SKUNK RIVER BASIN

05471040 SQUAW CREEK NEAR COLFAX, IOWA

LOCATION.--Lat 41°39'33", long 93°16'14" referenced to North American Datum of 1927, in NE 1/4 NE 1/4 sec.15, T.79 N., R.21 W., Jasper County, IA, Hydrologic Unit 07080105, on right bank on downstream side of bridge on South 44th Avenue West, 1.0 mi southwest from Colfax, and 1.6 mi upstream from mouth.

DRAINAGE AREA.--18.4 mi².

PERIOD OF RECORD.--Discharge records from May 1995 to September 2005.

GAGE.--Water-stage recorder. Datum of gage is 785.96 ft above National Geodetic Vertical Datum of 1929.

REMARKS.--Records for winter periods considered poor due to intermittent snow accumulation and subsequent melting.

A summary of all available data for this streamgage is provided through the USGS National Water Information System web interface (NWISWeb). The following link provides access to current/historical observations, daily data, daily statistics, monthly statistics, annual statistics, peak streamflow, field measurements, field/lab water-quality samples, and the latest water-year summaries. Data can be filtered by parameter and/or dates, and can be output in various tabular and graphical formats.

http://waterdata.usgs.gov/nwis/inventory/?site_no=05471040

The USGS WaterWatch Toolkit is available at:

http://waterwatch.usgs.gov/?id=ww_toolkit

Tools for summarizing streamflow information include the duration hydrograph builder, the cumulative streamflow hydrograph builder, the streamgage statistics retrieval tool, the rating curve builder, the flood tracking chart builder, the National Weather Service Advanced Hydrologic Prediction Service (AHPS) river forecast hydrograph builder, and the raster-hydrograph builder. Entering the above number for this streamgage into these toolkit webpages will provide streamflow information specific to this streamgage.

A description of the statistics presented for this streamgage is available in the main body of the report at:

http://dx.doi.org/10.3133/ofr20151214

A link to other streamgages included in this report, a map showing the location of the streamgages, information on the programs used to compute the statistical analyses, and references are included in the main body of the report.

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SKUNK RIVER BASIN

05471040 SQUAW CREEK NEAR COLFAX, IOWA

Statistics Based on the Entire Streamflow Period of Record

05471040 Monthly and annual flow durations, based on 1996–2005 period of record (10 years)
Percentage of days discharge equaled or exceeded / Discharge (cubic feet per second) / Annual flow durations
Oct / Nov / Dec / Jan / Feb / Mar / Apr / May / June / July / Aug / Sept / Annual / Kentau statistic / P-value
99 / 0.50 / 0.74 / 0.45 / 0.30 / 0.53 / 0.59 / 1.8 / 2.4 / 8.6 / 3.8 / 0.88 / 0.35 / 0.52 / -0.067 / 0.728
98 / 0.53 / 0.86 / 0.50 / 0.44 / 0.60 / 0.98 / 1.9 / 2.5 / 9.2 / 4.2 / 0.93 / 0.40 / 0.60 / -0.111 / 0.605
95 / 0.57 / 0.96 / 0.68 / 0.72 / 0.76 / 1.7 / 2.1 / 2.8 / 9.8 / 4.9 / 1.1 / 0.49 / 0.78 / -0.356 / 0.123
90 / 0.67 / 1.0 / 0.80 / 0.88 / 0.94 / 2.1 / 2.5 / 5.1 / 11 / 5.5 / 1.4 / 0.58 / 1.0 / 0.000 / 1.000
85 / 0.75 / 1.1 / 0.97 / 1.0 / 1.1 / 2.5 / 2.9 / 9.2 / 13 / 6.0 / 1.7 / 0.70 / 1.2 / -0.044 / 0.926
80 / 0.80 / 1.2 / 1.1 / 1.1 / 1.3 / 2.7 / 3.2 / 10 / 14 / 6.6 / 2.0 / 0.79 / 1.6 / 0.044 / 0.923
75 / 0.84 / 1.2 / 1.2 / 1.2 / 1.6 / 2.9 / 3.7 / 12 / 15 / 7.2 / 2.4 / 0.90 / 2.0 / 0.111 / 0.715
70 / 0.89 / 1.8 / 1.7 / 1.4 / 2.1 / 3.8 / 4.3 / 13 / 16 / 7.5 / 2.7 / 1.0 / 2.5 / 0.111 / 0.715
65 / 0.97 / 2.0 / 2.0 / 1.6 / 2.6 / 4.4 / 5.8 / 14 / 18 / 8.1 / 2.9 / 1.1 / 3.0 / 0.111 / 0.712
60 / 1.1 / 2.2 / 2.1 / 1.8 / 3.1 / 4.9 / 7.9 / 15 / 19 / 8.7 / 3.1 / 1.1 / 3.5 / 0.044 / 0.928
55 / 1.2 / 2.9 / 2.7 / 2.0 / 3.7 / 5.5 / 8.4 / 17 / 21 / 9.1 / 3.3 / 1.3 / 4.2 / -0.022 / 1.000
50 / 1.6 / 3.7 / 3.0 / 2.2 / 4.4 / 7.3 / 8.9 / 20 / 22 / 10 / 3.6 / 1.3 / 5.0 / -0.022 / 1.000
45 / 2.3 / 4.1 / 3.3 / 2.5 / 5.3 / 8.6 / 10 / 23 / 24 / 11 / 4.1 / 1.4 / 6.4 / 0.044 / 0.926
40 / 2.6 / 4.6 / 3.5 / 2.7 / 6.8 / 9.2 / 13 / 26 / 26 / 11 / 4.2 / 1.6 / 7.6 / 0.067 / 0.855
35 / 3.2 / 5.0 / 4.3 / 3.1 / 7.8 / 10 / 15 / 30 / 29 / 12 / 4.5 / 1.8 / 8.8 / 0.044 / 0.928
30 / 3.6 / 7.0 / 5.4 / 3.7 / 9.2 / 11 / 17 / 34 / 31 / 14 / 5.2 / 2.7 / 10 / 0.111 / 0.718
25 / 4.2 / 7.5 / 6.5 / 4.0 / 11 / 15 / 19 / 39 / 34 / 16 / 5.8 / 2.9 / 13 / 0.311 / 0.243
20 / 4.9 / 8.0 / 7.2 / 6.0 / 14 / 18 / 24 / 43 / 39 / 19 / 6.9 / 3.2 / 16 / 0.244 / 0.371
15 / 5.9 / 8.6 / 8.0 / 6.9 / 18 / 22 / 31 / 50 / 46 / 22 / 9.2 / 3.7 / 21 / 0.111 / 0.718
10 / 7.1 / 9.9 / 8.8 / 7.6 / 25 / 31 / 38 / 62 / 61 / 27 / 12 / 4.2 / 29 / -0.044 / 0.928
5 / 11 / 13 / 9.5 / 11 / 39 / 49 / 45 / 106 / 83 / 38 / 14 / 4.9 / 44 / -0.067 / 0.858
2 / 20 / 18 / 10 / 15 / 72 / 123 / 56 / 233 / 115 / 63 / 26 / 5.8 / 78 / -0.156 / 0.592
1 / 28 / 29 / 10 / 19 / 109 / 159 / 62 / 255 / 125 / 88 / 47 / 6.3 / 123 / 0.067 / 0.858

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SKUNK RIVER BASIN

05471040 SQUAW CREEK NEAR COLFAX, IOWA

05471040 Annual exceedance probability of instantaneous peak discharges, in cubic feet per second (ft3/s), based on the Weighted Independent Estimates method,
Annual exceed-ance probability / Recur-rence interval (years) / Discharge (ft3/s) / 95-percent lower confi-dence interval (ft3/s) / 95-percent upper confi-dence interval (ft3/s)
0.500 / 2 / 1,190 / 734 / 1,930
0.200 / 5 / 2,210 / 1,500 / 3,270
0.100 / 10 / 3,120 / 2,190 / 4,440
0.040 / 25 / 4,580 / 3,240 / 6,460
0.020 / 50 / 5,620 / 3,900 / 8,110
0.010 / 100 / 6,690 / 4,480 / 9,980
0.005 / 200 / 8,610 / 5,510 / 13,400
0.002 / 500 / 9,630 / 5,820 / 15,900
and based on the expected moments algorithm/multiple Grubbs-Beck analysis computed using a historical period length of 10 years (1996–2005)
0.500 / 2 / 1,350 / 692 / 2,540
0.200 / 5 / 2,900 / 1,590 / 6,940
0.100 / 10 / 4,280 / 2,320 / 13,200
0.040 / 25 / 6,430 / 3,310 / 28,700
0.020 / 50 / 8,340 / 4,080 / 49,400
0.010 / 100 / 10,500 / 4,850 / 82,800
0.005 / 200 / 13,000 / 5,610 / 135,000
0.002 / 500 / 16,600 / 6,600 / 252,000
Kentau statistic / -0.156
P-value / 0.592
Begin year / 1996
End year / 2005
Number of peaks / 10
05471040 Annual exceedance probability of high discharges, based on 1996–2005 period of record (10 years)
Annual exceedance probability / Recur-rence interval (years) / Maximum average discharge (ft3/s) for indicated number of consecutive days
1 / 3 / 7 / 15 / 30
0.990 / 1.01 / 78 / 55 / 30 / 17 / 14
0.950 / 1.05 / 117 / 81 / 47 / 28 / 22
0.900 / 1.11 / 146 / 98 / 58 / 37 / 27
0.800 / 1.25 / 192 / 123 / 74 / 49 / 34
0.500 / 2 / 326 / 186 / 114 / 76 / 51
0.200 / 5 / 561 / 271 / 164 / 107 / 72
0.100 / 10 / 749 / 326 / 194 / 123 / 84
0.040 / 25 / 1,030 / 392 / 228 / 140 / 97
0.020 / 50 / 1,260 / 440 / 251 / 150 / 105
0.010 / 100 / 1,520 / 486 / 273 / 158 / 113
0.005 / 200 / 1,800 / 530 / 292 / 165 / 120
0.002 / 500 / 2,220 / 588 / 316 / 173 / 128
Kentau statistic / -0.244 / -0.067 / 0.022 / 0.022 / 0.022
P-value / 0.371 / 0.858 / 1.000 / 1.000 / 1.000

(Annual nonexceedance probability of low discharges not determined because only 9 years of annual low-flow data were available for analysis.)

05471040 Annual nonexceedance probability of seasonal low discharges, based on July 1995 to September 2005 period of record (10–11 years)
Annual nonexceed-ance probability / Recur-rence interval (years) / Minimum average discharge (cubic feet per second) for indicated number of consecutive days
1 / 7 / 14 / 30 / 1 / 7 / 14 / 30
January-February-March / April-May-June
0.01 / 100 / 0.11 / 0.23 / 0.37 / 0.46 / 0.84 / 0.87 / 0.87 / 1.6
0.02 / 50 / 0.14 / 0.28 / 0.43 / 0.55 / 1.0 / 1.1 / 1.1 / 1.9
0.05 / 20 / 0.22 / 0.38 / 0.55 / 0.72 / 1.4 / 1.4 / 1.6 / 2.6
0.10 / 10 / 0.32 / 0.50 / 0.69 / 0.93 / 1.8 / 1.9 / 2.1 / 3.4
0.20 / 5 / 0.51 / 0.72 / 0.92 / 1.3 / 2.5 / 2.7 / 3.1 / 4.8
0.50 / 2 / 1.2 / 1.5 / 1.7 / 2.4 / 4.9 / 5.5 / 6.8 / 9.7
0.80 / 1.25 / 2.8 / 3.3 / 3.5 / 4.5 / 10 / 12 / 15 / 21
0.90 / 1.11 / 4.3 / 4.9 / 5.3 / 6.5 / 15 / 18 / 24 / 31
0.96 / 1.04 / 6.6 / 7.1 / 8.3 / 9.5 / 24 / 29 / 39 / 48
0.98 / 1.02 / 8.8 / 9.4 / 11 / 12 / 32 / 39 / 53 / 65
0.99 / 1.01 / 11 / 12 / 15 / 16 / 42 / 52 / 71 / 85
Kentau statistic / 0.067 / 0.156 / 0.067 / -0.067 / 0.044 / 0.067 / 0.156 / 0.200
P-value / 0.858 / 0.592 / 0.858 / 0.858 / 0.928 / 0.858 / 0.592 / 0.474
July-August-September / October-November-December
0.01 / 100 / 0.21 / 0.24 / 0.33 / 0.44 / 0.19 / 0.27 / 0.28 / 0.30
0.02 / 50 / 0.24 / 0.28 / 0.37 / 0.49 / 0.22 / 0.31 / 0.31 / 0.36
0.05 / 20 / 0.30 / 0.35 / 0.45 / 0.59 / 0.28 / 0.38 / 0.41 / 0.48
0.10 / 10 / 0.36 / 0.44 / 0.55 / 0.69 / 0.36 / 0.46 / 0.54 / 0.64
0.20 / 5 / 0.47 / 0.58 / 0.71 / 0.87 / 0.49 / 0.61 / 0.77 / 0.91
0.50 / 2 / 0.83 / 1.0 / 1.2 / 1.4 / 0.89 / 1.1 / 1.5 / 1.9
0.80 / 1.25 / 1.5 / 1.9 / 2.1 / 2.6 / 1.7 / 2.4 / 3.2 / 4.2
0.90 / 1.11 / 2.2 / 2.8 / 2.9 / 3.6 / 2.4 / 3.8 / 4.9 / 6.6
0.96 / 1.04 / 3.2 / 4.1 / 4.2 / 5.4 / 3.6 / 6.4 / 7.7 / 11
0.98 / 1.02 / 4.2 / 5.2 / 5.3 / 7.1 / 4.7 / 9.1 / 10 / 15
0.99 / 1.01 / 5.4 / 6.6 / 6.7 / 9.2 / 6.0 / 13 / 14 / 21
Kentau statistic / -0.127 / -0.091 / -0.127 / -0.091 / 0.133 / -0.022 / -0.111 / -0.067
P-value / 0.640 / 0.756 / 0.640 / 0.756 / 0.653 / 1.000 / 0.721 / 0.858

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