Question about snow distribution in watershed simulation

[chen ding]

According to a paper in Water Resources Research (2016) by Painter et al., the ATS  model prioritizes depositing snowfall in topographic depressions during snow distribution. Only when these depressions are filled to a certain depth does the snow begin to distribute more evenly across non-depressed areas.

However, I’ve encountered an issue in my watershed simulation. My basin has very high topographic relief—the elevation of the river channels  is often tens of meters lower than the surrounding terrain. At the same time, the snowfall amount in the region is not sufficient to allow accumulation in non-depressed areas. As a result, in my simulation, only the area directly over the river channel shows substantial snow accumulation, while other regions have little to no snow cover. This likely deviates from real-world conditions in the watershed.

I would like to know which parameters or variables I could adjust to improve this situation. Any suggestions would be greatly appreciated!

Chen,

[Painter, Scott]

Hi Chen, 

Yes, it is possible to change parameters in the snow redistribution model so that it moves less snow. However, the redistribution model was designed to redistribute snow in local micro topography. It’s quite heuristic and wasn’t really designed to distribute snow at watershed scales.  In a watershed model, a better approach would be to turn off the redistribution model and use spatially distributed snow precipitation to drive the model. Specifying that in the ATS input file is straightforward but you’ll need some offline method for distributing the incoming snow precipitation on the landscape. This could be done by developing correlations with landscape position and vegetation characteristics if you have sufficient data. A physically based snow redistribution model that takes topography and wind direction and speed as input would be an alternative approach. 

Scott 

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Date: Saturday, November 29, 2025 at 11:33 PM
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Subject: [EXTERNAL] Question about snow distribution in watershed simulation

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