Riparian Resources for Aspinall PDEIS

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of the operations alternatives mirrors the increase in percentage increase in the 6,040 cfs flows. The metric is change in percentage of bottomland. If the percentage change is ± 50 percent of Tess, then the duration is short -term. If the percentage change is greater than ± 50 percent, then the duration is long -term. Operation governed by the No- Action results is a Tong -term duration change in the community composition. Operations governed by action - alternatives A, B and D would each result in a short -term duration change in the community composition. Operation governed by action - alternative C results in a Tong -term duration change in community composition. INTENSITY: The No- Action reduces the percentage of bottomland in mesic community by 21 percent. This change is of minor intensity. Each action - alternative increases the percentage of bottomland in mesic community. Operation governed by action - alternatives A, B and b each has a negligible increase on percentage of bottomland returned to mesic communities. . Action - alternative C has a minor increase on the percentage of bottomland returned to mesic communities. TYPE: Operations under the No- Action and each of the action-alternatives is adverse with respect to improvement of bottomland plant community type resources. CONCLUSION: Conclusions are summarized in Table 4. Operation governed by the No- Action alternative can be expected to have a regional scale, long -term and major intensity impact to Black Canyon plant community resources. Continuation of operation by the No- Action would result in Toss of mesic communities at the expense of the encroachment of xeric communities. Operation governed by the No- Action has an overall adverse impact to Park vegetation resources. Operations governed by the action - alternatives A, B and D can be expected to have or action- alternative A can be expected to have a local -scale improvement on the regional - scale impact of the current operation. The short - duration of the operation and negligible intensity improvement on plant community type is expected to result in undesirable increases in xeric communities at the expense of mesic communities. The type of the impact is adverse. Operations governed by action - alternative C can be expected to local - scale improvement on the regional -scale impact of the current operation. Operation under action - alternatives will have a long -term change on park resources; the duration of the 6,000 cfs flows will increase the percentage of bottomland in mesic communities. successive intervals without a shearing flow is too long. The intensity is minor. Minor intensity improvement coupled with the long- term duration is not sufficient to preclude the loss of herbaceous vegetation to encroachment of xeric vegetation and the type of response is adverse.