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<br />-7 - <br /> <br />. <br /> <br />Nebraska, and Wyoming had an independent review of the data and model developed by <br />DOl (see Platte River Channel Dynamics Investigation, Parsons, May 2003). The Parson's <br />conclusions cast serious doubt regarding the definitive conclusions reached by DOl. The Sed <br />Veg model does appears to have some value however, significant process relationships <br />(geomorphic, plant physiology and the linkage of the two) and calibration and verification <br />issues persist. This "tool" forms the foundation upon which all assumptions and projections <br />of impacts are formed. <br /> <br />The National Academy of Science (NAS) review of Endangered and Threatened Species on <br />the Platte River, April 2004 had the following remarks regarding Sed Veg: "The committee <br />did not evaluated three items,...an advanced computer model, SEDVEG, to evaluate <br />interactions among hydrology, river hydraulics, sediment transport, and vegetation being <br />developed, but not yet competed or tested (emphasis added), by the USBR for application <br />on the Platte River, and "... the committee did not access the newer models because they have <br />not been completed or tested, but recommend that they be explored for their ability to <br />improve decision making, (emphasis added), The NAS further states: "The committee also <br />recognizes that there has been no substantial testing of the predictions resulting from the <br />DOl's previous model work, and it recommends that calibration of the models be improved", <br /> <br />. <br /> <br />There are significant unknowns regarding the use of Sed Veg and the DElS should not rely <br />on the promising but unproven too\. The DEIS contains no summary of the accuracy and <br />precision of Sed Veg both in terms of it's model processes and the raw data that is used for <br />model runs, For example is the precision of the flow and sediment data and vegetation <br />germination and mortality data greater than the predicted trends? The DElS team clearly <br />had concerns in this regard as they inappropriately modeled trends for 61 years even though <br />the length of the action alternatives is only 13 years. Any analysis done on the action <br />alternatives should be directly linked to the period of the federal action. In addition, there is <br />no quantitative discussion of the required river stage change and the number of days needed <br />to create sand bars and how that information is accounted for in the model or whether it <br />historically occurred. The DElS analysis appears simplistic with a one to one relationship <br />between river stage and sand bar formation, <br /> <br />No data is provided in the DElS showing that the prescribed flow relationships and the <br />magnitude and duration of flow recommendation and Sed Veg modeling will result in the <br />scouring of vegetation, It is equally likely that the hypothesized processes for vegetation <br />removal wiil have the opposite effect by: I) distributing seedling with a short term pulse and <br />2) late summer irrigation (release of so called forage fish flows) to ensure the survival and <br />growth of the seedling and narrowing of the channel. <br /> <br />It is requested that the Sed Veg model not be used to describe impacts. Given the <br />uncertainties in the knowledge a more qualitative assessment is needed with the <br />understanding that the action altematives will monitor effects and offset negative impacts as <br />necessary using proven habitat management methods. <br /> <br />6. The DEIS grossly understates the benefits of habitat acquisition and management and <br />restoration provided by the Governance Committee Alternative, especiaily in relationship to <br />the species use and needs on the Central Platte. The management of 10,000 and ultimately <br />29,000 acres of habitat for the species is conservatively more than enough to ensure that the <br />Flood Protection. Water Project Planning and Finance. Stream and Lake Protection <br />Water Supply Protection. Conservation Planning <br />