Scheduled Downtime
On Friday 21 April 2023 @ 5pm MT, this website will be down for maintenance and expected to return online the morning of 24 April 2023 at the latest

Irrigation schemes in v4.3

This post was from a previous version of the WRF&MPAS-A Support Forum. New replies have been disabled and if you have follow up questions related to this post, then please start a new thread from the forum home page.

Dear WRF community,

I'm looking into implementing irrigation schemes into simulation. From v4.2 there was already an irrigation scheme (sf_surf_irr_scheme namelist entry). However, in v4.3, NOAH-MP LSM, a new dynamic irrigation scheme is also implemented (opt_irr).

My question is: Are these two related to each other in any way? If one is activated, should other one be also activated, or they are mutually exclusive so only one of those should be used at a time? I can't find any information about intended way of using those two.

Thank you,
The two irrigations have no relation with each other. They are turned off by default. Therefore, you can turn on either of them and don't need to worry for the other one. I don't think these two schemes should be turned on simultaneously, although the model may still be able to run if doing so (this is my guess. I didn't try.)
Dear Ming,

Thank you, but do those two serve the same purporse in the model? The first implemented scheme basically increases soil moisture in the irrigated affected areas, but does NOAH-MP implementation do the same thing or something completely different? If it does the same, then they will be redundant and should not be used together because they will cumulatively make soil too wet; however if NOAH-MP irrigation scheme does not do that but something else, then it might work along first one just fine. Any insight about that detail?

Thank you again,

Please see my answers below:

(1) do those two serve the same purporse in the model?

yes they are. Both will activate irrigation that will first affect soil moisture, then subsequently affect soil temperature, HFX, LH, etc.

(2) does NOAH-MP implementation do the same thing or something completely different? If it does the same, then they will be redundant and should not be used together because they will cumulatively make soil too wet.

You are right that Noah-MP irrigation performs similar. This is why we recommend not to activate both schemes simultaneously. They should not be used together
This is an interesting topic.
I wanted to know which static datasets default irrigation and Noah-MP expects(from geogrid/wrfinput) for irrigation schemes. For eg. in the users guide, there is an option to give types of irrigation fraction(micro, drip etc.), irrigation rate,etc(I dont have irrigation types data). I only have data for percentage irrigated area. Will it be sufficient to run default irrigation scheme?
If Noah-MP irrigation scheme is being used can I run it without additional data(irrigation type fractional area coverage)?
Help is much appreciated.
Hi, Vins_94
For irrigation scheme used in NoahMP, you must provide the static data of irrigated land percentage. You don't need other input.
In namelist.input, you can specify the option of irrigation by opt_irr
Dear Chen,
Thank you for the swift reply.
That's great!!. So, as far as I understand, IRFRAC variable in wrfinput will be utilised to run the novel Noah-MP irrigation scheme. If you could provide any references or documentation regarding details on how the irrigation scheme inside Noah-MP works, it would be great. (Like, at what rate/frequency the irrigation is done. What kind of irrigation scheme is used by default(surface flooding etc)).
In India, we have Rabi and Kharif seasons (Pre and Post monsoon Respectively) of sowing/planting. I was interested to know the model in detail before jumping in for simulations. if I run the model for a whole year with option turned on, will it irrigate for whole year. or should I run model each year only for the irrigation time period.
Thank you for your help so far,
This scheme is pretty new and we don't have any publication yet.
For its application in India, I will talk to our expert, who is from India, and get some ideas. I will keep you posted once I have any feedback from him.

I have talked to our expert. Below is his suggestion:
If the user wants to activate the irrigation for a specific time like Rabi or Kharif, he needs to provide inputs like crop season, planting or harvest dates, etc. The data I shared for the release is only for the U.S. as we don't have any information on crops grown in other parts of the world. Notes on the irrigation method and other details provided in the readme.namelist file. We are working on the manuscript now. If the user can wait for two months we may share the manuscript (pre-published).

Hope this is helpful for you.
Dear Chen,
Thank you very much for your help and suggestions so far. I will wait and excited to see the paper.
Thanks for reminding of the paper issue. I just sent email to Dr. Prasanth Valayamkunnath and hope he can get back to me quickly.

I guess you can also contact him by yourself. his email address is:
Dr. Prasanth answered and I am sorry to tell that his paper is not ready yet. Below is his email:
The manuscript is not ready to share. We made some additional improvements to the irrigation model and working on the analysis. Since I have to finish other projects before this, I had to spend time on those projects. Will share you the manuscript once it is ready (Hopefully by end of March)