WSP07706

• File Number: 8200.765
• Description: White River General
• State: CO
• Basin: Yampa/White
• Water Division: 6
• Date: 1/1/1993
• Author: USGS
• Title: Sediment Transport and Water-Quality Characteristics and Loads - White River - Northwestern Colorado - Water Years 1975 through 1988
• Water Supply Pro - Doc Type: Report/Study

n02769

Analyses of the data shown in figures 14, 18-22,
and table 8 indicate the following:

1. For all streamflow ranges, concentrations of
the major ions increased downstream from
sites 1 and 2 to site 6. Concentrations of major
ions at sites 1-6 were greatest in low stream-
flow and least in high streamflow. Dissolved
solids ranged in concentration from about 100
to 250 mg/L at sites 1 and 2 to about 230 to
630 mg/L at site 6. The increases in dissolved-
solids concentrations (and related increases in
specific conductance) in low streamflow indi-
cated that base flows in the White River prob-
ably were maintained from ground water or
alluvial storage, or both, and from irrigation
return flow that had large concentrations of dis-
solved solids. During spring runoff, the large
concentrations of dissolved solids in base
flows were diluted by snowmelt that contained
small concentrations of dissolved solids.

2. The composition of dissolved solids at site 1
was mostly calcium, bicarbonate, and sulfate.
The composition of dissolved solids at site 2
was mostly calcium and bicarbonate. Sulfate
concentrations were greater at site 1 than at
site 2 probably because sulfate-rich minerals,
such as gypsum or anhydrite, were more com-
mon in surface and near-surface sedimentary
deposits in the North Fork Basin.

3. In low streamflow, the composition of dis-
solved solids in the main stem of the White
River changed from mostly calcium, bicarbon-
ate, and (or) sulfate in the upstream reaches
(upstream from site 4) to mostly calcium,
sodium, sulfate, and bicarbonate in the down-
stream reaches (sites 5 and 6). During snow-
melt runoff when streamflow in the White
River was greater than 1,000 ft3/s, calcium and
bicarbonate generally were the principal con-
stituents at all sites. Water hardness ranged
from moderately hard in the high streamflow
upstream from site 4 to very hard in medium
and low streamflow at site 1 and sites 3-6. The
increases of sodium and sulfate that occurred
downstream in low streamflow probably were
caused from irrigation return flow and from
ground water that had been in contact with the
extensive silt and shale deposits of the central
and downstream areas of the White River
Basin.

4. Sodium (Na) concentrations were compared
with calcium (Ca) and magnesium (Mg) con-
centrations using the sodium-absorption ratio
(SAR) of the water (U.S. Salinity Laboratory
Staff, 1954). The SAR is used with values of
specific conductance to assess the hazard of
sodium in replacing calcium and magnesium in
soil structures when the water is used for irriga-
tion. The ratio is expressed as:

(Na+)
SAR = J (Ca++) ~ (Mg++) ,

(7)

where ion concentrations (in parentheses) are
expressed in milliequivalents per liter. For the
range of values of specific conductance for the
White River, values of SAR generally less than
6 indicate a low sodium hazard. All values of
SAR at sites 1-6 were less than 2.1.

Annual loads of dissolved solids at sites 1-6 were
measured by using regression methods and assumptions
similar to the procedures described in the "Loads" sec-
tion of this report, except that instantaneous dissolved-
solids loads were regressed with daily stream discharge.
Instantaneous dissolved-solids load (Lds' in tons per
day) is a function of instantaneous stream discharge
(Q), in cubic feet per second, dissolved-solids concen-
tration (Cds)' in milligrams per liter, and the conversion
constant 0.0027. Dissolved-solids load is calculated as
follows:

Lds =(0.0027)QCds .

(8)

Data analyses indicated that a single regression for
each site was applicable for all hydrologic events
(table 9). Two regressions were used at site 4 to define
the slight differences in water quality for the periods
before and after early 1982. Daily loads of dissolved
solids (Ldsd) were computed by using the regression
information (table 9) and summed by water year to
obtain annual dissolved-solids loads (Lds.J for sites 1-4
for water years 1975-88 and sites 5 and 6 for water
years 1983-88.

Estimates of annual dissolved-solids loads at
sites 5 and 6 for water years 1975-82 were derived by
using two pairs of least-squares regressions. The first
pair of regressions related measured annual dissolved-
solids loads at sites 5 and 6 (water years 1983-88) with
measured annual dissolved-solids loads at site 4. The
second regression pair was obtained by relating

WATER-QUALITY CHARACTERISTICS AND LOADS 45

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