Hello everyone.
I want to run the NDR model, but I don’t know what numbers I should set for these two alternatives.
1- Subsurface Critical Length
and
2- Subsurface Maximum Retention Efficiency.
For both nitrogen and phosphorus.
I also read some articles. But none of them explained these things.
I didn’t understand anything from the InVEST manual guide either.
Can anyone help me, please?
Hi @h.kazmi -
Using sub-surface nitrogen parameters are optional, so if you do not have local information from hydrologists about these values, you can run the model only for surface nitrogen. Sub-surface parameters only apply to nitrogen, not phosphorus.
If you really want to use the sub-surface nitrogen parameters, the User Guide provides a small amount of guidance for default values, citing several sources, in the Data Sources appendix.
~ Stacie
Thanks.
I read that link. It had good points.
So, according to “Mayer et al. (2007), a global average of 200 m for the retention length, and 80% for retention efficiency can be assumed for vegetated buffers.”
The two values—200 m and 80% — can be used as defaults for subsurface nitrogen values.
