I was tasked to create a layer with the flooded areas if the sea / river level was to go up by X feet. There is no requirement to take Flow and Pour Points into account, just a simple raise in water level. I will be using ArcGIS and have access to all extensions. As an input I have a DTM (tiff) and coastline (shp) layers. I have found this very helpful video titled How to Model Coastal Flooding in ArcGIS which outlines the following process:

  1. Calculate
  2. Reclassify to have only a single value
  3. Convert to vector
  4. Remove polygons that are not touching the coastline (select by location)

Before creating a model from it, I thought there might be a dedicated tool for that, either in the Hydrology toolbox in the Spatial Analyst extension, in the ArcHydro toolboxes or in the Government toolbox.

Is it indeed the case? Which tool would be the best for that?

  • @Martin I think your comment has enough detail to qualify as an answer to this question so perhaps you would like to post it as one.
    – PolyGeo
    Dec 28, 2015 at 23:55

1 Answer 1


Your workflow should get you what you need.

I'd recommend to use Con for the first two steps (then you can aggregate them into only one step).

I don't know of any existing tool that does these steps, but if it exists it's most likely to be in ArcHydro (never heard of Government toolbox though). However, this is quite a simple process involving only three functions, so creating a Python function or Modelbuilder model for it shouldn't be too complicated.

If you plan on doing this multiple times, I'd go for Python and loop through every value you need to do the calculation for.

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