Creating a (Vertical) Hydrologic Buffer

06-20-2017 12:17 PM
New Contributor

Wondering if anyone has any experience in creating a vertical buffer adjacent a stream as opposed to the more typical horizontal buffer. I have a method planned but it seems awkward and less than ideal.

I'm attempting to create a (horizontal) buffer which will exist as 1 metre above a given stream's typical flow. The process will be eventually converted into a model or script but for the time being, i'm more interested in potential approaches.


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3 Replies
MVP Frequent Contributor

Just a thought - would it essentially be the same if you add 1 meter to your DEM only in the horizontal extent of the stream?  If so, you could probably do this with Raster Calculator.

Chris Donohue, GISP

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New Contributor

The reason for attempting to create a vertical buffer over a horizontal is to catch those 'low-lying' areas outside of the horizontal extent of both the stream and any existing horizontal buffer, which might be susceptible to flooding.

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MVP Esteemed Contributor

There are several ways to go about this, I would think a really good method to try (assuming you have access to Spatial Analyst) would be to 

1. Rasterize your stream line

2. Extract By Mask and Int to get integer cells of elevation at each location along the stream

3. Run Euclidean allocation to assign each location in your raster to the nearest stream elevation

4. Select areas where the difference between your allocated elevation and the DEM are less than your estimated flood height. The Raster Calculator is a good tool for this operation.

Since you may pick up some disconnected areas, you may want to convert the result to polygon and edit the results.

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