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 1999 TO SEPTEMBER 2000
DAILY MEAN VALUES | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| DAY | OCT | NOV | DEC | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP |
| 1 | 261 | 338 | 16 | -5.4 | -4.3 | 120 | 1.6 | -6.8 | 44 | 291 | 519 | 512 |
| 2 | 247 | 172 | 58 | 63 | 104 | 26 | -56 | -25 | 109 | 256 | 583 | 526 |
| 3 | 117 | 106 | -6.8 | -83 | 31 | -9.8 | 35 | -40 | 136 | 409 | 438 | 471 |
| 4 | 226 | 69 | 33 | 71 | -57 | 72 | 89 | 76 | 234 | 343 | 402 | 592 |
| 5 | 263 | 113 | 114 | -61 | -0.06 | 1.5 | -24 | 3.0 | 243 | 373 | 277 | 502 |
| 6 | 216 | 58 | 28 | 22 | -6.0 | -11 | -36 | 9.2 | 304 | 363 | 323 | 436 |
| 7 | 171 | 23 | -9.7 | 39 | 4.6 | 102 | e26 | 41 | 226 | 265 | 439 | 452 |
| 8 | 299 | 52 | 19 | 58 | 4.8 | 77 | e24 | 52 | 305 | 309 | 404 | 505 |
| 9 | 233 | 96 | 35 | 55 | -92 | 89 | e20 | 121 | 264 | 408 | 481 | 456 |
| 10 | 315 | 118 | 94 | 91 | 25 | 55 | e17 | 9.8 | 198 | 398 | 420 | 417 |
| 11 | 251 | 23 | 4.9 | 9.2 | 26 | 54 | e21 | -37 | 184 | 414 | 477 | 227 |
| 12 | 268 | 86 | 39 | -170 | -99 | 0.42 | e21 | 80 | 185 | 301 | 363 | 270 |
| 13 | 411 | 93 | 41 | 22 | -44 | -18 | e17 | -14 | 266 | 463 | 395 | 473 |
| 14 | 188 | 115 | 64 | -77 | 100 | 38 | e22 | 17 | 301 | 397 | 471 | 397 |
| 15 | 243 | 83 | 48 | -31 | -22 | 85 | e24 | 31 | 190 | 408 | 510 | 515 |
| 16 | 293 | 134 | 79 | -70 | -52 | 63 | e26 | 99 | 275 | 375 | 477 | 359 |
| 17 | 262 | 24 | 34 | -126 | -162 | 9.1 | e13 | 67 | 196 | 464 | 316 | 259 |
| 18 | 194 | -22 | 8.0 | 85 | -56 | -65 | e116 | 144 | 178 | 420 | 487 | 436 |
| 19 | 163 | 106 | -29 | -85 | 31 | 21 | e16 | 91 | 283 | 423 | 353 | 578 |
| 20 | 119 | 45 | 39 | 148 | 24 | -7.4 | e16 | -9.1 | 260 | 471 | 345 | 218 |
| 21 | 108 | 1.0 | 48 | 118 | 97 | -28 | e20 | 39 | 264 | 445 | 334 | 383 |
| 22 | 145 | 54 | -20 | 77 | 24 | -69 | e19 | 73 | 234 | 431 | 363 | 365 |
| 23 | 155 | -80 | 16 | 2.5 | -63 | -74 | e19 | 90 | 238 | 430 | 432 | 657 |
| 24 | 117 | 97 | 38 | -116 | -76 | 3.3 | e23 | 69 | 268 | 377 | 385 | 468 |
| 25 | 132 | -18 | -18 | 7.5 | -113 | 24 | e21 | 46 | 129 | 384 | 364 | 456 |
| 26 | 119 | 29 | 14 | -134 | -65 | -3.2 | e12 | -6.5 | 252 | 423 | 314 | 372 |
| 27 | 57 | 68 | -16 | -25 | 28 | 74 | -16 | -6.6 | 375 | 477 | 402 | 433 |
| 28 | 336 | 59 | -16 | -86 | -54 | 64 | -20 | 142 | 281 | 424 | 357 | 409 |
| 29 | 291 | 88 | 38 | -125 | -42 | -30 | 95 | 16 | 245 | 476 | 465 | 298 |
| 30 | 317 | -6.8 | 40 | 8.1 | --- | -54 | -3.2 | 33 | 335 | 361 | 501 | 142 |
| 31 | 316 | --- | -21 | 49 | --- | -99 | --- | 44 | --- | 359 | 445 | --- |
| TOTAL | 6833 | 2123.2 | 811.4 | -269.1 | -507.96 | 509.92 | 558.4 | 1248.0 | 7002 | 12138 | 12842 | 12584 |
| MEAN | 220 | 70.8 | 26.2 | -8.68 | -17.5 | 16.4 | 18.6 | 40.3 | 233 | 392 | 414 | 419 |
| MAX | 411 | 338 | 114 | 148 | 104 | 120 | 116 | 144 | 375 | 477 | 583 | 657 |
| MIN | 57 | -80 | -29 | -170 | -162 | -99 | -56 | -40 | 44 | 256 | 277 | 142 |
| e Estimated |
| STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1997 - 2000, BY WATER YEAR (WY) | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MEAN | 345 | 145 | 101 | 130 | 98.5 | 116 | 132 | 219 | 415 | 642 | 630 | 545 |
| 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 | 220 | 70.8 | 26.2 | -8.68 | -17.5 | 16.4 | 18.6 | 40.3 | 233 | 392 | 414 | 385 |
| (WY) | 2000 | 2000 | 2000 | 2000 | 2000 | 2000 | 2000 | 2000 | 2000 | 2000 | 2000 | 1999 |
| SUMMARY STATISTICS | FOR 1999 CALENDAR YEAR | FOR 2000 WATER YEAR | WATER YEARS 1997 - 2000 | |||
|---|---|---|---|---|---|---|
| ANNUAL TOTAL | 72112.17 | 55872.86 | ||||
| ANNUAL MEAN | 198 | 153 | ||||
| HIGHEST ANNUAL MEAN | ||||||
| LOWEST ANNUAL MEAN | ||||||
| HIGHEST DAILY MEAN | 783 | Jul 31 | 657 | Sep 23 | 1370 | Aug 6 1997 |
| LOWEST DAILY MEAN | -223 | Jan 2 | -170 | Jan 12 | -2450 A | Feb 21 1997 |
| ANNUAL SEVEN-DAY MINIMUM | -20 | Jan 8 | -68 | Jan 23 | -108 A | Feb 21 1997 |
| 10 PERCENT EXCEEDS | 531 | 432 | 742 | |||
| 50 PERCENT EXCEEDS | 124 | 87 | 258 | |||
| 90 PERCENT EXCEEDS | -5.0 | -29 | 3.7 | |||
|