The: Waters op the: Rio Grande: 33 
the McIntyre and Decker Springs, would greatly modify the Rio 
Grande waters even if a fairly large quantity of them should find their 
way into the river. They might change the volume of the river but 
they would not radically change the character of the water as we find 
the waters of the Poudre and other streams changed within very short 
reaches of their courses. If the volume of flow were the principal 
change effected, it would be purely a matter for mechanical measure¬ 
ment. The results of gaugings vary; some years they showed an in¬ 
crease and in other years they showed almost as decided a decrease. 
At this time it appears to be a matter for regret that the chemical ex¬ 
aminations and the gaugings were not made at the same time. This, 
however, is the first time that the peculiar problems presenting them¬ 
selves in connection with these waters have been made the subject of 
inquiry. 
FACTS INDICATE THAT RIVER LOSES IN VOLUME AND MAIN¬ 
TAINS CHARACTER OF MOUNTAIN STREAM 
It would appear from the results obtained that the Rio Grande, in 
flowing through the San Luis valley, loses in volume and maintains 
the character of its water as a mountain stream to such an extent that 
it is difficult to believe' that it is receiving any significant amount of 
return waters, even though the ground- and drain-waters given dif¬ 
fer in material respects from those found in or issuing from irrigated 
lands under cultivation in other sections. 
These facts seem almost incredible and yet they are concordant 
with one another. First, there is a loss of water between Del Norte 
and the State Bridge during some months. Second, there appears to 
be a mean gain between Del Norte, Colorado, and Ernbudo, N. M.* 
The discharge of the river at Del Norte, is given as 711,186 acre 
feet, the result of 17 years’ observation; at Ernbudo, 769,098 acre 
feet, observation of 14 years, a gain of approximately 58,000 acre feet. 
Dr. Siebenthal gives the comparative discharge of the Rio Grande at 
Del Norte, State Bridge and Ernbudo for 1900, 1901, 1902 and 1903. 
At Del Norte, he gives 641,017, 583,271, 315,790 and 921,561 acre 
feet for the respective years, and at Ernbudo 537,381, 572,153, 282,- 
032 and 1,006,600 acre feet. It will be noticed that there is a loss in 
three of the four years. Dr. Siebenthal gives these data in discussing 
the interstate aspect of the Rio Grande and shows that while the flow 
at the State Bridge is smaller than at Del Norte the loss is largely 
made up in the course of the Ernbudo canyon. His data show that 
this is the case in one year in four. This point made by Dr. Sieben¬ 
thal and the geologists whom he quotes is undoubtedly well taken but 
this point of view is an entirely different one from that from which 
♦Gaugings given by Dr. Siebenthal, Water Supply Paper No. 240, U. S. Geo. 
Surv. pp. 13-14. 
