05443500 DATA: Discharge Tables, 2004

ROCK RIVER BASIN

05443500 ROCK RIVER AT COMO, IL


LOCATION.-- Lat 41°46'58", long 89°44'59" (NAD of 1927), in NE1/4NE1/4 sec.25, T.21 N., R.6 E., Whiteside County, Hydrologic Unit 07090005, on left bank, 1 mi upstream from Como, 3 mi downstream from Rock Falls, 3.5 mi upstream from Elkhorn Creek, and at mile 69.2.

DRAINAGE AREA.-- 8,753 mi².

PERIOD OF RECORD.--
SURFACE-WATER DISCHARGE AND STAGE
	DISCHARGE: March to December 1905, October 1914 to September 1971, October 1977 to September 1986. Water years 1987-90, seven-month period (March to September). October 1990 to current year. Published as "at Sterling" 1905-6 and as "at Lyndon" 1914-34. Records published for both sites December 1933 to September 1934. Monthly discharge only for some periods, published in WSP 1308.
	STAGE: Water years 1994 to current year.
	PARTIAL RECORD: Annual maximum, water years 1972-77.
SURFACE-WATER QUALITY
	CHEMICAL: Water years 1978-91.

REVISED RECORDS.-- WSP 1308: 1915(M), 1917-18(M), 1922(M), 1924(M), 1926(M), 1928(M), 1931-32(M), 1934(M). WDR IL-79-1: Drainage area. WDR IL-97-l: 1996 (Dec. 12-23).

GAGE.-- Water-stage recorder, U.S. Army Corps of Engineers satellite telemeter and rain gage, and crest-stage gage. Datum of gage is 606.83 ft above NGVD of 1929. Jan. 6, 1905, to Feb. 17, 1906, nonrecording gage at Sterling, 3 mi upstream, at different datum. Nov. 24, 1914, to Sept. 30, 1934, nonrecording gage at Lyndon, 16.5 mi downstream at datum 22.46 ft lower.

REMARKS.-- Some diurnal fluctuation caused by powerplants upstream from station.

EXTREMES FOR PERIOD OF RECORD.--
SURFACE-WATER DISCHARGE AND STAGE: Maximum discharge, 59,700 ft³/s, Apr. 21, 1973, gage height, 15.66 ft, from rating curve extended above 41,200 ft³/s; maximum gage height, 17.51 ft, Feb. 7, 1938, ice jam; minimum discharge, 390 ft³/s, July 27, 2003, as a result of regulation.

REMARKS FOR CURRENT YEAR.-- Records fair except those for estimated daily discharges, which are poor.

Discharge, cubic feet per second, WATER YEAR OCTOBER 2003 TO SEPTEMBER 2004 DAILY MEAN VALUES
DAY	OCT	NOV	DEC	JAN	FEB	MAR	APR	MAY	JUN	JUL	AUG	SEP

1	1770	2820	4290	4590	e2200	5960	12000	5690	25800	13900	5760	4120
2	1640	2770	4290	4410	e2200	6630	11400	5790	26700	13400	5610	4080
3	1500	3460	3940	4320	e2200	6900	10800	5620	26000	12800	5590	3550
4	1790	3820	3750	4350	e2300	6660	10000	5120	25000	12700	6120	3660
5	1810	4890	3960	3950	e2600	7500	9220	5360	23900	13100	6520	3550

6	1690	5050	4040	3190	e2900	9930	8720	4930	22300	13700	5970	3350
7	1620	5320	3730	2080	e3000	11100	8380	5000	21200	13400	5600	3350
8	1690	5010	3860	1770	e3100	11000	8000	4560	20400	12700	5750	2910
9	1650	5510	3940	2810	e3000	10800	7810	4620	19100	12800	5520	3240
10	1640	5440	5230	3580	e2900	10500	7350	4460	18700	12900	5210	2910

11	1900	5180	7040	3270	e2800	9900	7280	4490	18600	12400	5040	2660
12	1750	4160	7410	3600	e2700	9570	6800	4810	19000	11700	5030	2610
13	1790	4320	6840	3580	e2600	8420	6750	5980	23200	10700	5030	2520
14	1850	3800	6340	3260	e2500	8120	6450	6320	25200	10500	4560	2510
15	1890	3970	6600	3410	e2500	7930	6220	7590	23100	9890	4590	2640

16	2150	4120	5460	3040	e2500	7670	6060	8810	21100	9420	3710	2860
17	2190	3710	6580	3360	e2500	7460	6000	8670	19700	9200	4000	2710
18	2110	3890	5620	3490	e2500	7330	5720	9750	19000	8940	3870	2300
19	2290	3900	5540	2930	e2500	7290	5740	10300	18700	8730	3800	3020
20	2430	4190	4880	2680	e2600	7010	5710	10200	18200	8580	3380	2670

21	2290	4690	4190	e2600	e2700	7190	5890	9730	18000	8220	3750	2620
22	2310	4130	5110	e2500	3040	7010	6520	11600	18600	8440	3390	2560
23	2280	4160	5460	e2400	3560	6810	6710	17500	18400	8360	3280	1990
24	2090	3980	5070	e2400	4840	7220	6930	20700	18000	8150	3240	1860
25	2210	4070	4190	e2400	5460	7710	6770	21700	17400	7830	3080	2200

26	2260	3470	3880	e2500	5790	8590	6810	21600	16900	7350	2880	2040
27	2330	3710	4100	e2500	6020	10100	6750	20600	16200	7240	3330	2020
28	2260	4230	4190	e2400	5950	11100	6290	20100	15800	6580	4210	2620
29	2210	4600	4300	e2300	5830	11600	6040	19700	15200	6500	4480	2260
30	2630	4210	4380	e2200	---	12300	5760	19800	14800	5970	4050	1880

31	2680	---	4400	e2200	---	12400	---	22000	---	5910	3940	---

TOTAL	62700	126580	152610	94070	95290	269710	220880	333100	604200	312010	140290	83270
MEAN	2023	4219	4923	3035	3286	8700	7363	10750	20140	10060	4525	2776
MAX	2680	5510	7410	4590	6020	12400	12000	22000	26700	13900	6520	4120
MIN	1500	2770	3730	1770	2200	5960	5710	4460	14800	5910	2880	1860
CFSM	0.23	0.48	0.56	0.35	0.38	0.99	0.84	1.23	2.30	1.15	0.52	0.32
IN.	0.27	0.54	0.65	0.40	0.40	1.15	0.94	1.42	2.57	1.33	0.60	0.35

e Estimated

STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1935 - 2004, BY WATER YEAR (WY)
MEAN	3841	4604	4282	4408	5919	9520	9123	6986	6589	5156	3849	3817
MAX	9633	15900	14120	13200	18020	19970	25070	16660	24500	22030	10820	15630
(WY)	1955	1986	1983	1946	1938	1948	1993	1960	2000	1993	1993	1938
MIN	1210	1408	1411	1047	1353	2432	3305	1652	1848	885	1147	999
(WY)	1964	1950	1964	1940	1940	1968	1958	1958	1936	1936	1936	1958

SUMMARY STATISTICS	FOR 2003 CALENDAR YEAR		FOR 2004 WATER YEAR		WATER YEARS 1935 - 2004
ANNUAL TOTAL	1306930		2494710
ANNUAL MEAN	3581		6816		5709
HIGHEST ANNUAL MEAN					12990	1993
LOWEST ANNUAL MEAN					2187	1964
HIGHEST DAILY MEAN	10700	May 16	26700	Jun 2	45200	A
LOWEST DAILY MEAN	1070	Sep 10	1500	Oct 3	524	Aug 9 1936
ANNUAL SEVEN-DAY MINIMUM	1180	Sep 6	1680	Oct 2	673	Aug 3 1936
MAXIMUM PEAK FLOW			26800	Jun 1	59700 B	Apr 21 1973
MAXIMUM PEAK STAGE			9.82	Jun 1	17.51 C	Feb 7 1938
INSTANTANEOUS LOW FLOW			647 D	Jan 8	390 E	Jul 27 2003
ANNUAL RUNOFF (CFSM)	0.409		0.779		0.652
ANNUAL RUNOFF (INCHES)	5.55		10.60		8.86
10 PERCENT EXCEEDS	6070		15900		11100
50 PERCENT EXCEEDS	3180		5000		4320
90 PERCENT EXCEEDS	1710		2260		1700

	A - June 15, 2000 and June 5, 2002.
	B - Gage height, 15.66 ft, from rating curve extended above 41,200 ft³/s.
	C - Ice jam.
	D - Result of freeze up.
	E - Result of regulation.

Table of Contents

Introduction

Station Descriptions

Surface-Water Data

Ground-Water Data

Meteorological Data

Biological Data