6/23
—
7.2
1500
10.0
1600
6/24
3.3
0600
10.8
0700
6/24
—
6.1
1700
10.4
1800
6/25
3.9
0600
11.4
0200
6/25
7.2
1800
11.0
1900
6/26
3.3
0600
11.4
0700
6/26
9.4
1700
10.4
1800
*6/27
3.3
0500
11.4
0600
6/27
—
10.0
1800
10.0
1800
6/28
3.3
0600
10.8
0700
6/28
—
8.9
1700
10.2
10.8
0700
6/29
4.4
0600
10.8
0700
6/29
—
9.4
1800
10.0
1800
6/30
4.4
0700
10.8
0800
6/30
—
8.9
1800
10.2
1900
7/1
4.4
0600
10.6
0700
7/1
—
8.9
1800
9.6
¦
1900
7/2
5.0
0700
10.6
0800
35
-------
TABLE 10 CONTINUED
DATE
1973
TEMPERATURES
TIME
DISSOLVED OXYGEN mg/1
TIME
MIN.
MAX.
MIN.
MAX.
7/4
14.4
1700
6.6
1200
7/5
7.8
0700
7.6
0800
7/5
13.8
2000
6.6
2000
7/6
00
0700
7.4
0200
7/6
. —
11.7
2000
7.0
2000
7/7
8.3
0700
7.4
0700
7/7
13.3
2200
6.8
2200
7/8
10.6
0900
7.4
0900
7/8
17.2
2100
6.2
2100
7/9
11.1
0800
—
7.2
0900
7/9
19.4
2200
5.8
2300
7/10
12.8
0800
6.4
0800
7/10
20.0
2200
5.2
¦
2400
7/11
12.2
/
.
6.0
7/11
18.3
5.6
*7/12
'
7/14
5.0
7.8
7/14
10.6
7.2
7/15
CO
7.8
7/15
....
_ _ __
7/17
5.0
7.4
7/17
11.1
6.8
*7/26
,
7/27
3.9
0700
9.6
0700
7/27
9.4
1800
8.8
160Q
7/28
5.6
0800
9.4
0800
7/28
8.3
1900
9.0
2000
7/29
4.4
0700
9.4
0800
7/29
6.7
1800
9.4
1900
7/30
3.9
0600
7.6.
0700
7/30
CO
1800
9.7
1800
7/31
4.4
—
0700
9.8
' 0700
7/31
7.8
1800
9.4
1900
*8/1
3.9
0200
10.0
0800
8/1
00
1800
11.2
1900
8/2
2.8
—
0600
12.0
0700
8/2
7.2
1600
11.0
1700
8/3
3.9
0600
11.4
0700
8/3
6.7
1800
n.o
1800
8/4
4.4
0600
—
11.4
0700
8/4
7.2
1800
10.8
1900
8/5
3.9
0700
11.4
0800
8/5
7.8
1500
10.6 .
-,
1700
8/6
. 4.4
0600
11.2
0800
8/6
7.8
1700
10.8
2000
36
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TABLE 10 CONTINUED
DATE
1973
TEMPERATURE °C
TIME
DISSOLVED OXYGEN mg/1
TIME
MIN.
MAX.
MIN.
MAX.
*8/7
7.8
_ _ _ _
0500
11.4
0700
8/7
8.3
1800
10.6
2200
8/8
4.4
0700
n.o
0900
8/8
7.2
1800
10.4
—
2000
8/9
4.4
0700
10.8
0900
8/9
6.7
1800
10.4
2000
8/10
4.4
0700
10.6
1000
8/10
ft/n
4.1
10.4
O/ 1 1
8/12
4.4
_ _ _ _
0800
10.4
0800
8/12
-—
7.2
1700
9,8
1200
8/13
3.9
0700
10.4
0700
8/13
7.2
1900
9.8
2300
8/14
6.1
0700
10.0
0800
8/14
8/15
3.9
0600
10.8
0800
8/15
7.2
1800
9.8
2000
*8/16
3.3
0700
9.8
0700
8/16
5.6
1800
11.8
2000
8/17
2.8
0700
12.2
0900
8/17
5.0
1800
11.8
2000
8/18
2.2
0700
12.4
0800
8/18
3.9
2000
11.8
2200
8/19
4.4
0600
11.8
0800
8/19
5.6
1800
11.4
2000
8/20
3.3
0700
11.8
0900
8/20
7.8
1700
10.8
1900
*8/21
4.4
0700
11.4
0900
8/21
5.6
1700
11.2
1800
8/22
3.9
0500
11.6
0600
8/22
5.6
1700
11.2
1700
8/23
2.8
0700
11.8
0800
8/23
6.7
1600
11.0
1800
8/24
2.8
0500
11.6
0500
8/24
5.6
1600
11.0
1800
8/25
2.8
0500
11.6
0500
8/25
5.0
1600
11.0
1800
8/26
3.3
0500
11.4
0500
8/26
5.6
1500
10.8
1700
8/27
2.8
0500
11.4
0500
8/27
5.0
1400
10.8
1600
8/28
2.8
0200
11.0
0200
*8/30
8/31
1.1
0700
12.8
0800
8/31
5.0
1700
12.0
1800
37
-------
TABLE 10 CONTINUED
DATE
TEMPERATURE0C
DISSOLVED OXYGEN rng/1
1973
MIN.
MAX.
TIME
MIN.
MAX.
TIME
9/1
1.1
—
0700
12.8
0900
9/1
—
5.0
1600
12.2
1800
9/2
0.6
—
0700
13.2
0900
9/2
—
3.9'
1600
12.4
1800
9/3
0.6
—
0600
13.4
0800
9/3
—
5.0
1600
12.2
1800
9/4
0.6
—
0600
13.4
0800
9/4
—
5.0
1600
12.4
1900
9/5
1.7
—
0700
13.0
0800
9/5
¦ —
5.6
1600
12.4
1600
9/6
1.7
—
0600
13.2
0800
9/6
—
5.6
1500
12.4
1600
9/7
1.1
—
0600
13.0
0800
9/7
—
5.0
1500
12.0
1700
9/8
1.7
—
0500
12.4
0700
9/9
2.8
—
0400
12.4
0700
9/9
—
4.4
1400
12.0
1600
9/10
1.7
—
0400
12.4
0600
9/10
—
4.4
1400
11.8
1600
9/11
0.6
—
0500
12.6
0700
9/11
—
4.4
1300
12.0
1500
DISSOLVED
TEMP. TEMPERATURES OXYGEN DISSOLVED OXYGEN mq/1
DATE
MIN.
MAX.
TIME
DATE
MIN.
MAX.
TIME
*9/18
—
1700
12.4
2100
9/19
0.6
—
0900
13.0
1100
9/19
—
1.7
2100
9/20
12.6
0100
9/20
0.6
—
0900
13.0
1200
*9/26
—
1.7
1900
12.6
2400
9/27
-0-
—
0900
13.0
1000
9/27
—
1.1
1800
12.6
2200
9/28
-0-
—
1000
13.0
1300
9/28
-0-
2100
12.6
0100
9/29
-0-
—
0800
12.8
1300
9/29
0.6
2000
12.4
0300
9/30
-0-
—
0300
12.6
0700
9/30
—
1.1
1600
10/1
12.2
2400
10/1
0.6
—
0100
12.4
0800
10/1
—
1.1
1500
12.0
2200
10/1
-0- •
—
2300
12.2
0800
10/2
1.1
2000
12.2
*10/3
1.1
1600
12.6
10/4
-0-
—
0800
12.6
10/5
—
-0-
1700
12.4
Temperature and dissolved oxygen constant until shut down on 10/12
* Calibration
38
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In general, the dissolved oxygen was always high, approaching 1 or
2 ppm of saturation. The diurnal change was usually less than 1 ppm.
Minimum water temperatures in the monitor were 3-5°C until the end of
August when they decreased, approaching 0°C by the middle of September.
Maximum temperatures were up to 5°C higher than the minimums through
June and July with the differences diminishing by August. In late
September the change was about 1°C and from October 5 until the shut-
down date on October 12, the water temperature was plus zero and
essentially constant. Corresponding D.O. was constant and close to
13.0 ppm.
Maximum water temperatures were recorded during late afternoon,
while minimums occurred in early morning. However, by mid-September,
it became difficult to determine the maximum and minimum times for both
temperatures and D.O. because of the low amplitude of their characteristic
sinusoidal curve. The D.O. response to temperature appeared to lag by
about an hour until mid-August after which the lag increased to about 2
hours. Again, broadening of the curves made it difficult to make accurate
readings. The change in D.O. during the lag time was only 0.1-0.2 mg/1.
It is uncertain whether the lag was the result of D.O. probe response or
the kinetics involved in the system.
DISCUSSION AND CONCLUSIONS
One intended objective for installing the field station was to obtain
continuous records of all parameters. This objective was not fully realized
during the period covered by this report. This failure to achieve continuity,
although discouraging, was not surprising when the total environmental condi-
tions are placed in perspective. In fact, one subsidiary objective was to
test, evaluate, and develop methods of coping with low winter temperatures
(down to minus 50°C), stream ice and icings, and reliable transportation.
Continuous monitoring at remote sites is always a challenge, especially
in the arctic and subarctic. It does not appear necessary to continuously
monitor water quality parameters from freezeup to breakup unless there is
some special reason to justify the effort. During the winter, changes in
aquatic systems are gradual and periodic sampling can achieve the desired
result since hydrologic events which might influence water quality simply
do not occur. However, monitoring during rapidly changing conditions be-
comes vital if these trends are to be understood. Hence, continuous moni-
toring of Poker and Caribou Creeks may be desirable during times of water-
shed perturbations on Poker Creek. In addition to the five parameters
measured in 1973, turbidity data would be of value.
Interpretation of field measurements and laboratory analyses during
the summer periods validate the earlier tentative conclusions that Poker
and Caribou Creeks have real differences in their water chemistry. Dif-
ferences among streams, in either watershed, are sufficient to necessitate
making careful conclusions in the future as one or more subrbasins is
impacted by some planned perturbation. These baseline data now provide
sufficient evidence of the natural variability among this group of eight
sub-basins to guide further research.
39
-------
Winter field and laboratory data show that some chemical parameters
change with time as winter progresses, whereas others are little influenced.
Conductivity and alkalinity are two chemical parameters whose values tend
to increase with time whereas pH is little changed. Dissolved oxygen
generally decreased under the prolonged ice cover in all streams but did
not exhibit the expected characteristic depletion. Nutrients in the
streams are in low concentrations and show little variability; the same
is true for heavy metals. Total carbon data are incomplete so conclusions
are no more than^tentative; however, Poker shows higher concentrations than
Caribou Creek which is probably a reflection of the total alkalinity measured
in these streams.
A trail up Poker Creek, completed in 1975, provided access to this
system and allowed winter sampling of the four tributaries. The construc-
tion of that trail completed the watershed network and permitted all-
season ground access to the tributaries. It is contemplated that all .
streams draining each sub-basin (eight in all) will be sampled at monthly
intervals during the next year to complete a baseline of water quality
data before any planned disturbances in Poker Basin are initiated. Both
creeks will be sampled by the monitors to verify that the system will func-
tion or can be repaired when air temperatures are extremely low and ice
covers the pump. A new unit containing probes for all the stream parameters
which can be placed directly in the stream will also be tested in Poker Creek.
40
-------
REFERENCES
1. American Public Health Association. 1971. "Standard Methods for the
Examination of Water and Wastewater," 13th Edition, New York.
2. Analytical Quality Control Laboratory. 1971. "Methods of Chemical
Analysis of Water and Wastes," U.S. Environmental Protection Agency,
Cincinnati.
3. Jinkinson, William M., Frederick B. Lotspeich, and Ernst W. Mueller.
1973. "Water Quality of Caribou-Poker Creeks Research Watershed,
Alaska," Working Paper No. 24, U.S. Environmental Protection Agency,
Arctic Environmental Research Laboratory, College, Alaska.
4. Schallock, Eldor W., and Frederick B. Lotspeich. 1974. "Low Winter
Dissolved Oxygen in Some Alaskan Streams," Ecological Research Series
No. EPA-660/3-74-008, U.S. Environmental Protection Agency, Arctic
Environmental Research Station, College, Alaska.
5. Slaughter, Charles W. 1971. "Caribou-Poker Creeks Research Watershed,
Interior Alaska," Special Report No. 157, U.S. Army, Cold Regions
Research and Engineering Laboratory, Ft. Wainwright, Alaska.
6. Slaughter, Charles W., and A. E. Helmers. 1974. "An Expanded Role
for Subarctic Watershed Research," Water Research Bulletin, No. 10,
pp. 256-265.
7. Slaughter, C. W., C. Hoffeditz, J. Morse, and D. McFarlane. 1974.
"A Subarctic Microclimatology Station," CRREL Technical Note, U.S.
Army, Cold Regions Research and Engineering Laboratory, Hanover, New
Hampshire.
ft U. S. GOVERNMENT PRINTING OFFICE: 1976-697-428/103 REGION (O
41
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