This dataset is not a hydrologic model and should not be used for hydrologic or hydraulic modeling of any kind. Its purpose is to study and wash ordering (networking) as well as wash density. This dataset starts with a one-meter spatial resolution digital elevation model (DEM) downloaded (in parts) from the US national map.

Steps:

• Download and combine 1-meter DEMs from the USGS National Map. The various parts were combined using tools associated with ArcGIS Pro v. 3.0.

• The “Fill” command was used to eliminate any sinks in the model. We did not check the veracity of the “hydro enforcement” of this data. Undoubtedly, there will be some culverts not accounted for, etc.

• Once the filled DEM was produced, flow direction and flow accumulation were conducted.

• Flow lines were determined by using a conditional limiting lines to those with a basin area equal or greater than 5,000 square meters ( ~1.24 acres).

• Stream ordering tools were used to assign Strahler numbers to each segment of stream line (a segment is between any two nodes).

These previous steps were all conducted within a “raster” environment. Once the ordering was completed, the raster was converted to polylines.

• Using the normal assign geometry tools, the following fields were added: StartX, StartY, EndX, EndY

• Geometry was used to determine the length (straight line) between the start and end coordinates

• A field “Sinuosity” was added and assigned the value of curved length (Shape length) divided by the straight-line length.

• The elevation of the start and end points of each segment was determined in two steps following the procedures outlined by ESRI. Note: This process required the feature class to be converted to 3d. Once the data was extracted the dataset was converted back to a 2D by following the process here.

• As the converting to stream ordering lost the drainage area value in the original raster, this data was re added as and attribute by the following process

  • For each segment, a point was added using the add points along a line command. The number of points was 50%, or, one point in the center of the line.

  • To these points, the drainage area was added from the original flow accumulation raster by using the extract multi values to points command.

• These points were joined to the Stream Order dataset by using the OBJECT ID and Orig_FID.

• To eliminate the Join, the Joined dataset was exported to a feature class of its own, this feature class.

• Slope of the segment was determined by taking the difference between the Z_Start and Z_End and dividing that difference by the Start2EndLen.