LandUseClasse Attribute Impermeable_frac

[Symona]

Hello,

I am trying to set up a model from scratch - or more precisely - via top-down approach in order to propperly learn and understand Raven and my catchment. I thus happend to notice something strange for my single - basin model.

For the beginning I defined the Impermeable_frac for the LandUse Class as 0. I take it this means that non of the area of the catchment is IMpermeable and water can travel into the soil everywhere.

However in this mode the WatershedMassEnergyBalance File shows that water is only moving from ATMOS_PRECIP --> PONDED_WATER and from PONDED_WATER-->SURFACE_WATER. Nothing is infiltrating into the Soil[0] (one-layer-soil).

My 1st simple model structure includes the following Processes:

:HydrologicProcesses
:Precipitation PRECIP_RAVEN ATMOS_PRECIP MULTIPLE
:Infiltration INF_GREEN_AMPT PONDED_WATER SOIL[0]
:Baseflow BASE_POWER_LAW SOIL[0] SURFACE_WATER
:EndHydrologicProcesses

However if I change the Impermeable_frac for the LandUse Class to 0.1, suddenly there is iinfinitesimal movement mostly OUT of the soil (cumulative sum for last timestep of PONDED_WATER --> SOIL[0])
0 --> 0
0.1 --> -2.29E-13
0.2 --> -3.86E-13
0.3 --> 2.98E-13
0.4 --> -1.21E-14
0.5 --> 0
0.6 --> -1.21E-14
0.7 --> -3.50E-14
0.8 --> -4.88E-15
0.9 --> 5.15E-14
1 --> 0

Maybe the numbers don't matter, but shouldn't there be infiltration into my soil?

[jrcraig]

Hi Symona,

It's hard to figure it out with only that information. I think the small negatives are simply roundoff error - the negative means nothing here. I would expect this behavior if the hydraulic conductivity of the soil is zero, the wetting front suction were zero, the porosity was zero, or if the soil layer were saturated. First check these, then try using INF_GA_SIMPLE to see if you have any more luck with that (only because I know that routine has been put through the wringer more). I think the Impermeable_Frac issue is a red herring.

[Symona]

Hello jrcraig,

hydraulic conductivity, porosity and wetting front suction are all auto generated by raven (0.001 mm/d, 0.426, -38888.8 -mm) & there is no intitial condition for the soil layer, so the storage should be 0. With those numbers I get the mentioned results and the same thing is happening if I use INF_GA_SIMPLE.

Inf_HBV works though.

[jrcraig]

the problem here is likely the negative wetting front suction being autogenerated by Raven. I will look into that. Try setting this to a reasonable positive value (~50-300mm)