This gaging station provides flow data essential to determine Illinois' diversion of Lake Michigan water. A U.S. Supreme Court Decree limits Illinois' diversion to an average of 3,200 ft3/s. Illinois' diversion includes water diverted from the lake for domestic water supply, for navigation and water-quality improvement in the Chicago Sanitary and Ship Canal system, and the stormwater runoff from a 673 mi2 diverted watershed area. Flows recorded at this station also include nondiversion flows. Gage-height telemeter at station.
DISCHARGE, IN CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES |
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DAY | OCT | NOV | DEC | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP |
1 | 2601 | 2586 | 2019 | e1372 | 3242 | 2393 | 1861 | 4340 | 5008 | 3335 | 3647 | 2908 |
2 | 2672 | 2224 | 1651 | e1576 | 3588 | 2088 | 1768 | 3589 | 8652 | 3364 | 2817 | 2608 |
3 | 3319 | 1525 | 1604 | e1465 | 3423 | 2274 | 2050 | 2792 | 5277 | 2788 | 3013 | 2751 |
4 | 3204 | 1866 | 1675 | e1503 | e2663 | 2523 | 2198 | 2829 | 4260 | 2764 | 2932 | 3246 |
5 | 2592 | 2548 | 1886 | e1471 | 3078 | 2124 | 1995 | 2475 | 3098 | 2830 | 3130 | 2909 |
6 | 2894 | 1897 | 3377 | e1747 | 2668 | 2441 | 1892 | 3128 | 2747 | 2719 | 2739 | 2847 |
7 | 2817 | 1778 | 4277 | 1569 | 2643 | 2915 | 1746 | 2953 | 2554 | 2690 | 3199 | 3243 |
8 | 2148 | 1957 | 2875 | 1646 | 2328 | 2360 | 2451 | 2198 | 2801 | 2697 | 2872 | 2386 |
9 | 2592 | 2000 | 2564 | 1813 | 2147 | 2300 | 7942 | 2248 | 2596 | 2677 | 3033 | 2340 |
10 | 2308 | 4763 | 2313 | 1697 | 2190 | 2353 | 4840 | 1745 | 4003 | 2973 | 2445 | 2469 |
11 | 2530 | 3473 | 2154 | 1730 | 2993 | 2312 | 3880 | 2448 | 4985 | 2545 | 3249 | 2276 |
12 | 1970 | 2819 | 1749 | 1707 | 2214 | 2498 | 3769 | 4865 | 4451 | 2590 | 4051 | 2361 |
13 | 2080 | 2661 | 2080 | 1713 | 2377 | 2986 | 2999 | 3459 | e11680 | 2733 | 2828 | 2325 |
14 | 2100 | 2536 | 1785 | 1745 | 2352 | 2590 | 3156 | 3081 | e6139 | 2815 | 3197 | 2350 |
15 | 2067 | 2399 | 1669 | 1722 | 1851 | 2492 | 3435 | 3137 | 4633 | 2801 | 4125 | 2482 |
16 | 1913 | 1832 | 1739 | 1793 | 2314 | 2636 | 7452 | 2567 | 3757 | e2803 | 3038 | 2168 |
17 | 5795 | 1699 | 1634 | 2568 | 1912 | 3799 | 5888 | 4723 | 3373 | 3164 | 2595 | 2047 |
18 | 5339 | 1787 | 1787 | 3214 | 1924 | 3814 | 4452 | 2714 | e2838 | 3377 | 2870 | 2287 |
19 | 3132 | 1789 | 1553 | 2538 | 2469 | 2742 | 3578 | 2650 | 2591 | e3802 | 4087 | 2144 |
20 | 2954 | 1829 | 1587 | 2215 | 2095 | 2584 | 3386 | 2565 | 2710 | 3868 | 3832 | 2008 |
21 | 2398 | 1785 | 1569 | 2635 | 1844 | 2533 | 4052 | 3160 | 2629 | e5407 | 3251 | 2309 |
22 | 2428 | 1731 | 1598 | 9745 | 1654 | 2315 | 7106 | 3554 | 3373 | 4051 | 3496 | 2150 |
23 | 2287 | 1683 | 1414 | 10981 | 1804 | 2366 | 10973 | 3609 | 2660 | 3828 | 3514 | 2070 |
24 | 2368 | 1645 | 1703 | 8973 | 1869 | 2415 | 7139 | 2807 | 3882 | 3562 | 3630 | 2202 |
25 | 2529 | 1437 | 1545 | 7550 | 2100 | 1894 | 6144 | e2187 | 3010 | 4041 | 3680 | 2207 |
26 | 2122 | 1603 | 1263 | 5118 | 2036 | 1893 | 4071 | e1618 | 3358 | 3463 | 3981 | 2033 |
27 | 2228 | 1575 | 1502 | 4354 | 2961 | 1747 | 6490 | 2020 | 3549 | 3002 | 3206 | 3153 |
28 | 2979 | 1625 | 1481 | 4662 | 2321 | 2134 | 7852 | 1815 | 2637 | 3102 | 3185 | 7202 |
29 | 2928 | 1644 | 1815 | 4302 | --- | 1614 | 7123 | 2171 | 2711 | e3309 | 3127 | 4173 |
30 | 2650 | 1812 | 1555 | 3628 | --- | 1667 | 4759 | 2051 | 2537 | e3219 | 2919 | 2762 |
31 | 2985 | --- | 1605 | 3641 | --- | 1899 | --- | 2631 | --- | 3599 | 3023 | --- |
TOTAL | 84929 | 62508 | 59028 | 102393 | 67060 | 74701 | 136447 | 88129 | 118499 | 99918 | 100711 | 80416 |
MEAN | 2740 | 2084 | 1904 | 3303 | 2395 | 2410 | 4548 | 2843 | 3950 | 3223 | 3249 | 2681 |
MAX | 5795 | 4763 | 4277 | 10981 | 3588 | 3814 | 10973 | 4865 | 11680 | 5407 | 4125 | 7202 |
MIN | 1913 | 1437 | 1263 | 1372 | 1654 | 1614 | 1746 | 1618 | 2537 | 2545 | 2445 | 2008 |
STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1985 - 1999, BY WATER YEAR (WY) | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
MEAN | 3304 | 3174 | 2770 | 2965 | 3015 | 3331 | 3608 | 3612 | 4043 | 4207 | 4440 | 4102 |
MAX | 5244 | 5244 | 3991 | 4347 | 4975 | 4791 | 5194 | 5491 | 6405 | 5426 | 6830 | 5181 |
(WY) | 1987 | 1986 | 1988 | 1993 | 1997 | 1985 | 1992 | 1990 | 1993 | 1986 | 1987 | 1986 |
MIN | 2620 | 2009 | 1904 | 2252 | 2192 | 2186 | 2534 | 2370 | 3288 | 3223 | 3249 | 2681 |
(WY) | 1998 | 1998 | 1999 | 1996 | 1996 | 1996 | 1997 | 1994 | 1995 | 1999 | 1999 | 1999 |
SUMMARY STATISTICS | FOR 1998 CALENDAR YEAR | FOR 1999 WATER YEAR | WATER YEARS 1985 - 1999 | |||
---|---|---|---|---|---|---|
ANNUAL TOTAL | 1137744 | 1074739 | ||||
ANNUAL MEAN | 3117 | 2944 | 3550 | |||
HIGHEST ANNUAL MEAN | 4113 | 1986 | ||||
LOWEST ANNUAL MEAN | 2944 | 1999 | ||||
HIGHEST DAILY MEAN | 12470 | May 7 | 11680 A | Jun 13 | 17870 | May 10 1990 |
LOWEST DAILY MEAN | 1263 | Dec 26 | 1263 | Dec 26 | 1263 | Dec 26 1998 |
ANNUAL SEVEN-DAY MINIMUM | 1500 | Dec 22 | 1500 | Dec 22 | 1500 | Dec 22 1998 |
INSTANTANEOUS PEAK FLOW | 14623 B | Jan 23 | 19466 C | Feb 21 1997 | ||
INSTANTANEOUS PEAK STAGE | 26.23 D | Apr 29 | 26.43 E | Feb 4 1996 | ||
INSTANTANEOUS LOW FLOW | -4088 | Dec 12 | F | |||
10 PERCENT EXCEEDS | 4710 | 4320 | 5220 | |||
50 PERCENT EXCEEDS | 2820 | 2600 | 3160 | |||
90 PERCENT EXCEEDS | 1790 | 1700 | 2170 |
Table of Contents |
Introduction |
Station Descriptions |
Surface-Water Data |
Ground-Water Data |
Meteorological Data |
Biological Data |