Latest Contributions by DeanDjokic

‎03-03-2022

When using HAND method for "flooding", the "Input Flood Depth" is the depth above stream centerline that you want to "flood" with. What that specific value is, is up to you. For example, if you use the "max depth of the creek", that is the equivalent of the "bankfull" and most of the resulting flood polygon should be contained within the channel. Anything higher should start spilling into the overbanks and you should get "flooding". So where do you get that number? Depends on what you are doing. It can come from the observations (e.g. high water mark or a stage from a gage) or through flow modeling and rating curve to convert flow to depth. If you are doing the rating curve approach, make sure that the rating curve is based on the same resolution data you used to derive HAND with (or is adjusted accordingly). And remember that inherent assumption in HAND flood modeling approach is that your water surface is uniform (constant) and parallel to the bottom of the channel. For each channel segment. So if you expect that the depth will change (significantly) as you go downstream, you should partition the overall stream into multiple segments that have uniform (but variable from segment to segment) depth and then use "Define HAND-based Flood Depth and Extent from Table" tool to get the floodplain. More work but might give you better results. If you stream segment is short, then first follow the approach you have presented (single reach), see if you like the results, and if not, then use the "table" approach. Note that you will have to reprocess the input data and partition the streams and get their catchments before you can use the "table" approach. Hope this helps.

‎09-17-2021

Great, and thanks for marking it as a "solution". Let me know how your work progresses with implementation of executeAH approach. The doc I have pointed you to can use some refresh and if we can make it better based on your experience (e.g. more clearly describe the process so there is less research you need to do), I'd be happy to do so. Feel free to reach out directly to me if you have any further questions/comments. ddjokic@esri.com.

‎09-16-2021

Try using the latest version of Arc Hydro Pro tools (2.8.13) that we just posted. You can use the direct link below if the tools are not showing on the ftp site yet (takes some time for them to show up after we post them into the system). https://downloads.esri.com/archydro/ArcHydro/Setup/Pro/2.8.13/ The problem you have seen is a problem with tool help (metadata) not with the actual python code. I also suggest that you do not import the full Arc Hydro toolbox. Instead import just the tools (modules) you need. That makes the code leaner and faster. Please review doc "Arc Hydro - Calling Arc Hydro Tools in Python" at https://community.esri.com/t5/water-resources-documents/arc-hydro-calling-arc-hydro-tools-in-python-pdf/ta-p/920821 to see how to do this. You can also inspect some of Arc Hydro tools and see how we call other Arc Hydro tools within them for additional examples.

‎07-19-2021

please provide steps you did BEFORE trying to run that function and the screenshot of the input to the tool. preferably in English (Google translate is not always easy to interpret :-)). thanks.

‎07-14-2021

Unfortunately, GeoHMS tools do not manage data in GCS. While most tools will work with it (e.g. terrain preprocessing and subbasin delineation), once you get into calculation of stream and watershed characteristics, GCS is not supported. There are workarounds, but you are better off projecting the DEM and starting from scratch (you cannot just project all raster derivatives).

‎07-12-2021

Please make sure you look into "Arc Hydro Tools Python" toolbox under the "Terrain Preprocessing" toolset. They should be there at the bottom of the list.

‎07-04-2021

I have rerun the full set of preprocessing functions in HEC-GeoHMS using the latest installs for Arc Hydro and HEC-GeoHMS for ArcGIS 10.8.1 and they completed successfully. I suggest that you reinstall Arc Hydro and HEC-GeoHMS. Please follow this process (in this specific order): uninstall HEC-GeoHMS (and HEC-GeoRAS if installed), and then Arc Hydro. Download the latest versions for 10.8.1 from the download ftp site (http://downloads.esri.com/archydro/😞 of Arc Hydro (10.8.0.34), HEC-GeoHMS (10.8.0.10) (and if needed HECGeoRAS - 10.8.0.3). Install them in that order. Start a new project and try again.

‎07-02-2021

If you are satisfied with the answer, can you please mark it as "Accept as Solution". That will place a "green check box" on the discussion and indicate to other users that the topic is "solved". Thanks.

‎07-02-2021

Please provide more detail. Which version of ArcMap and GeoHMS are you using? Did all previous steps complete correctly? Did you try to use Arc Hydro tools for preprocessing (instead of GeoHMS)? Also, while the initial tools (terrain preprocessing) should work on DEM geographic CS, that does not work for what follows (calculating areas and lengths). So my advice is to project the DEM first into meaningful local PCS and then do the rest of preprocessing on that DEM. And make sure you start a new project once you project the DEM and do all the preprocessing in that new project to avoid any potential "leftover" issues with changing projections.

‎06-29-2021

Many of Arc Hydro tools use optional data. "Level DEM" is one of them. The approach is rather simple - if you do not have the optional data, you do not need to use that tool (or that option in the tool). Level DEM in particular flattens the DEM within the lake feature class (and can "push" the DEM down within the lake by the offset). This is done to insure proper flow direction within the lake. If you do not have lakes in your system, this operation is not needed.

‎06-18-2021

:-). i might be, but if we communicate here, nobody else will benefit (and i also might not always be as responsive so you might be missing an opportunity for someone else to answer). make sure you post it on the water resources questions board: https://community.esri.com/t5/water-resources-questions/bd-p/water-resources-questions that is where you will find other "water" people.

‎06-18-2021

I think you are referring to HEC-GeoHMS capability. HEC-GeoHMS is not ported to Pro. But there is a fairly simple way to do it: Option 1. 1. Create a raster of soils (each soil type has a unique integer value). 2. Create a raster of land use (each land use has a unique integer value). 3. Use "Combine" Spatial Analyst tool to create a raster of unique combination of land use and soils. 4. Use "Reclass by Table" on the result of #3 to assign CN value to each unique combination derived in #3. The tricky part will be to develop the reclassify table. You could also use simple "Reclassify" if you want to type in values. Option 2. For more control, instead of using 1-3 above, once you have #1 completed, multiply it by some big round number (lets say 1000 so value of 1 becomes 1000, 2 2000, etc.) and then add that to #2. so if you had soil with value 1 and land use with value 2 at a location, the final value will be 1*1000+2 = 1002. Now you can map the 1002 to proper CN value and then use reclassify. You should move further discussion outside of Pro 2.5 document thread. You will get more views and possibly more answers. This thread is focused on questions related to the document, not general questions.

‎06-17-2021

what data do you have?

‎06-14-2021

From the point of view of DEM processing, dendritic terrains do not have sinks/depressions while deranged terrains do. Specifically with Arc Hydro tools, dendritic terrains have only streams (no sinks), deranged terrains have only sinks (no streams), and combined terrains have both. There are different workflows and tools to use for processing these three terrain types. Please review the details in Arc Hydro document "Arc Hydro - Overview of Terrain Preprocessing Workflows".

‎06-12-2021

Process of "projecting" (really resampling) DEM can introduce "sinks" into the elevation model. That would explain the discontinuities you are seeing. Make sure you fill sinks in the projected DEM before running flow direction and flow accumulation functions.

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My Ideas

Latest Contributions by DeanDjokic

Re: Define HAND-based Flood Depth and Extent tool (Arc Hydro)

Re: ArcHydro "EOL While Scanning String Literal" error when importing toolbox via ArcPy

Re: ArcHydro "EOL While Scanning String Literal" error when importing toolbox via ArcPy

Re: Archivos HECRas

Re: River Slope Errors

Re: Terrain Ruggedness Index (TRI) and Vector Ruggedness Measurement (VRM) - Two new Arc Hydro functions that quantify ruggedness on a DEM

Re: Hecgeo-HMS Error

Re: Lack of data outside of DEM

Re: Hecgeo-HMS Error

Re: Lack of data outside of DEM

Re: Arc Hydro for ArcGIS Pro 2.5

Re: Arc Hydro for ArcGIS Pro 2.5

Re: Arc Hydro for ArcGIS Pro 2.5

Re: The difference between dendritic and deranged terrains.

Re: Drainage discontinuation in ArcGIS 10.6

Re: Trace downstream broken

Re: Point Delineator tool in Archydropro

Re: Burn culverts into DEM

Re: What are DrainageLine_FS and Catchment_FS out...

Re: Fill (Spatial Analyst) vs Fill Sinks (Arc Hydr...