California Salmonid Habitat Inventory: Russian River Basin, California, 1996-2002

All stream surveys are dynamically segmented against 100k base hydrography routes.

The Dynamic Segmentation process is accomplished by 1)
Preparing a hydrography arc coverage with a unique numeric value
for each named stream 2) Ensuring flow direction for each stream
3) Building route/section topology for each stream 4) Preparing the
habitat table as linear event data with a)measure distances based
on field inputs and b)a unique key value for each named stream 5)
Calibrating routes based on field input from habitat table 6)
Displaying habitat tables in ArcView, converting to ArcView shapes
and distributing to field personnel.

1. DFG has obtained US Geologic Survey (USGS) Digital Line Graph
(DLG) 100,000 scale hydrography (See Appendix for Hydro Meta Data
and structure). In 1993, the US Environmental Protection Agency
(EPA) attached the River Reach File Version 3 (RF3) addressing
system to California's hydrographic coverage Arc Attribute Table
(.AAT). Arcs along the same named watercourse share a common
primary name code, or PNMCD. The unique key value for each stream
is the EPA national standard PNMCD.

2. Prior to building hydrography route/section topology, streams
must have consistent linear direction. I developed an Arc Macro
Language (AML) method for establishing direction of all streams
based on topology with no operator (See Appendix for flow.aml and
lake.aml). This process pathwalks each named stream from its
headwaters to its mouth and ensures all arcs point downstream
(including double lined streams). The DLG MINOR5 field is
populated with the arc numeric sequence of each stream from the
mouth.

3. I developed an ArcEdit AML which creates Route/Section
topology (See Appendix for mkroute.aml). The blanket Arc level
MAKEROUTE command will not ensure direction of all routes. The AML
creates one route for each unique PNMCD, in which the beginning
measure of the route is at the streams confluence (arc MINOR5 = 1
from flow.aml) and the ending measure is at the streams headwater.
The resulting Route Attribute Table (.RAT) has one record per
unique PNMCD. The resulting Section Attribute Table (.SEC) has one
record for arcs along each PNMCD.

4. Preparation of habitat data as event tables contains the
following processes: A) Insure the table has a properly populated
route relate item and B) create and populate measure items.

In some cases field personnel will not have the PNMCD value for
the surveyed stream, and will enter instead a latitude and
longitude of the stream confluence, the township range and section
number (called legal) and/or the stream name from the USGS 7.5
Minute Quadrangle. By cross referencing the quadrangle, lat/lon
coordinates, legal description or the stream name with the RF3
file, I find and enter the proper PNMCD value in the habitat table.
Each habitat table data will relate to the .RAT on the PNMCD.

The habitat table contains one record per habitat unit. The
LENGTH field is the length of each habitat unit, measured in feet.
Measure fields FROM, TO (for linear events), and LOCATION (for point
events) are added to the habitat table. The FROM field is equal
to the previous FROM value (0 for the first record). The TO field
is equal to the FROM field plus the LENGTH field. The LOCATION field
only populated when point event locations occur. While occurring
anywhere in a habitat unit, point events are surveyed with the same
length as a habitat unit. The LOCATION field equals half of the FROM
FROM field plus the TO field. Measure items are converted to meters,
the units of the hydrography coverage projection. Each record of a
habitat table will relate to the .SEC on the measure items FROM, TO
or LOCATION.

5. A point coverage for each survey, is made from each
tributary's confluence or road crossings and the end of the survey.
The end of survey point is digitized from a photocopied USGS
quadrangle. The points are attributed with the length to the mouth
taken from the habitat table, in meters. The Arc command
CALIBRATEROUTES uses the point coverage to correct the arc measured
distances with the field observed distances.

6. In Arcview, a view is added to a project and the hydrography
route topology added to the view. The habitat event table is added
to the project. With the view the active document, ADD EVENT THEME
from the VIEW menu is chosen. The Add Event Theme dialogue box is
populated, and the survey is displayed as an event theme. The
THEME CONVERT TO SHAPE menu choice converts the event theme to a
shape file. The shape file can be displayed and classified on any
or multiple fields in the Habitat Inventory. The process is
repeated for point events."