Functional linkage of
watersheds and
streams:
ArcGIS FLoWS tools
David Theobald, John Norman, Erin
Poston, Silvio Ferraz
Natural Resource Ecology Lab, Dept of Recreation
& Tourism, Colorado State University
Fort Collins, CO 80523 USA
26 July 2005
Project context

Challenges of STARMAP (EPA STAR):
Addressing science needs Clean Water Act
 Integrate science with states/tribes needs

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Assisting statisticians to test tenable hypotheses
generated using understanding of ecological
processes
Goal: to find measures that more closely represent our
understanding of how ecological processes are
operating
From watersheds/catchments as
hierarchical, overlapping regions…
River continuum concept (Vannote et al. 1980)
… to network of catchments
Benda et al. BioScience 2004
SCALE: Grain
Landscape
River Network
COARSE
Climate
Atmospheric deposition
Geology
Topography
Soil Type
Network Connectivity
Nested Watersheds
Land Use
Topography
Stream Network
Connectivity
Drainage Density
Flow Direction
Confluence Density
Network Configuration
Vegetation Type
Basin Shape/Size
Segment
Contributing Area
Segment
Tributary Size Differences
Network Geometry
Localized Disturbances
Land Use/ Land Cover
Reach
Riparian Zone
Riparian Vegetation Type
& Condition
Floodplain / Valley Floor Width
Microhabitat
FINE
Shading
Detritus Inputs
Cross Sectional Area
Channel Slope, Bed Materials
Large Woody Debris
Substrate
Overhanging
Vegetation
Biotic
Condition
Microhabitat
Biotic Condition, Substrate Type,
Overlapping Vegetation
Detritus, Macrophytes
USGS
NHD,
NED

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FLoWS v1 tools for
ArcGIS v9.0…
Will migrate to v9.1
Pre-processing segment contributing
areas (SCAs)
Automated delineation
 Inputs:
 stream
network (from
USGS NHD 1:100K)
 topography (USGS
NED, 30 m)
 Process:
 “Grow”
contributing
area away from segment
until ridgeline
 Uses WATERSHED
command
“true”
“adjoint”
catchments
catchments
Segments
Segments are linked to catchments
1 to 1
relationship
 Properties of
the watershed
can be linked
to network for
accumulation
operation

Landscape networks with Python


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
Need to represent relationships between features
Using graph theory, networks
Retain tie to geometry of features
Flow relationships table (like NHD, but flow-sorted!)
Implementation in ArcGIS


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Geometric Networks (ESRI – complicated, slow)
Landscape Networks: Open, simple, fast
Began with VBA (1.5 years), moved to Python (2
months)
Selections

Downstream
Example: Flow modification
Deynesius and Nilsson, Science (1994) –
77% of upper 1/3 of northern
hemisphere rivers are strongly or
moderately affected
- F = regulated/total channel length
- R = % of VMAD (cumulative reservoir live, gross
capacity)
Network-based flow modification
1. Degree of modification to flow = cumulative
annual flow – cum. dam max. storage:
Q’ = Q-S
2. Proportion of modified to VMAD (“natural”)
flow:
F = Q’/Q
RCL
TCL
Reservoirs
1. DEM Dam “shadow”
2. Slope
3. Flow dir.
4. Flow acc.
5. Hydro dist.
High
Example:
Coho salmon
distances
Example:
Coho salmon
distances
Example: 2D stream in Virginia
Example: 2D stream in Virginia
Example: 2D stream in Virginia
Example: 2D stream in Virginia
Next steps

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Increase range of applications
Attach additional datasets to SCA database
Land cover (urban, ag, “natural”)
 Historical, current, future housing density
 Indexing of National Inventory of Dams?

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From segments to geomorphological reaches,
gradient
Project/tool website:

www.nrel.colostate.edu/projects/starmap
Thanks!

Comments? Questions?

Funding/Disclaimer: The work reported here was
developed under the STAR Research Assistance
Agreement CR-829095 awarded by the U.S.
Environmental Protection Agency (EPA) to
Colorado State University. This presentation has not
been formally reviewed by EPA. The views
expressed here are solely those of the presenter and
STARMAP, the Program (s)he represents. EPA does
not endorse any products or commercial services
mentioned in this presentation.

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FLoWS:
www.nrel.colostate.edu/projects/
starmap
davet@nrel.colostate.edu
CR - 829095