LOCATION.-- Lat 41°53'18", long 87°37'16" (NAD of 1927), in NE1/4SW1/4 sec.10, T.39 N., R.14 E., Cook County, Hydrologic Unit 07120003, on left downstream side of bridge within the Columbus Drive bridge structure in Chicago, 0.5 mi downstream from Chicago River Lock and Dam. | |
DRAINAGE AREA.-- Indeterminate. | |
PERIOD OF RECORD.-- | |
SURFACE-WATER DISCHARGE AND STAGE | |
DISCHARGE: October 1996 to current year. | |
GAGE.-- Water-stage recorder, acoustical flowmeter and phone telemeter. Datum of gage is 579.48 ft above NGVD of 1929 (Chicago City datum). | |
REMARKS.-- This gaging station provides flow data 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 stormwater runoff from a 673 mi2 diverted watershed area. Estimated daily discharges determined from regression relations between this site and flow data from the Metropolitan Water Reclamation District of Greater Chicago-Chicago River Controlling Works. | |
EXTREMES FOR PERIOD OF RECORD.-- Maximum daily discharge, 1,370 ft3/s, Aug. 6, 1997, minimum daily, -2,450 ft3/s, Feb. 21, 1997, due to regulation to prevent flooding. | |
REMARKS FOR CURRENT YEAR.--Records good except those for estimated daily discharges, which are fair. | |
| Discharge, cubic feet per second, WATER YEAR OCTOBER 2002 TO SEPTEMBER 2003
DAILY MEAN VALUES | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| DAY | OCT | NOV | DEC | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP |
| 1 | 294 | 181 | 71 | -14 | -26 | -50 | 58 | 165 | 8.1 | e290 | 357 | 13 |
| 2 | 332 | 161 | 24 | 15 | 28 | 7.7 | e25 | 85 | -16 | e314 | 193 | 280 |
| 3 | 106 | 153 | -92 | 6.4 | -12 | -17 | e27 | 2.3 | 72 | e290 | 205 | 357 |
| 4 | 334 | 30 | -8.2 | -121 | 91 | -89 | e34 | 141 | 236 | e185 | 383 | 404 |
| 5 | 156 | 6.5 | 57 | 22 | 16 | -88 | e22 | 70 | 351 | e243 | 515 | 230 |
| 6 | 272 | 57 | 39 | 17 | -12 | -55 | e24 | 3.6 | 277 | e145 | 330 | 284 |
| 7 | 199 | 26 | 26 | 47 | 42 | -62 | e26 | 51 | 277 | e288 | 557 | 299 |
| 8 | 224 | -13 | -0.67 | 57 | -47 | 113 | e26 | 88 | 194 | e531 | 518 | 321 |
| 9 | 263 | -86 | -25 | 75 | -15 | 114 | -13 | 213 | 323 | e203 | 469 | 326 |
| 10 | 197 | 47 | -26 | 87 | 24 | 49 | -35 | 370 | 134 | 307 | 456 | 341 |
| 11 | 186 | 71 | -20 | 63 | 2.2 | -2.3 | 114 | 129 | 395 | 230 | 405 | 307 |
| 12 | 255 | 53 | -79 | -6.9 | -46 | 50 | 23 | 304 | 379 | 279 | 525 | 169 |
| 13 | 194 | 45 | -86 | 63 | -25 | 44 | -1.1 | 93 | 261 | 317 | 460 | 343 |
| 14 | 143 | 10 | 57 | 67 | -7.7 | 37 | 85 | 165 | 308 | 352 | 472 | 251 |
| 15 | 264 | 52 | 79 | 62 | 3.2 | -51 | 111 | 117 | 373 | 245 | 515 | 272 |
| 16 | 254 | 57 | -36 | 57 | -75 | -50 | 86 | 54 | 314 | 273 | 531 | 160 |
| 17 | 223 | 23 | -88 | 17 | -133 | 24 | 62 | 35 | 263 | 208 | 472 | 189 |
| 18 | 230 | -14 | -32 | -96 | -49 | 7.4 | 127 | 28 | 284 | 501 | 316 | 290 |
| 19 | 218 | 77 | 0.25 | -80 | -16 | 67 | 62 | -9.3 | 541 | 292 | 389 | 363 |
| 20 | 173 | 76 | 41 | 19 | -10 | -18 | 105 | 502 | 206 | 368 | 468 | 223 |
| 21 | 101 | 89 | 51 | 63 | -91 | -9.6 | 83 | 54 | 260 | 442 | 603 | 224 |
| 22 | 169 | 75 | 36 | 1.8 | -29 | 32 | 31 | 46 | 257 | 564 | 557 | 336 |
| 23 | 36 | -21 | 23 | 70 | 59 | 1.9 | -9.4 | 40 | 361 | 557 | 406 | 256 |
| 24 | -86 | 61 | -26 | -44 | 78 | 87 | 14 | 59 | 369 | 385 | 419 | 196 |
| 25 | -4.6 | 67 | 0.76 | 20 | -1.8 | -19 | 90 | 44 | 221 | 356 | 562 | 253 |
| 26 | 140 | 72 | -52 | 123 | -90 | -65 | 64 | 57 | 228 | 247 | 505 | 140 |
| 27 | 53 | 73 | -5.3 | 29 | -98 | -40 | 52 | 31 | 178 | 473 | 589 | 324 |
| 28 | -4.3 | 3.4 | 13 | -43 | -63 | -13 | 61 | 105 | e148 | 406 | 288 | 270 |
| 29 | -6.2 | 11 | 167 | -21 | --- | 67 | 51 | 226 | e201 | 417 | 407 | 246 |
| 30 | -69 | 103 | 32 | -86 | --- | -35 | 175 | 113 | e193 | 379 | 219 | 107 |
| 31 | 68 | --- | -11 | -72 | --- | -49 | --- | 88 | --- | 361 | 177 | --- |
| TOTAL | 4913.9 | 1545.9 | 129.84 | 397.3 | -503.1 | -11.9 | 1579.5 | 3469.6 | 7596.1 | 10448 | 13268 | 7774 |
| MEAN | 159 | 51.5 | 4.19 | 12.8 | -18.0 | -0.38 | 52.6 | 112 | 253 | 337 | 428 | 259 |
| MAX | 334 | 181 | 167 | 123 | 91 | 114 | 175 | 502 | 541 | 564 | 603 | 404 |
| MIN | -86 | -86 | -92 | -121 | -133 | -89 | -35 | -9.3 | -16 | 145 | 177 | 13 |
| e Estimated |
| STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1997 - 2003, BY WATER YEAR (WY) | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MEAN | 257 | 99.5 | 61.1 | 77.5 | 54.8 | 71.7 | 86.1 | 163 | 343 | 519 | 533 | 429 |
| MAX | 512 | 225 | 303 | 352 | 262 | 275 | 262 | 406 | 593 | 883 | 793 | 840 |
| (WY) | 1998 | 1997 | 1997 | 1997 | 1997 | 1997 | 1997 | 1997 | 1997 | 1997 | 1997 | 1997 |
| MIN | 128 | 29.6 | -8.86 | -10.0 | -18.0 | -0.38 | -2.49 | 40.3 | 207 | 322 | 338 | 235 |
| (WY) | 2001 | 2002 | 2001 | 2001 | 2003 | 2003 | 2001 | 2000 | 2001 | 2001 | 2001 | 2002 |
| SUMMARY STATISTICS | FOR 2002 CALENDAR YEAR | FOR 2003 WATER YEAR | WATER YEARS 1997 - 2003 | |||
|---|---|---|---|---|---|---|
| ANNUAL TOTAL | 53385.03 | 50607.14 | ||||
| ANNUAL MEAN | 146 | 139 | 226 | |||
| HIGHEST ANNUAL MEAN | 465 | 1997 | ||||
| LOWEST ANNUAL MEAN | 119 | 2001 | ||||
| HIGHEST DAILY MEAN | 816 | Aug 13 | 603 | Aug 21 | 1370 | Aug 6 1997 |
| LOWEST DAILY MEAN | -92 | Dec 3 | -133 | Feb 17 | -2450 A | Feb 21 1997 |
| ANNUAL SEVEN-DAY MINIMUM | -35 | Apr 5 | -58 | Feb 16 | -108 A | Feb 21 1997 |
| 10 PERCENT EXCEEDS | 418 | 381 | 555 | |||
| 50 PERCENT EXCEEDS | 79 | 75 | 167 | |||
| 90 PERCENT EXCEEDS | -26 | -35 | -18 | |||
|