Long Profiles (partial)

Stream channels typically display a concave profile (upward concave) over their length. Channels tend to develop and maintain this quasi-equilibrium shape over time due to several contributing factors, including subsidence of the adjacent basin, sea level rise, progradation of the delta, downstream fining of transported and stored sediment, abrasion (fining with distance downstream), and tributary effects on sediment concentration with distance downstream (Paola et al., 1992; Sinha & Parker, 1996). Convexities in the profile commonly occur where a channel crosses a fault, resistant band of rock, a collection of in-stream boulders, a paleosurface, or an precipitation boundary.

There are many ways to create channel long profiles. The method you choose depends on the scale of analysis, the tools, and the data available.

Method A: Google Earth & Excel
– Manually create a series of regularly-spaced Placemarks in Google Earth (GE). In most cases, the spacing between Placemarks need not be exact. For mountain channels, 1-2 km spacing is usually sufficient.

– Decide how to define your reaches early on – between consecutive points or every third point or whatever makes sense.

– Set up a spreadsheet in Excel with columns for Placemark#, Elevation (m), SinuousDistance (m), CumSinDist (m), StraightDistance (m), Slope (%), SinuosityIndex.

– Use the measurement tool in GE to find the sinuous channel length between consecutive Placemarks. Click, click, click a polyline path down the center of the channel. Be consistent in the distance between clicks. Record lengths in spreadsheet.

– Next mouse-over each Placemark to get it’s elevation (lower right edge of window). Record elevations in spreadsheet.

– Calculate the following in spreadsheet. Apply values to the downstream point.
Cumulative sinuous downstream distance at each point
Slope by reach in percent rise units (change in elevation/sinuous distance)
Sinuosity Index (sinuous distance/straight distance).

– Chart Elevation (Y) vs.┬áCumulative Sinuous Downstream Distance (X). Exaggerate the vertical axis considerably for display purposes.

 

METHOD B: Extract Vertices
– Add stream line shapefile (isolate a stream polyline shapefile created in Watershed Delineation lesson) or…
– Draw/digitize with Draw tools (manually create graphics), then Convert Graphics to Features (Right-click on Data Frame > Convert Graphics to Features)
– Add projected, filled DEM to map
– Create contours from DEM, tight spacing = twice that of reach length
– Select a stream segment
– Data Management Tools > Features > Feature Vertices to Points
– Spatial Analyst > Extraction > Extract Values to Points
– Plot Elevation vs. Downstream Distance
– Add additional information to profile figure:

Cultural Features: Towns, Bridges, Highways, RR crossings, Mines, etc.
Geologic units or other subsurface information (i.e., “top of Tertiary”)
Island count/Bar count
SL Index/Stream Power Index
Solute load/TMDL data
Channel slope
Bedrock bed/Alluvial bed
Ice jam reaches
Grainsize information
Mountain front/Slope breaks
Sinuosity Index
Ridgeline elevation profile
Bankfull channel width
Terrace surface profiles
Age data
Exhumation/Erosion data
Valley width
Knickpoint locations
Gauge locations
Landslide count
Rock strength/Fracture data
Precipitation gradient
Dams and reservoirs
Tributary confluences
Geologic structures (faults, fold axes)
Caves
Hotsprings/Spring deposits
Habitat/Vegetation/Land use boundaries
Archaeological sites/Fossil localities

 

METHOD C: Intersections to Points
– Start with a shapefile for the channel (streamline) and one for topographic contours, which can be created from a DEM (Spatial Analyst > Surface > Contour).
– ArcGIS can find the intersections between the two layers and convert them to points (
– Create an X,Y profile from the point data

** Use GME to do it –> http://www.spatialecology.com/gme/isectfeatures.htm

Refs
http://blogs.esri.com/esri/arcgis/2013/02/11/streetintersectionlist/
http://www.arcgis.com/home/item.html?id=a55a509bf752433582b7515d15f9a622
Good solutions by Mike Hargreaves –> http://forums.arcgis.com/threads/23215-create-point-shapefile-of-street-intersections-from-polyline-ArcEditor
http://gis.stackexchange.com/questions/17963/find-crossing-lines-in-arcgis
http://gis.stackexchange.com/questions/31359/find-intersection-points-of-two-polyline-features
http://forums.esri.com/Thread.asp?c=93&f=987&t=136165

METHOD D: Channel Profiler Tool (ArcGIS/MatLab)
http://www.geomorphtools.org/tools.htm
http://web.mit.edu/gis/www/profiler_code/

METHOD E: Cost Path from Pour Point in ArcGIS (in progress…..)
See: http://www.docstoc.com/docs/32947977/How-to-extract-a-river-profile-from-a-DEM

METHOD F:
Stack Profile tool (3D Analyst)…LINK

……

Other Random Notes:
Useful tools:
Data Management > Features > Dice

3D Analyst > … Add Surface Information tool
Uses a surface to interpolate heights for features, converts them to 3D in the background, calculates 3D properties, then writes the values to the input shapefile’s attribute table.

3D Analyst > … Interpolate Shape tool
Interpolates z-values (i.e., elevation) for a shapefile based on an underlying raster, TIN, or terrain surface.

Spatial Analyst > … Extract Values to Points
Extracts the values of a raster based on a set of point features and appends the values in a field named RASTERVALU in the attribute table of a new output shapefile.

General Refs
Demoulin et al. (2007) Geomorphology 91
Knuepfer (1994) EOS Transactions 75, p. 288
Pedrera et al. (2009) Geomorphology 105
Seidl et al. (1994) Journal of Geology 102
Tomkin et al. (2003) Journal of Geophysical Research 108
Troiani et al. (2008) Geomorphology 102
VanLaningham et al. (2006) ESPL
Whittaker et al. (2007) Basin Research 19
Whittaker et al. (2008) Geomorphology 100

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