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3. TEXT CHANGES Wetland and waterfowl related impacts associated with the 500,000 TPY Altemative would persist through mine life, and to some degree until aquifer recharge. However, the applicant would be subject to (ally compensating waterfowl habitat value lost as a result of groundwater pumping (see revisions to Section 2.4.1.1.8)." Page 4-20 (14) Column 1, paragraph 3, sentence 2: "The groundwater depletions (as shown in Table 43) although significant from this specific project, would ultimately reduce surface water volumes in the White River and downstream endangered species' fisheries due to the cumulative effects of all the projects in this area" should read: "Groundwater depletions shown in Table 4-3, although regionally insignificant for this individual project, would contribute cumulatively to reduced surface water volumes in the White River and downstream endangered species fisheries in association with other projects in the area (see Section 2.5, Baseline)." (14) Column 1, replace paragraphs 5 and 6: "Animal populations associated with Yellow Creek's palustrine wetlands would not be influenced by small compositional changes projected for inchannel emergent vegetation under the No Action, 50,000, and 125,000 TPY alternatives (see Section 4.9.6). Flow depletions projected for the 500,000 TPY Altemative have the potential to reduce or alter shrub-scrub and emergent wetland components by an appreciable, but undetermined degree (see Section 4.9.6). Stmcturally or compositionally unique habitat elements exist in the form of tamarisk stands (approximately 5 acres) and the nartow obligate emergent zone composed of sedges and bulrush adjacent to Yellow Creek's streambed (approximately 18 acres). Small existing populations of species dependent on these features, including yellow warbler, yellowthroat and song spartow, could very well be subject to many years of habitat reduction and displacement. However, wetland related mitigation requirements (see Section 2.4.1.1.8) should adequately compensate these habitat losses in the long-term:' (6, 11, 14) Column 2, Section 4.9.6: Replace entire section. 4.9.6 WETLAND HABITATS 4.9.6.1 Flow Depletion Impacts Without a complete understanding of the mechanics governing wetland systems in Yellow Creek, BLM is unable to predict precise consequences of long-term flow reductions. Assuming wetland extent, composition, and condition are a function of streamflow, any base flow reductions would be expected to alter the distribution and quantity of moisture available for wetland maintenance. It should be emphasized that flow depletions in Yellow Creek (Table 4-7A) would develop gradually, reaching maximum mlcs 25 to 27 years after mining begins. Although maximum depletion rates have been applied to all calculations, interim flow loss would average 50 percent lower for the No Action, 50,000 TPY, and 125,000 TPY alternatives, and 25 percent lower for the 500,000 TPY Altemative. Depletions could persist for many years after mine life, although progressive recovery of ground and surface waters should commence soon after groundwater pumping ceases. 4.9.6.1./ NoAtrlon,SO,000,andl?5,0007PYAlremarives Spring and early summer Bows are considered most important for plant establishment and growth-at a time when Yellow Creek's flows would be least influenced by mine-induced depletions (2 to 3 percent maximum, Table 4-7A). Average late summer Uow depletions would increase slightly to 3 to 5 percent. During drought influenced years, average depletions through the entire growing season may be 5 to 7 percent, becoming most pronounced during late summer low-Bow periods when 12 percent average reductions could be realized (short-term events could approach 20 percent). BLM expects no net reduction of in-channel wetland acreage Gom Bow loss associated with these alternatives (Table 4-7A), although small compositional changes in the herbaceous emergent zone may occur. This could appear as a linear constriction of the obligate herbaceous community along the 12.9 miles of affected stream, with compensatory expansion of facultative herbs. BLM would expect unit-for- unit "exchange" of obligate to facultative emergents, involving less than 5 percent of obligate vegetation most years, and no more than 10 percent d wring drought influenced years. Spring runoff and intense summer storm flows appear to regulate the distribution of shrub-scrub wetlands by supporting the proliferation of woody species in overflow areas and restricting shrub encroachment to the high water perimeter. Since periodic and seasonal Gooding would not be perceptibly influenced bymine-induced dewatering under 3-22