==========+=====+=====+=====+=====+=====+=====+=====+===== STATION | | | | | | | | AND | A | B | C | D | E | F | G | H DATE | | | | | | | | ----------+-----+-----+-----+-----+-----+-----+-----+----- 4-S | | | | | | | | August 9 | 0.0 | 154 | 16 | 28 | 3.5 |.083 |.250 |.225 | | | | | | | | 50-S | | | | | | | | August 9 | 0.0 | 125 | 24 | 20 | 2.5 |.669 |.427 |.240 | | | | | | | | 35-M | | | | | | | | August 9 | 0.0 | 366 | 15 | 108 | 9.4 |.220 |.750 |.080 | | | | | | | | 11-G | | | | | | | | July 8 | 0.0 | 272 | 15 | 60 | 4.5 |.060 |.625 |.140 | | | | | | | | 18-G | | | | | | | | July 22 | 0.0 | 183 | 10 | 60 | 1.6 |.938 |.293 |.240 ----------+-----+-----+-----+-----+-----+-----+-----+----- The banks of both the Big Blue and Little Blue rivers support narrow riparian forests comprised primarily of elm, _Ulmus americanus_, cottonwood, _Populus deltoides_, sycamore, _Platanus occidentalis_, and willow, _Salix_ spp. Maple, _Acer_ sp., oak, _Quercus_ spp., and ash, _Fraxinus_ sp. occur where the rivers flow near steep, rocky hillsides. Many of the hills are virgin bluestem prairies (_Andropogon_ spp.), but the floodplains are heavily cultivated. MUD-BOTTOMED STREAMS.--Streams of this kind are present in the watershed of the Black Vermillion River that enters Big Blue River from the east. The area east of the Big Blue River and north of the Black Vermillion River is till plains, where relief seldom exceeds 100 feet (Walters, 1954:12). Streams in this portion of the basin, and streams entering the Little Blue River from the west (Mill Creek and Horseshoe Creek systems), tend to have V-shaped channels, fewer riffles than the Little Blue and Big Blue rivers and in the gravelly streams (to be described later), and have bottoms of mud or clay, with few rocks (Plate 12, Fig. 1). However, in the extreme headwaters of most western tributaries of the Little Blue River (in Washington and Republic counties) sandy bottoms predominate. The Black Vermillion River flows on a broad floodplain and is a mud-bottomed, sluggish stream, with an average gradient of approximately one foot per mile. Fringe-forests of elm, cottonwood, sycamore, and willow persist along most of these stream-courses.