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BIOGEOGRAPHIC INFORMATION & OBSERVATION SYSTEM
BIOS Tutorial: In-Stream Habitat, Fish Passage
Analyzing In-Stream Habitat Reach Summary Data and Fish Passage Barrier Data
In the BIOS Mapviewer:
- First, open the BIOS Data Catalog by clicking the "Add BIOS Layers" tool (1).
- Then, filter the list of Available Layers by selecting the "Layer Name" filter field (2) and entering the search term "passage" in the Search Term box (3).
- Add the filter (4) and then check the "California Fish Passage Assessment Database" item (5) to add it to the "Checked Layers" box on the right.
- Then click the "Add Checked Layers to Map" button (6) to add this layer to the map.
Back in the map:
- Click the checkbox next to the added layer name to turn it on (7).
- Click on the layer name text to make it the "Active Layer".
- Finally, click the "Refresh Map" button to reflect your changes.
Next, open the stream reach dataset:
- Open the BIOS Data Catalog again by clicking the "Add BIOS Layers" tool (8).
- Choose the "layer name" filter (9) and enter the search term "reach" (10).
- Add the filter (11) and check the box next to the "Stream Habitat Surveys - North Coast - Reach Summaries" (12).
- Click the "Add Checked Layers to Map" button (13).
- Turn the layer on by checking the box next to it (14), and then refresh the map.
To focus on an area of the map supporting a high density of both passage assessment points and in-stream habitat lines:
- Select the "Zoom" tool (15) and draw a zoom box around the approximate area described in the graphic (16).
- Click the "Legend" tab to view the map legend (17) and confirm that both the In-Stream Habitat Data (lines, 18) and Passage Assessment Data (points , 19) are represented.
Make sure the "California Fish Passage Assessment Database" is the Active Layer (blue background on layer name), and using the "Spatial select" tool (20), select a group of points as indicated in the graphic (21).
The selected points will be highlighted in yellow (22), and the small yellow box next to the layer name (23) indicates the layer now has a selected set of records. In addition, the number of selected records and the attributes of each record appear in the results panel (24).
To better visually evaluate the next step of our analysis:
- Use the "Zoom" tool (25) to zoom into the area indicated on the graphic (26). The resulting map will display in-stream habitat data as thick lines of varying colors (27) and will obscure the passage assessment database points.
- Click on the upper "Active Layer Sort" arrow (28) to change the draw order of the Active Layer (in this case, the California Fish Passage Assessment Database layer), and move it on top of the In-Stream Habitat Data layer in the map.
- Refresh the map to show your changes.
A quick visual scan of the map will reveal some streams where in-stream habitat surveys were conducted, but that appear to be above barriers. This presents a data interpretation conflict. In-stream habitat surveys are intended to stop at the limit of anadromy (which could be a barrier, or could be the end of the stream). Possible reasons for this conflict include incorrect documentation of the survey end point or differences in what the in-stream habitat survey crew and the passage assessment evaluator consider a barrier.
One method for narrowing the possible apparent conflicts between these datasets is to reduce the Selected Set to only those records that are deemed total passage barriers:
- Make sure the "California Fish Passage Assessment Database" is the Active Layer and select the "Attribute query" tool (29).
- Clear the previous query parameters (if any, 30) and double-click the "barstatus" item in the left query panel (31).
- Click on the "=" operator (32) and select the "total" attribute from the right query panel (33).
- Click the "Select from Set" option near the bottom of the attribute query dialog box (34) and then execute the query (35).
This refined query now highlights only those passage assessment database points attributed as Total Barriers, and provides more satisfactory results. However, a few instances remain where stream surveys were completed in a stream apparently excluding fish use. Locate one of these instances, and using the "Zoom" tool (37), examine the stream at a fine scale (36, 38). Use the "Identify" tool (39) to select the point (40), and examine the attributes.