June 23, 2018, 05:40:24 PM

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Messages - Jonathan S. Clough

1
Using SLAMM / Re: Introduction
May 03, 2018, 08:40:44 AM
2
Sorry I let this thread go cold.  I have not seen this type of response.  Wonder if you figured it out.  You may want to check the "marsh collapse" parameter that could cause this problem if mis-set.
3
Tidal ranges affect SLAMM in many ways.  Certainly the model predicts significantly enhanced resilience to SLR for larger tidal range sites.

For one thing, a fixed change in tide levels (due to SLR) is a much higher percentage of the tide range in a microtidal site than a macrotidal.  This means that a marsh (that exists within the "tidal frame") can have much more elevation capital in a macrotidal site.

But with regard to the question at hand.  The SLAMM model does not directly model sediment inputs but those inputs come into account in the relationship between marsh accretion rate and marsh elevation.   See for example Figure 4 in this document.  https://www.sciencedirect.com/science/article/pii/S1364815216302705 ; This figure was derived based on the calibration of a model that does explicitly model sediment inputs (MAM3) 

We recognized that a model such as MAM3 generally predicts a single parabolic accretion-rate response to SLR (if you hold sediment inputs and tide range constant over time).  (The parabola has accretion rates on the y axis and marsh elevation relative to MTL on the x axis)  Therefore we allow for an input of this type of parabola to SLAMM.  A site with a larger tide range has more elevation capital to work with and will generally accumulate more sediment over a period of SLR.  MAM3 also predicts increased sedimentation rates in sites with larger tide ranges.

To generate the required parabola a site-specific empirical data analysis or application of a site-specific mechanistic model should be utilized. 

Hope this is useful and sorry about the long delay in response
4
The input files look good but there was one key issue.  The CRS units for SLAMM projects must be meters.  I am sorry if that has not been made clear enough through the GUI and/or users guide.  I will specify that on the file-input GUI for the next version .

Best regards -- Jonathan
5
If you are using a dike layer I would turn that off as a test.

Next thing to do is look at the elevation analysis -- Set Map Attributes, Elevation Analysis button towards middle of Analysis Tools tab.  Then "Run Elevation Analysis (This Site)  Double click on the category names to sort, sorting by n cells can be useful.  The 5th percentile for wetland classes should be around the minimum elevation. 

See the help file text for more information on interpreting the matrix on that page.  Also you can see this reference:

https://docs.google.com/spreadsheets/d/13AhT1PwsUsmOSA3LdGTtbWZIBIk1DoZ7D7KCheGlXtk/edit

If you want to email me the SLAMM6 and spatial files I will take a look at it, or you can just email the elevation-analysis matrix after exporting to Excel for now.

Good luck!  -- Jonathan
6
I ran multiple tests and, for my study files, when there is no dike input raster map, the maps produced have been identical whether "use dikes" is checked or not.  Are you willing to share your input files so that I can look into this further?   Regards -- Jonathan
7
If you do not have a dike file specified, the results should be identical.  Please let me know which version you are using and I'll run a test and ensure there is not a software bug causing this problem.
8
Using SLAMM / Re: Data Set
November 10, 2017, 02:14:58 PM
As you know, NRow and NCol and "lower left corner attributes" must match precisely.

In the QGIS world we use GDAL WARP to ensure that this is the case.

It is best to set the attributes precisely when converting from NWI polygons into a raster because re-projecting or moving raster files can result in data loss.

I cannot speak to the ESRI world -- anyone else?

Best regards -- Jonathan
9
I think the problem is that the ASCII DEM is treating 1.17e-38 as its NODATA value.  The GIS software is then not recognizing this NODATA value.  Try specifying a NODATA value of -9999 prior to conversion and this may solve the problem. 

Also, look at the header in the first lines of the ASCII DEM to see if that helps understand the problem (the NODATA value is defined there.)  The best way to do this is convert the file type to a TXT file and look at it in the Windows Explorer Preview pane (not Internet Explorer, just the Windows Explorer file manager).

Hope this is useful.
10
Model Formulation & Parameters / SLAMM DMMT Webinar
September 28, 2017, 07:23:42 AM
On November 3rd, at 10:30 AM EST, Warren Pinnacle Consulting Inc. will present the results of a multi-year sea-level rise modeling project supported by the New York State Energy Research and Development Authority (NYSERDA). This project has produced a new decision-support tool designed to help decisionmakers understand the benefits of different adaptation strategies for wetland management under uncertain future conditions. The presentation will focus on background of the project and results from three New York county case studies, as well as presenting a tutorial for users interested in learning how to use the tool.

SLAMM Marsh-Management Tool
Friday, November 3, 2017

10:30 am  |  Eastern Daylight Time (New York, GMT-04:00)  |  1 hr 30 mins
Register
After your request has been approved, you'll receive instructions for joining the meeting.

Need help? Go to http://help.webex.com.

Prioritization of marsh-management strategies can be a difficult undertaking. Ideally, a manager could evaluate the relative benefits of adaptation strategies and maximize wetland benefits while considering uncertainty both in future sea-level rise and dynamic marsh response. Warren Pinnacle has developed a modeling framework to evaluate the costs and benefits of management strategies while accounting for these uncertainties using the SLAMM marsh migration model. Model results are combined with ecosystem-valuation assessments from stakeholders that define a set of relative "wetland benefits" (e.g., habitat preservation, flood protection), and each site's wetland benefits can then be projected into the future and compared to the estimated costs for each adaptation strategy. By calculating the "wetland benefits per estimated cost" ratio, one can identify the most effective marsh management strategies.

11
Model Formulation & Parameters / Re: Min/Max Accretion
September 12, 2017, 09:59:02 AM
To understand these curves and parameters, please see the spreadsheet:

SLAMM6_Accretion_Release_6.5.xlsx

Which is installed along with SLAMM. 


You will see that the equations describe a third order polynomial which then can be scaled to the min and max accretion values.  That allows you to play games keeping the shape of the feedback curve intact but increasing or decreasing the minimum and maximum accretion values as part of a sensitivity or uncertainty analysis.

Let me know if you can't find the spreadsheet or have additional questions.
12
We have converted these to georeferenced compressed TIFF files and put them here:

https://www.dropbox.com/s/y4dgawl0j5hbrke/Charlotte_Harbor_TIF.zip?dl=0

We generally deliver data as GEOTIFF files now as they are georeferenced, well compressed (lossless), and quickly imported into any GIS software.

The problem was, the files were originally run and projected by TNC Florida (our project was designed to utilize previous work completed), and they chose the projection of NAD83 Florida West.  We did not reproject their raster files and ASC files do not carry their projection with them, thus resulting in the confusion.

Hope this is useful -- please let us know if you have any other questions or concerns!

-- Jonathan & Marco
13
Thanks for the heads up -- we will look at this issue tomorrow.

Best -- Jonathan
14
Using SLAMM / Re: Latest Versions of SLAMM
June 21, 2017, 03:05:16 PM
We're up to Build 239

Editable Max Fetch for Marsh -- Marsh horizontal erosion rates will now be applied when this editable marsh fetch has been exceeded for each marsh cell (previously this was hard-wired at 9km and this value will be loaded into older SLAMM6 simulations.).  This may be edited on a subsite by subsite basis.  This parameter is not relevant if the wave-energy erosion submodel is being utilized.

Also the "Last year of simulation variable" is always utilized even if "run specific years" is selected.  The interface was modified to make this more clear.

15
Now on GitHub https://github.com/WarrenPinnacle/SLAMM6.7

Editable Max Fetch Threshold for Marsh Erosion -- Marsh horizontal erosion rates will now be applied when an editable marsh fetch has been exceeded for each marsh cell (previously this was hard-wired at 9km and this value will be loaded as a default into older SLAMM6 simulations.).  The threshold may be edited on a subsite by subsite basis.  (This parameter is not relevant if the wave-energy erosion submodel is being utilized.)

We meant to add this as a feature of SLAMM 6.7 initially, but got so caught up in the new fancy wave power formulation that we forgot to modify the basic model.

Also -- the "Last year of simulation" variable is always utilized even if "run specific years is selected."  The interface was modified to make this more clear.