SLAMM Forum

General Category => Using SLAMM => Topic started by: pse1999 on February 24, 2018, 10:21:41 PM

Title: Regularly Flooded marsh conversion causing vast elevation changes
Post by: pse1999 on 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

for example (all elevations relative to MTL):

2006 2037 2068 2100     '06    '37    '68       '00
5   5      7      8         1.96    1.8     1.52   -1.19
5   5      7      8          2.11    1.9    -2.84  -3.25
3   3      7      8          1.93    1.66   1.28   -1.44
5   5      7      8          1.77    1.6      1.33   -1.39
5   5      7      8         1.82    1.65   1.38   -1.34

"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?

Any help would be very much appreciated.

Patrick
Title: Re: Regularly Flooded marsh conversion causing vast elevation changes
Post by: Jonathan S. Clough on May 02, 2018, 02:02:33 PM
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.