Latest Contributions by MarkBoucher

See.http://forums.arcgis.com/threads/76226-Assing-Unique-ID. Could be you need Arc Hydro 2.1. ... View more

I've been meaning to make a list of things to do before starting an Arc Hydro project. JAdams15's question pushed me to do it. This is more to remind myself and staff here that might venture into watershed processing than anything else. I hate making the same mistakes twice. Many of these ideas you'll find earlier in this thread. Getting a project started: For fastest processing, put the project directory on your local computer (C: drive). Processing over a network kills your speed. Keep the layer, file, and directory names short and with no spaces or non-alpha numeric characters. Use "_" if you must. I don't use "-". I suspect it causes problems. Make sure the HydroConfig Target Locations are correct. If you start the project and then move it to another folder, the Target Locations will not change on their own. The GeoHMSConfig Target Locations should be checked if using GeoHMS. Use the ApUtilities > Additional Utilities>Reset Target Locations menu command to reset them. I always check them under ApUtilities>Set Target Locations. Make sure the Spatial Analyst extension is selected under Customize>Extensions. Make sure your Geoprocessing Extents match the area you want to process. Use Geoprocessing>Environments>Processing Extent menu command. I make it match the DEM or the mask I used to extract the DEM for the project. In doing batch point delineation  I've had this change to the batch point extent and produce puzzling results. Disable Background Processing via Geoprocessing>Options menu. Set the "Max number of unique values to render" to a high number (I use 30,000,000: Don't ask me why.) Adjust this setting under Customize>ArcMap Options>Raster tab>Raster Dataset tab. Putting the agreestream, innerwall and outerwall layers in a geodatabase is a good idea. After you've been working on the project a while: If you are starting over on the process after getting much of the way through it, close Arc Map and via Windows Explorer delete the folders (would have the same name as your data frame) and the geodatabase (would have the same name as your mxd). This makes sure there are not locks on layers/rasters and no denials for overwriting files. The only layer I copy out of this is the Batch Point layer. I make a copy in the main directory so I don't have to create them again. Clear out the temp file directory. Do this as often as you think of it. There's a tool under ApUtilities that does this nicely. At times, a reboot of the PC does wonders. I'm not sure why this helps other than it might eliminate software conflicts if you are using more than one program. Please, please contribute if you see I'm missing something. Word Version Attached: ... View more

I think you are asking a bit much of GIS. Calculating the runoff volume is more of a hydrology function. Arc GIS and Arc Hydro don't perform hydrology calculations. They can help gather the data needed for hydrology (area, watershed slope, longest flow path, etc.). You've already done that it seems. It may be that the data you've collect is enough to calculate the runoff using a simplistic method such as the Rational Method. Your local jurisdiction (County or City) should be able to direct you on what procedures you should use. They would likely have runoff coefficients for you If you want a hydrograph, where the watershed is located could determine what standard you are using for the storm depth, duration, storm rainfall pattern, and a few more things. There are several methods for determining the rainfall/runoff. The local jurisdiction (County, City, State or Federal agency most involved in that watershed) may have a standard you need to follow to determine the flow rate at the pour point. So, I would find someone in your watershed's area who knows the what the hydrologic standards and methods are and follow their direction. A free program named HEC-HMS (HMS) created by the Corps of Engineers could likely be used for whatever standard they specify. ESRI has developed HEC-GeoHMS for the Corps to help transfer the input parameters from GIS to HMS. The GeoHMS process is somewhat complicated if you don't know GIS and HMS well. Hope this informs/helps. ... View more

This is a very good overview of the Arc Hydro process though it is about the Spatial Analyst Hydrology toolset. http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Understanding_drainage_systems/009z0000005m000000/ However, I have to disagree with the flow chart in this link (part of the same series). I would always perform a fill before running the flow direction. There is something wrong with the flow chart. It should show the process going from the dimensionless DEM box to a flow direction step then to the flow accumulation. Sorry, I'm being a little picky here, but someone new to this could get frustrated by the flowchart. The steps I use are posted and/or linked elsewhere in this thread (see post #2 in the post right before this one). http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Deriving_runoff_characteristics/009z0000005p000000/. The third paragraph in this link (part of the same series) points out that most DEMs have sinks. Mine always do, hence, why I always would run a fill sink process before I run the flow direction. http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/How_Fill_works/009z00000061000000/ ... View more

Check out solutions on this post: http://forums.arcgis.com/threads/48100-ArcHydro-Problem-Solvers. The post covers several problems, not just the one you are referring to. ... View more

William, I'd like to sent you my email address via the forum's Private Messaging system, but it doesn't look like your's is turned on. Sign in to the forum site and go to http://forums.arcgis.com/profile.php?do=editoptions. Search for private messaging and enable it. Then you should be able to click on my name on one of my posts to send me a message. If you get that far and I receive a msg, I'll reply with my email address. Thanks. Mark ... View more

I too have had to resort to the Geo-HMS tools for centroidal longest flow paths. ... View more

I think that technically the flow path (if you use it to measure the distance between cross sections) is to represent the "center of the mass of the flow" (see Reach Lengths on page 3-12 of the HEC-RAS Hydraulic Reference Manual: you can find it via the Help menu in HEC-RAS). ... View more

If you send the raster to me, I'll try to process it. Possibly you could create a zip file and then attach it to a post. ... View more

The error during conversion is explained here http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//00vq00000002010024.htm Try putting the agreestream layer in a geodatabase. Most layers are more "stable" in a geodatabase. This issue has been discussed before: http://forums.arcgis.com/threads/68360-Error-in-DEM-Reconditioning-in-Arc-hydro-10.  Putting the agreestream layer in the geodatabase gives each feature an OBJECTID which, I gather, is needed for the process to work. Other measures off the top of my head: Make sure the names of all data files do not have spaces. If you must have some kind of space then use the "_" character. Long names and names with spaces are things I stay away from. Make sure the geographic projections of all data are defined and are the same. Let me know if any of this helps. ... View more

Clarification on the process: http://forums.arcgis.com/threads/76491-unable-to-recondition-or-burn-stream-into-raster?p=268404#post268404 ... View more

William, I have been using Arc Hydro for a while and have taken two courses from ESRI on Arc Hydro. No one has ever said the agreestream layer had to have elevations. I have never needed to assign or burn in the slopes. When you burn in a stream using Dem Reconditioning, it simply results in a DEM that has lowered elevation where the streams are. When you process the DEM further, and get to the flow direction grid, then from there on in the process the elevations do not come into play. If you need to force an existing flow direction grid to change, you can modify it with polylines that have "direction". This direction is based on the from and to points of the polyline. This would be done via at the Flow Direction with Streams function. If you really want to assign or burn the stream slope in for some reason you could use the "Assign" or "Burn Stream Slope" functions under Terrain Processing>Dem Manipulation>. I've never had to use them. They might require elevations in the your polylines. In general, I don't think of wanting a topographically (elevation) correct DEM. I think of wanting a hydrologically (flow direction) correct DEM. The menu order follows the order you should follow (top to bottom). Here is the process I follow for dendritic stream systems. Terrain Processing>Dem Manipulation> Dem Reconditioning - This burns in the streams Build Walls - use streams for breach (if you have flat landscape you may need to do this in areas where man-made drainage overrides what happens on the surface) Fill Sinks Terrain Processing> (order of some items is can be different than below. See image of the Basic Dendritic Terrain Processing Model. You can see from it which datasets are dependent on which thus dictating order of processes.) Flow Direction Flow Accumulation Stream Definition Stream Segmentation Catchment Grid Definition Catchment Polygon Processing Drainage Line Processing Adjoint Catchment Processing Drainage Point Processing. [ATTACH=CONFIG]21221[/ATTACH] I've been collecting Arc Hydro tips at http://forums.arcgis.com/threads/48100-ArcHydro-Problem-Solvers. ... View more

Arc Hydro is a good tool to use. Here are several links that will give you tips on Arc Hydro. http://forums.arcgis.com/threads/53316-Why-can-t-I-define-a-stream-network http://forums.arcgis.com/threads/48100-ArcHydro-Problem-Solvers ... View more

Putting the data on your local drive instead of on the network will not only speed up the terrain processing, several functions that usually fail will magically work. ... View more

Assign UniqueID is in the Arc Hydro Tool Box. Maybe they took it off the toolbar for some reason. ... View more