U.S. Department of the InteriorU.S. Geological Survey

Loading Data into ArcHydro

Building the Global GeoDatabase

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Directory Structure

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Global Network

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Global Data Sets• All in Global.mdb geodatabase• hucpoly (tile boundaries)• streams (network to connect tiles)• hucpoints (outlets for tile polys)

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Step 1: Create Empty Geodatabase

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Step 2: Import data• First import a data set covering

ENTIRE area, i.e. all HUCs you plan to use

• This sets up the maximum spatial extent we can put into the “feature dataset”

• Make sure this data set at least covers the full desired extent

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The Import Coverage Tool

Type in “Layers here

click

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click

Don’ttouch!

Set to areasonable

value

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Building Global hucpoly

• Ideally no overlaps or gaps• Should be derived from fdr by

delineation• Start by delineating from outlet of

each HUC• Convert to a grid

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Building Global hucpoly (continued)

• Remove overlaps at top of non-headwaters HUCs via map algebra

• Convert to a shapefile hucshp in huc folder

• When finished, load shapefiles into global hucpoly feature class

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Building the hucpoint feature class

• These basically are the outlet points for each HUC

• You need one for each HUC, including the HUC furthest downstream

• Build these in ArcMap Editor

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Building the Global Network• Must build a Geometric Network of

streams• Just need mainstem streams needed

to connect our data tiles (8-digit HUCs)

• Coastal streams, and any stream not connecting an upstream HUC can be deleted

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Geometric Network Wizard• Build from existing features• Use hucpoint and streams feature classes• Name network HUC_Net• Build complex edges from streams feature

class• Use 2-m snap tolerance, both sets of

features• Include sources and sinks on hucpoints• Do not assign weights

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Set Flow Directions on Network

• Select outlet hucpoint• Set Ancillary Role to Sink• Click Set Flow Direction button on

Utility Network Analyst Toolbar• Or if streams from NHD, use

ArcHydro Tools, set flow opposite feature directions

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Assign HydroID’s

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Make Relationship Class HUCHasJunction

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Make Relationship Class HUCHasJunction

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Store Area Outlets

• ArcHydro Tools Toolbar

• Attribute Tools pulldown

• Or assignmanually