PLATTE RIVER BASIN

06725450 ST. VRAIN CREEK BELOW LONGMONT, CO

LOCATION.--Lat 40°09'30", long 105°00'48", in NW14NW14 sec.9, T.2 N., R.68 W., Weld County, Hydrologic Unit 10190005, on right bank 1,750 ft upstream from mouth of Boulder Creek, 1.8 mi downstream from Spring Gulch, and 4.7 mi southeast of Longmont.

DRAINAGE AREA.--424 mi2.

PERIOD OF RECORD.--October 1976 to September 1982, August 1984 to current year. For a complete listing of historical data available for this site, see http://waterdata.usgs.gov/co/nwis/inventory/?site_no=06725450

GAGE.--Water-stage recorder with satellite telemetry. Elevation of gage is 4,852 ft, above NGVD of 1929, from topographic map. Prior to Aug. 15, 1984, at site 150 ft downstream at same datum. Aug. 15, 1984 to Oct. 1, 1997 at site 70 ft downstream at same datum. Oct. 2, 1997 to Apr. 18, 2000 at site 100 ft upstream at same datum.

REMARKS.--Records fair except for estimated daily discharges, which are poor. Natural flow of stream affected by storage reservoirs, diversions for irrigation, and return flow from irrigated areas. 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.

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	52	43	32	27	27	28	57	63	971	144	81	127
2	75	39	32	28	27	28	65	59	637	117	72	112
3	60	39	32	28	29	29	58	58	441	69	68	115
4	57	36	33	28	28	28	52	59	326	58	66	108
5	53	36	32	28	26	27	44	62	286	67	69	96
6	50	36	32	29	28	28	48	59	244	78	61	89
7	47	36	31	29	31	27	44	56	257	58	75	93
8	46	34	31	28	31	27	51	64	138	47	93	104
9	43	32	32	28	28	26	43	73	88	39	70	99
10	42	32	32	28	27	29	40	252	120	41	57	89
11	40	31	32	28	28	43	42	151	263	48	53	84
12	39	31	31	28	26	44	44	96	343	51	51	82
13	40	31	31	28	27	27	44	85	344	48	52	79
14	40	31	31	29	25	26	46	86	317	51	47	79
15	41	32	30	29	27	26	78	116	358	53	39	75
16	43	32	31	28	27	25	63	263	349	58	37	73
17	49	33	31	28	26	38	48	166	278	66	37	79
18	44	34	31	28	27	89	56	152	354	66	97	96
19	41	36	31	28	26	89	57	147	282	79	81	76
20	42	35	31	28	26	84	50	143	292	80	54	67
21	42	35	31	26	27	76	44	117	279	87	50	63
22	43	36	31	28	26	69	47	106	294	76	48	69
23	41	34	30	28	26	59	69	91	295	75	46	76
24	38	36	30	29	26	63	82	99	291	79	50	63
25	39	37	30	30	27	56	65	93	306	71	51	60
26	37	34	32	28	29	51	63	95	265	83	53	60
27	36	34	30	29	29	47	68	152	161	96	52	61
28	37	35	29	30	30	52	73	333	134	107	60	65
29	46	34	28	28	---	52	71	496	147	90	74	69
30	43	33	28	29	---	46	68	407	149	85	292	78
31	42	---	28	26	---	e50	---	912	---	84	170	---
TOTAL	1,388	1,037	956	874	767	1,389	1,680	5,111	9,009	2,251	2,206	2,486
MEAN	44.8	34.6	30.8	28.2	27.4	44.8	56.0	165	300	72.6	71.2	82.9
MAX	75	43	33	30	31	89	82	912	971	144	292	127
MIN	36	31	28	26	25	25	40	56	88	39	37	60
AC-FT	2,750	2,060	1,900	1,730	1,520	2,760	3,330	10,140	17,870	4,460	4,380	4,930
STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1977 - 2003, BY WATER YEAR (WY)
MEAN	69.0	57.6	49.2	44.3	43.4	48.2	84.8	235	356	169	142	99.6
MAX	159	126	91.5	92.8	94.0	111	275	1,155	1,227	485	246	152
(WY)	(1985)	(1985)	(1985)	(1980)	(1980)	(1980)	(1998)	(1980)	(1995)	(1995)	(1999)	(1982)
MIN	44.8	34.5	30.8	25.7	27.4	28.9	27.5	35.8	63.3	71.0	57.9	53.7
(WY)	(2003)	(1979)	(1979)	(1978)	(2003)	(1982)	(1982)	(1977)	(1981)	(2002)	(2002)	(1977)

SUMMARY STATISTICS	FOR 2002 CALENDAR YEAR	FOR 2003 WATER YEAR	WATER YEARS 1977 - 2003
ANNUAL TOTAL	17,542	29,154
ANNUAL MEAN	48.1	79.9	117
HIGHEST ANNUAL MEAN			257 1995
LOWEST ANNUAL MEAN			51.3 2002
HIGHEST DAILY MEAN	119 May 24	971 Jun 1	2,580 May 30, 1995
LOWEST DAILY MEAN	28 Dec 29	25 Feb 14	20 Dec 28, 1990
ANNUAL SEVEN-DAY MINIMUM	29 Dec 25	26 Feb 14	22 Dec 26, 1990
MAXIMUM PEAK FLOW		1,070 Jun 1	3,600 Apr 30, 1999
MAXIMUM PEAK STAGE		5.47 Jun 1	6.87 Apr 30, 1999
ANNUAL RUNOFF (AC-FT)	34,790	57,830	84,430
10 PERCENT EXCEEDS	70	150	200
50 PERCENT EXCEEDS	41	48	64
90 PERCENT EXCEEDS	32	28	35

e Estimated.