05443500 DATA: Discharge Tables, 2001

ROCK RIVER BASIN

05443500 ROCK RIVER AT COMO, IL

LOCATION.-- Lat 41°46'58", long 89°44'59", 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 1994-2001.

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 sea level. 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 CUBIC FEET PER SECOND, WATER YEAR OCTOBER 2000 TO SEPTEMBER 2001 DAILY MEAN VALUES
DAY	OCT	NOV	DEC	JAN	FEB	MAR	APR	MAY	JUN	JUL	AUG	SEP

1	6700	4430	4880	e3250	e4800	16600	10900	8850	8930	7900	3280	4150
2	5800	4370	4950	e3300	e4800	14400	10600	8520	9380	7820	3720	3850
3	5860	4140	4850	e3350	e4800	13900	10200	9000	10000	8040	4890	3660
4	6140	4020	4610	e3400	e4900	14200	9910	8820	10300	7480	5400	3650
5	6160	3930	4820	e3450	e5000	14700	9720	9680	9990	7300	5400	3620

6	5830	4270	5230	e3500	e4900	12600	10100	10400	11500	6940	5410	3820
7	5980	3940	3640	e3600	e5600	11900	10000	10700	12500	6620	5560	4130
8	5400	4910	3750	e3700	e7000	11000	10500	10400	12300	6350	5260	4140
9	5140	5040	4720	e3800	e10000	10500	10200	10400	11700	6710	4910	5760
10	5080	5820	4220	e3800	e16000	9780	10200	9720	10700	6080	4730	6910

11	5080	6510	3990	e3800	e19000	9680	10900	10500	10600	5970	4160	6900
12	4870	6750	2780	e3750	e21000	10100	11800	10600	9200	5460	3840	6380
13	4500	6590	2140	e3700	e20000	10600	13700	11200	10100	5340	3590	6490
14	4450	6070	2170	e3700	e20000	11800	14200	11500	10800	5280	3750	6390
15	4740	5980	e2800	e3700	e19500	12000	14300	10700	10500	4950	3580	5950

16	5290	5590	e3000	e3700	e19000	13600	14000	10300	10300	4610	3370	5660
17	4290	5800	e3150	e3750	e17500	15000	14000	9880	10700	4060	3600	5490
18	2790	5060	e3300	e3800	e15000	15000	13000	9680	10600	4880	3710	5390
19	4480	5120	e3300	e3800	e13500	14900	12600	8560	10500	4530	3690	5970
20	4260	5210	e3300	e3800	e14000	14700	12300	8440	10200	3900	3590	6990

21	4850	5310	e3250	e3900	e14000	14600	12000	9040	10100	4440	3710	7970
22	4570	4740	e3200	e3900	14000	14400	12200	9690	10000	4110	3550	9180
23	4170	4730	e3200	e3900	13000	13800	11400	9040	9820	3810	3540	9150
24	4280	4940	e3100	e3900	12600	13600	12400	9340	9540	4330	3600	9460
25	4390	5050	e3100	e3900	e22100	13100	11800	9510	9240	4350	3810	10000

26	4130	5110	e3100	e3800	25400	13000	11600	9870	8990	3950	3860	9840
27	5060	5170	e3100	e3800	21400	12200	11600	9860	8900	3940	4040	8540
28	4810	5160	e3150	e3800	18800	12000	11100	9810	8240	3930	4110	8230
29	4650	5070	e3200	e4000	---	11700	10800	9810	8120	3870	4150	8330
30	4650	4960	e3200	e4600	---	11400	10200	9020	8200	3770	4440	7720

31	4350	---	e3250	e5000	---	11200	---	8880	---	3530	4490	---

TOTAL	152750	153790	110450	117150	387600	397960	348230	301720	301950	164250	128740	193720
MEAN	4927	5126	3563	3779	13840	12840	11610	9733	10060	5298	4153	6457
MAX	6700	6750	5230	5000	25400	16600	14300	11500	12500	8040	5560	10000
MIN	2790	3930	2140	3250	4800	9680	9720	8440	8120	3530	3280	3620
CFSM	.56	.59	.41	.43	1.58	1.47	1.33	1.11	1.15	.61	.47	.74
IN.	.65	.65	.47	.50	1.65	1.69	1.48	1.28	1.28	.70	.55	.82

e Estimated

STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1935 - 2001, BY WATER YEAR (WY)
MEAN	3795	4587	4255	4453	6014	9649	9229	6875	6270	5125	3851	3867
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 2000 CALENDAR YEAR		FOR 2001 WATER YEAR		WATER YEARS 1935 - 2001
ANNUAL TOTAL	2831230		2758310
ANNUAL MEAN	7736		7557		5699
HIGHEST ANNUAL MEAN					12990	1993
LOWEST ANNUAL MEAN					2187	1964
HIGHEST DAILY MEAN	45200	Jun 15	25400	Feb 26	45200	Jun 15 2000
LOWEST DAILY MEAN	2140 A	Dec 13	2140 A	Dec 13	524	Aug 9 1936
ANNUAL SEVEN-DAY MINIMUM	2540	Feb 3	2760 A	Dec 12	673	Aug 3 1936
MAXIMUM PEAK FLOW			26700 B	Feb 26	59700 C	Apr 21 1973
MAXIMUM PEAK STAGE			11.22 D	Feb 25	17.51 D	Feb 7 1938
INSTANTANEOUS LOW FLOW			1870	Oct 18	440	Aug 20 1934
ANNUAL RUNOFF (CFSM)	.88		.86		.65
ANNUAL RUNOFF (INCHES)	12.03		11.72		8.85
10 PERCENT EXCEEDS	15600		13300		11000
50 PERCENT EXCEEDS	5320		5830		4330
90 PERCENT EXCEEDS	3100		3600		1690

	A - Result of freeze up.
	B - Gage height, 9.78 ft.
	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