Information on Land Use/Veg/Soil

[ephilip]

Greetings!,
Would you please give bit more information regarding How SoilClasses, SoilProfiles, VegitationClasses, LandUseClasses (page 109) in the .rvp files and the SubBasins/HRUs in .rvh files are related. A chart would be great. Is GLACER, LAKE,ROCK, STANDARD reserved words? How WETLAND is handled. Is it only through the user defined parameters.
Your help is highly appreciated.

Thank you
Elizabeth

[rchlumsk]

Hi Elizabeth

Thanks for the question. As a general overview, here are a few helpful points to answer some of your questions:

- Raven typically operates as a semi-distributed model. This means that parameters are defined for HRUs based on the HRU properties, such as the soil class, vegetation class, or landuse class. Each of the classes has a certain set of parameters associated with it.
- in the rvi file, the number of soil layers and the names of each soil layer is defined. The soil layer names can generally be defined as whatever you like, or just be referred to as SOIL[0], SOIL[1], etc. The rvp file specifies the soil classes, soil profiles, and parameters related to each soil class.
- the vegetation, landuse, and soil classes associated with each HRU in the model are defined in the rvh file. The parameters listed in the rvp map to the HRUs with the corresponding vegetation/landuse/soil type (terrain classes can also be defined). Global parameters also exist in Raven, which are not part of any of the landuse/vegetation/soil/terrain classes.
- Raven does have a number of special HRU types, which you have identified correctly to include LAKE, ROCK, etc. (read more about these in the manual, pages 108 and 110).
- Currently WETLAND is not a special HRU type. There are a few ways to approach wetlands, either as a user-defined land use type or as a LAKE feature, depending on the size and nature of it (e.g. you could specify a LAKE type and a reservoir rating curve with zero outflow, if that is appropriate). As you have seen on page 108, you can specify processes that are conditional to the landuse type, which you could use to customize the handling of wetlands. I can also let you know that currently we have a number of grad students working on improving the handling of wetlands and similar features (bogs/fens/permafrost zones) in Raven, so keep an eye out for future improvements in this area.

Otherwise, I would refer you to the first Chapter of the Raven manual for a general understanding of Raven works, and how those definitions are connected. There are a number of example models and tutorial files that you can find on the Raven downloads page, which you can walk through and see how the HRUs and various files interact.
http://www.civil.uwaterloo.ca/jrcraig/Raven/Downloads.html

If you have any other questions or want more detail about something, please feel free to reply back with more :)

Cheers,
Rob

[ephilip]

Hi Rob,

Thank you for the reply. Got few of the points.

I am still not able to get the link between the .rvi, .rvh and .rvp files . In the Nith example LAND_USE_CLASS are AGRI1, AGRI2, FOREST1 and URBAN and the VEG_CLASS are CROP1,FOREST1 and URBAN1 in the rvh file. In the .rvp file you have VegetationClasses, VegetationParameterList, SeasonalCanopyLAI, LandUSeClasses has the follwoing list. : CROP1,FOREST1,URBAN1,WATER1 and WETLAND1.

I am not understanding how WATER1 and WETLAND1 that is not listed ion the .rvh file came to the .rvp came. Why these parameters are defined?

Thank you
Elizabeth

[rchlumsk]

Hi Elizabeth

In the Nith model from the tutorial, the WATER1 and WETLAND1 are indeed not listed in the rvh file, therefore they have no impact on the model (the parameters defined for these classes are essentially not tied to any HRU, and have no impact). You can test this by commenting out or changing those parameters and comparing the results. I am not sure of the history of the Nith model development, but I believe those are leftover from a different model configuration prior to using the model for the tutorials.

In general, the key point is that the parameters in the rvp file are linked to the HRU properties, defined in the rvh file. If a set of parameters is not defined for a specific class, then the DEFAULT class parameters will be used. There is also a set of parameters called Global Parameters, which are model parameters applied everywhere in the model, in case you come across those as well. These will typically be defined at the top of an rvp file.

Hope that helps!
Rob

[ephilip]

Hi Rob,

Thank you so much for clarifying the confusion. So if an HRU is defined with LAND_USE_CLASS and SOIL_PROFILE as GLACIER then the rvp file should have parameters for GLACIER defined.

Thank you
Elizabeth

[rchlumsk]

Hi Elizabeth

That is correct. If the parameters for GLACIER are not in the rvp file then the DEFAULT values will be used. Note that the GLACIER keyword is treated in some specific ways, refer to the manual for descriptions of the GLACIER-specific processes.

Please let me know if you have any other questions!

Cheers,
Rob

[ephilip]

Greetings!

Would you please explain how the parameters in the Example 1 are determined. I am not able to find the parameter CC_DECAY_COEFF in the user manual.

:LandUseParameterList
:Parameters, GR4J_X4, MELT_FACTOR, CC_DECAY_COEFF
:Units , d, mm/d/C, 1/d

Thank you
Elizabeth

[rchlumsk]

Hi Elizabeth

In general, these parameters are determined by calibration, particularly for conceptual parameters such as these (some more physically-based parameters can be measured or estimated otherwise, at least as a starting point).

The CC_DECAY_COEFF is a linear decay coefficient for decreasing cold content in the snowpack of the model. I believe it comes from the CEMANEIGE model, described in [url][/url]Valéry3ore detail (linked below).

http://www.sciencedirect.com/science/article/pii/S0022169414003321

Hope that helps!
Rob

[ephilip]

Hi Rob,

Page 108 talks about using conditional commands. Would you please explain bit more on HRU_TYPE and LAND_USE . Is it not both the same?
GLACIER, LAKE,ROCK are they defined under soil profile?

Thank you
Elizabeth

[rchlumsk]

Hi Elizabeth

The HRU_TYPE is set for both the soil type and land use (such as GLACIER or LAKE), and you can make a process conditional on the HRU based on this type. You could also make the process conditional based on the land use (for GLACIER or for non-reserved land use types, such as WETLAND) using the LAND_USE tag. If you want to make the process conditional for unique combinations of HRUs, you may also setup an HRU group in whichever way you like and make the process conditional for those HRUs.

Hope that helps,
Rob