70 
BULLETIN 82. 
SUMMARY. 
1. The general character of the water of our mountain streams is 
dependent upon the character of their collecting area and is essentially 
the same for the streams studied in this bulletin. 
*2 The character of the water changes rapidly as soon as it leaves 
the mountain section of its course and enters the plains. 
3. In the case of the Poudre water, used by the town of Fort Col¬ 
lins, the total solids contained in the water increases from 2.9 grains per 
imperial gallon, in the mountain section, to an average of perhaps 10.2 
grains as delivered to the town, an increase of three and one-third times 
the original amount present. 
4. This change is produced by its flowing through less than eight 
miles of its course lying within its plains section. 
5 The mineral substances held in solution by the water, as moun¬ 
tain streams, are derived principally from the felspars by the action of 
water and carbonic acid. Pure water attacks these minerals, but its 
action is greatly increased by the presence of carbonic acid. 
. 6 Our river and ground waters contain both strontia and lithia, 
which are shown to be dissolved out of the felspars by carbonated wa¬ 
ters, and which are therefore to be considered as their source. 
I . The amount of mineral matter which the Poudre carries through 
its canyon daily, assuming a flow of 3u0 second feet, is nearly twenty- 
six tons, equal to 320 cubic feet of solid rock, having the average density 
of quartz. 
«. The Poudre water is not nearly saturated, for by direct experi¬ 
ment with finely ground felspar we were able to bring 4.536 grains into 
solution in each imperial gallon. 
9 The composition of the material dissolved out of the felspar by 
water and carbonic acid, is almost identical with that held in solution by 
the river water. 
10. The organic matter in the river water is not large in quantity 
and, while probably of vegetable origin, became exceedingly offensive 
when the water was evaporated to a small volume 
II. The waters of the Boulder and Clear Creek agree closely in 
composition and character with that of the Poudre. 
12. The influence of the plains section of the stream upon the char¬ 
acter of the water is increased by the irrigation of the adjacent lands. 
13. The effect of storage is to increase the mineral matter held in 
solution. Some of the increase is derived from the ditches through 
which the water flows and from seepage directly into the reservoirs. 
14. A small increase, 0.5 grains per gallon, is due to evaporation, 
but by far the largest increase is shown in instances where seepage wa¬ 
ter is either intentionally stored or flows into the reservoir. 
15. In the case of Terry Lake the total solids found in two different 
years were 134.5 grains and 175.6 grains per imperial gallon. The average 
of which shows that this lake held in solution 27,127 tons of solids in its 
9,000 acre-feet of water. 
16 Windsor Lake, containing 14,000 acre-feet, held 18,894 tons in 
solution. 
17. The water with which these reservoirs were filled was taken, for 
the greater part, directly from the Poudre, and the rest of it indirectly, it 
having in the meantime passed into the soil and reappeared as seepage. 
18. The mineral matters held in solution in the different reservoirs 
differ considerably. Those of Terry Lake resemble in their composition 
