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386 Compularional Fluid Dynamics sides and around the tail end of the mid-channel gravel bar. At 2830mJls Wilh the low and intermediate sand supplies, the results were similar, with the deposit reach- ing capacity more rapidly with the intermediate sand su~ply. At 1270mJls. the sand volume with the high sand supply matched the 2830 m Is results with the low and intermediate sand supplies. Total deposition at 1270mJls with the low and inter- mediate sand supplies was relatively small. Considering only the sand deposited above the 708 mJ/s stage. the differences between the volumes deposited with the thrcc sand supplies at 1270mJ/s were relatively small (Figure 14.21). At 1270mJ/s, all thrcc sand conditions converged to a similar sand volume; the deposit reached capacity within about 6-10 hours with the high and intermediate sand supplies, whereas the deposit steadily grew over most of the simulation with the low sand supply. The significance of accommodation space created hy high stage was especially apparent in the results at 2830 mJ Is. At 2830 mJ Is, the sand deposits with the low and intermediate sand supplies were close to capacity after ahout 12 hours and reached a volume about seven times larger than with the lower discharge. With the high sand supply at 2830 mJ Is, sand deposit volume was nearly double the volume obtained with the two other sand conditions at 2830mJ/s (Figure 14.21). A more narrow focus on the deposits in region J, the critical region near the archaeological sites (Figure 14.22), showed a proportionately larger gap between the deposit volume at 2830 mJ Is with the high sand supply and the other cases than was evident for total depositional volumes for the entire reach (Figure 14.20). Total sand deposition near J for all cases except for the high sand supply at 2830 mJ Is and the low sand supply at l270mJls showed similar results at the end of the simulation. . Discharge (m3ts), send supply . 60 000 50 000 ;;- .5.40000 II E ~ ~ ,., 30 000 l1 II 13 ~20000 ell . .... 1270,Iow - - 1270, intermediate - 1270, high .....2830,low - - 2830, intermediate - 2830. high - Zero line -""' - -" ~~. --.. -" ....~...---.. ., .................... , .-.- . . . 10000 --- ------- 24 36 48 Time (hours) Figu,. 14.21 Modelled change in sand dep05ir volume above the 708m3/s stage in thtt Upper Unkar reach. o o .., ....-.......---........ 12 60 72 '. .