USGS Water-Year Summary for Site USGS 14211820

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	Available Parameters
	00060 Discharge(Mean)
	72137 Discharge,tide fltrd(Mean)

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Water year 2020: 2019-10-01 to 2020-09-30

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USGS Water-Year Summary 2020

14211820 COLUMBIA SLOUGH AT PORTLAND, OR

LOCATION - Lat 45°38'21", long 122°45'43" referenced to North American Datum of 1927, in NE 1/4 SE 1/4 sec.23, T.2 N., R.1 W., Multnomah County, OR, Hydrologic Unit 17090012, on right bank, 0.6 mi upstream from mouth and 1.25 mi upstream from confluence of Willamette and Columbia Rivers.

DRAINAGE AREA - Indeterminate.

REVISIONS HISTORY - Discharges approved and reported via NWISWeb for period Oct. 1 to Nov. 1, 2014 have been revised.

SURFACE-WATER RECORDS

PERIOD OF RECORD - October 1989 to current year.

GAGE - Water-stage recorder and acoustic velocity meter. Datum of gage is 1.53 ft above NGVD of 1929.

REMARKS - Flow significantly affected by astronomical tides. Daily mean discharges since water year 2007 are computed from filtered unit value discharge data. The Godin low-pass filter is used to remove tidal variations from unit values.

EXTREMES FOR PERIOD OF RECORD - Maximum daily discharge, 2,400 ft³/s Dec. 5, 1995, but may have been higher during periods of missing record Dec. 2-4, 1995, Feb. 10-14, 1996; maximum gage height, 27.26 ft Feb. 9, 1996, from floodmark; minimum daily discharge, -6,700 ft³/s Feb. 7, 1996, but may have been lower during periods of missing record Nov. 29 to Dec. 3, 1995, Feb. 8, 9, 1996.

DISCHARGE, CUBIC FEET PER SECOND
YEAR 2019-10-01 to 2020-09-30
DAILY MEAN VALUES
[e, Value has been estimated.]

Day	Oct
	2019
1	52.7
2	65.7
3	45.4
4	133
5	113
6	70.6
7	74.3
8	107
9	65.0
10	71.0
11	44.4
12	60.8
13	19.8
14	53.4
15	5.18
16	7.83
17	53.4
18	89.0
19	165
20	16.1
21	180
22	139
23	91.4
24	123
25	60.7
26	29.0
27	35.8
28	5.18
29	17.4
30	40.8
31	80.0
Total	2,115
Mean	68.2
Max	180
Min	5.18
Ac-ft	4,195

Day	Nov
2019
1	75.8
2	-1.21
3	133
4	53.0
5	79.5
6	60.4
7	78.2
8	50.0
9	12.0
10	94.1
11	37.3
12	37.0
13	65.1
14	57.6
15	34.9
16	85.6
17	76.1
18	19.2
19	185
20	160
21	139
22	94.6
23	51.5
24	38.8
25	21.2
26	1.22
27	45.4
28	51.5
29	33.6
30	120
--
Total	1,989
Mean	66.3
Max	185
Min	-1.21
Ac-ft	3,946

Day	Dec
2019
1	68.8
2	e64.7
3	147
4	68.5
5	146
6	55.1
7	145
8	132
9	49.7
10	93.7
11	75.2
12	77.9
13	82.2
14	47.5
15	149
16	76.9
17	97.0
18	65.7
19	85.1
20	173
21	239
22	165
23	164
24	121
25	93.1
26	119
27	125
28	143
29	80.9
30	120
31	93.4
Total	3,363
Mean	108
Max	239
Min	47.5
Ac-ft	6,671

Day	Jan
2020
1	165
2	112
3	70.2
4	220
5	158
6	115
7	106
8	84.2
9	127
10	-30.7
11	11.9
12	32.8
13	114
14	140
15	202
16	169
17	271
18	244
19	328
20	156
21	99.4
22	110
23	56.3
24	-72.1
25	56.3
26	182
27	334
28	167
29	5.01
30	202
31	225
Total	4,160
Mean	134
Max	334
Min	-72.1
Ac-ft	8,252

Day	Feb
2020
1	294
2	281
3	288
4	271
5	85.0
6	50.5
7	-25.5
8	-32.9
9	171
10	356
11	315
12	194
13	192
14	209
15	190
16	324
17	226
18	147
19	215
20	179
21	78.0
22	160
23	143
24	139
25	128
26	114
27	119
28	104
29	66.1
--
--
Total	4,980
Mean	172
Max	356
Min	-32.9
Ac-ft	9,878

Day	Mar
2020
1	217
2	215
3	99.2
4	116
5	56.9
6	88.2
7	104
8	69.3
9	71.3
10	151
11	134
12	144
13	88.5
14	204
15	166
16	137
17	137
18	150
19	76.2
20	109
21	46.7
22	88.5
23	16.8
24	116
25	101
26	93.6
27	110
28	74.0
29	99.6
30	113
31	137
Total	3,530
Mean	114
Max	217
Min	16.8
Ac-ft	7,000

Day	Apr
2020
1	190
2	135
3	205
4	123
5	34.5
6	105
7	51.1
8	128
9	37.7
10	126
11	112
12	168
13	118
14	171
15	99.4
16	166
17	30.1
18	92.4
19	56.1
20	44.9
21	17.5
22	6.43
23	89.3
24	29.0
25	57.3
26	81.0
27	59.1
28	28.1
29	79.0
30	177
--
Total	2,817
Mean	93.9
Max	205
Min	6.43
Ac-ft	5,587

Day	May
2020
1	131
2	28.8
3	114
4	64.5
5	82.3
6	91.2
7	56.3
8	-44.6
9	121
10	65.4
11	117
12	-60.9
13	160
14	-39.2
15	78.2
16	223
17	183
18	92.2
19	-8.04
20	-158
21	-130
22	22.6
23	84.3
24	127
25	155
26	265
27	216
28	138
29	-95.6
30	-99.4
31	-77.3
Total	1,903
Mean	61.4
Max	265
Min	-158
Ac-ft	3,774

Day	Jun
2020
1	-167
2	-345
3	-49.8
4	433
5	164
6	100
7	177
8	191
9	422
10	480
11	411
12	276
13	437
14	348
15	217
16	228
17	228
18	68.9
19	-61.3
20	-70.8
21	201
22	149
23	-33.2
24	72.5
25	133
26	33.5
27	160
28	68.4
29	103
30	111
--
Total	4,485
Mean	150
Max	480
Min	-345
Ac-ft	8,896

Day	Jul
2020
1	110
2	66.9
3	-148
4	138
5	353
6	388
7	160
8	266
9	147
10	146
11	184
12	259
13	171
14	99.5
15	102
16	148
17	34.2
18	77.8
19	194
20	-37.4
21	-72.6
22	112
23	40.5
24	101
25	55.3
26	89.4
27	29.4
28	94.6
29	145
30	51.1
31	105
Total	3,610
Mean	116
Max	388
Min	-148
Ac-ft	7,160

Day	Aug
2020
1	241
2	65.8
3	109
4	17.2
5	17.0
6	124
7	48.5
8	133
9	110
10	-1.94
11	72.1
12	159
13	141
14	87.4
15	86.1
16	45.6
17	20.6
18	56.5
19	41.2
20	7.37
21	-26.3
22	28.1
23	84.6
24	80.8
25	135
26	137
27	176
28	136
29	113
30	102
31	e12.4
Total	2,559
Mean	82.5
Max	241
Min	-26.3
Ac-ft	5,076

Day	Sep
2020
1	e-64.6
2	2.35
3	49.4
4	30.4
5	91.2
6	47.8
7	66.1
8	49.4
9	31.4
10	2.98
11	108
12	70.8
13	72.6
14	80.3
15	44.0
16	51.7
17	-21.3
18	2.14
19	77.7
20	66.1
21	72.2
22	52.2
23	39.8
24	181
25	202
26	237
27	181
28	27.8
29	-24.8
30	-15.3
--
Total	1,811
Mean	60.4
Max	237
Min	-64.6
Ac-ft	3,593

STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1990 - 2020, BY WATER YEAR (WY)
	Oct	Nov	Dec	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep
Mean	91.4	104	131	160	155	127	103	49.2	88.4	97.5	81.7	71.5
Max	142	170	302	326	280	330	348	174	266	187	142	123
(WY)	(1991)	(1997)	(2017)	(1997)	(2017)	(1999)	(2017)	(2012)	(2017)	(2012)	(2011)	(1996)
Min	39.4	49.9	11.4	91.4	44.1	26.3	6.20	-93.7	-13.2	9.89	6.45	16.0
(WY)	(2005)	(2003)	(2006)	(2009)	(2005)	(2017)	(1997)	(2008)	(1990)	(2003)	(2003)	(2005)

SUMMARY STATISTICS
	Water Year 2020		Water Years 1990 - 2020
Annual total	37,320
Annual mean	102.0		106.2
Highest annual mean			181.3	2017
Lowest annual mean			59.4	2006
Highest daily mean	480.0	Jun 10	2,400	Dec 05, 1995
Lowest daily mean	-345	Jun 02	-6,700	Feb 07, 1996
Annual 7-day minimum	-99.4	May 28	-940	Feb 07, 1996
Maximum peak flow	1,440^a	Aug 19	2,760^a	Apr 07, 2017
Maximum peak stage	12.05^b,c	Jun 03	27.26^c	Feb 09, 1996
Annual runoff (cfsm)
Annual runoff (inches)
10 percent exceeds	215.0		239.0
50 percent exceeds	92.3		98.0
90 percent exceeds	6.06		-13.6

^a All or part of the record affected by Urbanization, Mining, Agricultural changes, Channelization, or other
^b Gage height affected by backwater
^c Max gage height not associated with peak discharge

USGS Water-data graph for site USGS 14211820