WSP07477

• File Number: 8407
• Description: Platte River Basin - River Basin General Publications
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 7/14/1997
• Author: USGS
• Title: Hydrologic and Water-Quality Data - Guanella Pass Area - Colorado - Water Year 1995
• Water Supply Pro - Doc Type: Report/Study

Continuous data from the monitoring stations
were supported by monthly site visits during the
open-water season, and bi-monthly visits when ice
cover was present. Field measurements of streamflow
were made using the cUrrent-meter method (Buchanan
and Somers. 1969), The calibration of the water-
quality monitor was checked using field meters and
standard solutions prepared according to standard
procedures (R.W, Boulger. U,S. Geological Survey.
unpub, data, 1989). Data from these visits were
used to analyze and compute the continuous data
from the monitoring stations according to standard
procedures (Rantz and others. 1982; Kennedy, 1983;
R.W. Boulger. U.S. Geological Survey, unpub. data,
1989),
Seven water-quality samples were collected
during rain or turbidity events. An event is a rise
in streamflow or an increase in turbidity due to a
rainstorm. Field measurements of specific conduc-
tance, water temperature, dissolved oxygen, and
barometric pressure were made at streamside
(M.A. Sylvester and others, U.S. Geological Survey,
unpub. data, 1990). Turbidity and pH were measured
from samples taken from the churn splitter. Samples
for inorganic analysis were collected by equal-width-
increment (EWI) or equal-discharge-increment
(EDl) methods using a DH-SI polyethylene
isokinetic sampler and split for separate analyses
with a USGS churn splitter (Ward and Harr, 1990).
Samples requiring filtered water were filtered by using
a peristaltic pump and disposable 0.45-mm capsule
filters in an enclosed filter chamber. Trace-element
samples were preserved as necessary with ultrapure
nitric acid or nitric acid and potassium dichromate
(for mercury samples). Nutrient samples were chilled
to less than 40C.
Samples of suspended sediment were collected
by EWI or EDl methods with a DH-48 hand sampler
or DH-59 cable sampler (Guy and Norman, 1970)
and by the use of an automatic pumping sampler with
a fixed intake point (Edwards and Glysson, 1988).
Samples were collected for analyses of concentration
and percent finer than 0.062-mm. Multiple daily
samples were collected with the pumping sampler for
daily sediment load computations; however, those data
are not included in this report.

Hlgh- and Low-Streamflow
Water-Quality Sampling

A synoptic stream sampling design was
used to compare high- and low-streamflow regimes
among sites. The term "synoptic" is used to refer to
samples taken at approximately the same time of
year. The sampling sites are listed in table 3 and
shown in figure 3. A high-flow sample was collected
at 21 of the sites in mid-June. A low-flow sample was
collected at all 23 sites in early September. Instanta-
neous streamflow was measured by the current-
meter method (Buchanan and Somers, 1969). Field
measurements of specific conductance, water tempera-
ture. dissolved oxygen. and barometric pressure were
made at streamside (M.A. Sylvester and others,
U,S. Geological Survey, unpub. data, 1990). Turbidity
and pH were measured from samples taken from the
churn splitter. Samples for inorganic analysis were
collected by EWI or EDl methods using a DH-SI
polyethylene isokinetic sampler and split for separate
analyses with a USGS churn splitter (Ward and Harr,
1990). Samples requiring filtered water were filtered
by using a peristaltic pump and disposable 0.45-J.lm
capsule filters in an enclosed filter chamber. Trace-
element samples were preserved as necessary with
ultrapure nitric acid or nitric acid and potassium
dichromate (for mercury samples). Nutrient samples
were chilled to less than 40C.
Samples for organic analysis were collected
in a baked glass bottle by EWI, EDl, or dip methods,
The total organic carbon sample was not filtered,
whereas the dissolved organic carbon samples were
filtered through a 0.45-J.lm silver filter. Carbon
samples were chilled to less than 40C until analyzed.
Suspended-sediment samples also were
collected by EWI or EDl methods using appropriate
hand- or cable-operated isokinetic samplers (Edwards
and Glysson, 1988). Samples were collected for
suspended-sediment concentration and percentage
of particles finer than 0.062 mm using standard
techniques (Guy. 1969).

Road-Runoff Sampling

Road runoff in shoulder ditches and cross drains
was sampled from paved and unpaved sections of
the Guanella Pass road. The sites sampled are listed

8 HydrologIc and Water.Quallty Da'a, Guanella Paa. Area, Colorado, Watar Vea, 1995