05443500 DATA: Discharge Tables, 2005

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 (606.65 ft NAVD 1988). 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 and July 12, 2005, 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 2004 TO SEPTEMBER 2005 DAILY MEAN VALUES
DAY	OCT	NOV	DEC	JAN	FEB	MAR	APR	MAY	JUN	JUL	AUG	SEP

1	2260	2950	4120	3580	4060	8830	7350	3830	3490	2660	1880	1770
2	2380	3530	4100	3630	4170	8310	7350	3620	2970	2110	1830	1690
3	2230	4190	4120	4230	4360	7670	7540	3610	2870	1560	1470	1840
4	2260	3880	3940	4420	4100	7290	7510	3290	2890	2340	1500	1670
5	2290	3880	4130	4490	4090	7070	7480	3480	3210	1660	1570	1610

6	2260	3640	3650	2980	4800	6730	7400	3230	3500	1810	1480	1600
7	2400	3640	4160	3640	7030	7050	7220	3370	3800	2270	1440	1600
8	2610	3130	4590	4060	11900	8240	7520	3250	3920	1910	1460	1580
9	2630	3430	4900	4280	13700	8740	7260	3140	3840	1790	1370	1570
10	2690	3470	5060	3730	12700	8900	7010	3200	3470	1840	1380	1620

11	2730	3540	5180	3550	11200	9160	7060	3610	2890	1920	1700	1610
12	2740	3930	5110	4250	9990	9390	7230	3680	2920	1660	1750	1560
13	2600	4070	5410	5370	10200	9210	7180	4390	2570	1680	1920	1340
14	2470	3800	5190	7770	15300	8860	6940	4440	2790	1990	1770	1740
15	2360	3340	4050	8520	19800	8340	6780	4430	2830	1710	1620	1990

16	2540	3380	4180	8040	20000	7650	6370	4070	2900	1730	1530	1440
17	2770	2980	4510	7580	18500	7160	6410	4600	2850	1660	1560	1660
18	2410	3190	3770	e8800	17300	6920	6250	4800	2620	1440	1570	1610
19	2320	3260	3610	e9000	17200	6760	6040	4770	2370	1490	2980	1570
20	2050	3220	2770	e9000	16700	6850	5920	5060	2090	1340	3310	1600

21	2500	3520	2930	e8800	15900	7420	5800	5550	2130	1860	3200	1740
22	2340	3890	e3200	e8000	14900	7400	5660	5330	2140	1850	3140	1660
23	2540	3950	e3200	e7200	14500	7040	5460	5370	1810	2550	2490	1690
24	2970	3620	e3100	e6900	13900	7400	5410	5170	2080	1680	2470	2180
25	2910	3150	e3100	e6200	13000	7540	5300	4920	1810	1890	2370	1970

26	3630	3210	e3000	6130	11700	7410	5330	4610	1470	2060	2150	2420
27	3350	3250	e3000	7190	10400	7400	4960	4570	2410	2580	2110	2640
28	3500	3860	e3000	7060	9220	7230	4650	4200	2000	2770	2090	2110
29	3400	3900	e3100	5310	---	7380	4520	4330	2370	2890	1860	2500
30	3310	4070	3240	4910	---	7160	4220	4150	2350	2710	1910	2350

31	3540	---	3390	4440	---	7230	---	3710	---	2000	1880	---

TOTAL	82990	106870	120810	183060	330620	239740	191130	129780	81360	61410	60760	53930
MEAN	2677	3562	3897	5905	11810	7734	6371	4186	2712	1981	1960	1798
MAX	3630	4190	5410	9000	20000	9390	7540	5550	3920	2890	3310	2640
MIN	2050	2950	2770	2980	4060	6730	4220	3140	1470	1340	1370	1340
CFSM	0.31	0.41	0.45	0.67	1.35	0.88	0.73	0.48	0.31	0.23	0.22	0.21
IN.	0.35	0.45	0.51	0.78	1.41	1.02	0.81	0.55	0.35	0.26	0.26	0.23

e Estimated

STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1935 - 2005, BY WATER YEAR (WY)
MEAN	3822	4587	4276	4433	6015	9493	9081	6942	6530	5108	3820	3786
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 2004 CALENDAR YEAR		FOR 2005 WATER YEAR		WATER YEARS 1935 - 2005
ANNUAL TOTAL	2463490		1642460
ANNUAL MEAN	6731		4500		5689
HIGHEST ANNUAL MEAN					12990	1993
LOWEST ANNUAL MEAN					2187	1964
HIGHEST DAILY MEAN	26700	Jun 2	20000	Feb 16	45200	A
LOWEST DAILY MEAN	1770	Jan 8	1340	Jul 20,Sep 13	524	Aug 9 1936
ANNUAL SEVEN-DAY MINIMUM	2130	Sep 24	1460	Aug 4	673	Aug 3 1936
MAXIMUM PEAK FLOW			20400	Feb 15	59700 B	Apr 21 1973
MAXIMUM PEAK STAGE			8.02	Feb 15	17.51 C	Feb 7 1938
INSTANTANEOUS LOW FLOW			390	Jul 12	390	D
ANNUAL RUNOFF (CFSM)	0.769		0.514		0.650
ANNUAL RUNOFF (INCHES)	10.47		6.98		8.83
10 PERCENT EXCEEDS	15900		8120		11000
50 PERCENT EXCEEDS	4470		3530		4300
90 PERCENT EXCEEDS	2500		1680		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 - July 27, 2003 and July 12, 2005, result of regulation.

Table of Contents

Introduction

Station Descriptions

Surface-Water Data

Ground-Water Data

Meteorological Data

Biological Data