Parallel to the development of the Arc Hydro Data Model a series of Tools have been develop to aid and support the generation of complete datasets. Most of these tools have been integrated inside the Arc Hydro Tool bar which is of public domain and contains raster and vector oriented tools to empower the development of your spatial project. The tool bar is shown below and you may download it from at least two websites as described in the Downloads section of this website. The current version of the tool is shown below for reference.

9.1-Assign NextDownID to Drainage Areas like Catchments and Watersheds

The Arc Hydro model allows for tracing based on features (Not geometric network). For this to be applicable you have to tell each type of polygon feature what is its corresponding downstream polygon feature. In Arc Hydro this is accomplished by populated a NextDownID field for each feature with the HydroID of the next downstream feature. This task will have to be done manually unless your dataset contains some code that defines connectivity. One example of this intelligent codes is the Pfafstetter code. The USGS EDNA layers include this codes and if they are available you may use those Pfafstetter codes to define the NextDownIDs based on HydroIDs. (Use the NextDownID by Pfaf Tool and the corresponding tutorial)

For PfafTool go to: http://civilu.ce.utexas.edu/stu/whiteatl/hydrotools.html

9.2-For HydroJunction and Watershed/Catchment: Use StoreAreaOutlet tool to assign create a relationship between the Watersheds/Catchments and the HydroJunctions at their outlets.

9.3-For HydroJunction and Waterbody: Use The StoreAreaOutlet tool to assign create a relationship between the Waterbodies and the HydroJunctions at their outlets.

9.4-Optional: Delete HydroJunctions that do not represent Gages, Outlets, Control Points, and in general points of no hydrologic interest to your project.

You may accomplish this by selecting ALL Junctions with existing relationships, switching the selection, and deleting the Junctions with NO relationships (Do not delete Junctions representing MonitoringPoints or ControlPoints)

9.5-Compute Distances and Areas in Km and SqKm:

• For HydroEdge compute: LengthKm = [Shape_Length]/1000

• For Watershed compute: AreaSqKm = [Shape_Area]/1000000

• For Catchment compute: AreaSqKm = [Shape_Area]/1000000

• For Waterbody compute: AreaSqKm = [Shape_Area]/1000000

9.6-Apply the rest of ArcHydroTools

Browse through the ArcHydro Toolbar and apply the remaining tools to populate as many ArcHydro fields created by the Schema as possible. The purpose of this is to enhance the parameterization of your dataset with relevant hydrologic attributes that will aid in posterior analysis, water management tasks, and environmental modeling exercises.

Under ArcHydro Toolbar > Attribute Tools >

• Calculate Length Downstream for Edges
• Calculate Length Downstream for Junctions
• Find NextDownstream Junction (if it fails do it by selections)
• Find NextDownstream Line
• Consolidate Attributes (A relationship is needed between source and target/output layers, see Arc Hydro book)
• Accumulate Attributes (Connectivity is needed through network or NextDownID for the layer with the field we want to accumulate downstream, see Arc Hydro book)

9.7-Check the primary Relationships exist in your geodatabase and add the additional relationship classes that you might have included.

• HydroJunctionHasHydroPoint (HydroID > JunctionID association)

• HydroJunctionHasMonitoringPoint (HydroID > JunctionID association)

• HydroJunctionHasWatershed (HydroID > JunctionID association)

• HydroJunctionHasWaterbody (HydroID > JunctionID association)

• MonitoringPointHasTimeSeries (FeatureID > HydroID association)

• HydroJunctionHasCatchment (HydroID > JunctionID association)

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