River Hydraulics and Sediment Transport

Home Browse Search

clearing of vegetation from river island and modest increases in annual peak flows and, therefore, does not control channel degradation, increase open view widths, or build sandbars much more than under the Present Condition. r. , ,.,,,,,. 11IIVER CHANNEL RESTORATION All of the alternatives undertake measures which can affect the characteristics of the river channel in the Central Platte Habitat Area and the quality of the habitat provided there for the three target bird species. This occurs primarily through the changes in riverflow, described in the previous section, coupled with direct management of channel width and sediment load in the river, described in detail below. Ultimately, these actions affect the amount of useable roosting, nesting, and foraging habitat available in the river channel for the target bird species. The alternatives can vary by both their water management plan and their land management plan. With respect to considerations of channel morphology, there are three distinct land plans that use mechanical means to clear vegetation from river islands, at discrete locations, and then level the island surface by spreading the island sand into the surrounding river channeL Mechanical changes to the channel for each alternative are listed in table 5-26. Under the Governance Committee Alternative, Scenario 1, the land management plan would only clear the vegetation from selected river islands, with no leveling or changes to island topography. The first island clearing and leveling plan with vegetation removal and mechanical lowering of the islands would affect six potential locations and is used for the Governance Committee, Scenario 2; Water Leasing; and Wet Meadow Alternatives. The second island clearing and leveling plan, with mechanical changes to the channel at two potential locations, is used for the Water Emphasis Alternative. Table 4-1 lists commonly used RM locations and associated landmarks.