Good day,

Please tell me where I can find information about KC (crop coefficients) values for different trees or forests to be used in catchment modeling?

Thanks.
Anna

FAO Bulletin 56 has plenty of information on Kc values for crops, including fruit trees (see http://www.fao.org/docrep/X0490E/x0490e0b.htm ).

Does anyone know any sources for Kc values for non-agricultural land classes, such as forests?

Jack

> From: "Jack Sieber" <jack.sieber@sei-us.org>
>
> Hello Jack

I suggest that you contact Professor Ian Calder - details below:

Organization - Centre for Land Use and Water Resources Research
3rd Floor, Devonshire Building, University of Newcastle
Newcastle Upon Tyne NE1 7RU
United Kingdom

Email: I.R.Calder@ncl.ac.uk

best regards

Martin Parkes

Jack,

I have read your rticle: WEAP21 – A Demand-, Priority-, and Preference-Driven Water
Planning Model, Part II, one of authors of which you are. Here you discuss the caseIn this article the case study of Sacramento River Basin is given. Could you please tell me what Kc-s have you used in this case study for different land types (deciduous, evergreen, shrubs, grass, irrig.pasture) before and after calibration, if you have this data still available.
I have problem with one of the catchments I am modeling (Tskenistskali river in Georgia). It seems that I have too much parameters to calibrate and I want to have initial values as best as possible. That's why I am seeking for these kc-s from somewhere.
Thanks again.
Anna

Dear Anna,

Hi, this is Samuel Sandoval, from the University of Texas at Austin. I
haven't done so much about hydrological modeling, I'm more expert in
planning model. Althought, Charlotte Amato, Eusebio Ingol, and Daene
McKinney have done something in that area, in fact, Eusebio Ingol and Dr.
McKiney have done the calibration for the Conchos BAsin, in Mexico, I think
it will be great that you take a look to the on-line report they did. This
is the link,

http://www.crwr.utexas.edu/reports/2006/rpt06-12.shtml

If you want more information you can contact Dr. MiKinney or you can send an
email directly to Eusebio Ingol, who was the person who calibrate the model.
I hope this can help you.

Samuel

As a first guess, I would recommend setting all Kc's to a value
of 1.0. Since we are modeling soil moisture, soil water deficits will
reduce ET even with PET is large. I use the Kc value to "tweak" certain
crop/land use types... so usually, I have values that range between 0.9
and 1.1 The higher values would be crops that Et above a reference crop
value, where the lower values are crops that Et below a reference crop
value under non-water limiting conditions.
In the case of FAO models, I think Kc's are basically used as a surrogate
to soil water deficits, but with the WEAP soil moisture model, we are
explicitly modeling those deficits. dy

Not sure if this will still be useful, but I came across a report that said that the ET of coniferous forests (in the Pacific Northwest of the US) is about 83% that of a reference crop (pasture), so I assume that the Kc would be less than that of the reference crop by about the same amount? For more info, see Black, Spittlehouse, Novack (1989). Estimation of areal evapotranspiration. In Spittlehouse, D.L. eds, Estimating ET from Land Surfaces in BC. IAHS. Publication # 177. p. 245-256.