Pool: THE VEGETATION OF THE SANDHILLS OF NEBRASKA 201 



reach of the roots of most sandhill species of plants, and they are 

 then in little better condition than before the rain came so far as 

 capillary water is concerned. The usual heavier rains varying in 

 amount from 1 to 2 inches are thus completely taken up by the soil 

 and no surface drainage results. Occasional heavier rain storms, 

 however, produce considerable run-off. 



The streams and lakes of the sandhills seldom, if ever, show an 

 increase in volume immediately following even the heaviest down- 

 pours. Knowing that run-off is practically nil for the region, one 

 can not fail to appreciate the very gradual but constant delivery of 

 these volumes of water via subterranean routes until it finally reaches 

 the streams and lakes through springs. Fluctuations of this ground 

 water from season to season, however, produce noticeable variations 

 in the delivery of water to springs and consequently also in the level 

 of the surface waters of the region. Numerous intermittent lakes 

 owe their nature to this condition. Variations of this sort are not so 

 evidently reflected in the volume of the swiftly moving streams as 

 with the ponds and lakes. There is a well-known alternation of 

 periods of a few years each when there is considerably more precipi- 

 tation with other less moist periods which are commonly known as 

 "dry seasons." The level of the water in many of the lakes has been 

 reported to vary through this cycle. 



The most important stream of the sandhill region is the Loup 

 River, the three branches of which, the North Loup, the Middle 

 Loup, and the South Loup, rise in marshy flats toward the central 

 portion of the region. These streams flow in a southeasterly course 

 and unite east of the sandhill region to form a single stream which 

 farther eastward" pours into the Platte near Columbus. Of these 

 three branches the North Loup carries the most water, while the 

 South Loup, with the shortest course, is characterized also by the 

 least volume. Through the sandhills portion of its course the 

 Middle Loup is reported (58) to have a fall of about eight feet per 

 mile and hence develops considerable velocity. The channel is con- 

 tinually shifting its position in the narrow valley and the river wan- 

 ders back and forth across the flood plain. Many of these meanders 

 eventually become separated from the channel as cut-off lakes or 

 ponds. 



The Dismal River is an important tributary of the Loup from 

 the south. Heading from two points in the marsh and lake region 

 of Hooker, Grant, and McPherson counties, this river continues 



