Steps in building a
channel-network dataset.
1.Build
a contiguous DEM over entire watershed (IfSAR, LiDAR, NED).
Decisions: resolution,
coordinate system.
2.Calibrate
synthetic channel-network extent.
Decisions: length scale
for topographic attributes, channel density.
3.Hydrologic conditioning.
a)Build a water mask.
b)Identify road crossings
(LiDAR).
c)Existing line work for hydrologic
enforcement.
d)Drain or fill closed
depressions.
e)Define flow directions.
4.Build linked channel-node
dataset.
5.Build GIS output
files.
a)Routed
channel network.
Decisions: reach length,
upslope extent.
b)Attributes (contributing
area, gradient, flow length, etc.)
c)Flood-plain polygons.
d)Drainage wings.
e)Run other needed analyses
(road erosion, etc.)
6.Verify
(field surveys, other data sets), Quality Control. Iterate.
Ensure all subsequent
analyses properly functional.