New runoff method for single column

[AlexisRenchon]

Purpose

This PR adds a method of runoff specifically for single site runs, which assumes that water at the top of the soil column (from precipitation or snow melt) which is in excess relative to infiltration capacity is runoff.

To-do

• Method functions, BC conditions (! need docstring for abstractrunoffmodel)
• Unit tests (! WIP)
• Add runoff method in atmospheric drivers (? is this needed ?)
• Call that method in experiments
• Add docs

Content

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• I have read and checked the items on the review checklist.

[AlexisRenchon]

@juliasloan25
Hey Julia,
This PR should be pretty simple, we are just adding an AsbtractRunoffModel, but we get an error:

ERROR: The following 1 direct dependency failed to precompile:

ClimaLand [08f4d4ce-cf43-44bb-ad95-9d2d5f413532]

Failed to precompile ClimaLand [08f4d4ce-cf43-44bb-ad95-9d2d5f413532] to "/home/runner/.julia/compiled/v1.10/ClimaLand/jl_xbjQuI".
ERROR: LoadError: TypeError: in Type{...} expression, expected UnionAll, got Type{ClimaLand.Soil.Runoff.InfiltrationExcess}
Stacktrace:
  [1] top-level scope
    @ ~/work/ClimaLand.jl/ClimaLand.jl/src/standalone/Soil/boundary_conditions.jl:1001

and I am not sure why it happens... (very similar code just above in boundary_conditions.jl to define the TOPMODELRunoff methods do not have this error).
Note I am also surprised the error is at line 1001, which is the beginning of a docstring

[juliasloan25]

@juliasloan25 Hey Julia, This PR should be pretty simple, we are just adding an AsbtractRunoffModel, but we get an error:

ERROR: The following 1 direct dependency failed to precompile:

ClimaLand [08f4d4ce-cf43-44bb-ad95-9d2d5f413532]

Failed to precompile ClimaLand [08f4d4ce-cf43-44bb-ad95-9d2d5f413532] to "/home/runner/.julia/compiled/v1.10/ClimaLand/jl_xbjQuI".
ERROR: LoadError: TypeError: in Type{...} expression, expected UnionAll, got Type{ClimaLand.Soil.Runoff.InfiltrationExcess}
Stacktrace:
  [1] top-level scope
    @ ~/work/ClimaLand.jl/ClimaLand.jl/src/standalone/Soil/boundary_conditions.jl:1001

and I am not sure why it happens... (very similar code just above in boundary_conditions.jl to define the TOPMODELRunoff methods do not have this error). Note I am also surprised the error is at line 1001, which is the beginning of a docstring

Hi Alexis! Usually when the error points to the start of a docstring, the error is actually in the line of code immediately after that docstring. In this case, the error is coming up because you dispatch on <: InfiltrationExcess{FT} (here), but InfiltrationExcess isn't defined to take a type parameter FT. Locally, I removed {FT} from the dispatch and it precompiles fine :)

[AlexisRenchon]

@braghiere @kmdeck Do we still want to do this? Or should we close this PR?

[braghiere]

Well, we need the runoff term for site level runs. Can we quickly finish it and merge it?

[kmdeck]

completed following this PR's approach in PR #702