hi,

I ran Slamm 6 with the NWI photo date turned off and my results were a bit different than when I ran it with it checked on. My initial condition and photo date outputs were exactly the same when I had it off. I am wondering if this is another good way to 'error check' the input?

Caroline

I am using a 3 meter cell size for CA and 6 meters for NC. I will turn off the overwash parameter in NC and see if that fixes the problem. Thanks.

I now understand the negative values and I read through the elevation analysis section (and user guide). I guess I just need to play around a little with the elevations and see what I get.

Interesting I tried setting the frequency of large storms to 25 years and I get streaking inland of several categories after 2050 (25 yr increments). I noticed I get alot of streaking in my NC runs as well. Is that ok, or do I need to adjust a particular setting?  thanks.

Caroline

I ran the elevation analysis in Slamm 6 and have the statistical output. I am unclear what it all means though. 

The output table shows minimum elevations from -1 (estuarine beach, tidal flat, ocean beach and inland shore) to 1 (should I have negative values? How are the stats helpful? I am not clear what I should be comparing or looking at in those columns.

My initial condition (3 meter dem 2005, nwi 2006) and 2006 files have similar output except 2006 has alot more Estuarine Beach and an inland open water pond converts partly to esturine open water (that can't be accurate).

Also some of the code 20 (irregular flooded marsh) is converted to code 8 (regular flooded marsh), when I look at the lidar it follows the code 20 that was converted, so maybe that is more accurate?

Code 6 is reduced (I only have a small area in this category) in the 2006 output vs the initial condition. I read somewhere in the manuals that that code usually needs to be adjusted. How do I adjust it? or any of the others?

When I ran Slamm with a 10 meter DEM, only the beach was reduced significantly between the initial condition and the first year (2005 in that case).

I am also wondering how the elevation graphics tools help. I have looked at the profile and 3d view- should they be smooth? When I ran my 10 meter dem in slamm the tool showed smooth elevations with the preprocessor set to false. When I set it to true the elevations were up and down where roads etc were located in the marsh. Which is correct? I don't have any dikes and I 'burned' the impervious layer (1 and 2 slamm codes) into the nwi slamm layer as mentioned in one of the manuals.

one other question: I set my run using lidar data to 0 for frequency of large storms since I read that pertains to barrier islands and I have no barrier islands nearby. But is that accurate? There are big storms in the winter here.

I hope this makes sense. Thanks for your help.

caroline

hi,

I have read through the posts and technical manuals and I am still not clear about how V-Datum works or if I should be using it. I converted my offshore raster data to points (for Carpinteria Marsh in CA) per the V-Datum manual and then ran through V-datum. I subtracted the output elevations from the input DEM and the values were all the same (0.83 m) which is exactly the same parameter as the NAVD88 correction I input into my header file from NOAA. So why would I need to use V-Datum? To use it would I then convert the points back to raster (with land as no data?) and input into Slamm 6? How is this useful if all the values are the same?

V-datum also can integrate land and sea but the DEM I am using (and also one I am using in NC- Beauford area) has already integrated the ocean and the land together (both are using vertical datum NAVD88). If I did need to do this I am unclear how I would go about it. Thanks.

Caroline

Hi,

I am running Slamm on Carpinteria Marsh near Santa Barbara. I ran it using the accretion/sed/erosion rates for Puget Sound which I would assume are much different for Carpinteria. I have searched the literature high and low but can't seem to find any rates for Carpinteria. I did find an accretion rate for Tijuana slough:  "Vertical Accretion Rates and Heavy Metal Chronologies in Weland Sediments of the Tijuana Estuary" but this area may be different that further north. I found some data for SF Bay but again that is much further north and has differerent conditions. Any ideas where I might find this info?

Thanks,

Caroline