Latest Contributions by ChristineDartiguenave

If you use subwatershed delineation with all input points the resulting subwatersheds will not overlap. Christine Dartiguenave Esri Water Resources Team ... View more

This happens only for some projections and when data gets stored in a new feature dataset created by Arc Hydro. At this time we are not sure what is going on or what is missing or how to fix it. Workaround seems to be to manually create the target features and set its spatial projection. Then the new data created in that dataset should be ok. If you have specific data that triggers this issue you can send it to us ([email protected]) and we will take a look. Christine Dartiguenave Esri Water Resources Team ... View more

You could use the flow accumulation grid to identify the cells that are a multiple of the number of cells you would like to have in each catchment, and then perform a subwatershed delineation on all these points at once. The issue however is dealing with confluences. There are going to be some jumps in the flow accumulation sequences so you will not be able to get exactly the same areas and may need to some editing to identify the locations of the points to use. Christine Dartiguenave Esri Water Resources Team ... View more

I have seen something similar before. The issue was not with the lines being multipart but with the spatial reference being corrupted. Basically all features were selected when clicking on one. Copying the features into a new feature class fixed the spatial reference (same way as using multipart to single part since it creates a new feature class). Christine Dartiguenave Esri Water Resources Team ... View more

One way of doing this is to edit the projection file associated to the input grid. - Open the prj file associated to the grid (prj.adf) in a text editor. - Set the parameters Units to the desired value (e.g. FEET, METERS) for the ground unit if not set. - Set the parameters Zunits to the desired value for the z-unit. This parameter is set to NO if the z-unit is not explicitly defined: in that case the z-unit is assumed to be the same as the ground unit. The zunits parameter may be set using a unit name (e.g. METERS, FEET) or a number in the projection file: this number represents the number of zunits that are needed to equal one meter (not one ground unit). For example, for a ground unit in meters, a z-unit in centimeter is defined as: Units  METERS Zunits 100 as there are 100 cm in 1m. For a ground unit in feet, a z-unit in centimeter is defined as: Units  FEET Zunits 100 as there are 100 cm in 1m. Christine Dartiguenave Esri Water Resources Team ... View more

The elevations are relative elevations, not real ones. They ensure that the elevations in the streams decrease in the digitized direction. The objective is to obtain correct flow direction grids - you should not use any edited dems as source of elevations for any analyses. Christine Dartiguenave Esri Water Resources Team ... View more

Arc Hydro started with dendritic terrain processing only but has been extended over the years through work with the Southwest Florida Water Management District to handle both flat areas with sinks (what we call Deranged terrain) and structures such as culverts or pipes. Deranged Terrain In flat areas water may flow toward the sinks. There are catchments associated to sinks in Arc Hydro as well. The connectivity between deranged catchments is established  through the lowest point on the  shared boundary (Drainage Morphology tools). You can also set a preferential path between the catchments that will allow you to trace "downstream" like in a dendritic terrain network. Structures Basically you can extent your standard Arc Hydro Geometric Network with junction/edges representing the structures that you would need in your model. Arc Hydro does not do modeling but will help you with preparing the input data required for your model and with visualizing your results. Christine Dartiguenave Esri Water Resources Team ... View more

As we are moving toward the geoprocessing environment, we have removed these functions from the toolbar because you can use out-of-the-box ArcGIS geoprocessing tools to get the same results: Slope greater than 30 and Slope greater than 30 and facing North: you can use the Spatial Analyst's Con tool to set the conditions on the input slope grid. Weighted flow accumulation: you can use the Spatial Analyst's Flow Accumulation tool with an input weight raster. Christine Dartiguenave Esri Water Resources Team ... View more

There is a tool in the Arc Hydro Tools toolbox > Attribute Tools toolset called Assign River Order that will calculates the stream order using 3 different methods: Strahler: if different upstream orders, then maximum of the upstream orders, if more than 1 with maximum order, then max order +1. Shreve: add upstream orders. PU_Order: downstream feature river order = maximum of upstream features river order + 1 (PU stands for Processing Unit). This tool uses the attributes HydroID/NextDownID in the input feature class to determine the downstream direction. It does not support flow splits or loops at this time. Christine Dartiguenave Esri Water Resources Team ... View more

Are you filling the reconditioned DEM? If you do, are your burnt in streams allowed to flow outside of the DEM? If they do not, then they will trap the water within the dem, be considered as sinks and filled in. Christine Dartiguenave Esri Water Resources Team ... View more

This issue was fixed in the 2 versions of HEC-GeoHMS posted last Thursday (2/7/2013) on our ftp site. HEC-GeoHMS 10.0.0.118 for ArcGIS 10      10.1.0.27 for  ArcGIS 10.1 Christine Dartiguenave Esri Water Resources Team ... View more

If you are using ArcGIS 10, I would upgrade to Arc Hydro 2.1. Assign UniqueID is still in the ApUtilities menu in versions 2.1 (ArcGIS 10) and 10.1 (ArcGIS 10.1) for sure. We added it to the toolbox but did not remove it from the toolbar. Christine Dartiguenave Esri Water Resources Team ... View more

The Burn Stream Slope function was introduced to enforce the flow direction once the water reaches the stream, to deal with cases where the elevation in the stream (after burning) goes the wrong way. This function modified the elevation so that it decreases along the digitized direction of the streams. The Assign Stream Slope function had to be run first to populate the required elevation fields. These 2 functions have been replaced by the Create Drainage Line Structures/Adjust Flow Direction in Streams function. The first one creates the Stream Flow Direction Grid enforcing the flow direction in the streams and the second one imposes this Stream Flow Direction Grid onto the Flow Direction Grid to create the Stream Adjusted Flow Direction Grid. Christine Dartiguenave Esri Water Resources Team ... View more

The main objective of the AdjointCatchment feature class is to speed up performance for watershed delineation. It does not need to be visible in the map. It represents the aggregated catchments upstream of any given catchment. However, if you to visualize a subset, you could setup a definition query to show only the features meeting your specified criteria (Definition Query tab in the Properties window). Christine Dartiguenave Esri Water Resources Team ... View more