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 1997 TO SEPTEMBER 1998 DAILY MEAN VALUES |
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DAY | OCT | NOV | DEC | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP |
1 | 2762 | e2266 | 1815 | 1794 | 2655 | 1997 | 4390 | 2841 | 2436 | 3407 | 2885 | 3236 |
2 | 2497 | e1805 | 1938 | 1984 | 2928 | 2107 | 3783 | 2814 | 2301 | 3059 | 2870 | 2744 |
3 | 2599 | e1991 | 2011 | 2039 | 2999 | 1993 | 3471 | 2111 | 2618 | 3373 | 2680 | 2688 |
4 | 2897 | 2024 | 1741 | 6237 | 2398 | 2289 | 3123 | 2927 | 2312 | 5528 | 7362 | 3036 |
5 | 2698 | 2021 | 1838 | 5338 | 2576 | 2112 | 3538 | 2603 | 2250 | 4386 | 7786 | 2822 |
6 | 2516 | 2586 | 1926 | 5966 | 2243 | 1877 | 2239 | 3206 | 2491 | 3414 | 5889 | e2757 |
7 | 2900 | 2077 | 1647 | 5067 | 2200 | 2200 | 3361 | 12470 | 2270 | 4475 | 6013 | e6357 |
8 | 3025 | 1929 | 1743 | 7993 | 2106 | 4880 | 4422 | 12116 | 2323 | 4678 | 5207 | e4127 |
9 | 3211 | 1998 | 1951 | 5990 | 2240 | 6564 | 4553 | 8185 | 3662 | 3644 | 4513 | e2974 |
10 | 3074 | 1870 | 3208 | 4937 | 2057 | 4786 | 3466 | 5062 | 3471 | 3779 | 3839 | e2757 |
11 | 2952 | 1684 | 2943 | 3863 | 5296 | 4413 | 3805 | 4184 | 6574 | 3392 | 4130 | 2817 |
12 | 3036 | 2118 | 2709 | 3374 | 3921 | 3897 | 3427 | 3795 | 4341 | 3272 | 3673 | 2496 |
13 | 3032 | 1814 | 2435 | 2751 | 3500 | 3127 | 2922 | 3407 | 3867 | 3503 | 3600 | 2878 |
14 | 2286 | 2004 | 2138 | 2689 | 3305 | 3732 | 3423 | 3341 | 3983 | 3402 | 3328 | 2958 |
15 | 2066 | 2429 | 1776 | 2639 | 2809 | 2893 | 3360 | 2752 | 2459 | 3674 | e3250 | 3332 |
16 | 2167 | 2472 | 2089 | 2067 | 2940 | 2683 | 2893 | 2672 | 3050 | 3365 | e3311 | 3007 |
17 | 2097 | 2035 | 1692 | 2317 | 4069 | 5209 | 3134 | 2625 | 2766 | 3585 | e2817 | 3013 |
18 | 1999 | 1671 | 1798 | 2117 | 5414 | 8180 | 3204 | 2496 | 3319 | 3808 | 3089 | 2624 |
19 | 2297 | 1929 | 1905 | 1891 | 4162 | 7369 | 2720 | 2739 | 3416 | 3894 | 3386 | 2659 |
20 | 1774 | 1742 | 1871 | 2253 | 3247 | 5599 | 3150 | 2230 | 3521 | 3972 | 3092 | 2758 |
21 | 1893 | 1851 | 1755 | 1935 | 3229 | 4568 | 4475 | 2128 | 2983 | 3011 | 3061 | 3217 |
22 | 2024 | 1549 | 2118 | 2123 | 2947 | 4464 | 3896 | 2201 | 2730 | 3173 | e3854 | 2475 |
23 | 1937 | 1642 | 2434 | 2379 | 2462 | 3565 | 3521 | 2360 | 2677 | 3698 | e3542 | 2522 |
24 | 2369 | 1817 | 2861 | 1896 | 2322 | 2823 | 2820 | 3466 | 2663 | 3130 | e4765 | 2302 |
25 | 2050 | 1764 | 3791 | 1808 | 2571 | 2825 | 3716 | 2825 | 3257 | 3146 | 5682 | 2512 |
26 | 3187 | 1783 | e1480 | 2246 | 2252 | 2646 | 3281 | 2437 | 4277 | 2839 | 3846 | 2435 |
27 | 5309 | 1956 | 2500 | 1682 | 2241 | 2669 | 3112 | 2271 | 5007 | 2602 | 3868 | 2418 |
28 | 2930 | 2574 | 2022 | 2090 | 2539 | 3223 | 2869 | 2539 | 4775 | 3058 | 3598 | 2613 |
29 | 2826 | 2714 | 2014 | 2441 | --- | 2802 | 3549 | 2686 | 3880 | 2736 | 3821 | 3223 |
30 | 2557 | 2150 | 1993 | 2272 | --- | 2603 | 2976 | 2272 | 3317 | 2714 | 3326 | 3223 |
31 | 2245 | --- | 1739 | 2287 | --- | 5264 | --- | 2159 | --- | 2805 | 2727 | --- |
TOTAL | 81212 | 60265 | 65881 | 96465 | 83628 | 115359 | 102599 | 111920 | 98996 | 108522 | 124810 | 88980 |
MEAN | 2620 | 2009 | 2125 | 3112 | 2987 | 3721 | 3420 | 3610 | 3300 | 3501 | 4026 | 2966 |
MAX | 5309 | 2714 | 3791 | 7993 | 5414 | 8180 | 4553 | 12470 | 6574 | 5528 | 7786 | 6357 |
MIN | 1774 | 1549 | 1480 | 1682 | 2057 | 1877 | 2239 | 2111 | 2250 | 2602 | 2680 | 2302 |
STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1991 - 1998, BY WATER YEAR (WY) | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
MEAN | 3040 | 3087 | 2661 | 2953 | 2951 | 3246 | 3767 | 3637 | 4064 | 4084 | 4098 | 3747 |
MAX | 4098 | 4419 | 3373 | 4347 | 4975 | 4084 | 5194 | 5053 | 6405 | 4770 | 4723 | 4974 |
(WY) | 1992 | 1991 | 1991 | 1993 | 1997 | 1993 | 1992 | 1992 | 1993 | 1996 | 1993 | 1992 |
MIN | 2620 | 2009 | 1964 | 2252 | 2192 | 2186 | 2534 | 2370 | 3288 | 3501 | 3446 | 2966 |
(WY) | 1998 | 1998 | 1996 | 1996 | 1996 | 1996 | 1997 | 1994 | 1995 | 1998 | 1996 | 1998 |
SUMMARY STATISTICS | FOR 1997 CALENDAR YEAR | FOR 1998 WATER YEAR | WATER YEARS 1991 - 1998 | |||
---|---|---|---|---|---|---|
ANNUAL TOTAL | 1149296 | 1138637 | ||||
ANNUAL MEAN | 3149 | 3120 | 3446 | |||
HIGHEST ANNUAL MEAN | 4074 | 1993 | ||||
LOWEST ANNUAL MEAN | 3095 | 1994 | ||||
HIGHEST DAILY MEAN | 17281 | Feb 21 | 12470 | May 7 | 17530 | Nov 28 1990 |
LOWEST DAILY MEAN | 1480 A | Dec 26 | 1480 A | Dec 26 | 1480 A | Dec 26 1997 |
ANNUAL SEVEN-DAY MINIMUM | 1740 | Nov 20 | 1740 | Nov 20 | 1740 | Nov 20 1997 |
INSTANTANEOUS PEAK FLOW | 14909 B | May 7 | 19466 C | Feb 21 1997 | ||
INSTANTANEOUS PEAK STAGE | 26.27 D | Mar 16 | 26.43 E | Feb 4 1996 | ||
INSTANTANEOUS LOW FLOW | -321 | Mar 16 | F | |||
10 PERCENT EXCEEDS | 4250 | 4560 | 5040 | |||
50 PERCENT EXCEEDS | 2860 | 2820 | 3070 | |||
90 PERCENT EXCEEDS | 1950 | 1930 | 2110 |
Table of Contents |
Introduction |
Station Descriptions |
Surface-Water Data |
Ground-Water Data |
Meteorological Data |
Biological Data |