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10 Overview of Suspended-Sediment Transport Monitoring - Existing management actions taken through WY 2003, under the Record-of-Decision (ROD) have failed to meet even the expectations contained in the Glen Canyon Dam EIS that, compared to the no action alternative, the preferred alternative would result in sand resources in the CRE increasing over time, The basic finding of the mass-balance project team is that downstream transport of new sand inputs occurs much more rapidly than was previously predicted by the Glen Canyon Dam EIS writing team (Rubin et aI., 2002). The rapid export of new sand inputs measured during 1999 through 2003, from sediment-starved upstream reaches such as Marble Canyon, indicates that the ecosystem's sand supply does not become progressively enriched over multi-year periods, except during periods when monthly release volumes are at about 700,000 acre feet or lower, Ifmost ROD dam operations prevent new sand inputs from accumulating within the river channel, then re-deposition of new sand inputs cannot occur during occasional controlled floods, termed "BeachlHabitat-Building Flows," Such periodic releases are intended to restore and maintain sand bars that have experienced erosion since dam closure, Suggested alternatives for better conserving new sand inputs include timing the release of bar-building floods to more closely follow significant periods of sand input from tributaries, Another alternative is to schedule BHBF releases during periods when ROD operations at Glen Canyon Dam reflect below-average basin-hydrology conditions, Nutrient Mass Balance - Under Construction Evolving Geomorphic Framework Coarse-Grained Inputs and Impacts: Webb and others, of the USGS, have estimated lesser tributary contributions for both fine and coarse sediments between Glen Canyon Dam and Upper Lake Mead, They find that fine sediment inputs from the Glen and Marble Canyon reaches of the ecosystem are, on average, likely to be a factor of two greater than the estimate used by the EIS writing team in preparing the fine-sediment mass balance reported in the GCD- EIS, Although the fine sediment inputs into this critical upstream reach may be significantly higher than previously assumed, the grain-size data published in the report indicate that those sediment inputs are as fine or finer than inputs from the Paria River, This finding suggests that while sand inputs from ungaged sources are significant and worth monitoring for management GCMRC FY2005-2006 Draft Annual Work Plan (November 10,2003)