WSP07478

• File Number: 8272.600.60
• Description: Colorado River Basin Salinity Control Program - Basin Member State Info - Utah
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 3/1/1982
• Title: Salt Uptake in Natural Channels Traversing Mancos Shales in the Price River Basin - Utah
• Water Supply Pro - Doc Type: Report/Study

Table 6,8, Coefficients in the microchannel
salt loading function y "" axb.
N Shale Type a b r2
I-'"
0 Undivided 23.9 0.71 0.981
r.Jl Upper Blue Gate 66.8 0.73 0.986
Middle Blue Gate 94.0 0,67 0.991
Lower Blue Gate 2.0 0.74 0.966
Tununk 1.2 0,79 0.993
Masuk 1.7 0.82 0.997

(predominantly from microchannel sources for
Middle Blue Gate and predominantly overland
flow for Lower Blue Gate). This variation is
cauaed partially by the high degree of
variability within the same geologic shale
type.

Some types of shale were not sampled as
intensely as others. Even so, compari.son
between Table 6.9 and the much larger loads
of Table 6.6 is interesting, Table 6.6 is
extrapolated on the aSBumption that all the
shales in the basin are of the undivided
type. Because of the relatively high salt
producing potential of the undivided shale
(see Table 6.9), this assumption would be
expected to increase the predicted salt load
from overland flows.

In contrast, there is a close agreement
on the amount of salt at Woodside attributed
to first order channels. This might have
been expected because Ponce (1975) and White
(1977) suggested that the pickup of salt ia
more influenced by shale type for overland
flows than for channel flows.

The Utah Division of Water Resources
(1975) estimated an average runoff coef-
ficient of about 9 percent between Castle
Gate and Woodside, with the valley \,ortion of
that section yielding less than inch of
water per year on the average. The model
results for Coal Creek also estimated that an
average of about 9 percent of the precipita-
tion within this reach becomes surface
runoff. If interflow and groundwater were
added, the estimated basin yield would be
somewhat greater, but these quantities are
small on the valley floor area of the Price
River Basin.

The reasonableness of these general
comparisons and the lack of model sensitivity
to the values given for input parameters
confirm that the first generation model as
programmed is on the right track. Field data
for validity testing are needed for model
refinement.

Table 6.9. Estimated salt production from surface flows for various shale types in the Price
River Dasio.

Salt Produced
(lbs/acre/year) Acres of
Shale lUcro- Overland Shale in Basin
channel Flow Total
-----
Undivided 24,1 71.5 95.6 119,000
Middle Blue Gate 19,8 1.4 21.2 36,9008
Mas uk 1.2 1.4 2.6 52,400
Tununk 1.0 7.9 8,9 14,400
Upper Blue Gate 48,7 30,0 79.2 36,900a
Lower Blue Gate 1.2 21.5 22.7 36,900a
TOTALS

Percentage of salt produced by the basinb

aAssuming equal areas of the three Blue Gate shale members.

bUsing a total of 405,500 tons per year as estimated by Ponce (1975).

63

Total Salt Produced
in Basin (tons/year)
Micro- Overland
channel Flow Total
1430 4250 5680
365 25 390
30 35 65
7 57 64
900 550 1450
20 400 420
2752 5317 8069
0.68% I. 31% 2,0%