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The weighting by the square root of the catchment size, as opposed to the simple arithmetic average (which essentially gives proportionally larger weight to the small rivers as they have usually many more pixels in the basins), gives more weight to the larger rivers in the area averaging and thus . Therefore, in a basin with a proportionally much larger river with a lot of very small rivers will single large river near the outlet (such as the Danube or Amazon, etc.) and lots of comparably very small rivers, the large river will have noticeable contribution to the area average.
Figure 6. Example snapshot of the basin summary maps with the lead time navigation indicated and the categories and basin colours explained.
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