30 
BULLETIN 61, U. S. DEPARTMENT OF AGKICULTURE. 
The sodium-potassium ratio has been discussed in another section. The calcium- 
magnesium ratio shows a marked decrease for the lake waters as compared with river 
waters. This can be explained by the fact that calcium readily precipitates as car- 
bonate or sulphate, or may be removed by the agency of vegetable organisms l . The 
removal of calcium would leave the magnesium in greater relative amount. There is 
no doubt that magnesium is also precipitated as a carbonate, but is not eliminated at 
as great a rate as calcium. Chlorides are more abundant than sulphates in the lake 
waters as compared with river waters. This is undoubtedly due to the precipitation 
of the sulphate radical by lime. Carbonates and bicarbonates are in less relative 
proportion in lake waters than in river waters. This is accounted for by the precipita- 
tion of calcium and magnesium as insoluble carbonates. 
Borates are conspicuous in Owens, Mono, and the lakes of southern Oregon. The 
waters of Owens Lake are noteworthy on account of the content of nitrates and arsenic 
compounds. 
Certain regional characteristics become noticeable in a comparison of the chemical 
content of lake waters. The lakes of the Bonneville Basin are conspicuous for their 
lack of carbonates and bicarbonates and theirhigh content of chlorides. Sulphates 
are present, but in moderate amount. The high content of these lakes in salines is 
to be noted also. The regional rocks of the Bonneville Basin are, for the greater part, 
sedimentaries. Limestones are common. 
The lakes of the Lahontan Basin have a much lower saline content, and contain 
chlorides, sulphates, and carbonates. Chlorides usually .dominate, but in Pyramid, 
Winnemucca, and Humboldt Lakes carbonates are somewhat greater in amount than 
chlorides. The regional rocks are characterized by a greater area of igneous rocks 
than the Bonneville Basin. 
Owens and Mono Lakes contain chlorides and carbonates in greatest amount. Chlo- 
rides are greater in amount than carbonates and sulphates are least. These lakes are 
Characterized by a high saline content. The regional rocks are predominatingly 
igneous. The southern Oregon lakes are low in sulphates and have about equal 
amounts of chlorides and carbonates. In the case of only one lake are the chlorides 
exceeded by the sulphates. The regional rocks are igneous. 
ANNUAL SALINE CONTENT OF RIVER DISCHARGES. 
The rate at which salines are accumulating at present in the basin lakes can be 
calculated approximately from the mean annual flow of the principal rivers and their 
saline content. As has been mentioned before, the chemical data are insufficient, 
and, consequently, the conclusions give only approximate results. It is believed 
that the figures are conservative and rather under than overestimates. In Table XVI 
(Appendix) are given the tons of salines discharged by the Owens, Humboldt, Truckee, 
Walker, and Bear Rivers. The total salines discharged by these five rivers into their 
lake basins is 1,692,153 tons per annum. 
An approximate determination has been made for four basins and is given in the 
accompanying table: 
Discharge of salines into four important lake basins 
Basin. 
Total 
run-off 
per 
annum 
for basin. 
Rivers typical of run- 
off water. 
Mean 
annual 
flow of 
these 
rivers. 
t0 SL™ n_ i discharged 
fWnf i per annum 
Total 
salines 
discharged 
per annum 
into basin. 
Bonneville 
Sec-feet. 
3,583 
2,406 
306 
724 
Sec-feet. 
1,860 
1,504 
306 
1,030 
! 
Tons. 
1.9 : 1,259,235 
1.6 
Tons. 
2,392,546 
Lahontan 
Walker, Humbolt, 
and Truckee 
457,630 
Owens 
1.0 
.7 
102,228 
155,335 
102,228 
Southern Oregon lakes 
Truckee 
108, 734 
Bui. No. 108, TJ. S. Geol. Survey, p. 94. 
