STREAM ROUTES & REACH ROUTES

based on 1:100,000 scale River Reach files

WHAT IT IS

The Oregon Department of Fish & Wildlife has developed a stream routing system in 
Arc/Info for the Applegate and is developing the same system for the entire state. These 
coverages are based on the USGS 1:100K River Reach Files which have been enhanced to 
include two separate route systems.  The first route system, named STREAMS, uses 
stream names to create a unique route for each stream in a given basin.  The second route 
system, named REACH, creates a unique route for each river reach in the basin.  
Information on fish distribution/habitat and management areas are stored in DBASE (.dbf) 
"event" tables that relate to the STREAMS and REACH route system.

The routing system allows users to attach information to the stream data based on the 
association of that information to certain river mile segments. For the STREAMS coverage 
the stream name is the unique identifier and river miles are recorded from zero (0) at the 
stream mouth to "xx" miles at the beginning (headwaters) of the stream. Data such as fish 
presence (or any other linear information) can be related to the portion of the stream based 
on stream miles. For example, "old growth conifer vegetation is present from mile 2.3 to 
mile 14.2 and from mile 21 to mile 25.8." 

The REACH coverage does essentially the same thing as the STREAM coverage except that 
a river reach within a basin is the unique identifier (recorded as a function of the HUC 
numbering system). In the River Reach data a reach is defined as a stream segment between 
tributaries (and happens also to represent a single arc in the Arc/Info coverage). In the 
REACH routing system then, each stream segment has a unique id and starts at zero (0) 
miles and ends at "xx" miles where the next stream segment begins again at zero (0) miles.

An important point to keep in mind is that "stream miles" are determined from the GIS 
coverage and represent--BUT ARE NOT EQUAL TO--actual miles on the earth. Actual 
stream miles may vary from map stream miles due both to the necessary generalization of 
the mapping (at 1:100,000 scale this is relatively course data at the level of the sub-
watershed) and natural shifts over time in the course of rivers.

Because the REACH system is based on stream segments and the STREAM system is 
based on entire streams the REACH system has many more records. While both systems 
accomplish that same task, the REACH system offers one potential advantage. Since any 
variation in map miles and actual miles is likely to be compounded towards the end of any 
given stream, the segmentation of streams may provide a means to reduce this variation.

While this system of stream routes provides advantages to ODFW in reducing data storage 
needs and facilitating access to ODFW fish distribution data, it also provides opportunities 
for local users to develop other linear or point information associated with streams.


COMPLICATIONS

The route system was developed using dynamic segmentation in Arc/Info. The dynamic 
segmentation process creates several files that are additional to the normal compliment of 
files in an Arc/Info coverage. These files act behind the scenes to dynamically generate the 
route system from the source coverage. When imported into ArcView from an Arc/Info 
export (.e00) file some of these key files are not imported, therefore the routed coverages 
(STREAMS & REACHES) do not appear. To avoid this, the coverage must be read into 
ArcView directly as an Arc/Info coverage (without exporting).


HOW TO USE the STREAM or REACH ROUTES IN ARCVIEW

FIRST, open or create a project in ArcView.

In a project view, choose "add theme" from the view menu. Find the APPLEG coverage. 
In the ArcView add theme dialog box APPLEG will appear as a folder. Open the APPLEG 
folder and note that there are three files: "route.reach," "route.streams," and "arc."  Add all 
of these to the view. They will appear in the view as Reach, Streams, and APPLEG, 
respectively.

APPLEG is essentially identical to the 1:100,000 USGS River Reach coverage. The others 
are the two routed layers. Streams and Reach appear identical to each other graphically but 
differ from APPLEG in that braided streams and ditches have been eliminated. The data 
tables for Streams and Reach differ slightly. The primary field for Streams is "name" 
(stream name) and for Reach it is "Rrn" (River reach number).

There are two associated tables (.dbf files) that can be used to create event themes based on 
the Streams [but not the Reach] layer. They are HAB.dbf and MANAGE.dbf.

SECOND,to add these existing files as event themes:

1) In the view (it doesn't matter what if any themes are active or drawn) under the view 
menu select "add event theme." 

2) In the event theme dialog box click the middle button (looks like a ruler) in the upper left 
to indicate a linear event theme. Note that the appearance of the dialog box changes.

3) At the ROUTE THEME option select "STREAMS" [note that APPLEG is not available 
as it is not a routed theme]

4) At the ROUTE FIELD option select "Name" [for stream name]

5) Select the radio button for lines rather than points. [It is possible to add points along a 
linear feature--note the box changes slightly again]

6) At the TABLE option select "HAB.DBF" [this is the event table. Alternatively use 
"MANAGE.DBF" as the event table. Note that everything below this point in the dialog 
box pertains to the event table.]

7) At the EVENT FIELD option select "Name" to match your choice in the ROUTE 
FIELD. [Both could be Stream_ID instead, but either way they must be the same]

8) Make sure FROM FIELD  and TO FIELD are "From" and "To" respectively.

9) Click "OK" and the event theme appears at the top of the view. The extent of the theme 
is limited to the extent of any fish habitat for the Applegate. [Note the contents of the 
associated attribute table and see the dictionary for HAB and MANAGE below]

10) If desired this can be saved as a seperate shape file.

_________________________
_________________________
HAB.DBF
Description:    
This linear event table contains the fish habitat distribution data for all fish species.  Data 
was obtained first through field interviews with ODFW Biologist, then followed by editing 
of hard copy maps.  Data represents professional judgment of the ODFW District Biologist 
that has jurisdiction of the HUC.  ODFW District Biologist opinions supersedes any data in 
this data set if contradictions arise.

ITEMS:
----------
STREAMS-ID:     Key Field to link to STREAMS
HABITAT:                Fish Habitat Type:      1 = Spawning & Rearing 
                                                2 = Rearing Only Areas
                                                3 = Migration & Presence
SPECIES:                Fish Species:           1 = Coho
                                                2 = Fall Chinook
                                                3 = Spring Chinook
                                                4 = Winter Steelhead
                                                5 = Summer Steelhead
                                                6 = Chum
                                                7 = Brown Trout
                                                8 = Rainbow Trout
                                                9 = Cutthroat Trout
                                                10 = Bull Trout
FROM:           Start point of event
TO:                     End point of event
LENGTH:         Length of event
NAME:           Name of stream the event occurs on

_______________________________
MANAGE.DBF
Description:  
This linear event table contains the various fish management areas that have been adopted 
by different agencies for salmon management

ITEMS:
----------
STREAMS-ID:     Key field linking table to the STREAMS route system
NAME:           Name of stream the event occurs on
MANAGENUM:      Management Area Type (Agency/Organization):
                                1 = FEMAT Tier 1 Watershed (USFS)
                                2 = Aquatic Diversity Area (American Fisheries Society)
                                3 = Source Areas for Coho (ODFW)
                                4 = Essential Coho Habitat for Instream Mining (DSL)
                                5 = CSRI Important Areas (ODFW)
FROM:           Start point of event
TO:                     End point of event
LENGTH:         Length of event


___________________________
___________________________
OTHER USE

The route systems provide a great opportunity to easily create local data sets in the 
Applegate. Data may be in the form of linear sections of streams (say stretches of 
vegetation type, restored sections, etc.) or points along streams (such as monitoring sites, 
dams, swimming holes, junked cars, etc.). 

These data can be developed as tables that specify the type of "event" (e.g., junked cars); 
additional information on the event (e.g. car color, condition, year); the stream it occurs on 
(e.g., Williams Ck.); and the mile point (or miles from and to for linear events).

When developing local event tables to link with the route coverages, however, keep in 
mind the variation between map miles and "real" miles. To maintain relative accuracy, the 
to and from points should be based on the map data rather than purely on distance 
measured on the ground.

Unfortunately, ArcView cannot identify a distance point on a route from a graphic entry. 
That is, one cannot click on a point along a route theme and expect ArcView to respond 
with the map distance measure. At best, the route distance for a given point can be derived 
iteratively through trial and error by entering a series of "guesses" and viewing them 
repeatedly to narrow in on the actual point. This may not be as tedious as it sounds.

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Documentation compiled by Interrain Pacific (10/96) based on ODF&W documentation and 
conversations with ODF&W staff.