WSP01269

• File Number: 8170
• Description: Arkansas Basin Water Quality Issues
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 8/1/1997
• Author: Doug Cain
• Title: U.S. Geological Survey Data Collection and Studies in the Arkansas River Basin
• Water Supply Pro - Doc Type: Report/Study

20

COLORADO WATER

. August 1997

we see a somewhat different picture (Figure 8). The variation
that we see after Pueblo Reservoir went in appears to be
greater. We see a slight increasing trend in salIS at this site.
Some of the effects of improved water quality or more consistent
waler quality are not present at this site. Looleing at records
from Fountain Creele, this increasing trend is because of an
increase in dissolved solids coming out of Fountain Creele that
are measured at this station.

One other site I would lilee to show you is the site below John
Martin Reservoir both before and afler the 1980 operating plan
(see Figure 9). We see something similar to what we saw in
Pueblo Reservoir. There is less variation, but also, generally,
water quality since 1980 below John Martin has improved. There
are fewer salts in the river at that point. We believe this is
because of a dramatically increased now. In general, when the
Oows are higher the sailS in the waler are lower.

As some of you may have read in the newspaper recently, the
State of Kansas has expressed concerns about the problems in the
aquifer along the Arleansas River in Kansas because of salIS
moving into that aquifer from the river. Based on the worle that
we have done, it appears that since 1980, at least at the Lamar site
(we do nOl have the data to loole at this in detail at the site near
thestate line), water quality has probably improved (see Figure
10). I am not sayingit is great water quality, because dissolved
solids 8tthe state line are still very high, but there definitely is an
improvement at that site.

SPECIFIC CONDUCTANCE

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One other study that I would lilee to mention is a two-year study
done in cooperation with the Purgatoire River Water Conservancy
District to loole allosses in stream now along thaI river. The
prevailing wisdom, based upon a number of fairly specific studies
in the past, was that there was a lot of water loss in the Purgatoire
River between Trinidad Dam and the mouth of the Purgatoire near Las Animas. We looleed at about 12 years of data for that
period, and it appears that on average, at least in the lower two-thirds of that reach, losses are fairly small. In fact, sometimes
there are even gains. It appears that the earlier studies may have looleed at fairly specific situations when losses were quite high.

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Fig. 7. Specifie Conductance at Arkansas River Above
Pueblo, 1966-94.

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The information presented in this arRcte is based on several recently approved or published reports, including:

Water-quality data for the Arkansas River Basin, southeastern Colorado, 1990-93, by R.G. Dash and R.E Ortiz (USGS Open-File
Report 95-464).

Metal speciation in the upper Arkansas River, Colorado, 1990-93, by M.L. Clark and M.E. Lewis (Water-Resources Investigations
Report 964282).

Evaluation of stream now traveltime and stream now gains and losses along the lower Purgatoire River, southeastem Colorado, by
R.G. Dash and P. Edelmann (Water-Resources Investigations Report 96-4291).

Water-quality assessment of the Arleansas River Basin, southeastern Colorado, 1990-93, by R.E Ortiz, M.E. Lewis, and M.J. Radell
(Water-Resources Investigations Report 97-4111, in press).