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. . 1) prior to native fish (especially humpback chub) spawning, or larval dispersal; 2) after the peak of rainbow trout spawning at Lees Ferry; 3) several weeks after the peak concentrations of wintering bald eagle and waterfowl 4) prior to the Neotropical bird and waterfowl breeding seasons; 5) during a month in which high flows occurred in the pre-dam era; 6) prior to the peak release of non-native saltcedar (Tamarix ramosissima) seeds in late April and May, to allow riparian soils time to desiccate after the test flow, thereby reducing saltcedar germination; and 7) prior to the recreational river rafting season to reduce recreation and safety impacts (Patten et al. in press), For an event to occur in 1998, these and other considerations will be assessed. The Technical Work Group (TWG) is working to develop criteria for natural and cultural resources, but because these may not be finalized in time to apply for the 1998 flow, the TWG may find it necessary to otherwise attain consensus on resource needs and impacts related to a BHBF in 1998 before Reclamation agrees to implement the flows. KANAB AMBERS NAIL SPECIES ACCOUNT Distribution and Abundance The Vaseys Paradise population of KAS, at a spring at Colorado River Mile 31 ,5R, in Grand Canyon, Arizona, is one of only two known populations in the southwest (Spamer and Bogan 1993a, 1993b), Vaseys Paradise is a popular water source and attraction site for Colorado River rafters; however access is limited by the dense cover of poison ivy (Toxicodendron rydbergii) and the nearly vertical terrain (Stevens et al. 1997b), No KAS have been detected at more than 100 other Grand Canyon springs surveyed from 1991 through 1997. Rematched historic photographs ofVaseys Paradise (e,g, Turner and Karpiscak 1980:58-59) reveal that vegetative cover has increased greatly at lower stage elevations since completion of Glen Canyon Dam, and that flow regulation by the dam has increased primary KAS habitat area at Vaseys Paradise by more than 40%. All vegetation below the approximate 90,000 cfs stage was scoured by annual pre-dam floods in normal years. Stevens et al. (1997b) defined primary KAS habitat at Vaseys Paradise as that dominated by crimson monkeyflower (Mimulus cardinalis), non-native watercress (Nasturtium officinale), sedge (Carex aquatilis) and smartweed (Polygonum amphibium), Secondary, or marginal, habitat has been defined as patches of other riparian vegetation that are not dominated by these species and are not used extensively by KAS, Land surveys from 1995 through 1997 revealed rapid changes in 1998 GeD Beach/Habitat Building Flow 7 Biological Assessment