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<br />.'\
<br />CY
<br />
<br />(Beach/HabiJllt Building Test Flow continued from page 4)
<br />
<br />This test of the beacblhabitat-building flow requires a tremen-
<br />dous amonnt of coordination, as well as consolidation of
<br />resean:h efforts. Reduced funding levels are providing an
<br />opportunity to put into practice the recommendation for a more
<br />inlegmtive approach to the Glen Canyon Dam Long-term
<br />Monitoring Program, including research efforts, monitoring, and
<br />logistics. Successful application of the inlegmtion will provide
<br />a prototype for long-term monitoring. It will not be easy, but it
<br />is feasible tIuough coordination, patience. and good luck.
<br />
<br />The &hedule
<br />
<br />The beacblhabitat-bui1ding test flow is scheduled to begin on
<br />March 22, 1996, with 4 days of a constant 8,000 cubic feet per
<br />second (cfs) flow to allow for acquisition of pre-release aerial
<br />photogmphy and to establish a baseline for the research and
<br />monitoring studies. This photogmphy will record pre-event
<br />conditions of beaches, debris flows, backwatelS. and tributaI)'
<br />mouths.
<br />
<br />On March 26, the flow will increase at 4.000 cfs per hour
<br />(cfslhr) until a flow of approximately 45,000 cfs is reached. The
<br />4,000 cfslhr increase in flow rate bas been identified in the ElS
<br />process and will not, in itself, induce erosion of the sediment
<br />deposits. The 45,000 cfs level will be reached by first increas-
<br />ing Glen Canyon Dam powerplant releases, and then augment-
<br />ing with releases through the hollow-jet tubes. The fmallevel
<br />
<br />iJ
<br />
<br />of the high flow release will be dependent upon reservoir eleva-
<br />tion, powerplant load capacity, and safety considerations. The
<br />45,000 cfs level will be held relatively constant for 7 full days.
<br />During this high flow period, monitoring activities at key cuI-
<br />twa1 and environmental sites will be ongoing. This relatively
<br />constant 45,OOO-ds flow level will mobilize sediment in the
<br />river bottom. This suspended sediment will be deposited on
<br />beaches at the higher elevations as the high releases are lowered.
<br />This flow will also scour out and rejuvenate backwatelS.
<br />
<br />On April 2, the high releases will be IlIIIIped clown in a three-
<br />step process, over 2 days, in order to maximize the deposition of
<br />stable sediment deposits. The three steps are:
<br />
<br />Step 1: 45,000 eft to 35,000 eft@ 1,5ooefslhr
<br />
<br />Step 2: 35,000 eft to 20,000 eft@ 1,000 efslhr
<br />
<br />Step 3: 20,000 eft to 8,000 eft@500efs/hr
<br />
<br />The 8,000 cfs-Ievel will be held constant for 4 days to allow for
<br />collection of post-event aerial photogrnphy and surveying mea-
<br />surements. On April 8, the flows will return to the "normal"
<br />April interim flow releases, predicted to be fluctuating between
<br />8,000 and 12,000 cfs.
<br />
<br />Post-event monitoring and research will be initiated concurrent
<br />with Glen Canyon Dam Transition Monitoring.
<br />
<br />BEACH/HABITAT - BUILDING TEST FLOW -1996
<br />Releases
<br />
<br />50,000
<br />
<br />40,000
<br />
<br />(J)
<br />LL
<br />o
<br />
<br />30,000
<br />
<br />4,OOOcfs
<br />.........l.,.ltOtilltnJr....
<br />
<br />oi
<br />:a
<br />IV 20,000
<br />a;
<br />a:
<br />
<br />'-..
<br />
<br />10,000
<br />
<br />45 000 cfs
<br />
<br />i,500cfs
<br />-.. ~..~~~,.~.~~....
<br />
<br />
<br />o
<br />~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ b ~ ~
<br />~~~~~~~~~~~~~~~~~~
<br />
<br />Date
<br />
<br />(continued 011 page 11)
<br />
<br />5
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