MODPATH create_mp7 with mpbas

[WaterqualityFloris]

Hi all,

I have this flopy code snippet that sets up a modpath simulation. I add a porosity to the simulation through an array called ' porosity' with Modpath7Bas, after setting up the simulation with create_mp7

mp = flopy.modpath.Modpath7.create_mp7(
    modelname=mpnamb,
    trackdir="backward",
    flowmodel=gwf,
    model_ws=ws,
    rowcelldivisions=1,
    columncelldivisions=1,
    layercelldivisions=1, create basic backward tracking modpath simulation
    exe_name='mp7',
    verbose=True
)

mpbas = flopy.modpath.Modpath7Bas(mp, porosity=porosity)

mp.write_input()
mp.run_model(silent=True, report=True)

However, when I run this code, I get this error:

flopy/mbase.py:668: UserWarning: Two packages of the same type, Replacing existing 'MPBAS' package.
warn(

This results from me using Modpath7Bas. I did not expect this warning and wasn't able to find a good example on how to otherwise set up this problem. It seems that it does not affect calculation results, which have an output that I would expect with changing porosity in my model. However, should I be worried about this warning and are there ways to work around it? If you have a good advise or a relevant section in the documentation or in these discussions that I missed, I'd be glad to get that from you! Looking forward to hearing your advice,

Floris

[martclanor]

Hi Floris,

I think it's because Modpath7.create_mp7 creates already a Modpath7Bas object internally. Perhaps a possible solution is to copy the implementation inside create_mp7 (as linked below) to your script, then passing porosity to the Modpath7Bas object

flopy/flopy/modpath/mp7.py

Lines 463 to 509 in f96d173

	# create MODPATH 7 model instance
	mp = Modpath7(
	modelname=modelname,
	flowmodel=flowmodel,
	exe_name=exe_name,
	model_ws=model_ws,
	verbose=verbose,
	)
	# set default iface for recharge and et
	if mp.flow_version == "mf6":
	defaultiface = {"RCH": 6, "EVT": 6}
	else:
	defaultiface = {"RECHARGE": 6, "ET": 6}
	# create MODPATH 7 basic file and add to the MODPATH 7
	# model instance (mp)
	Modpath7Bas(mp, defaultiface=defaultiface)
	# create particles
	if nodes is None:
	nodes = []
	node = 0
	for ib in mp.ib.flatten():
	if ib > 0:
	nodes.append(node)
	node += 1
	sd = CellDataType(
	columncelldivisions=columncelldivisions,
	rowcelldivisions=rowcelldivisions,
	layercelldivisions=layercelldivisions,
	)
	p = NodeParticleData(subdivisiondata=sd, nodes=nodes)
	pg = ParticleGroupNodeTemplate(particledata=p)
	# create MODPATH 7 simulation file and add to the MODPATH 7
	# model instance (mp)
	Modpath7Sim(
	mp,
	simulationtype="combined",
	trackingdirection=trackdir,
	weaksinkoption="pass_through",
	weaksourceoption="pass_through",
	referencetime=0.0,
	stoptimeoption="extend",
	particlegroups=pg,
	)

Maybe it's a good idea to include porosity as a parameter of create_mp7, I'll try to submit a PR on this.