FAQ: What are these vertical/horizontal streaks in model output:
Maps of SLAMM results occasionally include green linear stripes of fresh marsh moving through what was previously dry land (red). These stripes are a result of the SLAMM soil saturation algorithm which is geographically quite simple. The water table for each cell is estimated by moving unidirectionally in the off-shore direction and finding the nearest wetland cells. This water table is then adjusted for the estimated increase in the fresh water table due to sea level rise. If the estimated water table is greater than the elevation of the dry land, saturation takes place and the dry land is predicted to be converted to wetland.
Because of the unidirectional search algorithm, horizontal streaks may appear on model results as shown above. Despite this minor loss of geographic realism on output maps, the algorithm does provide useful information about the susceptibility of dry land to water saturation due to changes in the water table.