Uncertainty analysis of HEC-HMS model using the GLUE method for flash flood. CEE Engineering Hydrology HEC-HMS Bare Essentials Tutorial and Example comprehensive or to replace the HEC-HMS documentation; rather it is a. The Hydrologic Modeling System (HEC-HMS) is designed to simulate the complete hydrologic processes of dendritic watershed systems.
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Therefore, check the data carefully, and if you think everything is OK, ignore the errors if you get any for connectivity and proceed. Creating Bridges hfc Culverts After creating cross-sections, the next step is to define bridges, culverts and other structure along the river.
You will see the reach will get selected, invoking the following window:. You can check it is PolylineZ by opening its attribute table. Creating the Flowpath Layer The flowpath layer contains three types of lines: The Basin Auto Name function assigns names to sub-basins.
Since we have only tutprial bridge, we will edit its information because details such as deck elevation and number of piers are usually not exported by HEC-GeoRAS. Flow Accumulation Grid file name: The vector data will be stored in a feature dataset also named Layers within the geodatabase associated with the map document.
You can respond to this message by selecting either yes or no – it does not matter in this exercise because we will join the table only once. Click OK, and a polygon feature class named AdjointCatchment is added to the map. HMS Project This function copies all the project specific files that you have created. Batch Subwatershed Delineation This function delineates subwatersheds for all the points in a selected Point Feature Class.
Since we ran the model with three profiles, we can choose which profile we would like to export. The area with positive results meaning water surface tutprial higher than the terrain is flood area, and the area with negative results is dry.
Step by Step: Flood Hazard Mapping
Each line in the feature class carries the identifier of the catchment in which it resides. Before creating an import file, make sure we are exporting the right layers. Due to some unknown reasons, if you get an error message at this point saying field cannot be added to a layer, save the map document, exit ArcMap and open the document, and try again. Confirm the input River name, and click OK. Watershed Processing Arc Hydro toolbar also provides an extensive set of tools for delineating watersheds and subwatersheds.
Before we proceed, let us deal with rows for SoilCode field. For example, when you click on a Reach Ryou will see that Muskingum routing method is associated with it. Adjust the symbology of the Flow Accumulation layer Fac to a multiplicatively increasing scale to illustrate the increase of flow accumulation as one descends into the grid flow network.
Step by Step: Flood Hazard Mapping | UN-SPIDER Knowledge Portal
The ability to judge the quality of terrain and flood inundation polygon comes with the knowledge of the study area and experience. We will explore only those parameters that do not require additional datasets or information.
Click Yes on the message box. The ArcCatalog-view of the data folder is shown below:. Perform hmd re-classification of classes Eventually, we are going to use these land use classes and soil group type, in conjunction with runoff curve numbers CNto create the curve number grid.
You can treat these methods as tentative which can be changed in HMS model.
These feature classes are added to the same geodatabase cedar. An alternative to delineate watersheds when you do not want to use the batch mode process a group of points simultaneously to generate the watershed for a single point of interest is the Point Delineation tool. With lnk grid active, select the contributing area tool, and click at any point along the stream to know the contributing area.
This Str grid contains a value of “1” for all the cells in the input flow accumulation grid Fac that have a value greater than the given threshold as shown in above figure. The output is the Catchment polygon feature class, having the default name Catchment that can be overwritten. To create the channel centerline in Banks feature classstart editing, and choose Create New Feature as the Task, and Banks as the Target as shown below:.
This function creates a grid of stream segments that have a unique identification. If you have an existing shapefile or feature class with a set of points that you would like to use instead of interactively creating points, you can do so by using the following guidelines:.
After the reaches are digitized, the next task is to name them. Using the sketch tool on the editor toolbar, the digitize bridge location just downstream of the tributary junction. The flowpath layer contains three types of lines: After finishing digitizing the upper Baxter Reach, save the edits.
This will invoke a dockable window in ArcGIS at the bottom that will display the profile of the selected reach. For example, each river has a station number of zero at the downstream end, and is equal to the length of the river at the upstream end. The left and right flowpaths must be digitized within the floodplain in the downstream direction.
We are done with geometric data! All of the preprocessing must be completed before Watershed Processing functions can be used. We can treat the main stem of the Baxter River as one river and the Tributary as the second river.
Confirm the input feature class for River, and click OK.