USGS Water-Year Summary for Site USGS 11160500

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	00060 Discharge(Mean)

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Water year 2022: 2021-10-01 to 2022-09-30

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USGS Water-Year Summary 2022

11160500 San Lorenzo River at Big Trees, CA

LOCATION - Lat 37°02'40", long 122°04'17" referenced to North American Datum of 1927, Santa Cruz County, CA, Hydrologic Unit 18060015, in Zayante Grant, on right bank, 12 ft upstream from bridge on Henry Cowell State Park Road, 200 ft upstream from Shingle Mill Creek, 0.25 mi south of town of Felton, 0.3 mi downstream from Zayante Creek, 0.9 mi northwest of Big Trees Station on Southern Pacific Railroad, and 5.3 mi northwest of Santa Cruz.

DRAINAGE AREA - 106 mi².

REVISIONS HISTORY - WSP 1315-B: 1938 (maximum discharge). WSP 1715: Drainage area. Discharge values on Dec. 13, 2021 were revised on July 7, 2022.

SURFACE-WATER RECORDS

PERIOD OF RECORD - October 1936 to current year. Monthly discharge only for some periods, published in WSP 1315-B. CHEMICAL DATA: Water years 1906-07, 1952-67, 1969-70, 1973-75, 1977, 1980-81. WATER TEMPERATURE: Water years 1965-82, daily. SEDIMENT DISCHARGE: Water years 1973-82, daily; 1986, 1990-93, monthly.

GAGE - Water-stage recorder and crest-stage gage. Datum of gage is 230.06 ft above NAVD of 1988. Prior to Oct. 6, 1972, at site 1.3 mi downstream at different datum.

REMARKS - Low flow partially regulated by Loch Lomond Reservoir since 1961, capacity, 8,820 acre-ft, and by an inflatable fiber dam located 500 ft upstream from gage. Many small diversions upstream from station for domestic supply.

EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 30,400 ft³/s, Dec. 23, 1955, gage height, 22.55 ft, site and datum then in use, from rating curve extended above 11,000 ft³/s, on basis of slope-area measurement of peak flow, maximum gage height, 28.85 ft, Jan. 5, 1982; minimum daily discharge, 5.6 ft³/s, July 27, 28, 1977.

DISCHARGE, CUBIC FEET PER SECOND
YEAR 2021-10-01 to 2022-09-30
DAILY MEAN VALUES

Day	Oct
	2021
1	8.14
2	8.04
3	8.14
4	8.16
5	8.21
6	8.45
7	8.55
8	8.57
9	8.72
10	9.36
11	9.62
12	9.62
13	9.74
14	10.1
15	9.68
16	9.41
17	9.49
18	10.0
19	10.3
20	14.8
21	31.7
22	35.1
23	20.2
24	481
25	748
26	110
27	51.5
28	36.4
29	29.8
30	26.5
31	24.3
Total	1,782
Mean	57.5
Max	748
Min	8.04
Ac-ft	3,534

Day	Nov
2021
1	38.0
2	48.5
3	33.2
4	29.6
5	27.0
6	24.9
7	23.3
8	22.6
9	123
10	66.3
11	44.4
12	36.3
13	32.0
14	29.2
15	27.5
16	26.2
17	25.0
18	24.2
19	23.6
20	22.9
21	22.5
22	22.2
23	21.8
24	21.3
25	21.0
26	20.6
27	20.3
28	20.0
29	19.8
30	19.6
--
Total	937
Mean	31.2
Max	123
Min	19.6
Ac-ft	1,858

Day	Dec
2021
1	19.4
2	19.2
3	19.2
4	19.1
5	18.9
6	18.9
7	20.1
8	19.6
9	20.2
10	19.8
11	19.5
12	45.2
13	2,950
14	1,140
15	414
16	1,380
17	433
18	268
19	203
20	161
21	138
22	245
23	1,290
24	1,230
25	810
26	748
27	821
28	575
29	648
30	638
31	424
Total	14,770
Mean	477
Max	2950
Min	18.9
Ac-ft	29,310

Day	Jan
2022
1	329
2	276
3	265
4	294
5	241
6	213
7	194
8	177
9	161
10	148
11	137
12	129
13	120
14	114
15	107
16	101
17	96.6
18	91.6
19	85.4
20	80.4
21	77.3
22	74.3
23	70.5
24	68.1
25	66.4
26	63.6
27	61.1
28	58.7
29	56.8
30	54.5
31	53.4
Total	4,064
Mean	131
Max	329
Min	53.4
Ac-ft	8,062

Day	Feb
2022
1	55.1
2	58.4
3	56.5
4	55.1
5	53.9
6	52.5
7	46.1
8	41.5
9	40.4
10	39.3
11	38.1
12	37.1
13	35.6
14	34.7
15	34.7
16	33.7
17	32.2
18	31.6
19	31.3
20	31.0
21	30.5
22	30.8
23	30.9
24	29.6
25	29.0
26	28.5
27	28.1
28	27.1
--
--
--
Total	1,073
Mean	38.3
Max	58.4
Min	27.1
Ac-ft	2,129

Day	Mar
2022
1	26.7
2	26.2
3	25.8
4	26.5
5	27.2
6	28.3
7	49.6
8	37.2
9	34.9
10	34.3
11	32.6
12	31.7
13	31.5
14	31.4
15	30.7
16	30.6
17	30.1
18	29.4
19	30.0
20	30.6
21	28.9
22	28.2
23	27.6
24	27.1
25	26.5
26	26.3
27	31.8
28	114
29	48.1
30	35.1
31	32.1
Total	1,051
Mean	33.9
Max	114
Min	25.8
Ac-ft	2,085

Day	Apr
2022
1	30.3
2	28.9
3	28.0
4	26.8
5	26.2
6	25.6
7	24.8
8	23.9
9	23.3
10	23.0
11	28.3
12	28.4
13	26.0
14	25.6
15	26.3
16	89.2
17	52.9
18	38.4
19	38.5
20	34.7
21	94.9
22	57.8
23	45.6
24	40.1
25	37.2
26	34.9
27	33.7
28	32.9
29	31.9
30	31.2
--
Total	1,089
Mean	36.3
Max	94.9
Min	23.0
Ac-ft	2,161

Day	May
2022
1	30.3
2	29.5
3	29.3
4	28.9
5	28.1
6	27.7
7	27.4
8	27.4
9	27.7
10	27.8
11	27.6
12	27.1
13	26.6
14	26.3
15	25.6
16	25.4
17	25.3
18	24.9
19	24.0
20	23.3
21	23.0
22	22.8
23	22.6
24	22.0
25	21.5
26	21.6
27	21.9
28	21.5
29	20.8
30	20.4
31	20.1
Total	778
Mean	25.1
Max	30.3
Min	20.1
Ac-ft	1,544

Day	Jun
2022
1	19.6
2	19.1
3	19.0
4	19.1
5	20.2
6	20.3
7	19.3
8	18.5
9	18.2
10	17.9
11	17.3
12	17.3
13	17.4
14	17.3
15	16.9
16	16.4
17	16.7
18	16.6
19	17.1
20	17.2
21	16.7
22	16.2
23	16.2
24	16.4
25	16.4
26	16.4
27	16.1
28	15.9
29	15.1
30	15.5
--
Total	522
Mean	17.4
Max	20.3
Min	15.1
Ac-ft	1,036

Day	Jul
2022
1	15.6
2	15.7
3	15.9
4	16.1
5	15.9
6	15.5
7	15.6
8	15.0
9	14.9
10	15.0
11	14.9
12	14.8
13	14.9
14	14.8
15	14.5
16	14.1
17	14.1
18	13.8
19	13.7
20	13.5
21	13.3
22	13.5
23	13.4
24	13.8
25	13.8
26	13.8
27	13.7
28	13.5
29	13.4
30	13.5
31	13.5
Total	448
Mean	14.4
Max	16.1
Min	13.3
Ac-ft	888

Day	Aug
2022
1	13.2
2	12.8
3	12.6
4	12.5
5	12.7
6	12.6
7	12.5
8	12.5
9	12.9
10	12.8
11	12.3
12	12.2
13	12.0
14	11.7
15	11.9
16	12.2
17	12.1
18	12.1
19	12.0
20	12.0
21	12.0
22	12.4
23	12.4
24	12.6
25	12.6
26	12.3
27	12.3
28	12.6
29	12.7
30	12.7
31	12.4
Total	385
Mean	12.4
Max	13.2
Min	11.7
Ac-ft	763

Day	Sep
2022
1	11.9
2	11.5
3	11.3
4	11.0
5	10.6
6	10.6
7	10.5
8	10.6
9	10.6
10	11.0
11	11.1
12	10.4
13	10.7
14	11.8
15	12.2
16	11.6
17	11.7
18	36.8
19	42.6
20	20.3
21	16.1
22	14.9
23	14.2
24	13.5
25	13.4
26	13.1
27	13.2
28	12.9
29	12.9
30	12.9
--
Total	426
Mean	14.2
Max	42.6
Min	10.4
Ac-ft	845

STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1937 - 2022, BY WATER YEAR (WY)
	Oct	Nov	Dec	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep
Mean	23.5	47.6	159	305	385	290	169	69.8	40.3	26.3	19.8	17.6
Max	176	461	1,319	1,626	1,913	1,482	1,048	322	131	65.8	44.0	52.1
(WY)	(1963)	(1951)	(1956)	(2017)	(2017)	(1983)	(2006)	(1983)	(1998)	(1983)	(1983)	(1959)
Min	6.99	11.4	14.7	13.2	16.6	21.4	12.3	11.6	9.37	6.66	6.50	6.69
(WY)	(2016)	(1991)	(1991)	(2014)	(1977)	(1977)	(1977)	(1977)	(1977)	(1977)	(1977)	(2015)

SUMMARY STATISTICS
	Water Year 2022		Water Years 1937 - 2022
Annual total	27,330
Annual mean	74.9		128.2
Highest annual mean			405.1	2017
Lowest annual mean			13.2	1977
Highest daily mean	2,950	Dec 13	17,000	Dec 23, 1955
Lowest daily mean	8.04	Oct 02	5.60	Jul 27, 1977
Annual 7-day minimum	8.24	Oct 01	5.79	Jul 26, 1977
Maximum peak flow	5,600	Dec 13	30,400	Dec 23, 1955
Maximum peak stage	16.06	Dec 13	28.85	Jan 05, 1982
Annual runoff (cfsm)	0.706		1.21
Annual runoff (inches)	9.59		16.4
10 percent exceeds	114.0		264.0
50 percent exceeds	24.2		32.0
90 percent exceeds	11.9		13.0

USGS Water-data graph for site USGS 11160500