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

for station 07117000 (Arkansas River near Nepesta) has decreased at an average
rate of about 1.3 (ft3/s)/yr and that the annual mean discharge for station
07124000 (Arkansas River at Las Animas) has decreased at an average rate of
about 4.9 (ft3/s)/yr.

Table 8.--Coefficients and statistics from linear-regression analysis betwEen
annual mean discharge at the indicated station and time

Regression Standard error
slope of estimate Correlation
Station (cubic feet of the slope coefficient Period of record
per second (cubic feet per
per year) second per year)
07086000 1.8 0.5 0.41 1910-80
07089000 -0.3 0.1 .40 1912-23, 1949-80
07106000 -3.0 2.4 .30 1939-54
07109500 -1.4 4.4 .06 1939-51, 1965-80
07116000 -2.2 1.1 .35 1940-67
07117000 -1. 3 3.5 .06 1936-80
07119500 -0.6 0.2 .42 1921-24, 1939-80
07123000 -2.3 1.3 .21 1912-80
07124000 -4.9 2.8 .27 1939-80
07124500 -0.4 0.2 .21 1916-60, 1962-80
07126500 -1.0 0.6 .21 1925-80
07128500 -2.4 0.8 .43 1922-31, 1948-80
071305001 -9.1 4.1 .33 1938-80
071305001 -3.7 1.5 .36 1938-41, 1943-80
07133000 -4.5 1.7 .31 1912-55, 1959-80
07134100 -1.2 0.5 .63 1968-80
07137500 -4.4 3.7 .21 1951-80
lRemoving one outlier from the regression analysis.

A statistical analysis to compute the correlation coefficient of monthly
mean discharge and monthly precipitation for every combination of streamflow-
gaging stations and precipitation stations was performed. Of the 1,650 pos-
sible combinations tested, only 34 were statistically different from zero at
the I-percent level of significance; only 27 of those had more than 2 years of
concurrent record. Considering 1,650 combinations of purely random numbers,
one would expect about 16 or 17 correlations significantly different from zero
at the I-percent significance level. Apparently then, monthly precipitation,
by itself, is not a good indicator of monthly discharge. The only statisti-
cally significant results from this analysis are: (1) Station 07104000
(Monument Creek at Pikeview) correlated with five different precipitation
stations (2446, 3828, 5730, 6131, and 8781) with the highest correlation

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