The portion of the Calumet River, in the city of Chicago, county of Cook, State of Illinois, lying between the intersections of this river with the two lines described below, is a nonnavigable stream within the meaning of the Constitution and laws of the United States: Beginning at a point on the south line of the north half of section 36, township 37 north, range 14 east, of the third principal meridian, one thousand eight hundred and seventy-three and seven-hundredths feet west of the east line of said section; thence northwesterly on a straight line to a point three thousand two hundred and eighty feet west of the east line and seven hundred and eighty-five feet south of the north line of said section; and Beginning at a point five hundred and eighty-five feet east of the west line and seven hundred and thirty-two feet north of the south line of section 31, township 37 north, range 15 east, of the third principal meridian; thence north forty-six degrees and thirty minutes east along a straight line to the easterly water’s edge of said river. The right to alter, amend, or repeal this section is expressly reserved. (June 14, 1937, ch. 338, §§ 2, 3, 50 Stat. 258 , 259.)