OutdoorNebraska

18 Nebraska Game and Parks Commission • Floating The Good Life PLATTE RIVER/BRAIDED RIVER Braided Rivers This river type as shown in Figure 4 is found in a variety of valley types from deep glacial outwash valleys to relatively flat plains. Nebraska rivers that exhibit this characteristic type include the Republican, Platte (pictured on right), North Loup (downstream of Ord), White, and portions of the Upper Missouri. General characteristics of braided rivers include: • Multiple channel system exhibiting a braided pattern that is displayed as a series of various bar types and unvegetated islands, which shift position frequently during storm events. • Very wide and shallow rivers that are not incised deeply and can be contained in narrow or confined valleys. • In valleys with moderately steep slopes, braided channel patterns can develop in very coarse materials compared to developing in finer materials present in wide, flat valleys. • Bank erosion rates are high and sediment supply is generally unlimited. • Very low sinuosity with channel adjustments occurring due to aggradation and lateral extension. • River bedform is the result of a convergent/divergent process of localized bed scour and sediment deposition. • Rivers are considered "flashy" with water levels rising and falling very quickly during and after storm events. Figure 4: Braided Rivers Braided rivers are characterized by wide, shallow channels with water flowing in two or more channels around sand and gravel bars or islands. This river type generally very high energy and unstable. Determining the optimal location for a river trail access on a braided river can be aided with the review of historic AERIAL PHOTOGRAPHS which can assist in showing where fewer issues of constantly changing bank and channel conditions can be seen. There is one primary THALWEG (dark blue) and several secondary flow paths (light blue). The thalweg is generally more stable than the secondary flow paths. POINT BARS and ISLANDS are exposed during low flows and submerged during high flows. Vegetation may become established on these bars and islands that can help stabilize these features. BANK EROSION is generally high providing an unlimited supply of sediment (soil, sand, and gravel) into the water. BRAIDED RIVERS

• Cover