on 99 streams tributary to Lake Superior and 

 83 stations on 56 Lake Michigan tributaries. 



MATERIALS AND METHODS 



Water samples were taken from midstream 

 in 1 -liter polyethylene bottles and held in 

 these containers until analyses were com- 

 pleted. The polyethylene bottles were rinsed 

 with river water before they were filled. 



Analyses of water usually were completed 

 within 8 hours after collection but not later 

 than 30 hours. If the analyses could not be 

 completed on the day of collection, the samples 

 were stored in a refrigerator and studied the 

 following day. Water samples were warmed 

 to 21° C. (70° F.), and turbid samples were 

 passed through Whatman No. 12 filter paper 

 prior to analyses. 



Determinations for aluminum, copper, and 

 iron were made as soon as possible after 

 samples were collected. 



Deternninations were limited to analytical 

 procedures adaptable to field use. A Hach DR 

 photoelectric colorimeter i was used for color- 

 imetric measurements. 



The following analytical procedures were 

 used: 



Temperature (° C.)--Water temperatures 

 were taken to the nearest ° F. with a hand or 

 pocket thermometer at the time of sampling 

 and converted to ° C. 



Aluminum (Al)- -Determinations were made 

 by the aluminon method (Hach Chemical Com- 

 pany, 1963). 



Copper (Cu)--Copper was deternnined by 

 the cuprethol method (Hach Chemical Com- 

 pany, 1963). 



Iron (Fe)- -The 1, 10-phenanthroline method 

 was used for iron determinations (Hach Chemi- 

 cal Company, 1963). 



Magnesium (Mg++)--Magnesium was calcu- 

 lated as the difference between total hardness 

 and calcium. 



Calcium (Ca++)--The EDTA titrimetric 

 method was used (American Public HealthAs- 

 sociation, 1960). 



Chloride (C 1 ")- -Chloride was determined 

 by the mercuric nitrate nnethod (American 

 Public Health Association, 1960). 



Nitrate (NO3" )- -Determinations were nnade 

 by the brucine method (American Public Health 

 Association, 1960). 



Nitrite (N02')--The sulfanilic acid - 1, 

 naphthylamine method was used (Hach Chenni- 

 cal Connpany, 1963). 



Silica (Si02)- -Determinations were made by 

 the silicomolybdate method (Hach Chemical 

 Company, 1963). 



' Trade names referred to In this publication do not im- 

 ply endorsement of the commercial products. 



Sulfate (S04~)--The turbidimetric method 

 was used to determine sulfate (Hach Chemical 

 Company, 1963). 



Tannin and lignin - - Determinations were 

 made by the tyrosine method (Hach Chemical 

 Company, 1963). 



pH--A Beckman Zeromatic pH meter was 

 used to measure pH. 



Alkalinity - - Phenolphthalein and total alka- 

 linities were determined by titration (Anneri- 

 can Public Health Association, I960). 



Hardness - - Total hardness was determined 

 by EDTA titration method (American Public 

 Health Association, 1960). 



Conductivity - -Conductivity was measured 

 at 20° C. (68° F.) and corrected to 18° C. 

 (640 F.) by correction factors given by Smith 

 (1962). Measurements were made with an 

 Industrial Instruments, Model RC- 16B2, con- 

 ductivity bridge. 



The streams where water samples were 

 collected were numbered in geographical se- 

 quence from east to west along the south shore 

 of Lake Superior (fig. 1) and counterclock- 

 wise starting from the northeast shore at the 

 outlet of Lake Michigan (fig. 2). The number 

 of each stream is used to identify the stream 

 in the tables. The locations where water 

 samples were taken on each stream are given 

 in the Appendix. The asterisks designate the 

 streams where more than one location was 

 sanapled. 



CHOCOLAY RIVER AND MAJOR 



TRIBUTARIES, 

 MARQUETTE COUNTY, MICH. 



The Chocolay River, a tributary to Lake 

 Superior, was sampled at four locations in 

 Marquette County, Mich. The main stem ofthe 

 Chocolay River and its three major tribu- 

 taries. Big Creek, Cedar Creek, and Cherry 

 Creek, accounted for 85 to 90 percent of the 

 volume at the mouth. The flow varied from 

 3.5 to 7.1 m.3/sec. (125 to 250 c.f.s.), but 

 flows were higher during the spring runoff or 

 heavy rains. The main stream is 26 knn. (16 

 miles) long and has 208 km. (129 miles) of 

 tributary streams, and drains about 412 km. 2 

 (159 sq. miles) (Brown, 1944). 



The flow of the main stem of the Chocolay 

 River usually ranged from 0.8 to 2.0 m.3/sec. 

 (30 to 70 c.f.s.), but discharges were higher 

 during the spring runoff and heavy rains. The 

 water was usually clear, light to moderate 

 color, and slightly alkaline. Turbidity and color 

 increased during rapid runoff. 



Water quality data were collected on the 

 main stem of the Chocolay River at the U.S. 

 Highway 4 1 bridge fronn December 1962 through 

 December 1965) (table 1). Concentrations of 

 calcium, total alkalinity, and total hardness, 

 and conductivity readings were lowest during 

 the spring runoff and other periods of increased 



