Search found 30 matches

by EladD
Tue Jun 06, 2017 10:57 pm
Forum: Hydrus 1D
Topic: Modelling Infiltration
Replies: 1
Views: 1675

Re: Modelling Infiltration

Dear Marcus,
This is the bread and butter of HYDRUS-1D.
Initial conditions in the soil profile can be entered by the user in pressure/moisture content terms.

I would be happy to assist (send me a private message).
All the best,
Elad
by EladD
Mon Jun 05, 2017 11:50 pm
Forum: Hydrus 1D
Topic: water balance with 'surface layer' boundary
Replies: 4
Views: 3452

Re: water balance with 'surface layer' boundary

I took the time to run it again for 'Sandy clay', with Ksat=2.88 cm/d. Nevertheless, for stability i made the following changes: (1) min time step=1e-7; (2) add 'Air entry of -2cm' to accommodate the fine soil. Results were: Precipitation: sum(rTop)=-12.5 cm; Infiltration sum(vTop)=-3.99 Runoff: sum...
by EladD
Tue May 30, 2017 11:33 pm
Forum: Hydrus 1D
Topic: Initial Condition
Replies: 8
Views: 7414

Re: Initial Condition

Q=K x i x A
In your case, i guess the 35ml/min would be the Q?
What is your column size (cross-section)? that would be A.
What is the gradient across it (from top to bottom) ? that would be i.
by EladD
Mon May 08, 2017 1:16 am
Forum: Hydrus 1D
Topic: ground water level in bottom boundary condition
Replies: 4
Views: 4054

Re: ground water level in bottom boundary condition

Maybe this illustration will help:
by EladD
Tue Mar 07, 2017 9:41 pm
Forum: Hydrus 1D
Topic: Convergence error
Replies: 1
Views: 1953

Re: Convergence error

Hi, I recommend running the flow simulation first, with the root uptake but no solute transport. If error occurs, that might be due to BC or dynamics at that time interval. What does the lower BC represents? in other words, why setting it as Constant pressure Head and not deep/free drainage ? In sem...
by EladD
Tue Mar 07, 2017 9:31 pm
Forum: Hydrus 1D
Topic: PARAMETER MEANING
Replies: 1
Views: 1521

Re: PARAMETER MEANING

No, its not the number of iterations. The C ### is the column number 1..n, where n/2 is the number of curves shown on the specific graphic window. Odd columns list time steps, even columns list the values. Two columns for each curve. The R ### is the row number 1..m, where m is the sum of T_level pr...
by EladD
Thu Jan 19, 2017 9:54 pm
Forum: Hydrus 1D
Topic: Evaporation and Transpiration
Replies: 5
Views: 4637

Re: Evaporation and Transpiration

Sounds strange. For a 25 yr simulation including water flow, meteorology, solute flow, root uptake and root growth: Infiltration 1453 cm Bare soil simulation: E 1427 cm, Bot 27 cm. Vegetated land (i enter crop height, root depth, LAI, Albedo): E 1002 cm, T 428 cm, Bot 24 cm. Minor changes in soil mo...
by EladD
Mon Jan 16, 2017 10:08 pm
Forum: Hydrus 1D
Topic: hydru 1d regarding hydraulic conductivity
Replies: 2
Views: 2074

Re: hydru 1d regarding hydraulic conductivity

Hi, What do you mean 'hydraulic conductivity is varying with depth' ?? If you set more than 1 material, than you should expect that each material will have its own Ksat at the end of the optimization. If you set 1 material, and just viewing the hydraulic conductivity profile (results of simulation) ...
by EladD
Fri Dec 16, 2016 2:18 am
Forum: Hydrus 1D
Topic: Salt precipitation and evaporation
Replies: 1
Views: 4469

Re: Salt precipitation and evaporation

Published in the forum: https://www.pc-progress.com/forum/viewtopic.php?f=4&t=2374 Re: Evaporation in saline soil column simulation. Post by Jirka » Thu Jan 16, 2014 8:58 pm The standard HYDRUS module does not consider precipitation/dissolution of salts. Only the Unsatchem (Major Ion Chemistry) modu...
by EladD
Tue Dec 06, 2016 11:11 pm
Forum: Hydrus 1D
Topic: Solute outflux through the top boundary
Replies: 2
Views: 2180

Re: Solute outflux through the top boundary

Thanks Jirka,
The model you have linked does solves the first issue raised.
I intent to extend its use to deep drainage applications (more in private message).
:D
Thanks also for clarifying the second issue.
E
by EladD
Fri Dec 02, 2016 12:50 am
Forum: Hydrus 1D
Topic: Solute outflux through the top boundary
Replies: 2
Views: 2180

Solute outflux through the top boundary

Hi Jirka and Forum users, I would like to simulate a section with known water (and solute) flux at the top, which alternate between period of inflow and outflow. I tried two strategies. 1) Atmospheric BC = which allows water to flow out, but no solutes. That makes sense for 99% of cases, so i tried ...
by EladD
Fri Dec 02, 2016 12:01 am
Forum: Hydrus 1D
Topic: Saturated Water Content
Replies: 3
Views: 2256

Re: Saturated Water Content

Hi spedram,
Maybe you should consider reducing thetaR while reducing thetaS?
In many cases it is the range between these two parameter that counts for water balance purposes, rather than actual values.

Regards
Elad
by EladD
Sun Nov 13, 2016 11:07 pm
Forum: Hydrus 1D
Topic: Boundary Condition
Replies: 3
Views: 2926

Re: Boundary Condition

Hi Variable ponding depth= Variable Pressure Head. There is a way around with 'Variable Pressure Head/Flux' BC. In the 'Time Variable' menu specify: 1) FluxTop=precipitation-evaporation (as you estimate it) at times when there is no ponding; FluxTop=0 otherwise. 2) hTop=ponding depth at ponding time...
by EladD
Thu Nov 03, 2016 10:33 pm
Forum: Hydrus 1D
Topic: Boundary Conditions at the Water Table - Deep Drainage BC
Replies: 7
Views: 6666

Re: Boundary Conditions at the Water Table - Deep Drainage B

Hi Adam,
Dr Simunek is doing his best to support all users of HYDRUS through this forum...yet...he is not required to solve every issue arised.
Like all scientists i'm sure he will appreciate some courtesy...

I've attached a sketch below for your consideration- i hope it could clear things.
by EladD
Wed Nov 02, 2016 4:50 am
Forum: Hydrus 1D
Topic: Infiltration and solute transport (Scaling effect)
Replies: 2
Views: 2479

Re: Infiltration and solute transport (Scaling effect)

benmary,
I'm sure you know what you are simulating, yet, i would expect that in natural systems water will flow laterally in the saturated section.
As it sounds, in your 30m profile, water can only flow vertically, e.g. within a glass jar that has opening (?) only at the bottom.
Elad