PLATTE RIVER BASIN

06730200 BOULDER CREEK AT NORTH 75TH STREET NEAR BOULDER, CO

LOCATION.--Lat 40°03'06", long 105°10'42", in SE14NW14 sec.13, T.1 N., R.70 W., Boulder County, Hydrologic Unit 10190005, on left bank, 50 ft downstream (revised) from bridge on North 75th Street, 0.2 mi downstream from Boulder feeder ditch, and 6 mi northeast of Boulder.

DRAINAGE AREA.--304 mi2.

PERIOD OF RECORD.--October 1986 to current year. For a complete listing of historical data available for this site, see http://waterdata.usgs.gov/co/nwis/inventory/?site_no=06730200

GAGE.--Water-stage recorder with satellite telemetry, and concrete control. Elevation of gage is 5,106 ft above NGVD of 1929, from topographic map.
Prior to Apr. 14, 2003 gage located at site 100 ft upstream at same datum.

REMARKS.--Records poor. Flow is partially regulated by Barker Reservoir, and affected by Boulder feeder ditch, Boulder sewage treatment plant, and Public Service power plant. Starting about Feb. 2003, Boulder Sewage Treatment Plant moved its wastewater discharge (point) to site about 300 ft downstream from current gage location and City of Lafayette began diversions for municipal supply upstream from gage. 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	67	55	e25	e26	e28	e10	e21	31	1,300	131	59	60
2	116	43	e25	e26	e20	e14	e69	20	945	120	40	57
3	81	45	e25	e27	e18	e16	e77	25	681	106	39	67
4	70	39	e28	e28	e16	e10	e74	20	468	84	47	51
5	62	34	e28	e29	e13	e5.9	e68	24	354	71	71	35
6	54	34	e27	e27	e14	e3.1	e62	17	215	57	72	28
7	55	32	e26	e27	e17	e2.6	e50	24	204	52	70	37
8	53	32	e25	e26	e16	e5.9	e43	36	126	35	70	45
9	53	28	e25	e28	e15	e11	e32	38	93	27	80	48
10	57	27	e27	e34	e17	e12	e35	213	130	26	84	49
11	56	27	e26	e36	e20	e13	e38	140	182	25	80	38
12	50	25	e24	e36	e24	e15	e48	107	219	26	92	39
13	50	26	e23	e36	e25	e13	e69	84	211	e29	95	24
14	50	23	e23	e34	e27	e14	e106	86	216	e32	97	21
15	50	20	e23	e31	e24	e16	127	123	249	e36	96	25
16	49	21	e23	e30	e21	e14	102	278	260	e40	97	18
17	47	20	e24	e30	e19	e14	101	169	221	46	95	15
18	46	21	e25	e30	e17	e27	106	147	359	50	135	14
19	57	20	e27	e30	e16	e45	146	148	387	66	120	8.8
20	58	19	e28	e30	e16	e61	102	200	332	62	107	9.8
21	59	19	e29	e30	e15	e75	81	185	259	65	95	7.3
22	59	19	e25	e30	e13	e78	83	165	219	55	96	6.9
23	63	17	e28	e32	e12	e58	94	176	243	43	101	8.6
24	59	18	e34	e33	e13	e92	119	252	232	32	93	12
25	53	20	e40	e27	e12	e61	85	259	246	49	79	12
26	48	20	e43	e25	e8.6	e65	79	266	176	72	86	16
27	49	e29	e39	e24	e6.5	e33	82	353	132	66	92	18
28	49	e27	e33	e25	e8.0	e13	79	735	108	64	81	14
29	67	e26	e27	e25	---	e4.8	78	1,060	108	73	65	9.4
30	80	e25	e26	e27	---	e6.0	54	1,700	125	72	161	12
31	67	---	e26	e30	---	e8.3	---	1,600	---	70	92	---
TOTAL	1,834	811	857	909	471.1	816.6	2,310	8,681	9,000	1,782	2,687	805.8
MEAN	59.2	27.0	27.6	29.3	16.8	26.3	77.0	280	300	57.5	86.7	26.9
MAX	116	55	43	36	28	92	146	1,700	1,300	131	161	67
MIN	46	17	23	24	6.5	2.6	21	17	93	25	39	6.9
AC-FT	3,640	1,610	1,700	1,800	934	1,620	4,580	17,220	17,850	3,530	5,330	1,600
STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1987 - 2003, BY WATER YEAR (WY)
MEAN	49.5	53.2	49.7	46.1	43.7	48.8	85.0	190	287	201	139	73.2
MAX	77.8	81.7	74.9	68.3	61.3	90.6	236	465	868	492	235	111
(WY)	(1997)	(1998)	(1989)	(1987)	(1996)	(1998)	(1998)	(1995)	(1995)	(1995)	(1999)	(1995)
MIN	31.5	27.0	27.6	28.8	16.8	26.3	37.4	97.3	86.0	57.5	86.7	26.9
(WY)	(1987)	(2003)	(2003)	(2002)	(2003)	(2003)	(1989)	(2002)	(2002)	(2003)	(2003)	(2003)

SUMMARY STATISTICS	FOR 2002 CALENDAR YEAR	FOR 2003 WATER YEAR	WATER YEARS 1987 - 2003
ANNUAL TOTAL	21,900	30,964.5
ANNUAL MEAN	60.0	c84.8	106
HIGHEST ANNUAL MEAN			198 1995
LOWEST ANNUAL MEAN			61.0 2002
HIGHEST DAILY MEAN	208 May 24	1,700 May 30	1,700 May 30, 2003
LOWEST DAILY MEAN	17 Nov 23	e2.6 Mar 7	e2.6 Mar 7, 2003
ANNUAL SEVEN-DAY MINIMUM	19 Nov 19	e7.2 Mar 4	e7.2 Mar 4, 2003
MAXIMUM PEAK FLOW		a2,050 May 30	a2,050 May 30, 2003
MAXIMUM PEAK STAGE		4.97 May 30	b4.97 May 30, 2003
ANNUAL RUNOFF (AC-FT)	43,440	c61,420	76,660
10 PERCENT EXCEEDS	124	172	215
50 PERCENT EXCEEDS	51	39	62
90 PERCENT EXCEEDS	26	14	33

e Estimated. a From rating curve extended above 500 ft3/s. b Maximum gage height, 7.85 ft, May 17, 1995, site and datum then in use. c Significantly affected by changes in water operations by Cities of Boulder and Lafayette that began about Feb. 2003.