RIO GRANDE BASIN

08251500 RIO GRANDE NEAR LOBATOS, CO

LOCATION.--Lat 37°04'43", long 105°45'23", in NE14NW14 sec.27, T.33 N., R.11 E., Conejos County, Hydrologic Unit 13010002, on right bank at highway bridge, 5.7 mi north of Colorado-New Mexico State line, 8 mi downstream from Culebra Creek, 11 mi east of Lobatos, and 14 mi east of Antonito.

DRAINAGE AREA.--7,700 mi2, approximately, includes 2,940 mi2 in closed basin in northern part of San Luis Valley, CO.

WATER-DISCHARGE RECORDS

PERIOD OF RECORD.--July 1899 to current year. Monthly discharge only for some periods, published in WSP 1312. Published as "at Cenicero" 1899-1901, and as "near Cenicero" 1902-4. Statistical summary computed for 1931 to current year. For a complete listing of historical data available for this site, see http://waterdata.usgs.gov/co/nwis/inventory/?site_no=08251500

REVISED RECORDS.-- WSP 210: Drainage area. WSP 1312: 1919 (monthly discharge and runoff). WDR CO-78-1: 1976.

GAGE.--Water-stage recorder with satellite telemetry. Datum of gage is 7,427.63 ft above NGVD of 1929. Prior to Nov. 8, 1910, nonrecording gages at same site and datum.

REMARKS.--Records good except for estimated daily discharges, which are poor. Natural flow of stream affected by storage reservoirs, transmountain diversions, diversions for irrigation and municipal use, ground-water withdrawals, return flows from irrigated areas, and flows from sewage-treatment plants.

COOPERATION.--Records collected and computed by Colorado Division of Water Resources and reviewed by Geological Survey.

EXTREMES OUTSIDE PERIOD OF RECORD.--Maximum stage of June 18, 1903, is greatest since at least 1828.

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	23	23	e135	e105	e220	195	85	71	224	93	14	13
2	24	24	e140	e115	e210	187	85	79	244	90	12	12
3	20	30	e135	e125	e210	181	86	93	182	79	12	29
4	15	71	e155	e135	e190	181	85	76	151	80	16	31
5	13	130	e155	e145	e175	185	71	56	135	82	15	20
6	18	142	e155	e140	e140	206	64	58	139	72	15	16
7	19	137	e150	e140	e120	177	58	60	151	64	14	14
8	19	103	e120	e140	e180	183	52	66	157	58	15	14
9	19	91	e105	e145	e175	182	44	60	223	57	15	16
10	14	62	e110	e150	e175	183	44	59	279	53	15	28
11	15	47	e100	e160	e190	183	44	58	265	47	15	22
12	15	41	e110	e160	e205	185	39	61	218	42	15	21
13	15	42	e115	e165	e215	193	36	67	196	37	15	21
14	16	42	e120	e160	e240	187	35	73	184	38	14	25
15	16	37	e130	e160	e240	205	36	83	209	47	10	19
16	16	30	e140	e160	205	218	41	122	232	40	14	16
17	17	38	e115	e155	213	227	42	112	206	36	17	15
18	18	53	e130	e160	213	230	66	146	181	33	25	13
19	18	49	e115	e160	218	205	65	160	173	30	15	12
20	18	48	e110	e160	207	165	51	164	154	28	8.4	11
21	20	47	e105	e160	201	142	47	172	160	27	6.4	10
22	21	48	e140	e165	e185	117	46	158	160	28	5.8	10
23	23	43	e125	e170	e180	107	48	134	146	27	15	9.8
24	25	48	e100	e175	e180	109	52	210	128	27	9.3	11
25	24	122	e115	e175	e185	96	65	210	113	27	7.9	12
26	23	e125	e105	e185	e204	70	71	195	102	24	7.7	10
27	26	e135	e105	e185	209	71	69	146	103	21	8.4	10
28	26	e145	e100	e195	195	60	78	121	108	20	11	11
29	26	e125	e100	e200	---	80	83	143	97	20	14	11
30	28	e135	e100	e190	---	80	81	218	94	46	14	11
31	27	---	e105	e205	---	80	---	186	---	21	14	---
TOTAL	617	2,213	3,745	4,945	5,480	4,870	1,769	3,617	5,114	1,394	404.9	473.8
MEAN	19.9	73.8	121	160	196	157	59.0	117	170	45.0	13.1	15.8
MAX	28	145	155	205	240	230	86	218	279	93	25	31
MIN	13	23	100	105	120	60	35	56	94	20	5.8	9.8
AC-FT	1,220	4,390	7,430	9,810	10,870	9,660	3,510	7,170	10,140	2,760	803	940
STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1931 - 2003, BY WATER YEAR (WY)
MEAN	184	309	282	263	314	413	505	1,082	1,199	427	167	133
MAX	1,401	1,199	763	521	595	884	2,326	4,958	4,470	2,754	1,281	938
(WY)	(1942)	(1942)	(1942)	(1986)	(1986)	(1987)	(1985)	(1987)	(1941)	(1995)	(1999)	(1999)
MIN	12.9	59.6	61.7	75.7	102	66.0	32.3	31.2	19.8	1.28	3.21	1.91
(WY)	(1957)	(1955)	(1964)	(1957)	(1957)	(1957)	(1935)	(2002)	(1977)	(1951)	(1956)	(1956)

SUMMARY STATISTICS	FOR 2002 CALENDAR YEAR	FOR 2003 WATER YEAR	WATER YEARS 1931 - 2003
ANNUAL TOTAL	35,800.9	34,642.7
ANNUAL MEAN	98.1	94.9	a440
HIGHEST ANNUAL MEAN			1,264 1987
LOWEST ANNUAL MEAN			70.9 1964
HIGHEST DAILY MEAN	391 Mar 14	279 Jun 10	b9,110 Jun 22, 1949
LOWEST DAILY MEAN	4.3 Aug 1	5.8 Aug 22	c0.00 Jul 16, 1950
ANNUAL SEVEN-DAY MINIMUM	4.9 Jul 28	8.6 Aug 20	0.00 Jul 16, 1950
MAXIMUM PEAK FLOW		302 Jun 10	d11,600 May 8, 1952
MAXIMUM PEAK STAGE		f1.56 Jun 10	g8.76 May 8, 1952
ANNUAL RUNOFF (AC-FT)	71,010	68,710	318,700
10 PERCENT EXCEEDS	275	195	951
50 PERCENT EXCEEDS	37	81	240
90 PERCENT EXCEEDS	8.4	14	38

e Estimated. a Average discharge for 31 years (water years 1900-30), 846 ft3/s; 612,900 acre-ft/yr, includes period of extensive development for irrigation. b Maximum daily discharge for period of record, 13,100 ft3/s, Jun 8, 1905. c No flow at times in 1950-51, 1956. d Maximum discharge for period of record, 13,200 ft3/s, Jun 8, 1905, gage height, 9.1 ft, from rating curve extended above 8,000 ft3/s. f Maximum gage height, 2.19 ft, Feb 1, backwater from ice. g Maximum gage height for period of record, 10.0 ft, Jun 18, 1903.