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 2000 TO SEPTEMBER 2001
DAILY MEAN VALUES | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| DAY | OCT | NOV | DEC | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP |
| 1 | 164 | -45 | 11 | -1.4 | 14 | -49 | 113 | 51 | 91 | 408 | 297 | 308 |
| 2 | 247 | 24 | 2.0 | 147 | -17 | -40 | 26 | 36 | 179 | 290 | -342 | 264 |
| 3 | 188 | 84 | -97 | -65 | -30 | -25 | 74 | 60 | 162 | 210 | 115 | 246 |
| 4 | 181 | 7.4 | -22 | -41 | -18 | 7.0 | -53 | -19 | 161 | 223 | 296 | 374 |
| 5 | 154 | -49 | 69 | 0.56 | -28 | 58 | -98 | -14 | 204 | 347 | 317 | 289 |
| 6 | 154 | 1.3 | -3.5 | 11 | -64 | 32 | -85 | -64 | 185 | 263 | 366 | 301 |
| 7 | 82 | 77 | -4.2 | -17 | -49 | 3.3 | -28 | 58 | 187 | 284 | 305 | 181 |
| 8 | 139 | 49 | 7.1 | -9.3 | -74 | 44 | 33 | 66 | 162 | 291 | 371 | 219 |
| 9 | 147 | 116 | -18 | 20 | 60 | 31 | 14 | 47 | 186 | 364 | 467 | 469 |
| 10 | 192 | 73 | -9.5 | -67 | 72 | -13 | 42 | 28 | 228 | 384 | 293 | 417 |
| 11 | 216 | 13 | -129 | -48 | -8.8 | -28 | -30 | 128 | 127 | 283 | 303 | 381 |
| 12 | 229 | 23 | 104 | -22 | -38 | -48 | 102 | 78 | 461 | 286 | 286 | 457 |
| 13 | e128 | 48 | -118 | -147 | -101 | 76 | -39 | 30 | 198 | 309 | 411 | 401 |
| 14 | e110 | 35 | 29 | -103 | -31 | 28 | -73 | 36 | 223 | 277 | 309 | 339 |
| 15 | e162 | 140 | 123 | 7.9 | -74 | -14 | -84 | 175 | 527 | 281 | 256 | 295 |
| 16 | 169 | 171 | 5.1 | 126 | 65 | 11 | 82 | 105 | 218 | 371 | 340 | 248 |
| 17 | 135 | 41 | 97 | 59 | 139 | -26 | 40 | 83 | 128 | 389 | 372 | 305 |
| 18 | 179 | 24 | 3.7 | -13 | 29 | 241 | -13 | 187 | 270 | 328 | 341 | 428 |
| 19 | 142 | 13 | -13 | -10 | -12 | -5.4 | -51 | 126 | 184 | 340 | 786 | 373 |
| 20 | 64 | 60 | -68 | -33 | 17 | -33 | -27 | 83 | 152 | 396 | 428 | 318 |
| 21 | 40 | 71 | 110 | -30 | -23 | -11 | 33 | 85 | 179 | 308 | 319 | 235 |
| 22 | 3.4 | 37 | 16 | -57 | 74 | -21 | -50 | 214 | 221 | 357 | 304 | 354 |
| 23 | 15 | -16 | -121 | -25 | -98 | 7.0 | 95 | 78 | 214 | 357 | 458 | 460 |
| 24 | 77 | -51 | 19 | 2.7 | -151 | 102 | -21 | 82 | 224 | 340 | 390 | 166 |
| 25 | 99 | -23 | 78 | -123 | 30 | 78 | -19 | 182 | 198 | 305 | 339 | 79 |
| 26 | 123 | 45 | -91 | -20 | 4.2 | 68 | 51 | 87 | 207 | 346 | 624 | 317 |
| 27 | 272 | 21 | -44 | -59 | -49 | 29 | -1.7 | 209 | 184 | 258 | 480 | 708 |
| 28 | 73 | 3.0 | -38 | 7.4 | 2.9 | -47 | -26 | 136 | 207 | 264 | 447 | 296 |
| 29 | 20 | 5.3 | -7.3 | 66 | --- | -70 | -97 | 172 | 191 | 355 | 355 | 349 |
| 30 | 6.7 | 39 | -136 | 63 | --- | -44 | 16 | 135 | 155 | 372 | 177 | 298 |
| 31 | 63 | --- | -29 | 69 | --- | -82 | --- | 18 | --- | 410 | 259 | --- |
| TOTAL | 3974.1 | 1037.0 | -274.6 | -311.14 | -358.7 | 258.9 | -74.7 | 2678 | 6213 | 9996 | 10469 | 9875 |
| MEAN | 128 | 34.6 | -8.86 | -10.0 | -12.8 | 8.35 | -2.49 | 86.4 | 207 | 322 | 338 | 329 |
| MAX | 272 | 171 | 123 | 147 | 139 | 241 | 113 | 214 | 527 | 410 | 786 | 708 |
| MIN | 3.4 | -51 | -136 | -147 | -151 | -82 | -98 | -64 | 91 | 210 | -342 | 79 |
| e Estimated |
| STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1997 - 2001, BY WATER YEAR (WY) | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MEAN | 301 | 123 | 79.3 | 102 | 76.4 | 94.1 | 105 | 193 | 373 | 578 | 572 | 502 |
| 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 | 34.6 | -8.86 | -10.0 | -17.5 | 8.35 | -2.49 | 40.3 | 207 | 322 | 338 | 329 |
| (WY) | 2001 | 2001 | 2001 | 2001 | 2000 | 2001 | 2001 | 2000 | 2001 | 2001 | 2001 | 2001 |
| SUMMARY STATISTICS | FOR 2000 CALENDAR YEAR | FOR 2001 WATER YEAR | WATER YEARS 1997 - 2001 | |||
|---|---|---|---|---|---|---|
| ANNUAL TOTAL | 50841.76 | 43481.86 | ||||
| ANNUAL MEAN | 139 | 119 | 259 | |||
| HIGHEST ANNUAL MEAN | 465 | 1997 | ||||
| LOWEST ANNUAL MEAN | 119 | 2001 | ||||
| HIGHEST DAILY MEAN | 657 | Sep 23 | 786 | Aug 19 | 1370 | Aug 6 1997 |
| LOWEST DAILY MEAN | -170 | Jan 12 | -342 | Aug 2 | -2450 A | Feb 21 1997 |
| ANNUAL SEVEN-DAY MINIMUM | -68 | Jan 23 | -54 | Jan 8 | -108 A | Feb 21 1997 |
| 10 PERCENT EXCEEDS | 432 | 354 | 654 | |||
| 50 PERCENT EXCEEDS | 72 | 76 | 216 | |||
| 90 PERCENT EXCEEDS | -50 | -49 | -12 | |||
|