III. Comprehensive Geomorphic Assessment from Lexington to Chapman, Nebraska
<br />The key focus questions to be answered are:
<br />Are the historical and current river channels really different (except for vegetation); is the river longitudinally homogeneous, and is the river
<br />equilibrium? If not, why not, and what's controlling the shape?
<br />What are the current number, size and spatial distribution of sand bars in the Platte from Lexington to Chapman?
<br />If multiple channels are combined into single, wide channels, will these efforts be in concert with the river's geomorphology?
<br />To what extent do manmade features control the river morphology and how should the residual effects be factored in restoration planning?
<br />What active channel (and unobstructed) widths could be supported by today's flow regime if vegetation was artificially removed?
<br />Are pulse flows and addition of sediment capable of maintaining a wider channel once vegetation is removed?
<br />can the data collected by all the various investigations be put to maximum use and assure
<br />Lability of geomorphic interpretations at individual test sites over the entire targeted river
<br />lent and over the Iona -term?
<br />can the results of the various investigations be interpreted into appropriate long -term geomorphic implications given the limited number of years of
<br />How can the results of the various investigations be interpreted, integrated, and evaluated with a multi - disciplinary geomorphologic perspective to ensure
<br />development and application of a successful and cost - effective program over the long -term?
<br />OT worK
<br />Question Answered By:
<br />A5, 136-7, 1310, C21, E1 -2
<br />A15, 136, 1310, C16
<br />136, C16, C21, E1 -3
<br />A15, 136, 1310 -13, C17
<br />132 -3, C10, E1 -3
<br />E1 -3
<br />A15, B2, C21, E3
<br />A15, E3
<br />IA15, BD C17, 021, E3
<br />This investigation will provide the critically- needed qualitative and quantitative geomorphic assessment of the Platte that has been the source of many of the unresolved questions and
<br />hypotheses. Existing data will be compiled and a substaintial amount of new data on the current and historical form of the river will be collected, focusing primarily on the reach from
<br />Lexington to Chapman with possible extensions upstream and downstream. This assessment is critically needed because it has not been previously done, it is known that the river has not
<br />been and is not homogeneous (for example, the historical and current river below the city of Kearney is distinctly different in morphology {form) than upstream of that location), and the
<br />factors shaping the river must be understood before attempting to create a different river through adaptive management. Development of a comprehensive assessment of the river's form
<br />and processes controlling the form are necessary precursors to implementation of any treatments intended to modify the river's form.
<br />All classical texts on river management advise that any attempts to modify a river must be done with an understanding of, and in concert with, processes that shape the river. Too many
<br />questions regarding the current and historical river form and process remain unresolved to avoid this assessment. One of the primary uses of this assessment will be to determine whether
<br />processes, trends and treatments at single locations can be effectively extrapolated to the entire river reach based on geomorphic compatibility. Because of the importance of the relative
<br />state of the river's form at the turn of the century, this analysis will include an assessment of the current geomorphology as well as that existing in the late 1800's and early 1900's. The
<br />comprehensive geomorphologic assessment will also provide a forum for interaction among the various investigation components to allow development of an appropriate interpretation of
<br />the results of the various investigations regarding meeting of habitat objectives from a sediment, vegetation, and geomorphic perspective. Key to the geomorphological integration of the
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<br />the three level process of qualitative geomorphology, quantitative geomorphic and related analyses, and modeling. In addition to the refinements of individual physical processes in Tasks I
<br />and Il, a substantial amount of modeling of integrated physical processes is proposed in this task for several reasons. This integrates the sediment, vegetation, hydrologic and hydraulic
<br />processes. Another reason is that the field work will occur under a limited range of hydrologic and hydraulic conditions, and modeling allows extrapolation to other conditions. In addition,
<br />long -term implications of the restoration activities and prediction of conditions under full implementation require evaluation by modeling and related analyses in addition to monitoring.
<br />Budget Summary
<br />Totals
<br />Year 1
<br />Year 2
<br />Year 3
<br />Year 4
<br />Yrs 5 -13
<br />Labor Cost
<br />$1,463,200
<br />$165,000
<br />$106,000
<br />$411,000
<br />$445,200
<br />$336,000
<br />Direct Non -Labor Cost
<br />$79,500
<br />$23,300
<br />$13,600
<br />$9,200
<br />$5,900
<br />$27,500
<br />Contract Services
<br />$826,000
<br />$176,000
<br />$295,000
<br />$10,000
<br />$10,000
<br />$335,000
<br />Contingency
<br />$355,305
<br />$54,645
<br />$62,190
<br />$64,530
<br />$69,165
<br />$104,775
<br />TOTAL
<br />$2,724,005
<br />$418,945
<br />$476,790
<br />$494,730
<br />$530,265
<br />$803,275
<br />15%
<br />
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