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TP-2: The maintenance of tern and plover populations in the central Platte requires/does not require that sandpits and river continue to function together to provide nesting and foraging habitat. TP-3: Ephemeral nesting areas in the river are/are not needed for long-term nesting success of tern and plover. TP-4: Existing river flows influenced by drought, floods, hydrocycling, etc., do/do not provide a sufficient forage base (invertebrate/fish recruitment, survival, and correct composition) throughout the central Platte River study reach for populations of terns and plovers during the season. III.C.3. Pallid Sturgeon (PS) CEM The draft CEM for pallid sturgeon (Figure 7) was developed using the process generally described above in Section III.A. Hypothesis corresponding to linkages in the CEM are found in the table below. Pallid Stur eon H otheses PS-1: Current habitat in the lower Platte River is/is not suitable for adult and juvenile pallid sturgeon. PS-2: Water related activities above the Loup River do/do not im act allid sturgeon habitat. PS-3: Non-Program actions (e.g., harvest, stocking, Missouri River conditions) determine the occurrence of pallid sturgeon the lower Platte River III.C.4. Physical Process (PP) CEM Draft CEMs and corresponding hypotheses regarding the overall physical processes of the Platte River, including wet meadows, are discussed in the following table and illustrated in Figures 8, 9, and 10. The CEMs were developed using the technical subgroup as described above in Section III.A. Physical Processes Hypotheses Flow-Sediment-Mechanical Approach PP-1: Flows of varying magnitude, duration, frequency and rate of change affect the morphology and habitat quality of the river, including: • Flows of 5,000 to 8,000 cfs magnitude in the habitat reach for a duration of three days at Overton on an annual or near-annual basis will build sand bars to an elevation suitable for least tern and piping plover habitat; • Flows of 5,000 to 8,000 cfs magnitude in the habitat reach for a duration of three days at Overston on an annual or near-annual basis will increase the average width of the vegetation-free channel; • Variations in flows of lesser magnitude will positively or negatively affect the sand bar habitat benefits for least terns and piping plovers. PP-2: Between Lexington and Chapman, eliminating the sediment imbalance of approximately 400,000 tons annually in eroding reaches will: • Reduce net erosion of the river bed; • Increase the sustainability of a braided river; • Contribute to channel widening; September 1, 2006 Adaptive Management Plan 16