PLATTE RIVER BASIN

06730500 BOULDER CREEK AT MOUTH NEAR LONGMONT, CO

LOCATION.--Lat 40°09'08", long 105°00'52", in NW 14 SW 14 sec.9, T.2 N., R.68 W., Weld County, Hydrologic Unit 10190005, on left bank 0.6 mi upstream from mouth, 1.0 mi downstream from State Highway 254, and 4.8 mi southeast of Longmont.

DRAINAGE AREA.--439 mi2.

PERIOD OF RECORD.--March 1927 to September 1949, May 1951 to September 1955, October 1978 to September 1990, October 1991 to current year. For a complete listing of historical data available for this site, see http://waterdata.usgs.gov/co/nwis/inventory/?site_no=06730500

GAGE.--Water-stage recorder. Elevation of gage is 4,860 ft above NGVD of 1929, from topographic map. Prior to June 10, 1939, at site 0.8 mi upstream at different datum. June 10, 1939 to Sept. 30, 1949, at site 1.0 mi upstream, at different datum. May 1, 1951 to Sept. 30, 1955, at site 1.4 mi upstream, at different datum.

REMARKS.--Records fair except for estimated daily discharges, which are poor. Natural flow of stream affected by transmountain, transbasin, and storage diversions, diversions for irrigation, water-treatment plants, and return flows 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	5.3	28	22	22	33	22	74	42	972	116	17	35
2	5.7	26	22	23	26	27	112	38	818	96	12	26
3	5.4	26	22	22	28	28	118	32	619	56	8.6	21
4	4.9	23	22	22	27	27	127	26	410	35	7.9	20
5	5.3	18	22	23	27	26	110	26	326	21	8.0	13
6	4.5	24	21	24	27	25	116	22	233	14	8.1	9.7
7	4.4	24	21	23	29	25	105	17	241	14	9.1	9.3
8	4.4	25	21	23	30	23	99	11	184	17	9.8	9.0
9	4.4	23	23	23	26	22	83	13	127	12	9.7	8.9
10	4.6	21	23	27	27	23	81	223	139	11	11	10
11	4.7	21	21	e26	25	23	82	320	174	9.8	12	8.5
12	4.5	17	21	e25	25	25	123	167	199	9.8	11	7.8
13	4.5	18	20	e25	25	24	148	94	196	9.6	11	7.3
14	4.6	19	20	25	25	24	165	66	207	9.3	10	6.9
15	4.6	20	20	26	26	23	158	63	230	9.2	11	6.6
16	4.4	19	e21	26	25	23	135	278	264	9.0	11	6.4
17	4.3	20	e21	24	25	25	111	204	205	8.6	11	5.8
18	e4.9	20	e22	26	25	68	117	196	388	8.8	13	6.6
19	e4.1	21	e22	27	25	82	168	177	421	19	44	6.3
20	e4.5	21	e22	24	24	96	172	226	337	20	13	5.6
21	e4.6	22	e22	25	23	114	105	199	271	19	12	5.6
22	e5.4	21	e22	24	23	117	80	151	213	13	12	4.8
23	e5.4	20	e22	e24	23	107	92	149	245	9.3	12	4.7
24	e4.9	21	e22	e24	26	133	171	187	244	9.5	12	4.9
25	e4.9	23	e22	24	26	108	145	214	259	10	13	4.8
26	e4.6	23	e22	24	20	110	100	185	218	16	13	4.4
27	e4.6	26	e22	26	16	133	88	276	153	13	13	5.0
28	5.5	23	e22	26	17	93	73	470	114	11	12	4.9
29	6.1	22	21	26	---	65	61	864	99	14	12	4.6
30	16	22	21	33	---	58	52	1,070	100	22	120	4.5
31	30	---	22	34	---	64	---	1,170	---	15	141	---
TOTAL	186.0	657	669	776	704	1,763	3,371	7,176	8,606	656.9	620.2	277.9
MEAN	6.00	21.9	21.6	25.0	25.1	56.9	112	231	287	21.2	20.0	9.26
MAX	30	28	23	34	33	133	172	1,170	972	116	141	35
MIN	4.1	17	20	22	16	22	52	11	99	8.6	7.9	4.4
AC-FT	369	1,300	1,330	1,540	1,400	3,500	6,690	14,230	17,070	1,300	1,230	551
STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1927 - 2003, BY WATER YEAR (WY)
MEAN	34.3	43.9	49.1	50.8	50.0	52.4	94.3	172	189	44.0	23.5	23.6
MAX	127	109	93.8	104	120	148	581	1,101	976	367	164	440
(WY)	(1985)	(1998)	(1939)	(1980)	(1980)	(1983)	(1942)	(1942)	(1947)	(1983)	(1999)	(1938)
MIN	0.70	0.48	1.16	2.94	2.75	2.58	1.15	1.06	1.22	1.09	0.55	0.54
(WY)	(1955)	(1955)	(1940)	(1935)	(1935)	(1935)	(1954)	(1955)	(1954)	(1954)	(1954)	(1954)

SUMMARY STATISTICS	FOR 2002 CALENDAR YEAR	FOR 2003 WATER YEAR	WATER YEARS 1927 - 2003
ANNUAL TOTAL	6,734.8	25,463.0
ANNUAL MEAN	18.5	69.8	69.1
HIGHEST ANNUAL MEAN			220 1983
LOWEST ANNUAL MEAN			3.93 1954
HIGHEST DAILY MEAN	106 May 24	1,170 May 31	2,300 Sep 3, 1938
LOWEST DAILY MEAN	1.0 Apr 29	e4.1 Oct 19	a0.00 Dec 9, 1934
ANNUAL SEVEN-DAY MINIMUM	1.1 Apr 26	4.5 Oct 13	0.00 Apr 11, 1935
MAXIMUM PEAK FLOW		1,240 May 31	b4,410 Sep 3, 1938
MAXIMUM PEAK STAGE		4.34 May 31	6.94 Sep 3, 1938
ANNUAL RUNOFF (AC-FT)	13,360	50,510	50,060
10 PERCENT EXCEEDS	51	186	127
50 PERCENT EXCEEDS	5.2	23	35
90 PERCENT EXCEEDS	1.5	5.6	2.0

e Estimated. a No flow at times many years. b Site and datum then in use, from rating curve extended above 340 ft3/s, on basis of slope-area measurement of peak flow.