STREAM POLLUTION 
385 
waters, as the Snake (Columbia River system), the Rio Grande (below headwaters), 
the Colorado and Gila Rivers, and the upper Missouri and Yellowstone below the 
mountains, a specific conductance of 2,000 mho was not unusual, the general range 
of specific conductance of these streams being between 200 and 2,000 mho, with 
SPECIFIC CONDUCTIVITY IN MHO * IQ* AT 23* C 
RIVER SYSTEMS 
0 
499 
300 
999 
IOOO 
1490 
1300 
1000 
2000 
2499 
2300 
2999 
3000 
3499 
3300 
3999 
4 000 
4499 
4500 
4999 
COMPOSITE 
LOCALITIES WITH GOOO FISH 
FAUNA 
381 DETERMINATIONS 
MISSISSIPPI 
GOOD FISH FAUNA 
222 DETERMINATIONS 
MISSISSIPPI 
MEDIUM, POOR, OR NO FISH 
FAUNA 
263 DETERMINATIONS 
MISSISSIPPI 
IMPOUNDED WATERS 
HASTINGS POOL (MINN.) 
7 DETERMINATIONS 
1 
MISSISSIPPI 
IMPOUNDED WATERS 
LAKE PEPIN (MINN. WIS > 
180 DETERMINATIONS 
| 
MISSISSIPPI, IMPOUNDED WATER 
LAKE DAVENPORT AND MOUNE 
POOL (IOWA, ILLINOIS) 
174 DETERMINATIONS 
1 
MISSISSIPPI 
IMPOUNDED WATERS 
LAKE KEOKUK ( IA.. ILL.) 
722 DETERMINATIONS 
h 
MISSOURI 
HEADWATERS 
10 DETERMINATIONS 
.ti 
MISSOURI 
BELOW HEADWATERS 
133 DETERMINATIONS 
OHIO 
40 DETERMINATIONS 
b 
TENNESSEE 
144 DETERMINATIONS 
1 
ATLANTIC COAST STREAMS 
47 DETERMINATIONS 
L 
GULF COAST STREAMS 
10 DETERMINATIONS 
d 
RIO GRANDE 
23 DETERMINATIONS 
1 
COLORADO RIVER SYSTEM 
41 DETERMINATIONS 
to 
COLUMBIA RIVER SYSTEM 
39 DETERMINATIONS 
du 
0 
499 
1 M T 
300 
999 
n 1 1 
IOOO 
1499 
nil 
1300 
1999 
2000 
2499 
2300 
2999 
3000 
3499 
3300 
3999 
4000 
*499 
4300 
4999 
SPECIFIC CON&UCTIVITY-IN MWO * 10® AT 23° C 
Figure 15. — A comparison of the specific conductivity values of the waters of various river units. 
extreme readings of almost 5,000 mho X 1 O ' at 25° C. However, good mixed fish 
faunae of such species as normally inhabit these western streams were usually not 
found in waters with specific conductance greater than 2,000 mho X 10“ 6 at 25° C. 
These high conductivity values for certain western waters were clearly due to the 
natural high solids content of these waters which drain areas rich in the various 
soluble alkalis. 
