Hydrologic Models

ESRI has a set of tools to model the flow of water based on Digital Elevation Models (DEMS)

Data

There are many types and sources of elevation data.

• Shuttle Radar Tomography Mission (SRTM) Source: NASA circa 2000

  • Resolution 1 Arc Second (30m) and 3 Arc Seconds (90m)
  • Datum WGS84
  • Download source: https://earthexplorer.usgs.gov/ (requires login)

• ASTER Global Digital Elevation Model (GDEM) Source: NASA circa 2009

  • Resolution 1 Arc Second (30m)

• National Elevation Dataset (NED) Source: USGS (compiled from multiple sources)

  • Resolution 1 Arc Second Nationally (30m), 1/3 Arc Second (10m) and 1/9 Arc Second (3m) for certain areas.
  • Datum NAD83
  • Download Source: https://viewer.nationalmap.gov/basic/

• Lidar (3 FT)

  • Oregon Lidar Download (https://gis.dogami.oregon.gov/lidarviewer/)
  • Point cloud data: (ftp://lidar.engr.oregonstate.edu/)
  • Metro Point Cloud Data: (https://coast.noaa.gov/htdata/lidar2_z/geoid12b/data/6377/) or https://coast.noaa.gov/dataviewer/

Hydrology Model:

Once you've acquired your data you can run geoprocesses provided that you have the licences required- spatial analyst and 3D analyst.

• Fill
• Flow Direction
• Flow Accumulation
• Con
  • Conditional: Flow Accumulation
  • True: Flow Direction
  • False: Flow Direction
• Stream Order
  • Con
  • Flow Direction
• Stream to Feature
  • Stream Order
  • Flow Direction
    • expression grid code <> 1, 2, 3
    • Colour ramp blue
• Basin
• Raster to Polygon

ESRI also has proprietary geoprocessing tools for calculating watersheds and downstream traces. It uses the NED from the USGS as their primary data source though there are others as well.