05443500 DATA: Discharge Tables, 2002

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 1994-2002.
	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 daily discharge, 440 ft³/s, Aug. 20, 1934.

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

DISCHARGE, in CFS, WATER YEAR OCTOBER 2001 TO SEPTEMBER 2002 DAILY MEAN VALUES
DAY	OCT	NOV	DEC	JAN	FEB	MAR	APR	MAY	JUN	JUL	AUG	SEP

1	6980	8920	6910	e5050	4560	7740	7420	9150	6640	6240	3150	5090
2	7230	8280	6770	e5050	4720	7560	7310	8780	6530	5960	3090	4980
3	6430	8260	6590	e5050	4650	7280	7660	8800	6740	5710	3310	4940
4	6080	7810	6510	e5000	4640	5920	7560	8850	23200	5310	2930	4980
5	6220	7210	6260	e5000	4390	4900	6980	8650	45200	5060	3090	4690

6	5730	7160	6620	e5000	4170	6180	7320	8480	36100	4870	3070	4740
7	6620	7030	6010	e5000	4260	7880	7280	8800	27000	4280	3080	4230
8	7070	6810	6310	e5000	4430	7800	8000	8000	23500	4880	3000	4360
9	5120	6330	6100	e5000	4490	7900	10700	7960	21200	4830	2930	4200
10	4580	6510	6030	e5000	4540	11700	14500	8180	19600	4570	2790	3920

11	3860	6310	6060	4960	6570	12700	15500	8080	18900	4380	2770	3790
12	4810	5930	5890	e5000	5980	11900	14700	10100	17700	4140	2410	3680
13	5360	5870	6010	4900	5820	12000	14200	12400	16500	4150	3440	3660
14	5740	6330	6170	4830	5600	11600	13600	11600	15600	4050	3050	3550
15	6130	6320	6490	4910	5600	11200	12700	11600	15000	3530	3260	3480

16	6710	6290	6420	4870	5700	10900	12000	11100	14200	3730	3480	3640
17	6120	6450	6100	5150	5390	9970	11400	10700	13200	3340	3390	3190
18	5720	6370	6500	5230	5450	9000	10200	10300	12500	3450	3290	3560
19	5630	6210	6310	5060	5310	9500	10500	10200	11400	3350	3120	3590
20	5620	5940	6440	4800	5770	9240	10100	9470	10600	3430	2580	3660

21	5470	6000	6300	4740	7450	8710	9890	8950	9980	3350	2150	4240
22	5260	5710	6310	5300	8430	8260	9980	8460	9280	3250	4460	4140
23	7380	5620	6300	4650	8750	8310	9350	7990	9170	3390	12800	3930
24	9680	5690	6340	4650	8730	8240	9630	7920	8500	3260	13300	3910
25	12900	6270	e6000	4910	8520	8030	9250	7570	8200	3290	10700	3720

26	14300	7480	5790	4530	8600	7920	9140	7620	7910	3270	9860	3410
27	12900	6770	4440	4620	8370	8580	8930	7530	7630	3390	9470	3570
28	12700	7310	4130	4680	8030	6920	9060	7160	7400	3390	8860	3600
29	11500	7030	5630	4680	---	7730	8960	7100	6980	3340	8420	3370
30	10600	7090	5610	4630	---	7770	8990	7410	6600	2820	8130	3700

31	9350	---	5080	4650	---	7680	---	7080	---	3130	6970	---

TOTAL	229800	201310	188430	151900	168920	271020	302810	275990	442960	125140	156350	119520
MEAN	7413	6710	6078	4900	6033	8743	10090	8903	14770	4037	5044	3984
MAX	14300	8920	6910	5300	8750	12700	15500	12400	45200	6240	13300	5090
MIN	3860	5620	4130	4530	4170	4900	6980	7080	6530	2820	2150	3190
CFSM	0.85	0.77	0.69	0.56	0.69	1.00	1.15	1.02	1.69	0.46	0.58	0.46
IN.	0.98	0.86	0.80	0.65	0.72	1.15	1.29	1.17	1.88	0.53	0.66	0.51

e Estimated

STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1935 - 2002, BY WATER YEAR (WY)
MEAN	3857	4624	4286	4460	6015	9634	9243	6908	6407	5107	3870	3869
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 2001 CALENDAR YEAR		FOR 2002 WATER YEAR		WATER YEARS 1935 - 2002
ANNUAL TOTAL	2960860		2634150
ANNUAL MEAN	8112		7217		5725
HIGHEST ANNUAL MEAN					12990	1993
LOWEST ANNUAL MEAN					2187	1964
HIGHEST DAILY MEAN	25400	Feb 26	45200	Jun 5	45200	B
LOWEST DAILY MEAN	3250 A	Jan 1	2150	Aug 21	524	Aug 9 1936
ANNUAL SEVEN-DAY MINIMUM	3410	Jan 1	2860	Aug 6	673	Aug 3 1936
MAXIMUM PEAK FLOW			48800	Jun 5	59700 C	Apr 21 1973
MAXIMUM PEAK STAGE			13.65	Jun 5	17.51 D	Feb 7 1938
INSTANTANEOUS LOW FLOW			661	Aug 22	440	Aug 20 1934
ANNUAL RUNOFF (CFSM)	0.93		0.82		0.65
ANNUAL RUNOFF (INCHES)	12.58		11.20		8.89
10 PERCENT EXCEEDS	13500		11500		11200
50 PERCENT EXCEEDS	6940		6310		4360
90 PERCENT EXCEEDS	3800		3440		1700

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

Table of Contents

Introduction

Station Descriptions

Surface-Water Data

Ground-Water Data

Meteorological Data

Biological Data