WSP10847

• File Number: 8102
• Description: Arkansas River Hydrographs
• Basin: Arkansas
• Date: 1/1/1985
• Author: USGS
• Title: Selected Hydrographs and Statistical Analyses Characterizing The Water Resources of the Arkansas River Basin, Colorado
• Water Supply Pro - Doc Type: Publication

A statistical test (Kendall Tau) was computed for the April 1 measure-
ments at all the stations to identify possible time trends in the snowpack
data. The test indicated that only station 6K07, Four Mile Park, had a trend
statistically different from zero at the I-percent significance level. There
is no information to account for or discount this apparent upward trend
(fig. 40).

Correlation analysis was computed between each precipitation station and
snow-survey course, using the monthly precipitation and respective first-of-
the-month snowpack data. Only a few correlation coefficients were statis-
tically different from zero at the I-percent significance level, and none of
them was greater than 0.40. Analysis of incremental snowpack (net change dur-
ing the month) and monthly precipitation also showed no statistical correla-
tion. A correlation analysis between annual precipitation at all stations and
April 1 snowpack at all snow-survey courses indicated that only station 3063,
Fountain (2NW) (IN) was statistically different from zero at less than the
2-percent significance level. Annual precipitation at that station correlated
with the April 1 snowpack measurements at 6 different snow-survey courses
(6KI7, 6K07, 6K04, 5M1M, 6L04, and 6K03S), with correlation coefficients rang-
ing from 0.39 to 0.61. No explanation is available as to why precipitation at
this station, and only this station, correlated with snowpack data.

Discharge

Streamflow-gaging stations where discharge data have been collected were
selected based on the length of record and geographic location. The
46 streamflow-gaging stations chosen are listed in table 6, and 44 stations
are shown on plate 1. Stations 07137500 and 07137000 (not shown on plate 1)
are located in Kansas but are used in the analyses to represent flow leaving
the State of Colorado. The record available since 1920 and the average
discharge for each station are shown in table 7. Hydrographs of annual mean
discharge for these 46 stations are shown in figures 55-93 (stations 07079500,
East Fork Arkansas River near Leadville, and 07081000, Tennessee Creek near
Leadville, are added together and plotted with station 07081200, Arkansas
River near Leadville, in fig. 55; stations 07099400, Arkansas River above
Pueblo, and 07099500, Arkansas River near Pueblo, are both plotted in fig. 68;
stations 07108500, St. Charles River near Pueblo, 07108800, St. Charles River
near Vineland, 07108900, St. Charles River at Vineland, and 07109000,
St. Charles River at mouth near Pueblo, are plotted in fig. 75; and stations
07137000, Frontier Ditch near Coolidge, Kans., and 07137500, Arkansas River
near Coolidge, Kans., are added together and plotted in fig. 93). There is no
substantial flow entering the Arkansas River between the State line and
station 07137500. Tables of monthly discharges are presented in the "Supple-
mental Information" section at the end of the report. It should be noted that
the average discharge reported in table 7 and in the "Supplemental Informa-
tion" section may be somewhat different from values published elsewhere. This
difference is because all the average discharges presented in this report are
averages of monthly mean values and, thus, do not account for variable number
of days per month, as do most published annual or period-of-record means,
which are usually computed from daily mean values.

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