January 28, 2020, 04:47:35 PM


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Thanks for the reply. I have soil saturation turned off, the dike layer is correctly rendering in the "Set map attributes", and I'm defining the entire area protected by dikes.

I've sent you an email with some screen shots showing my execution options, the dike layer rendering, and the output showing land cover change even in the diked areas.

A potential work around to this problem is changing the diked areas to "Developed Dry Land" and running the simulation with the "Protect Developed Dry Land" option. This takes some additional pre-processing and post-processing of the rasters but it does work.

The cells are updated every time step, correct.

SLAMM actually tracks partial conversions of cells over time -- it was originally created many years ago when computers were much less powerful and cell sizes were therefore much larger (150-500meter).  For this reason it has always tracked multiple land types in each cell.  For this reason the tables of output are not always precisely what you would get when adding up the area of the raster maps.  After erosion to tidal flat, the elevation of the cell would be set to the elevation of the flat or MTL if there is no adjacent flat. 

In some of our older runs we found that the flat itself, became protective against further erosion at the marsh-to-open-water interface.  For this reason marshes erode directly to open water.   https://github.com/WarrenPinnacle/SLAMM6.7/blob/master/PROGRAM/Categories.pas ; line 627

-- Jonathan

You are correct.  However, soil saturation is not affected by dikes which could be causing the differences you are seeing.   Try turning soil saturation off.

Are you rendering the dike layer in "Set map attributes" to ensure that the software is interpreting your data layer correctly?  

And I think you get this, but you define the entire area protected by dikes using "classic" mode rather than the location of the dike itself.  

If none of these answer your question, feel free to post or email me some screen caps showing what you are seeing.

Thanks!  -- Jonathan
I'm running some simulations of SLAMM with and without the classic dike layer (specifying land protected by dikes). Aren't these dikes supposed to keep land cover from changing? Per the technical guide: "In the traditional model, if a cell is defined as protected by a dike or levee it is not permitted to change."

When I run the simulations, land cover is changing even in cells protected by dikes. If I compare this diked-scenario with the same simulation but with dikes turned off, the only differences between the two results are in areas "protected" by dikes. So clearly the dikes are having some effect on land cover change, but not the effect I expected. I thought they would completely prevent any land cover change in the diked area.

Am I incorrect in my interpretation of how the dike layer works? I'm using the most recent version of SLAMM (6.7 beta).
Using SLAMM / Re: Error Reading Headers
Last post by Jonathan S. Clough - May 14, 2019, 01:02:04 PM
So glad you solved the problem!  I will make a note for the next version to override the Windows settings so that a decimal point is used in either case, so this does not pose a problem in future versions.  Thanks -- Jonathan
Model Formulation & Parameters / Re: New Site Parameters in 6.7...
Last post by TMazor - May 13, 2019, 03:49:11 AM
Thank you so much for the very helpful reply!
I have two technical questions on how the lateral marsh erosion is implemented in SLAMM 6.7.
1)Let's say the rate of marsh erosion is 2 m/yr. How are the cells actually updated?
I assume the cells are updated every time step, maybe every year.
How do you implement the erosion of 2 m in a cell that is likely much larger than 2 m?
Do you implement a sort of partial cell erosion?

2)Also, when you erode a cell marsh by lateral erosion, what elevation do you impose to the update cell? A fixed elevation of the tidal flat?

1. Yes, this replaces the default 9km.  It will not use the 9km default if 0 is used, therefore if you wish to use that default, please input 9.0.

2. Leaving these as zero should not have an impact on your simulation. 

3. These can be left at zero.  Please see the latest model application documents for some information about how we have set this parameter in the past.



Sorry about the long delay in response!  -- Jonathan
Using SLAMM / Re: Error Reading Headers
Last post by JackieRaw - April 14, 2019, 01:41:46 AM
Hi Jonathan,

I have found the solution to this problem. It was a simple default setting that needed to be changed on my computer. My Windows 10 machine was set up with US English as the default language, with a comma to be used as a decimal point instead of a full stop. This prevented the ASCII files from being loaded because the decimals were being read as commas, even if the original files were correctly formatted.

All is working smoothly now.


Model Formulation & Parameters / New Site Parameters in 6.7 ver...
Last post by TMazor - April 10, 2019, 06:17:15 PM
I would like some clarity with some of the new input parameters in SLAMM 6.7.

1) The Marsh Erosion Fetch (km) -  is this a maximum value to input instead of the default 9km that was previously in the other versions? If this is left "0", will it use the 9km default, or do I need to input a max value?

2) H1-H5 inundation Parameters - since these relate to infrustructure, if I am not including roads etc., then can I leave these inputs as "0" ?

3) Irreg-Flood Collapse and Reg-Flood Collapse (m) - do these parameters need to be put in for SLAMM to run correctly? I'm not sure how to calculate these values, or if there are default values that can be used here. Any references or material on how to calculate these would be great.

Many thanks!

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