SAN JUAN RIVER BASIN

09354500 LOS PINOS RIVER AT LA BOCA, CO

LOCATION.--Lat 37°00'34", long 107°35'56", in NE14NW14 sec.22, T.32 N., R.7 W., La Plata County, Hydrologic Unit 14080101, on downstream end of right abutment of the Denver & Rio Grande Western Railroad Co. bridge, at southeast edge of La Boca, 0.5 mi upstream from Spring Creek, and 2 mi upstream from maximum elevation of Navajo Reservoir.

DRAINAGE AREA.--520 mi2.

PERIOD OF RECORD.--October 1950 to current year. Monthly discharge only for some periods, published in WSP 1733. For a complete listing of historical data available for this site, see http://waterdata.usgs.gov/co/nwis/inventory/?site_no=09354500

REVISED RECORDS.--WDR CO-00-2: Drainage area.

GAGE.--Water-stage recorder with satellite telemetry. Datum of gage is 6,127.21 ft above NGVD of 1929.

REMARKS.--Records good except for estimated daily discharges, which are poor. Flow regulated by Vallecito Reservoir (station 09353000, capacity 125,640 acre-ft.) 24 mi upstream since April 1941. Diversions for irrigation of about 55,000 acres upstream from station. Several measurements of specific conductance and water temperature were obtained and are published in the "Supplemental Water-Quality Data For Gaging Stations" section of this report.

EXTREMES OUTSIDE PERIOD OF RECORD.--A flood on Oct. 5, 1911 has not yet been exceeded.

Discharge, cubic feet per second 

WATER YEAR OCTOBER 2002 TO SEPTEMBER 2003

DAILY MEAN VALUES

DAY	OCT	NOV	DEC	JAN	FEB	MAR	APR	MAY	JUN	JUL	AUG	SEP
1	26	30	22	e15	e17	26	43	41	65	72	101	68
2	30	28	22	e15	e17	25	49	36	71	74	102	55
3	37	27	23	e15	17	24	52	43	60	74	164	52
4	37	28	23	e15	16	25	47	39	58	79	104	56
5	30	29	21	e15	e17	26	42	28	55	78	68	53
6	28	27	20	e15	16	24	41	29	61	73	55	51
7	27	26	19	e15	17	25	40	25	65	76	55	59
8	23	23	20	e15	17	28	38	20	68	71	59	50
9	21	85	20	e15	17	36	34	19	68	65	70	564
10	18	67	20	e15	18	49	34	41	65	65	63	727
11	17	36	e19	e15	20	88	39	36	66	65	58	151
12	17	27	e19	e16	19	122	48	33	71	70	58	74
13	16	23	e19	e16	27	106	55	27	70	67	59	52
14	16	21	e19	e16	57	80	60	27	74	69	55	41
15	15	19	e18	e16	41	66	67	61	72	67	51	37
16	20	17	e17	e16	28	68	70	46	72	64	69	31
17	49	17	e17	e17	24	164	64	37	83	67	82	28
18	32	17	e16	17	24	146	65	38	94	64	106	25
19	44	16	e16	e17	26	94	59	37	112	63	71	27
20	48	16	e16	e17	22	71	50	34	124	63	55	27
21	47	19	e16	e17	20	68	44	39	103	72	50	26
22	38	22	e16	e17	19	70	42	39	94	69	55	25
23	41	23	e16	e17	17	62	47	47	92	68	55	25
24	44	24	e16	e17	18	68	48	70	84	72	50	25
25	40	25	e16	e17	22	71	43	70	83	71	51	24
26	39	25	e16	17	29	71	47	99	86	76	47	23
27	58	25	e16	e17	30	68	52	85	85	112	48	24
28	46	22	e16	e17	29	60	55	60	80	125	65	23
29	40	20	e16	e17	---	53	51	56	77	119	57	23
30	37	20	e16	e17	---	47	48	61	73	120	61	22
31	34	---	e16	e17	---	45	---	59	---	104	82	---
TOTAL	1,015	804	562	500	641	1,976	1,474	1,382	2,331	2,394	2,126	2,468
MEAN	32.7	26.8	18.1	16.1	22.9	63.7	49.1	44.6	77.7	77.2	68.6	82.3
MAX	58	85	23	17	57	164	70	99	124	125	164	727
MIN	15	16	16	15	16	24	34	19	55	63	47	22
AC-FT	2,010	1,590	1,110	992	1,270	3,920	2,920	2,740	4,620	4,750	4,220	4,900
STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1951 - 2003, BY WATER YEAR (WY)
MEAN	192	132	100	73.5	94.8	215	337	418	493	293	234	211
MAX	672	709	396	182	362	972	1,339	1,719	1,555	1,381	1,349	725
(WY)	(1987)	(1987)	(1983)	(1985)	(1993)	(1993)	(1979)	(1958)	(1979)	(1957)	(1999)	(1997)
MIN	32.7	26.8	18.1	16.1	22.9	31.7	22.6	40.6	60.8	23.8	13.0	33.4
(WY)	(2003)	(2003)	(2003)	(2003)	(2003)	(2002)	(2002)	(2002)	(2002)	(2002)	(2002)	(2002)

SUMMARY STATISTICS	FOR 2002 CALENDAR YEAR	FOR 2003 WATER YEAR	WATER YEARS 1951 - 2003
ANNUAL TOTAL	11,778.1	17,673
ANNUAL MEAN	32.3	48.4	236
HIGHEST ANNUAL MEAN			582 1973
LOWEST ANNUAL MEAN			44.6 2002
HIGHEST DAILY MEAN	114 Sep 11	727 Sep 10	4,560 Jul 27, 1957
LOWEST DAILY MEAN	6.6 Aug 28	15 Oct 15	6.1 May 1, 1977
ANNUAL SEVEN-DAY MINIMUM	8.7 Aug 23	15 Jan 1	8.3 Apr 30, 1977
MAXIMUM PEAK FLOW		1,490 Sep 10	a6,400 Jul 27, 1957
MAXIMUM PEAK STAGE		6.28 Sep 10	b8.95 Jul 27, 1957
ANNUAL RUNOFF (AC-FT)	23,360	35,050	171,000
10 PERCENT EXCEEDS	58	80	542
50 PERCENT EXCEEDS	28	39	131
90 PERCENT EXCEEDS	14	16	48

e Estimated. a From rating curve extended above 5100 ft3/s. b Maximum gage height, 9.00 ft, backwater from ice, sometime during period, Dec 23, 1990 to Jan 17, 1991.