There was a recent discussion about this topic that may be helpful to your problem also. In any case, one reason that observed marsh erosion is limited may be due to the fact that when marsh is eroded, land cover is converted to tidal flat. As a result, the marsh behind will not be connected to open water, and thus not eroding anymore, until the fringe of tidal flat is gone (permanently submerged or eroded away). So you may want to increase tidal flat erosion rate or change the code as suggested in the erosion issue discussion I was mentioning above.
Both Technical Documentation and User's Manual have lots of information that may help answering many questions.
As it is written in the User's Manual for the Historic Trend: "Used to estimate subsidence or uplift unless a raster file of land movement is specified". Uplifit is modeled by setting the historical tend less than 1.7 mm/yr (see also Elevation Model in Technical Documentation).
Both Technical Documentation and User's Manual have lots of information that may help in answering many questions.
Erosion: As it is written in the technical documentation: "Erosion is only predicted to occur at a land-cover to open water interface".
Accretion: the cell accretes no matter inundation. However, if accretion is defined on a cell covered by marsh and this is not inundated then the overall model land-cover, elevation and tides may be at least questionable.
Models predict that SLR rate will continue to increase after 2100. So you need to know what the SLR curves look like after 2100. But just as a approximate estimate, you can use Table 1 of the Technical Documentation and assume that after 2100 SLR increases with the same rate observed between 2075 2100 and calculate when 2.5 m would be reached after 2100. Hope it helps.
Hi, the User's Manual explains it all. Basically, you have to add Base_dike.txt to the project and then have Base_dike2025.txt, and Base_dike2050.txt (four digit year following the dike layer base name) in the project directory. Good Luck.
Hi, I do not know what is the scale of your map, but it is possible that inside the purple rectangle there is less than 9 km fetch. Your code change has not modified much in that sense since marsh erode only if erosion> moderate and moderate is still <=9km as it was before. So what you want to do is to define: Erosion=Moderate if AdjMaxFetch <= 1,2,3,4... (whatever the fetch you want) and Erosion=Heavy > 1,2,3,4,.... In that case marsh will start to erode with fetch greater than 1,2,3,4....
On a side note, it looks that the dryland now is converting to estuarine beach meaning that the fetch is >Heavy (Severe) there. Not sure why. Look at the code changes (and search for the words Heavy and Moderate in transfer.inc to see the implications).
You are right, the Procedure Erode is the function to change the fetch.
However, one reason that observed marsh erosion is limited may be due to the fact that when marsh is eroded, land cover is converted to tidal flat. As a result, the marsh behind will not be connected to open water, and thus not eroding anymore, until the fringe of tidal flat is gone (permanently submerged or eroded away). So you may want to increase tidal flat erosion rate or change the conversion rule for marshes to Estuarine Water instead to Tidal Flat; change the line Convert(Cell,Clss,Tidalflat,-99) to Convert(Cell,Clss,EstuarineWater,-99) in the Procedure ErodeMarsh.
Unfortunately this information is rarely (if ever) provided with the elevation data. Therefore, using professional judgement, we recently select 0.2495, which is relatively high. This values provides clustered areas of uncertainty, meaning that when there is an elevation point with an error it is also likely that points around have errors with similar amplitude and sign (e.g. all elevations are higher or lower in the area).
In the uncertainty analysis set up for the DEM you can define the RMSE and the Autocorrelation Coefficient. SLAMM calculates and shows the uncertainty field (more random when less correlated). This is applied to the entire area and there is no option to input different elevation errors depending on the land cover, slopes or subsite. To be safe, I would use the highest estimated RMSE.
Hi, although this is a new feature that belongs to the wish list model development, with the current version you cannot add or edit the classes. You can only change their upper and lower boundaries in the elevation analysis window.
Hi, as the code is open source you can certainly manipulate it to better fit your needs. However, you also need a Visual Pascal Compiler. We use Delphi (we tried Free Pascal but it did not compile). Read Help/About/SourceCode/Info for more information.
The function with the SLR scenarios is EustaticSLChange.