WSP09211

• File Number: 8220.101.10
• Description: Colorado River-Water Projects-Glen Canyon Dam/Lake Powell-Glen Canyon Adaptive Management-
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/2005
• Author: Wiele-Torizzo
• Title: Modeling of Sand Deposition in Archaeologically Significant Reaches of the Colorado River in Grand Canyon
• Water Supply Pro - Doc Type: Report/Study

J88 Compur.wonoJl FlUid Dyndmics

S.J.nd de:po..ih most likel) to be of gr~al~~1 bcn~lit to artefact presenalion wer~ the:
de:pvsils n~ar J abo"e the 70b m),s stage (Figure 14.22). Sand deposIt volumes near J
abo"e 708m"is .....ere small at 1270m.lls for all sand supplies compared ......ith th~
re~ults at 2~30m"s, The increa:.ed accommodatIOn space al 2lSJOm.js JlIo......ed for
much brger deposih with the low and Interm.:dial~ )and supplies than those formed
at 1270m1,.s. With th!: high sand supply. s..lnd dep~)Sit volume near J abo....e th~
708m~ s stJge ......as three limes the sand depi)sit .olume at 2~30m~ s with the t......o
.:Jther lower sand supphe:s About half of the increaS( in tOlal deposil vl)lume for the
re:ach ..hown In Figure 14.21 al 2830m)is \!oith the high sand ..upply ......as a re..ult of
incre:asc:d d~positlon near J. In aU cases. some deposition occurred In that re~ion
.1Iong the bank. ;tided in part by the pre..ence oi debris Ihdl was deposited upstream
near Ih~ tight bank durin~ the ~me e"entthal formed Ihe mid-channd bar. With the
hlghe~H ..and supply. thefl~ ......as sufficient depo..ition to initlale substantial bars 10 the
lee of that debris; thus large deposits \.\-ere formed ,It the most ad....antageou.. slIe for
the preservalion of archal.llogical artefacts.

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14. 7 Discus.~ion

~1oddlin~ resulls show significant vand-bilit) in deposilion volumes rdating to
.:hannd shape .1:> ......ell .is to discharge and S<tnd ..upply (Figure 14.23). In reaches

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Lava Chuar 1

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Lo_rTanr'lel'

Palisades

Upper Ullur

Otscharge (m3/S). sand supply
";::0;'1 1270.10....
E3 1270,lIllermediale
-J 1270. htgtl
2830, low
g 28J0, 1l'11ermedlale
<= 2830. hlQh

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Figu" 14.11 Ch.mge in -.Jnd \ollJme divided b" (('deh length .It (he end or the modell,n,~
penod. The ch,mge 1M Sdnd \'ohml(' 15 dn,ded by (('den Il'ngrh (0 ;dof,tdrt' the CompdflSDn 01
the erfec! or chdnnel rTlOrpholog)' on s.U1d depililtlon Jnd eros/OIl.

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