Station list     Available data
ILLINOIS RIVER BASIN


415755087525300                         O'HARE AIRPORT AT CHICAGO, IL



LOCATION.--Latitude 41°57'55", longitude 87°52'53", in NE1/4NW1/4NW1/4 sec.16, T.40 N., R.12 E., Cook County

PERIOD OF RECORD.--October 1, 1998 to September 30, 1999.

GAGE.--An 8-in.-diameter, unheated, tipping-bucket rain gage.

REMARKS.--Snowfall-affected data can result during cold weather when snow fills the rain-gage funnel and then melts as temperatures rise. Snowfall-affected data are subject to appreciable errors.

MAXIMUM FOR PERIOD OF RECORD.--Maximum, 2.92 in., estimated, October 17, 1998.

MAXIMUM FOR CURRENT YEAR.--Maximum, 2.92 in., estimated, October 17, 1998.
RAINFALL, IN INCHES, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999
DAILY MEAN VALUES
DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP
1 0.00 0.00 0.00 0.00 0.02 0.00 0.00 0.00 1.04 0.60 0.00 0.00
2 e.51 .00 .00 .00 .14 .11 .00 .00 .00 .00 .00 .00
3 .00 .00 .00 .00 .00 .00 .00 .00 .01 .00 .00 .00
4 .00 .00 .00 .00 .00 .00 .33 .00 .00 .00 .00 .00
5 e.77 .02 .00 s.01 .07 .00 .10 .07 .00 .00 .00 .00
6 e.13 .00 .85 .00 .00 .00 .03 .23 .17 .00 .00 .00
7 .00 .00 .00 .00 .00 s.01 .00 .01 .00 .00 .18 .00
8 .00 .07 .00 .00 .00 .00 1.65 .00 .00 .00 .00 .00
9 .00 .27 .00 .00 .00 .00 .25 .00 .02 .60 .02 .00
10 .00 .90 .00 .00 .00 .00 .07 .00 .00 .00 .00 .00
11 .00 .00 .00 .00 .34 s.02 .01 .98 .64 .00 .00 .00
12 .00 .00 .00 .00 .00 s.15 .00 .46 .00 .00 .30 .17
13 .00 .00 .00 .00 .00 s.02 .00 .00 1.93 .00 .10 .00
14 .00 .00 .00 .00 .00 s.03 .00 .00 .00 .00 .00 .00
15 e.04 .00 .00 .00 .00 .00 .84 .01 .00 .00 .00 .00
16 e.11 .00 .00 s.42 .05 .00 .45 .00 .00 .00 .00 .00
17 e2.92 .00 .00 .40 .00 .00 .00 .74 .00 .17 .00 .00
18 e.22 .00 .00 .00 .00 .00 .03 .07 .00 .00 .05 .00
19 .00 .00 .00 .00 .00 .00 .00 .00 .00 .05 .75 .04
20 .00 .00 .00 .00 .00 .00 .18 .00 .00 .02 .00 .00
21 .00 .00 .00 .71 .00 .00 .16 .68 .00 1.66 .00 .12
22 .00 .00 .00 .48 .00 .00 1.48 .01 .21 .01 .00 .00
23 .00 .00 .00 .81 .00 .00 .68 .15 .11 .28 .38 .00
24 .00 .00 .00 .01 .00 .00 .00 .00 .01 .00 .07 .00
25 .00 .00 .00 .00 s.08 .00 .00 .00 .00 .00 .26 .00
26 .00 .00 .00 .00 .24 .00 .00 .00 .00 .07 .00 .00
27 .46 .00 .00 .00 .11 .00 1.17 .00 .01 .00 .00 .48
28 .03 .00 .00 .00 .04 .00 .00 .00 .01 .00 .00 1.47
29 .00 .00 s.02 .00 -- .00 .00 .00 .01 .00 .00 .09
30 .00 .40 .00 .00 -- .00 .00 .00 .00 .00 .00 .00
31 .00 -- .00 .00 -- .00 -- .37 -- .00 .00 --

TOTAL 5.19 1.66 0.87 2.84 1.09 0.34 7.43 3.78 4.17 3.46 2.11 2.37
s Snowfall-affected precipitation
e Estimated


Table of Contents

Introduction

Station Descriptions

Surface-Water Data

Ground-Water Data

Meteorological Data

Biological Data