|Topography used in this study, the top layer is porous, |
the lower layer is bedrock
The two main models used here are the mass source and the porous media models.
|Initial condition before rainfall*|
|Intermediary stage, the ground is still|
mostly soaking water
The precipitation map can be fully defined both spatially and temporally across the entire domain, and porous behaviors can be modeled both for saturated and un-saturated media.
|Torrent formations following heavy precipitation. Note the water pooling and main torrent formation in the canyon on the right, and the strands of heavy discharge into the pre-existing body of water on the left.|
You can also view the video on youtube here.
Finally it's very interesting to look at the time series of water depth located at a probe placed near the lower end (elevation wise) where I was expecting to see the great volume flow and water pooling. Initially, while the porous layer is actively absorbing water, we see no surface water pooling. Then once the layer becomes saturated, we observe a rapid increase in water depth, until we finally observe the steady state balance between the influx of precipitation and the outflow via the torrent.
Finally I note that you can be a lot more sophisticated with the mapping of the precipitation rates by simply tiling your domain into various sub-components (they can be of arbitrary shape by the way):
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*All simulations post-processed with FlowSight, coming soon in FLOW-3D v11