Subject: Root zone conductivity Posted: 3/6/2018 Viewed: 107 times
I use the soil moisture method of WEAP model and I have two questions about the root zone conductivity rate at full saturation. I know that this parameter should be calibrated, but I'm confused about the parameter range change. I saw various papers that determined the range of root zone conductivity changes between 20 and 200 mm/month.
(Ingol-Blanco, E., & McKinney, D. C. (2012). Development of a hydrological model for the Rio Conchos Basin. Journal of Hydrologic Engineering, 18(3), 340-351.)
On the other hand, I have a guideline that, based on the type of soil, gives a Saturated Hydraulic Conductivity. The soil in my study area is loam, with a Saturated hydraulic conductivity of 0.00037 cm / s, which is equal 9590 mm/month. I think that's the right amount.
(Schroeder, P. R., Dozier, T. S., Zappi, P. A., McEnroe, B. M., Sjostrom, J. W., & Peyton, R. L. (1994). The hydrologic evaluation of landfill performance (HELP) model: engineering documentation for version 3.)
I have two questions.
1-Is the concept of root zone conductivity rate different from Saturated hydraulic conductivity?
2- If these two concepts are same, the hydraulic conductivity obtained in these papers is not small? I think 200 mm /month is very small.
Ms. Stephanie Galaitsi
Subject: Re: Root zone conductivity Posted: 4/16/2018 Viewed: 74 times
The Root Zone Conductivity is the conductivity rate at full saturation (when z1=1.0). However, that does not mean that it is equivalent to the "Saturated hydraulic conductivity" found in other equations. To truly understand how the Root Zone Conductivity is used, I recommended opening the WEAP help menu, going to search, and search "soil moisture method" to find the Help topic that has the title "Soil Moisture Method." This details all the calculations involved, as well the diagram of the soil moisture model. This will show you how WEAP uses the data plugged in to the parameter "Root Zone conductivity."
The default parameters may very well be small for your system - the parameter values can value a great deal.