Last post by Pat Prado - April 04, 2018, 06:42:19 AM
I was wondering if someone could clarify if SLAMM takes into account that higher sediment inputs seem to happen in systems with greater tydal ranges, which could lead to enhanced resilience to SLR compared to systems with lower tydal ranges. Is the model calibrated to simulate this effect?
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 .
Last post by pse1999 - February 24, 2018, 10:25:56 PM
I think one way you can do it is when you convert the polygon (NWI shp) to a raster through the tool you can set the processing extent the already created DEM raster through the "environments.." button to match your other rasters. There should be a box you can click where it will snap to the raster.
Last post by pse1999 - February 24, 2018, 10:21:41 PM
I am curious if anyone else who has used SLAMM to evaluate elevations has noticed when a cell converts to regularly flooded marsh that elevation decreases exponentially more than other classification types? data derived from the below example is sourced from the GCPLCC dem and NWI ASCII files
"8" is classified as "Regularly flooded marsh" and as seen it gradually decreases at first to essentially falling down a hole in the latter time steps. Is this common? is it the time step interval that is too large?
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:
Last post by Hartney - February 12, 2018, 08:50:42 AM
I have been running a model for the Pearl River LA/MS region. The model runs smoothly but there is never any wetland change, even with 6m of SLR and no accretion values. I have been able to run other models with parameters based on journal studies, including Pascagoula, and those models do show wetland change. Some things I have double checked (based on answers to similar posts on this forum) include elevation data units, DEM/NWI date, and the NAVD88 to MTL conversion (based on the Bay Waveland Yacht Club, MS tidal station: https://tidesandcurrents.noaa.gov/datums.html?units=1&epoch=0&id=8747437&name=Bay+Waveland+Yacht+Club&state=MS ). My accretion values are based on Louisiana's Coastwide Reference Monitoring System (CRMS). What other parameters should I be looking at to fix the issue? At this point, it feels like I'm missing something obvious so I'm hoping for an extra set of eyes to help me brainstorm what the issue may be.
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
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.