73 



measurements, and attributes many of the changes to such waves 

 rather than to return seepage. These waves are attributed to local ' 

 precipitation, cloudy weather, which checks eva[)oration, or clear, 

 Avindy weather, which greatly increases evaporation. The men 

 makino; the measurements mav overtake such waves or be overtaken 

 b}^ them in such a way that it is impossible to get any check upon 

 their influence. It will be noted that throughout the entire portion 

 of the stream measured there are alternating gains and losses in the 

 How. This may be attributed partly to the waves of increase and 

 decrease mentioned above and partly to changes in the channel. The 

 stream in some sections flows over solid rock, in others over beds of 

 bowlders (PI. IV, fig. 1), and in other sections winds back and forth 

 over beds of deep sand (PL IV, fig. 2). Under such conditions 

 varying i)ortions of the water which is finding its way down the val- 

 ley will be in the visible stream which is measured. The measure- 

 ments should not, therefore, be given too much weight. Considering 

 long sections of the river, the measurements through Wyoming show 

 a net loss, while those between the Wyoming-Nebraska State line 

 and Kearney show a net gain. It is not safe to base on these meas- 

 urements any positive statements as to what would occur if condi- 

 tions were different, but they seem to indicate that if ditches in 

 Colorado or the upper sections of Wyoming were closed only a part 

 of the water shut out of these ditches would reach Nebraska. Meas- 

 urements in Nebraska seem to indicate that the closing of the ditches 

 along the upper section of the stream within that State would increase 

 the supply lower down as far as the vicinity of North Platte, below 

 which there are large losses in the stream. The stream between 

 North Platte and Kearney has from the earliest times gone dry in 

 many years and been extremely Ioav in every year, and it does not 

 seem probable that the closing of the ditches above would noticeably 

 increase the supply in the surface channel in this section of the river. 

 The measurements of the water levels in wells, referred to on page 56, 

 show that the water table for some distance north of the river has a 

 slope to the south, which is not interrupted by the river, and indicate 

 that water which passes into the sand in this section finds its way out 

 of the valley of the Platte into the streams to the south. In the 

 immediate vicinity of the Nebraska-Wyoming line there is a gain in 

 the flow of the river, the notes of the measurements showing that in 

 the section from Torrington to the State line the return seepage is 

 almost exactly equal to the amount diverted in the section. There is 

 prospect of large increase in the use of the water in this section im- 

 mediately above the State line in Wyoming. The measurements 

 seem to indicate that a large part of the water diverted in this section 

 will return to the stream for use in Nebraska. 



A large number of irrigators and ditch men in the vicinity of 



